Clinical Cardiology

Comprehensive study resource covering cardiac anatomy, ischemic disease, heart failure, valvular disease, arrhythmias, cardiomyopathies, hypertension, and high-yield board review. Every concept, every maneuver, every drug you need to know.

1. Cardiac Anatomy and Physiology

Chambers Valves Coronaries Conduction Hemodynamics PV Loops

Anatomy

Chambers: RA receives SVC/IVC/coronary sinus.
RV pumps to pulmonary circulation (pulmonary trunk).
LA receives 4 pulmonary veins.
LV pumps to aorta (systemic circulation).
LV has the thickest myocardium (concentric). Valves: AV valves: tricuspid (RA -> RV), mitral (LA -> LV).
Semilunar: pulmonary (RV -> pulmonary trunk), aortic (LV -> aorta).
S1 = mitral + tricuspid closure.
S2 = aortic + pulmonary closure.
A2 precedes P2 (inspiration splits P2).
Coronary Arteries: LCA -> LAD (anterior wall, septum, apex) + LCx (lateral wall, posterior).
RCA -> RV, inferior wall, SA node (60%), AV node (90%), PDA (dominance ~85% right dominant). Conduction System: SA node (RA, intrinsic rate 60-100) -> AV node (slow conduction, delay) -> His bundle -> bundle branches (LBB, RBB) -> Purkinje fibers (fast conduction). Coronary Sinus: Drains cardiac veins into RA. Pericardium: Fibrous outer + serous inner (visceral + parietal).
Pericardial fluid 15-50mL reduces friction.

Cardiac Physiology

Cardiac Output: CO = HR x SV.
SV determined by preload, contractility, afterload.
Frank-Starling mechanism: increased preload (EDV) -> increased force of contraction (within limits). Preload: Ventricular EDV (end-diastolic volume).
Increased by: increased venous return, increased filling time, increased compliance.
Decreased by: hypovolemia, tachycardia, diuretics. Afterload: Wall stress during systole = (P x r)/(2 x h). LaPlace law.
Increased afterload (HTN, AS) -> increased wall stress -> LVH. Contractility: Inotropic state.
Positive: catecholamines (β1), Ca2+, digitalis.
Negative: β-blockers, CCBs, HF, acidosis. PV Loops: X-axis = volume, Y-axis = pressure.
ESPVR (end-systolic PV relationship) slope = contractility.
EDPVR (diastolic) reflects compliance.
Loop area = stroke work.
Wall tension (LaPlace): T = P x r / h.
Increases with dilation (↑r) and pressure (↑P); decreases with hypertrophy (↑h).
Oxygen Supply/Demand: Demand = HR x SBP x contractility (rate-pressure product).
Supply determined by coronary perfusion pressure (CPP = aortic DBP - LVEDP) and diastolic filling time.
Supply-demand mismatch -> ischemia.

EKG Basics

P wave: atrial depolarization.
PR interval: 120-200ms (AV conduction).
QRS: 80-120ms (ventricular depolarization). QTc: T wave: ventricular repolarization.
ST segment: isoelectric -> deviation indicates ischemia/injury.
U wave: hypokalemia, bradycardia. Axis: Normal -30 degrees to +90 degrees.
Left axis (-30 degrees to -90 degrees): LBBB, LVH, inferior MI, WPW.
Right axis (+90 degrees to +180 degrees): RVH, RBBB, COPD, dextrocardia.
Rate: 300/big boxes (1 big box = 0. 2s at 25mm/s). LVH criteria: Sokolow-Lyon (S in V1 + R in V5/V6 > 35mm), Cornell (R in aVL + S in V3 > 28mm men, > 20mm women). RVH: R > S in V1, R in V1 + S in V5/V6 > 10. 5mm, right axis.

High-Yield Pearls

RV = thin-walled, crescent-shaped, low-pressure pump. LV = thick-walled, concentric, high-pressure pump.
LAD supplies anterior septum, apex, anterolateral wall. LCx supplies lateral/posterior wall. RCA supplies RV, inferior wall, SA/AV node.
CPP = aortic DBP - LVEDP. Tachycardia ↓ diastolic time -> ↓ supply. HTN ↑ afterload -> ↑ demand.
Bazett formula: QTc = QT / sqrt RR. Use Fridericia for HR > 100 (QTc = QT / ^3 sqrt RR).
LVH: Sokolow-Lyon > 35mm, Cornell > 28mm (M), 20mm (F). Strain pattern = asymmetric ST depression/T inversion in lateral leads.

Red Flags

Wide QRS ( > 120ms) = ventricular rhythm or aberrancy. VT until proven otherwise in wide-complex tachycardia.
Marked ST elevation with reciprocal changes = STEMI until proven otherwise. Activate cath lab.
Low voltage + electrical alternans = large pericardial effusion / tamponade. Check echo urgently.
Prolonged QT ( > 500ms) = high risk of torsades. Correct K+, Mg2+, stop culprit drugs.

2. Ischemic Heart Disease

Stable Angina ACS NSTEMI STEMI Management Complications

Stable Angina Pectoris

Episodic chest pain from fixed atherosclerotic stenosis.
Provoked by exertion/stress/emotion, relieved by rest/NTG.
Predictable pattern.
Diagnosis: exercise stress test (ECG changes > 1mm horizontal/downsloping ST depression, or imaging perfusion defect).
Coronary CTA or invasive angiogram for definitive anatomy.
Treatment: antianginals (� 1/2 -blockers first-line, CCBs, long-acting nitrates), antiplatelet (ASA), statin (high-intensity), risk factor control.
Revascularization (PCI or CABG) for symptomatic despite medical therapy, or high-risk anatomy (left main, proximal LAD, multi-vessel with LV dysfunction).
FFR (fractional flow reserve) guides PCI (=0. 80 = ischemic).

Acute Coronary Syndrome

Spectrum: unstable angina (UA, no troponin elevation)? NSTEMI (troponin rise, ST depression/T inversion)? STEMI (ST elevation, Q waves).
Pathophysiology: plaque rupture/erosion? platelet activation, thrombus formation (white = platelet-rich UA/NSTEMI, red = fibrin-rich STEMI).
Presentation: substernal chest pressure, radiation to jaw/neck/L arm, dyspnea, diaphoresis, nausea, fatigue.
Atypical presentations: women (dyspnea, fatigue, indigestion), diabetics (silent ischemia), elderly (AMS, SOB). Initial management: O2 if SpO2 NSTEMI: risk stratify (TIMI or GRACE score).
Early invasive ( 140). Medical management: ASA + P2Y12 inhibitor (ticagrelor or prasugrel) + anticoagulation (UFH, enoxaparin, bivalirudin) + � 1/2 -blocker + statin. STEMI: Emergency revascularization.
Door-to-balloon time < 90min if primary PCI available.
Fibrinolysis if PCI not available within 120min (door-to-needle < 30min).
Contraindications to fibrinolysis: prior ICH, ischemic stroke < 3mo, active bleeding, recent major surgery/trauma, suspected aortic dissection. After PCI: ASA lifelong + P2Y12 inhibitor (DAPT) for 6-12mo (depending on stent type, bleeding risk).
High-intensity statin (atorvastatin 80mg or rosuvastatin 40mg). � 1/2 -blocker (carvedilol, bisoprolol, metoprolol succinate).
ACEi/ARB (especially if LVEF =40%, hypertension, diabetes, CKD).
Aldosterone antagonist if EF =40% and post-MI. Cardiac rehab.
Eplerenone (post-MI with EF =40% + diabetes/HF).

STEMI Localization and Complications

Localization by leads: Anterior/septal (V1-V4) = LAD.
Lateral (I, aVL, V5-V6) = LCx.
Inferior (II, III, aVF) = RCA.
Posterior (V1-V3 reciprocal ST depression, tall R, upright T) = LCx or RCA.
RV infarct (V4R ST elevation) = RCA proximal.
Complications: Arrhythmias (VT/VF most common cause of death in first 24h, bradycardia/AV block in inferior MI).
Mechanical: papillary muscle rupture (acute MR, holosystolic murmur + pulmonary edema), ventricular septal rupture (new holosystolic murmur + RV failure), free wall rupture (P waves without QRS = electromechanical dissociation, tamponade, death).
LV thrombus (anterior MI, especially with apical akinesis)? anticoagulate 3-6mo.
Pericarditis (Dressler syndrome, weeks after MI, fever + pleuritic pain + pericardial rub, treat ASA/NSAIDs).
CHF/pulmonary edema (acute HF).
Ventricular aneurysm (persistent ST elevation, dyskinesia, risk of thrombus/arrhythmia).

High-Yield Pearls

STEMI = PCI < 90min or fibrinolysis < 30min. "Time is muscle."
DAPT (ASA + P2Y12i) for 6-12mo post-PCI (DES) or 1mo (BMS). Ticagrelor/prasugrel preferred over clopidogrel in ACS.
Inferior STEMI: always get right-sided EKG (V4R) to screen for RV infarct � 1/2 avoid nitrates/diuretics (preload dependent).
Posterior MI: suspect when anterior leads show ST depression + tall R � 1/2 get posterior leads (V7-V9).
TIMI risk score: 7 variables (age =65, =3 CAD risk factors, known CAD, ST deviation, =2 angina events in 24h, ASA use, elevated cardiac markers). Low risk = early conservative vs high risk = early invasive.

Red Flags

STEMI + new murmur + pulmonary edema = papillary muscle rupture � 1/2 urgent echo + surgery.
Free wall rupture: PEA arrest, sudden death � 1/2 highest risk 3-5d post-MI.
Ventricular septal rupture: new holosystolic murmur + step-up O2 saturation from RA to PA.
Dressler syndrome (post-MI pericarditis): weeks after MI. Treat with ASA/colchicine; avoid NSAIDs if post-MI (impaired healing).
Stent thrombosis: acute ( < 24h), subacute (1-30d), late ( > 30d). Stop DAPT? massive risk. Ensure adherence.

3. Heart Failure

HFrEF HFpEF NYHA/ACC GDMT Acute Decompensation Advanced Therapies

Classification and Staging

By EF: HFrEF (EF =40%), HFmrEF (EF 41-49%), HFpEF (EF =50%). ACC/AHA Stages: A (at risk), B (pre-HF, structural disease but no symptoms), C (structural + symptoms), D (refractory/advanced). NYHA Class: I (no limitation), II (slight limitation, comfortable at rest), III (marked limitation, less than ordinary activity causes symptoms), IV (symptoms at rest, any activity worsens). Etiology: Ischemic (most common), HTN, valvular, cardiomyopathy (dilated, hypertrophic, restrictive), myocarditis, alcoholic, chemotherapeutic (anthracyclines, trastuzumab), peripartum, thyrotoxicosis/high-output, infiltrative (amyloidosis, sarcoidosis, hemochromatosis).

Pathophysiology

Index event?? CO? neurohormonal activation: RAAS (? renin,? aldosterone? salt/water retention, vasoconstriction, fibrosis), SNS (? NE? tachycardia,? contractility,? � 1/2 -receptors), vasopressin (? H2O retention), natriuretic peptides (BNP, ANP � 1/2 counterregulatory).
Maladaptive remodeling: LV dilation (eccentric hypertrophy), fibrosis, apoptosis,? contractility? progressive HF.
HFpEF: impaired lusitropy (active relaxation + passive stiffness), often HTN, LVH, aging, obesity.
LV filling pressures?.
Diagnosis: clinical (dyspnea, orthopnea, PND, edema, JVD, S3 gallop), labs (BNP > 100 or NT-proBNP > 300 for acute HF, > 125 for chronic), echo (EF, diastolic function, wall motion, valvular).
Chest X-ray: cardiomegaly, cephalization, Kerley B lines, pleural effusion.

GDMT for HFrEF (Guideline-Directed Medical Therapy)

"Fantastic Four" pillars: (1) � 1/2 -blocker (carvedilol, bisoprolol, metoprolol succinate � 1/2 reduces mortality + hospitalizations). (2) ACEi/ARB/ARNI (sacubitril/valsartan preferred if tolerated � 1/2 reduces mortality + hospitalizations, superior to ACEi). (3) Aldosterone antagonist (spironolactone, eplerenone � 1/2 reduces mortality, use with K+ monitoring, Cr Other agents: Diuretics (loop � 1/2 furosemide, torsemide, bumetanide � 1/2 symptomatic relief, no mortality benefit).
Hydralazine + isosorbide dinitrate (African Americans with persistent symptoms, or ACEi intolerant).
Ivabradine (if HR =70 on max � 1/2 -blocker, sinus rhythm).
Digoxin (reduces hospitalizations, no mortality benefit, narrow therapeutic window).
Vericiguat (sGC stimulator, recent worsening HF). Device therapy: ICD (EF =35% on GDMT � 1/2 3mo, NYHA II-III, expected survival > 1yr).
CRT (QRS =150ms with LBBB, EF =35%, NYHA II-IV, on GDMT).
Heart transplant LVAD (destination or bridge-to-transplant).

Acute Decompensated Heart Failure

Clinical: dyspnea at rest, orthopnea, elevated JVD, S3, lower extremity edema, pulmonary edema (crackles, frothy sputum), hypotension or hypertension, hypoxemia.
Precipitants: non-adherence to diet/meds, ischemia, arrhythmia (AFib), infection, PE, renal failure, toxins (NSAIDs, alcohol, cardiodepressants).
Management: O2/NIPPV (CPAP/BiPAP) if respiratory distress.
IV loop diuretics (furosemide 1-2x home dose IV).
Vasodilators (nitroglycerin IV, nitroprusside) if hypertensive + no severe stenosis.
Inotropes (dobutamine, milrinone) if low CO, peripheral hypoperfusion � 1/2 use as bridge, not routine (? mortality).
Vasopressors (norepinephrine) if cardiogenic shock.
Ultrafiltration if diuretic resistant. Treat precipitants.
Avoid NSAIDs, CCBs (verapamil/diltiazem).
Discharge on optimized oral GDMT.

HFpEF Management

No therapy proven to reduce mortality until recently.
SGLT2i (empagliflozin, dapagliflozin) reduce HF hospitalization in HFpEF (EMPEROR-Preserved, DELIVER).
Treat comorbidities: HTN (to target < 130/80), AFib (rate/rhythm control), obesity (weight loss, GLP-1 RA), diuretics for volume overload (loop diuretics).
ARNI may benefit those with EF at lower end (45-50%).
Avoid aggressive GDMT (no mortality benefit shown for � 1/2 -blockers, ACEi/ARB, MRAs in HFpEF, though used for comorbidities).

High-Yield Pearls

GDMT for HFrEF: � 1/2 -blocker + ARNI + MRA + SGLT2i + diuretic PRN. All reduce mortality (except diuretics).
ARNI (sacubitril/valsartan) is superior to enalapril (PARADIGM-HF). Do NOT combine with ACEi within 36h (angioedema risk).
SGLT2i: dapagliflozin/empagliflozin reduce CV death + HF hospitalization across full EF spectrum.
ICD if EF =35% on =3mo GDMT. CRT if QRS =150ms LBBB + EF =35%.
HFpEF: treat HTN, AFib, obesity, volume. SGLT2i now first-line for hospitalization reduction.
Inotropes (dobutamine, milrinone) only for bridge � 1/2 associated with increased mortality in clinical trials.

Red Flags

New-onset HF with low output (cool extremities, hypotension, narrow pulse pressure)? urgent echo + cardiology.
Cardiogenic shock: SBP < 90, CI < 2.2, PCWP > 15, lactate?? inotropes + MCS (IABP, Impella, VA-ECMO) + revascularization.
Hyperkalemia with MRA/spironolactone: hold if K+ > 5.0, check Cr. Do not start if Cr > 2.5 or K+ > 5.0.
Amiodarone + � 1/2 -blocker: bradycardia risk. Amiodarone has multiple toxicities (thyroid, liver, pulmonary, corneal, blue skin).
HFpEF with cardiac amyloidosis (ATTR or AL): suspect if LVH with low voltage (echo strain, cardiac MRI, PYP scan for ATTR).

4. Valvular Heart Disease

Stenosis Regurgitation Murmurs Maneuvers Intervention

Aortic Stenosis (AS)

Most common valvular disease.
Triad: angina, syncope (exertional), HF (dyspnea).
Onset of symptoms = poor prognosis (2-3yr mortality without intervention).
Etiology: degenerative/calcific (elderly, most common), bicuspid aortic valve (presents 50-70y), rheumatic (rare).
Murmur: late-peaking, crescendo-decrescendo systolic, RUSB, radiates to carotids.
S2 paradoxically split (severe).
Carotid: parvus et tardus (slow upstroke, low volume). Associated with: LVH (pressure overload).
Diagnosis: echo (valve area 40mmHg, velocity > 4m/s).
Treatment: surgical AVR (SAVR) or TAVR depending on age, risk, anatomy.
Medical: avoid vasodilators (preload dependent), treat HTN cautiously.
When symptoms + severe = urgent intervention.
Dobutamine stress echo for low-gradient, low-flow AS with low EF (assess contractile reserve).

Aortic Regurgitation (AR)

Chronic: LV volume overload? eccentric LVH? gradual decompensation.
Etiology: bicuspid, aortic root dilation, endocarditis, rheumatic, connective tissue (Marfan, Ehlers-Danlos, syphilitic aortitis).
Murmur: high-pitched, decrescendo, early diastolic LLSB, leaning forward with breath held.
Austin Flint murmur (functional mitral stenosis from regurgitant jet).
Wide pulse pressure (increased SBP, decreased DBP), bounding pulses, head bobbing (de Musset), water-hammer pulse (Corrigan), capillary pulsations (Quincke).
Diagnosis: echo (vena contracta, regurgitant fraction, LV dimensions).
Treatment: SAVR (or TAVR for severe + high-risk).
Medical: vasodilators (nifedipine, ACEi) for chronic severe AR with LV dilation but before symptoms.
Acute AR: endocarditis, aortic dissection. Emergent surgery.
Medical: nitroprusside + inotropes (no time for remodeling).

Mitral Stenosis (MS)

Almost always rheumatic (post-inflammatory).
More common in women.
Murmur: low-pitched, mid-diastolic, opening snap (if valve pliable) then diastolic rumble at apex with bell.
First heart sound is loud (M1).
Presents as LA enlargement? AFib (frequent), dyspnea, hemoptysis, thromboembolism.
Pulmonary HTN develops over time? RVH, right HF.
Diagnosis: echo (MVA < 1. 5 cm2 severe, mean gradient).
Treatment: percutaneous mitral balloon valvuloplasty (PMBV) if valve morphology favorable (MGH Wilkins score =8).
Surgical: commissurotomy or MVR if not amenable.
Medical: rate control (� 1/2 -blocker, CCB), diuretics, anticoagulation (AFib or prior embolic event).
Avoid strenuous activity.

Mitral Regurgitation (MR)

Primary (organic): mitral valve prolapse (MVP), chordal rupture, rheumatic, endocarditis, myxomatous degeneration.
Secondary (functional): LV dilation/dysfunction (ischemic, DCM)? annular dilation? MR.
Murmur: holosystolic, high-pitched, apex radiating to axilla.
MVP: mid-systolic click + late systolic murmur.
Diagnosis: echo (vena contracta, PISA/EROA, regurgitant volume).
Treatment: primary severe MR with symptoms or LV dysfunction? mitral valve repair (preferred) or replacement.
Secondary MR: treat HFrEF first (GDMT).
Transcatheter edge-to-edge repair (MitraClip) for selected patients (COAPT criteria: EF 20-50%, LVEDD =70mm, symptomatic despite GDMT).
Acute MR: papillary muscle rupture (post-MI)? emergent surgery + IABP.

Murmur Maneuvers

Valsalva (strain): ? preload?? most murmurs.
Increases HOCM (systolic) and MVP (click earlier, murmur longer).
Squatting: ? preload +? afterload?? most murmurs,? HOCM and MVP.
Standing: ? preload?? most murmurs,? HOCM and MVP.
Handgrip/amyl nitrite: ? afterload?? MR, AR, VSD;? AS, HOCM.
Inspiration: ? right-sided murmurs (tricuspid, pulmonic) � 1/2 Carvallo sign.
RV transient obstruction (Valsalva release): all murmurs return louder briefly.
Endocarditis prophylaxis: only for high-risk (prosthetic valve, prior IE, CHD, transplant valvulopathy) before dental procedures � 1/2 amoxicillin 2g PO 30-60min pre.

High-Yield Pearls

Severe AS triad: angina, syncope, HF. Any symptom + severe AS = replace valve.
Acute AR differs from chronic: tachycardia, soft S1, early closure of MV, pulmonary edema, normal pulse pressure.
MVP: mid-systolic click + late systolic murmur. Myxomatous leaflets. Most common valvulopathy (2-3%).
HOCM murmur: increases with Valsalva, decreases with squatting. MR: holosystolic, increases with handgrip.
S2 paradoxically split in severe AS, LBBB, HOCM, PDA. Fixed split in ASD.
Prosthetic valve thrombosis: urgent echo (TTE + TEE), consider fibrinolysis or re-do surgery.

Red Flags

Severe AS + hypotension: cautious with nitrates, avoid aggressive afterload reduction (preload dependent).
Acute AR (endocarditis, dissection): emergent surgical consultation. Stabilize with nitroprusside + dobutamine.
Mitral valve prolapse with myxomatous disease: risk of chordal rupture, infective endocarditis, CVA.
Prosthetic valve endocarditis: suspect if fever + new murmur +/- embolic phenomena. TEE essential.
Severe calcific AS in elderly: TAVR if high or prohibitive surgical risk (PARTNER, CoreValve trials).

5. Arrhythmias and Conduction

SVT AFib Flutter VT VF Brady Antiarrhythmics

Supraventricular Tachycardia

Narrow QRS ( 100/min. AVNRT: Most common (60%). Reentrant AV node.
P waves hidden (pseudo-R V1).
Abrupt onset/offset.
Treatment: vagal maneuvers, adenosine 6mg IV push (repeat 12mg).
Avoid in asthma (bronchospasm). Alternatives: CCB (verapamil/diltiazem IV), β-blocker IV, synchronized cardioversion if unstable.
Ablation is curative. WPW: Accessory pathway (Kent bundle), delta wave, short PR, wide QRS. Risk: AVRT, AFib with preexcitation -> VF.
Acute: procainamide, amiodarone, cardioversion.
Do NOT give AV nodal blockers (adenosine, CCB, digoxin) -> may accelerate pathway. Ablation curative. Atrial Tachycardia: P wave! = sinus.
Treat: β-blockers, CCBs, ablation.
MAT: >= 3 P morphologies, irregular.
Associated with COPD. Treat underlying.

Atrial Fibrillation and Flutter

AFib: Irregularly irregular, no P waves.
Most common arrhythmia. Risk: HTN, HF, CAD, valvular, obesity, OSA, alcohol, hyperthyroid, aging.
Classification: paroxysmal ( 7d), long-standing ( > 1yr), permanent.
Rate vs rhythm control (no mortality difference, AFFIRM).
Rate: β-blockers first, CCBs (diltiazem, verapamil), digoxin (HF).
Target HR Anticoagulation: CHA2DS2-VASc. M >= 2, F >= 3: OAC (DOAC preferred over warfarin -> lower ICH, no monitoring).
DOACs: apixaban, rivaroxaban, edoxaban, dabigatran.
Warfarin if mechanical valve, rheumatic MS, ESRD. Atrial Flutter: Typical sawtooth (negative in II/III/aVF, positive V1). Atrial rate ~300.
Ventricular rate variable (2:1, 3:1, 4:1).
Same management as AFib.
Isthmus ablation curative.
Both: risk tachycardia-induced cardiomyopathy.

Ventricular Arrhythmias

PVCs: Wide QRS, compensatory pause.
Benign if no structural HD.
Treat if symptomatic, > 20% burden (PVC-induced CMP), sustained VT/VF. β-blockers, CCBs, ablation.
NSVT: 3+ PVCs Sustained VT: Monomorphic (scar post-MI) vs polymorphic (ischemia, electrolytes, channelopathy).
Stable: amiodarone 150mg IV, procainamide.
Unstable: synchronized cardioversion. Torsades: Polymorphic VT + prolonged QT.
Causes: drugs (class Ia/III, macrolides, FQ, antipsychotics), hypokalemia, hypomagnesemia, bradycardia, congenital LQTS.
Treatment: IV MgSO4 2g, K+ > 4. 5, overdrive pacing. Stop culprit. VF/Pulseless VT: Shock 200J -> CPR -> epinephrine q3-5min -> amiodarone 300mg -> shock. ICD: Primary if EF <= 35% on GDMT.
Secondary if survived cardiac arrest/sustained VT.

Bradyarrhythmias and Heart Block

Sick sinus: Sinus brady, pauses, tachy-brady.
Pacemaker if symptomatic. 1st degree AVB: PR > 200ms. Benign.
Mobitz I (Wenckebach): Progressive PR prolongation -> dropped QRS. Usually AV nodal. Benign.
Mobitz II: Fixed PR, dropped QRS without PR change.
Infranodal (His-Purkinje).
High risk of complete heart block -> pacemaker. 3rd degree AVB: Complete dissociation of P and QRS.
Wide escape = worse. Requires pacing.
Pacemaker indications: Mobitz II, complete AVB, symptomatic brady, bifascicular + syncope, alternating BBB.
VVI (single), DDD (dual), CRT (biventricular for HF + LBBB + EF <= 35%).

Antiarrhythmic Drugs (VW Classes)

Class I (Na+ blockers): Ia (quinidine, procainamide � 1/2 QRS/QT prolong).
Ib (lidocaine, mexiletine � 1/2 VT/ischemia).
Ic (flecainide, propafenone � 1/2 SVT/AFib, normal hearts only; CAST trial -> increased mortality post-MI).
Class II (β-blockers): Metoprolol, bisoprolol, carvedilol.
CAD, HF SVT, VT, rate control.
Class III (K+ blockers): Amiodarone (multi-channel, safest in structural HD; toxicity: thyroid, pulmonary, liver, cornea, neuropathy, blue skin).
Sotalol (β effects + class III).
Dofetilide (AFib, renal adjust).
Ibutilide (acute AFib IV).
Class IV (Ca2+ blockers): Verapamil, diltiazem. AV nodal blockers.
Negative inotrope (avoid in HFrEF). Other: Adenosine, digoxin, MgSO4.

Syncope and Channelopathies

Syncope: Reflex (vasovagal), orthostatic, cardiac (arrhythmia, structural).
Workup: history, orthostatics, EKG, echo, monitoring.
Admit if: exertional/supine, fam hx SCD, abnormal EKG, structural HD, abnormal vitals. LQTS: Prolonged QT -> torsades.
Congenital (Romano-Ward, Jervell-Lange-Nielsen).
Treat: β-blocker, mexiletine, ICD if high risk. Brugada: RBBB-like + ST elevation V1-V3 (coved = type 1).
Risk of VF. ICD.
Avoid class Ic Na+ blockers. ARVC/D: Fibrofatty replacement of RV -> VT.
Epsilon waves (V1-V3). ICD. CPVT: Catecholaminergic polymorphic VT. β-blockers, flecainide, ICD.

High-Yield Pearls

Adenosine: 6mg IV rapid push, then 12mg. May cause transient asystole (normal), bronchospasm (avoid in asthma).
WPW + AFib: avoid AV nodal blockers (adenosine, CCB, digoxin) -> can accelerate conduction via accessory pathway -> VF.
CHA2DS2-VASc: CHF, HTN, Age >= 75 (2), DM, Stroke/TIA (2), Vascular disease, Age 65-74, Sex category (female = 1).
DOACs preferred over warfarin for AFib (lower ICH). Warfarin for mechanical valves, rheumatic MS, severe renal disease.
CAST trial: flecainide/encainide increased mortality post-MI -> never use class Ic in CAD or structural HD.
Amiodarone: most effective AAD but most toxic. Baseline PFTs, LFTs, TFTs. Monitor q6-12mo.

Red Flags

Torsades: prolonged QT + polymorphic VT. Stop culprit, give IV MgSO4, K+ > 4.5, overdrive pacing.
Mobitz II: high risk of complete heart block -> pacemaker. Do not rely on atropine (infranodal).
ICD storm: >= 3 appropriate shocks in 24h. Treat ischemia, electrolytes, amiodarone, catheter ablation.
Syncope with structural HD or concerning EKG: admit and monitor. Loop recorder if unexplained.
Brugada pattern: do not give class Ic antiarrhythmics (may unmask/induce VF).

6. Cardiomyopathies and Pericardial Disease

DCM HCM RCM Myocarditis Pericarditis Tamponade IE

Dilated Cardiomyopathy (DCM)

LV dilation + systolic dysfunction (EF < 40%). Most common CMP.
Etiology: ischemic (most common), idiopathic, genetic (sarcomeric, lamin A/C, dystrophin), viral myocarditis (coxsackie B, parvovirus B19), alcohol, chemotherapy (anthracyclines, trastuzumab), peripartum, thyrotoxicosis, sarcoidosis, hemochromatosis, Chagas, HIV, tafamidis (amyloid). Presentation: HF symptoms (SOB, edema, orthopnea).
Diagnosis: echo (LVEDD, EF, wall motion), CMR (inflammation, fibrosis, iron, sarcoid), EMB if suspected myocarditis/sarcoid/amyloid.
Treatment: GDMT (β-blocker, ACEi/ARB/ARNI, MRA, SGLT2i).
ICD/CRT as indicated.
Treat underlying cause (alcohol cessation, iron chelation, steroids for sarcoid, anthracycline cessation).
Cardiac transplant for end-stage.

Hypertrophic Cardiomyopathy (HCM)

Most common inherited cardiac disease (sarcomere mutations: β-myosin heavy chain, myosin binding protein C).
LVH (asymmetric septal), myocyte disarray, fibrosis.
LVOT obstruction (HOCM) in ~70%.
Presentation: dyspnea, chest pain, syncope (exertional), SCD (young athletes).
Exam: harsh systolic murmur LLSB, increases with Valsalva, decreases with squatting.
Bifid carotid pulse, S4.
Diagnosis: echo (septal thickness >= 15mm, SAM of mitral valve, LVOT gradient at rest or provoked), CMR (delayed enhancement = fibrosis, risk marker), genetic testing.
Risk stratification for SCD: age, family history HCM/SCD, NSVT, LVH thickness, LVOT gradient, unexplained syncope, abnormal BP response to exercise, LA size, fibrosis on CMR.
Treatment: β-blockers first-line (reduce HR, gradient).
Verapamil/disopyramide if refractory.
Septal reduction therapy (myectomy vs alcohol septal ablation) for severe gradient + symptoms despite medical therapy.
ICD for high SCD risk.
Avoid: hypovolemia, vasodilators, high-intensity exercise, competitive sports.

Restrictive Cardiomyopathy (RCM) and Myocarditis

RCM: Impaired diastolic filling (stiff ventricle), normal/near-normal systolic function.
Causes: infiltrative (amyloidosis, sarcoidosis, hemochromatosis, Fabry, Gaucher), storage (glycogen), endomyocardial (Löffler, endomyocardial fibrosis), idiopathic. Presentation: HFpEF-like (JVD, edema, ascites, Kussmaul sign).
Diagnosis: echo (bi-atrial enlargement, restrictive filling pattern), CMR, biopsy.
Distinguish from constrictive pericarditis (CT/MRI: pericardial thickening, septal bounce, respiratory variation). Myocarditis: Inflammation of myocardium.
Causes: viral (coxsackie B, parvovirus B19, EBV, CMV, influenza, COVID-19), bacterial, giant cell, eosinophilic, autoimmune (SLE, sarcoid), toxins (alcohol, cocaine), drugs (anthracyclines, immune checkpoint inhibitors, clozapine).
Presentation: flu-like prodrome + chest pain, dyspnea, arrhythmia, HF, troponin elevation, diffuse ST elevation (mimics STEMI but without coronary obstruction � 1/2 "myopericarditis").
Diagnosis: echo (LV dysfunction), CMR (Lake Louise criteria: edema + hyperemia + LGE), EMB (gold standard).
Treatment: supportive (HF GDMT + arrhythmia management).
Avoid NSAIDs in acute phase.
Immunosuppression if giant cell, eosinophilic, sarcoid, autoimmune.
Recovery in > 50%; some need transplant or MCS.

Pericardial Disease

Acute Pericarditis: Triad: pleuritic chest pain (worse supine, better leaning forward), pericardial friction rub (triphasic), diffuse concave ST elevation + PR depression.
Etiology: idiopathic/viral (most common), post-MI (Dressler), uremic, TB, connective tissue disease, neoplastic (lung, breast, lymphoma, melanoma), drugs (procainamide, isoniazid, minoxidil).
Diagnosis: echo (rule out tamponade, effusion size), ECG (diffuse ST elevation, PR depression, no reciprocal changes vs STEMI), inflammatory markers (CRP, ESR).
Treatment: ASA 800mg q4-8h or NSAIDs (ibuprofen 600-800mg TID) + colchicine 0. 6mg BID (weight-adjusted) for 3mo (reduces recurrence).
Avoid anticoagulation if possible.
Corticosteroids if refractory/autoimmune/uremic.
Pericardial Effusion and Tamponade: Fluid accumulation -> ↑ intrapericardial pressure -> impaired RV filling -> hypotension, JVD, muffled heart sounds (Beck triad).
Pulsus paradoxus ( > 10mmHg drop in SBP with inspiration).
EKG: low voltage, electrical alternans.
Echo: effusion, RA/RV collapse (diastolic).
Treatment: urgent pericardiocentesis (echo or fluoroscopy guided).
Avoid nitrates diuretics (preload dependent).
Constrictive Pericarditis: Thickened/fibrotic pericardium -> impaired diastolic filling.
Causes: post-cardiac surgery, TB, radiation, idiopathic. Features: Kussmaul sign (paradoxical JVP rise with inspiration), pericardial knock, -> HF with normal EF.
CT/MRI for pericardial thickness.
Distinguish from RCM with echocardiography (septal bounce, annulus reversus, respiratory variation), cardiac catheterization (equalization of diastolic pressures, dip-and-plateau).
Treatment: pericardiectomy.

Infective Endocarditis (IE)

Modified Duke Criteria: 2 major OR 1 major + 3 minor OR 5 minor.
Major: (1) positive blood cultures (typical pathogen from 2 sets, persistently +, Coxiella serology); (2) endocardial involvement (vegetation, abscess, new dehiscence).
Minor: predisposition, fever, vascular phenomena, immunologic, microbiologic. Native valve: S. aureus (most common), viridans strep, Enterococcus.
Prosthetic: early ( 1yr, similar to native). IVDU: S. aureus (tricuspid).
Treatment: empiric vancomycin + ceftriaxone (native), vancomycin + cefepime + gentamicin (prosthetic). Targeted: MSSA nafcillin/cefazolin, MRSA vancomycin/daptomycin. Strep: PCN/ceftriaxone 4wk.
Enterococcus: ampicillin + ceftriaxone 6wk.
Surgery indications: HF, uncontrolled infection (abscess, persistent bacteremia), prevention of embolism (large mobile > 10mm after embolus, > 15mm with high risk).
Prophylaxis: only for high-risk (prosthetic valve, prior IE, CHD, transplant valvulopathy) before dental procedures (amoxicillin 2g PO).

High-Yield Pearls

HCM: β-blockers first-line. Septal myectomy for severe obstruction. ICD for SCD prevention.
Acute pericarditis: diffuse ST elevation + PR depression. Treat with ASA/NSAIDs + colchicine. Avoid acute-phase NSAIDs post-MI (Dressler).
Cardiac tamponade: Beck triad (hypotension, JVD, muffled hearts) + pulsus paradoxus. Urgent pericardiocentesis.
Constrictive vs RCM: CT/MRI for pericardial thickness. Septal bounce, annulus reversus, respiratory variation on echo.
Myocarditis: troponin + diffuse ST elevation + normal coronaries = myopericarditis. CMR is diagnostic. Supportive care.
IE: Duke Criteria. TEE superior to TTE for prosthetic valves, abscesses.

Red Flags

HCM + unexplained syncope, family history SCD, LVH >= 30mm, NSVT -> high SCD risk -> ICD.
Giant cell myocarditis: rapid progressive HF, VT, heart block. EMB confirms. High-dose immunosuppression + transplant evaluation.
Cardiac tamponade: PEA arrest can be first presentation. Perform bedside echo FAST.
Prosthetic valve IE: TEE required. High mortality. Early surgery often needed.
S. aureus IE with valve perforation/abscess: urgent surgery. Persistent bacteremia despite abx -> look for metastatic seeding.

7. Hypertension and Prevention

BP Targets Pharmacotherapy Lipids ASCVD Risk Statins Lifestyle

Hypertension Classification and Targets

ACC/AHA 2017: Normal ( = 140/90).
Hypertensive crisis ( >= 180/120).
Target BP: general White coat HTN: elevated in office, normal out -> ABPM or HBPM.
Masked HTN: normal office, elevated out.
Secondary HTN: resistant ( >= 3 drugs including diuretic), onset 55, malignant, abrupt onset.
Causes: renal artery stenosis (fibromuscular dysplasia young women, atherosclerotic elderly), chronic kidney disease, primary hyperaldosteronism (Conn syndrome: hypokalemia + HTN), pheochromocytoma (paroxysmal HTN + palpitations + diaphoresis + pallor), Cushing, coarctation of aorta (upper > lower extremity BP, rib notching), OSA, thyroid/parathyroid disease, drugs (NSAIDs, decongestants, steroids, cocaine, OCP, EPO, cyclosporine). Workup: BMP, aldosterone/renin ratio, metanephrines, cortisol, TSH, renal US, CTA/MRA renal arteries.

Antihypertensive Therapy

First-line (non-black >= 60 or any age with CKD/DM): thiazide-like diuretic (chlorthalidone), CCB (amlodipine), ACEi (lisinopril), ARB (losartan).
Black patients: thiazide or CCB preferred first-line. β-blockers not first-line for HTN alone (use if CAD, HF, migraine, tachyarrhythmia).
Second-line: add from complementary class.
Resistant HTN ( >= 3 drugs including diuretic): add spironolactone.
If CrCl Pregnancy: labetalol, nifedipine, methyldopa.
Avoid ACEi/ARB (fetotoxic).

Lipid Management and ASCVD Risk

Lipid panel: LDL-C (primary target), HDL-C, triglycerides, non-HDL-C, apolipoprotein B.
ASCVD risk estimator: Pooled Cohort Equations (ACC/AHA).
Indications for statin: (1) Clinical ASCVD (MI, stroke, PAD, coronary revascularization) -> high-intensity statin (atorvastatin 40-80mg, rosuvastatin 20-40mg). (2) LDL >= 190 (familial hypercholesterolemia) -> high-intensity statin. (3) DM age 40-75 with LDL 70-189 -> moderate-intensity statin (atorvastatin 10-20mg, rosuvastatin 5-10mg, simvastatin 20-40mg); high-intensity if >= 7. 5% ASCVD risk or risk enhancers. (4) Primary prevention: age 40-75, LDL 70-189, >= 7. 5% ASCVD risk -> moderate-to-high intensity statin.
Shared decision making if 5-7. 5%. Risk enhancers: FH+, metabolic syndrome, CKD, inflammatory disease (RA, SLE, psoriasis), HIV, premature menopause, South Asian ancestry, elevated Lp(a), hs-CRP >= 2, ABI Non-statin add-on: Ezetimibe, PCSK9i (evolocumab, alirocumab) if ASCVD + LDL >= 70 despite maximally tolerated statin, or FH with LDL >= 100 on statin + ezetimibe.
Icosapent ethyl (Vascepa) 4g/day for TG >= 150 + ASCVD/DM (REDUCE-IT).
Fibrates: for severe TG > 500 (prevent pancreatitis). Lipid targets: LDL < 70 for ASCVD, < 100 for DM/high-risk primary, < 130 for low/intermediate.
Non-HDL 30 higher than LDL targets.

Lifestyle and Prevention

Smoking cessation: #1 preventable cause. Diet: Mediterranean (fruit, veg, whole grain, fish, olive oil, nuts) � 1/2 Level A for CVD prevention. DASH diet for HTN.
Sodium = 5% loss if overweight). Alcohol: Cardiac rehab for ASCVD: reduces mortality by 25%.
Influenza vaccine recommended.
Aspirin primary prevention: age 40-59 with ASCVD risk >= 10% AND low bleeding risk (no prior GI bleed, no bleeding disorder, no NSAIDs, age = 70.
Diabetes screening: age 35+, BMI >= 25 plus risk.
Cardiac risk assessment before non-cardiac surgery: RCRI (Lee index: CAD, CHF, CVA, CKD, DM, high-risk surgery).
Elective -> optimize GDMT.
Urgent -> proceed with medical optimization.
Routine stress test not indicated if functional capacity >= 4 METs. β-blocker continuation (do NOT start day of surgery � 1/2 POISE trial risk).

High-Yield Pearls

SPRINT: intensive SBP < 120 reduced CV events and mortality, but more hypotension, AKI, syncope.
First-line HTN: thiazide, CCB, ACEi, ARB. β-blocker not first-line unless CAD/HF/migraine/tachyarrhythmia.
Resistant HTN: add spironolactone. Check aldosterone/renin ratio.
Statin indication: ASCVD, LDL >= 190, DM (40-75), or elevated ASCVD risk.
PCSK9i: LDL reduction ~60%. Monthly subcutaneous injection. Use if maximal statin + ezetimibe not enough.
High-intensity statin: atorvastatin 40-80mg, rosuvastatin 20-40mg. Reduces LDL by =50%.

Red Flags

Hypertensive emergency with aortic dissection: β-blocker first + nicardipine, SBP 100-120. Do NOT give vasodilator alone without β-blocker (reflex tachycardia? shear).
Pheochromocytoma: paroxysmal HTN + palpitations + headache + diaphoresis + pallor. Pre-op phenoxybenzamine + β-blocker (after α blockade).
Pregnancy HTN: avoid ACEi/ARB (fetotoxic). Labetalol, nifedipine, methyldopa.
Aspirin primary prevention: bleeding risk assessment. No benefit >= 70 (ASPREE).
Rhabdomyolysis with statin: myalgia + CK > 10x ULN. Hold statin. Atorvastatin/rosuvastatin safer than simvastatin.

8. Cheatsheets and Mnemonics

Quick Remembers Differential Tables Decision Aids

Chest Pain DDx

Pulmonary � 1/2 PE, pneumothorax, pneumonia, pleuritis
Large vessel � 1/2 aortic dissection, TAK, Ehlers-Danlos
Acute coronary � 1/2 MI, unstable angina, coronary spasm
Cardiac non-coronary � 1/2 pericarditis, myocarditis, HCM, AS, MVP
Kay (GI) � 1/2 GERD, esophageal spasm, PUD, pancreatitis, cholecystitis
Skeletal � 1/2 costochondritis (Tietze), rib fracture, fibromyalgia
Kick (skin/neuro) � 1/2 herpes zoster, cervical radiculopathy

Murmur Maneuvers

↓ Valsalva (↑ intrathoracic P): ↑ HCM, ↓ AS, MR, VSD, AS
↑ Venous return (squat, leg raise, volume): ↑ AS, MR, VSD, AS; ↓ HCM
↑ Afterload (handgrip, squat): ↑ MR, VSD, AR; ↓ AS, HCM
Inspiration: ↑ right-sided murmurs (TR, PS)
Expiration: ↑ left-sided murmurs (MR, AS, AR)
Amyl nitrite: ↓ AS, MR; ↑ HCM

Murmur Location and Character

Aortic Stenosis: RUSB, systolic crescendo-decrescendo, radiates to carotids
Aortic Regurg: LLSB, diastolic decrescendo, leaning forward with expiration
MR: apex, systolic blowing, radiates to axilla, handgrip ↑
MS: apex, diastolic rumble + opening snap, pre-systolic accentuation
TR: LLSB, systolic, increases with inspiration (Carvallo sign)
VSD: LLSB, holosystolic, palpably harsh, loud
HCM: LLSB, systolic, Valsalva ↑, squatting ↓

EKG Speed-Read

Rate: 300/150/100/75/60/50 (large boxes)
Rhythm: regular vs irregular, P before QRS?
Axis: I ↑, aVF ↑ = normal; I ↓, aVF ↑ = RAD (RVH, PE, RBBB); I ↑, aVF ↓ = LAD (LBBB, LAFB, LVH, inferior MI)
Intervals: PR < 200, QRS < 120, QTc <= 440 (M) / <= 460 (F)
ST elevation: STEMI (reciprocal changes, evolve), pericarditis (concave, diffuse + PR depression), LVH, LBBB, BER
ST depression: ischemia, LVH strain, digoxin effect, reciprocal to STEMI
T waves: peaked = hyperK, inverted = ischemia/LVH/pericarditis (late), flattened = hypok/hypoMg
Pathologic Q waves: prior MI, HCM, sarcoid, LBBB, WPW, ARVC

ACS Biomarkers Timing

Troponin (I/T): onset 3-4h, peak 24-48h, duration 4-10d
CK-MB: onset 4-6h, peak 18-24h, duration 2-3d
Myoglobin: onset 1-2h, peak 6-9h, duration 24h (not specific)
hs-cTn: 0h/1h algorithm -> rule-out with < 5 ng/L and low-risk, delta >= 5 -> rule-in
0h/2h algorithm preferred in ED. Single hs-cTn < 4 ng/L (limit of blank) = very low risk

HF Drug Dosing Quick Reference

β-blockers: bisoprolol 1.25-10mg QD, carvedilol 3.125-25mg BID, metoprolol succ 25-200mg QD � 1/2 up-titrate q2-4wk
ACEi: lisinopril 2.5-40mg QD, ramipril 1.25-10mg QD, enalapril 2.5-20mg BID
ARNI: sacubitril/valsartan 24/26-97/103mg BID � 1/2 switch from ACEi after 36h washout
MRA: spironolactone 12.5-50mg QD, eplerenone 25-50mg QD � 1/2 monitor K+ and Cr
SGLT2i: dapagliflozin 10mg QD, empagliflozin 10mg QD
Loop diuretic: furosemide 20-80mg BID, torasemide 5-40mg QD

Antiarrhythmic Quick Summary

Adenosine: narrow complex SVT, AVNRT, AVRT. 6 -> 12mg IV push.
Amiodarone: wide and narrow (AFib, VT, VF). 150mg IV/300mg IV push. Toxic: thyroid, lung, liver, cornea, skin, nerves.
Procainamide: WPW, AFib with WPW, VT. 17mg/kg IV. QRS widening = stop.
Lidocaine: VT only (post-MI). 1-1.5mg/kg IV. CNS toxicity.
Flecainide/Propafenone: AFib, SVT. Normal hearts ONLY. Do NOT use in CAD/structural HD (CAST).
Digoxin: AFib rate control (not first-line), HF. Narrow TI. ↑ toxicity with hypokalemia, CKD, amiodarone.
MgSO4: Torsades, preeclampsia, severe asthma. 2g IV.

Heart Sound Mnemonics

S1: Mitral and Tricuspid closure. Loud = MS, short PR (HCM). Soft = MR, long PR, AS, LBBB.
S2: Aortic and Pulmonic closure. Splitting: normal (inspiration), wide (RBBB, PS, ASD), fixed (ASD), paradoxical (LBBB, AS, HCM, PDA).
S3: Ventricular gallop (rapid filling). Normal in children/pregnancy. HF, MR, AR, constrictive.
S4: Atrial gallop (stiff LV). LVH, HCM, AS, HTN, post-MI, acute HF.
Opening Snap: MS (pliable valve).
Pericardial knock: Constrictive pericarditis.
Tumor plop: Atrial myxoma (pedunculated).

Top 10 Cardiology Trials

1. ISIS-2 (1988): Aspirin + streptokinase ↓ mortality in STEMI � 1/2 foundation of reperfusion + antiplatelet.
2. GUSTO-1 (1993): tPA (accelerated) > streptokinase for STEMI. Number needed to treat = 100 for 30d survival.
3. HOPE (2000): Ramipril ↓ CV death/MI/stroke in high-risk patients without HF � 1/2 the power of ACEi.
4. CURE (2001): Clopidogrel + ASA vs ASA alone in NSTEMI � 1/2 dual antiplatelet standard.
5. MERIT-HF (1999): Metoprolol CR/XL ↓ mortality in HFrEF � 1/2 established β-blocker foundation.
6. RALES (1999): Spironolactone ↓ mortality in severe HFrEF � 1/2 MRA for all.
7. PARADIGM-HF (2014): Sacubitril/valsartan > enalapril in HFrEF � 1/2 ARNI is superior.
8. DAPA-HF (2019): Dapagliflozin ↓ HF hospitalization + CV death � 1/2 SGLT2i for HFrEF regardless of DM.
9. SPRINT (2015): Intensive SBP < 120 ↓ CV events + mortality � 1/2 changed BP targets.
10. FOURIER (2017): Evolocumab + statin ↓ CV events in ASCVD � 1/2 PCSK9i benefit.

Valvular Disease Quick Summary Table

Lesion	Murmur	Echo Measure	Severe Threshold	Intervention
AS	Systolic, RUSB, -> carotids	AVA, mean gradient, ΔV	AVA < 1.0 cm^2 or mean >= 40 mmHg or Vmax >= 4 m/s	SAVR or TAVI
AR	Diastolic decrescendo, LLSB	v-wave, PHT, LV size	vena contracta >= 0.6, PHT < 200ms, LVESD >= 50	SAVR
MR	Holosystolic, apex -> axilla	EROA, RVol, LV size	EROA >= 40 mm^2 or RVol >= 60 mL	MV repair/replacement
MS	Diastolic rumble + OS, apex	MVA, mean gradient	MVA <= 1.5 cm^2 or mean >= 5-10 mmHg	PMBC (commissurotomy) vs MVR
TR	Holosystolic, LLSB, insp ↑	EROA, RVol, RA/RV size	EROA >= 40 mm^2, RA > moderate, IVC dilated	TV repair (annuloplasty) vs replacement
PR	Diastolic decrescendo, LUSB, after P2	RVol, RV size, PR index	RVol >= 45 mL, RV enlargement	PVR (homograft)

9. Treatment Tables and Drug Formulary

First-Line Dosing Guidelines Emergency Protocols

STEMI Management Protocol

Pre-hospital/ED: O2 if sat avoid nitrates + preload dependent), morphine 2-4mg IV (if pain not relieved), β-blocker (metoprolol 5mg IV q5min x 3 if no HF/cardiogenic shock/brady/heart block). Reperfusion: Primary PCI goal FMC-to-device Antiplatelet/anticoagulant: P2Y12 inhibitor (ticagrelor 180mg load, prasugrel 60mg load � 1/2 avoid if prior CVA/TIA, age >= 75, weight Post-PCI: DAPT (ASA + P2Y12) for 12 months.
GDMT: β-blocker (indefinite), ACEi/ARB (if EF <= 40%, anterior STEMI), MRA (if EF <= 40% + HF or DM), high-intensity statin.

HFrEF GDMT Cocktail

Quadruple therapy (start low, titrate to target): (1) β-blocker (bisoprolol 1. 25mg -> 10mg daily, carvedilol 3. 125mg -> 25mg BID, metoprolol succ 25mg -> 200mg daily) � 1/2 up-titrate q2-4wk. (2) ARNI (sacubitril/valsartan 24/26 -> 97/103mg BID) over ACEi.
If cannot tolerate, ACEi (lisinopril 2. 5 -> 40mg). (3) MRA (spironolactone 12. 5 -> 50mg daily, eplerenone 25 -> 50mg daily) � 1/2 check K+, Cr after 1-2wk. (4) SGLT2i (dapagliflozin 10mg daily, empagliflozin 10mg daily) � 1/2 regardless of diabetes.
Add loop diuretic (furosemide, torasemide) for volume overload.
Ivabradine: add if sinus rhythm HR >= 70 despite max β-blocker.
Digoxin: add if persistent symptoms despite GDMT (DIG trial).
Vericiguat: recent HF hospitalization (VICTORIA).
CRT: if LBBB + QRS >= 150ms + EF ICD: if EF Advanced therapies: LVAD (bridge to transplant/destination), heart transplant.

NSTEMI/Unstable Angina Management

Medical stabilization: ASA, P2Y12 inhibitor (ticagrelor, clopidogrel), anticoagulation (UFH, enoxaparin, bivalirudin, fondaparinux). β-blocker, nitrate.
Risk stratification: GRACE score -> early invasive vs ischemia-guided.
Early invasive ( 140, refractory ischemia, dynamic EKG, ventricular arrhythmia, HF/cardiogenic shock). Revascularization: PCI or CABG.
CABG preferred for left main, 3-vessel CAD, 2-vessel + proximal LAD + DM, complex anatomy (SYNTAX score).
Diabetic + multivessel: CABG > PCI (FREEDOM trial).
PCI for single/double vessel, distal lesions, non-complex anatomy. Post-PCI: DAPT 12mo.
Consider shorter DAPT (3-6mo) if high bleeding risk (PRECISE-DAPT).
Consider longer DAPT ( > 12mo) if high ischemic risk (DAPT score).

AFib Management Algorithm

Step 1: Hemodynamically unstable? -> synchronized cardioversion (120-200J biphasic). Step 2: Stable = 48h or unknown duration: anticoagulate (preferably DOAC) for >= 3wk before and 4wk after cardioversion (or start on TEE-guided cardioversion). Step 3: Rate control: β-blocker or CCB (diltiazem, verapamil) first-line.
Digoxin if HFrEF, β-blocker intolerant. Target HR Step 4: Rhythm control: DC cardioversion, AAD (flecainide/propafenone if no structural HD and no CAD; amiodarone/sotalol/dofetilide if structural HD).
Catheter ablation (PVI) early if paroxysmal/symptomatic (EARLY-AF, STOP-AF trials). Step 5: Anticoagulation: CHA2DS2-VASc score.
If M >= 2 or F >= 3 -> OAC (DOAC first unless mechanical valve, rheumatic MS, ESRD on dialysis).
HAS-BLED score for bleeding risk but not a reason to withhold OAC.
Left atrial appendage occlusion (Watchman) if OAC contraindicated.
Pill-in-the-pocket: flecainide 200-300mg or propafenone 450-600mg PO for acute conversion in selected low-risk patients.

Cardiogenic Shock Management

Definition: SBP Immediate: identify cause (echo: LV function, MR, VSD, RV, tamponade).
Urgent revascularization (PCI/CABG) within 90-120min (SHOCK trial).
Medical management: vasopressor (norepinephrine first-line � 1/2 SOAP II: NE > dopamine for shock, less arrhythmia).
Dobutamine if mixed vasopressor/inotrope.
IABP (Bridge to revascularization or recovery; no mortality benefit in routine use � 1/2 IABP-SHOCK II). MCS: Impella (LV unloading, axial flow pump � 1/2 higher complication rate).
VA-ECMO (biventricular failure, refractory shock � 1/2 bridge to decision/recovery/transplant). SCAI shock stages: A (at risk), B (pre-shock), C (classic), D (deteriorating), E (extremis).

Hypertensive Emergency Protocol

Definition: SBP >= 180 or DBP >= 120 + acute TOD.
Goal: reduce MAP by no more than 25% in first hour (to prevent hypoperfusion); target 160/100-110 at 2-6h; then gradual reduction to normal over 24-48h.
Preferred IV agents: Nicardipine (5-15 mg/h, titrate q5-15min) � 1/2 titratable, no reflex tachycardia.
Clevidipine (1-4 mg/h, double q3min).
Labetalol (10-20 mg IV bolus, then 0. 5-2 mg/min infusion) � 1/2 avoid in asthma, heart block.
Nitroprusside (0. 25-10 μg/kg/min) � 1/2 most titratable but risk of cyanide/thiocyanate toxicity, coronary steal.
Fenoldopam (0. 1-1. 6 μg/kg/min) � 1/2 dopamine agonist, maintains renal perfusion.
Aortic dissection specific: SBP 100-120, HR Pregnancy: labetalol 20mg IV -> 40mg -> 80mg q10min, or nifedipine immediate-release 10-20mg PO. Avoid ACEi/ARB.

Pericarditis Treatment Regimen

First-line: ASA/NSAIDs (ibuprofen 600-800mg TID, aspirin 800mg q4-8h, indomethacin 25-50mg TID) + colchicine 0. 6mg BID (if Second-line: corticosteroids (prednisone 0. 2-0. 5 mg/kg/day) if refractory, autoimmune, uremic, or contraindication to NSAIDs.
Taper over 2-4wk � 1/2 higher recurrence risk with steroids (CORP trial).
Recurrent pericarditis: colchicine (reduces recurrence 50%).
Anakinra (IL-1 inhibitor) for colchicine-resistant (IRAP trial).
Pericardiectomy for refractory, recurrent, constrictive.
Avoid: anticoagulation if possible during acute episode (risk hemopericardium).

Endocarditis Antibiotic Regimens

Empiric (native valve): vancomycin 15-20 mg/kg q12h + ceftriaxone 2g IV q24h.
Empiric (prosthetic valve): vancomycin + cefepime 2g q8h + gentamicin 1 mg/kg q8h (or + rifampin if > 12mo post-op).
MSSA: nafcillin/oxacillin 12g/day or cefazolin 6g/day IV for 6wk.
MRSA: vancomycin (trough 15-20) or daptomycin 10 mg/kg IV for 6wk.
Viridans strep (PCN-susceptible): PCN G 12-18 million U/day or ceftriaxone 2g IV for 4wk.
Enterococcus (ampicillin-susceptible): ampicillin 12g/day + ceftriaxone 2g q12h (or gentamicin) for 4-6wk.
Fungal: amphotericin B + flucytosine; valvular surgery.
HACEK (Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella): ceftriaxone 2g IV q24h for 4wk.
Surgery indications: HF, uncontrolled infection, prevention of embolism (large mobile > 10mm vegetation, recurrent emboli, > 15mm).

Lipid-Lowering Therapy Algorithm

ASCVD: high-intensity statin (atorvastatin 40-80mg, rosuvastatin 20-40mg).
If LDL >= 70 on maximal statin + ezetimibe 10mg, add PCSK9i.
LDL >= 190 (FH): high-intensity statin + ezetimibe.
Add PCSK9i if LDL >= 100 on max oral therapy.
Repeat lipid panel >= 4wk after initiating/changing therapy.
DM + age 40-75 + LDL 70-189: moderate-intensity statin.
If ASCVD risk >= 7. 5% or risk enhancers, high-intensity statin.
Primary prevention: moderate-to-high intensity if LDL 70-189 + >= 7. 5% risk.
Shared decision 5-7. 5%.
Hypertryglyceridemia: TG >= 500 -> fibrate (fenofibrate, gemfibrozil) + omega-3 to prevent pancreatitis.
Icosapent ethyl (Vascepa) 4g/day for TG >= 150 + ASCVD or DM.
Fasting vs non-fasting: non-fasting acceptable for screening; fasting for TG > 400, FH, monitoring.

Key Drug Interactions and Safety

ACEi + ARB + MRA + K+ supplements -> hyperkalemia. Check K+ within 1-2wk of starting MRA.
ARNI + ACEi -> angioedema risk. Must have 36h washout.
Warfarin + amiodarone -> ↑ INR. Reduce warfarin by 25-50%.
Digoxin + amiodarone/verapamil/CCB -> digoxin toxicity. Reduce digoxin dose by 50%.
Ticagrelor + high-dose ASA ( > 100mg) -> ↓ efficacy. Keep ASA 81mg.
Prasugrel: do not use in CVA/TIA, age >= 75, weight < 60kg (increased bleeding).
β-blocker withdrawal: do not stop abruptly -> rebound tachycardia, ischemia, HTN.

10. Study Tips and Exam Preparation

Board Review Key Trials High-Yield Topics Clinical Reasoning

How to Use This Guide

Cardiology is one of the highest-yield subjects for USMLE, MBBS, and internal medicine boards.
Master these core topics in order: (1) EKG interpretation - the single most important skill. (2) Chest pain evaluation - ACS vs pericarditis vs PE vs aortic dissection. (3) HF management - GDMT quadruple therapy and the RCTs behind them. (4) Valvular disease - when to intervene and why. (5) Arrhythmias - ACLS algorithms, antiarrhythmic classes, and which drugs are safe in structural heart disease. (6) HTN - JNC/ACC guidelines, secondary causes, and emergency management.
Use the cheat cards above for rapid recall before exams.

Top High-Yield Concepts

Fundamentals

Coronary anatomy (LAD vs LCx vs RCA territories), EKG leads and their wall views, heart sounds (S1-S4, murmurs by location and maneuver), cardiac output and PV loops, Frank-Starling.

ACS

STEMI vs NSTEMI vs unstable angina, TIMI/GRACE scores, primary PCI vs lytics, DAPT duration (12mo standard, shorter if high bleeding risk, longer if high ischemic risk), GDMT post-MI.

HF

HFrEF vs HFpEF, GDMT (BB + ARNI/ACEi + MRA + SGLT2i), CRT/ICD criteria, staging (A, B, C, D), acetylsalicylic acid not indicated in HF without CAD.

Valves

AS (AVA < 1.0, mean gradient >= 40, TAVI vs SAVR), MR (primary vs secondary, edge-to-edge repair), IE Duke criteria and surgery indications.

Arrhythmias

AFib (CHA2DS2-VASc, DOAC, rate vs rhythm, ablation), VT/VF (ICD, amiodarone), AV block (Mobitz II/3rd -> pacemaker), WPW (avoid AV nodal blockers), antiarrhythmic classes (I-IV).

HTN

ACC/AHA stages, first-line agents, secondary HTN workup, hypertensive emergency (aortic dissection SBP 100-120 with BB + vasodilator).

Lipids

Statin indications (ASCVD, LDL >= 190, DM, ASCVD risk >= 7.5%), high vs moderate intensity, ezetimibe/PCSK9i add-on, Icosapent ethyl for TG.

Trials

PARADIGM-HF, DAPA-HF, SPRINT, FOURIER, RALES, MERIT-HF, CURE, ISIS-2, GUSTO-1, ISCHEMIA, PARTNER, EARLY-AF, FREEDOM, POISE, CAST.

Clinical Reasoning Frameworks

Chest pain: Is it cardiac? Vital signs, EKG, troponin (0h/1h algorithm).
If unstable (hypotension, pulmonary edema, shock) -> urgent echo, STEMI protocol.
If stable risk stratify (TIMI/GRACE).
Dyspnea on exertion: HF vs CAD vs COPD vs deconditioning.
Check BNP (HF > 100 pg/mL), echo, PFTs. Syncope: Cardiac (structural HD, arrhythmia) vs reflex vs orthostatic.
High-risk features: exertional, supine, family hx SCD, abnormal EKG, structural HD. Admit if high-risk. Palpitations: Holter ( Pre-operative cardiac eval: RCRI score.
Elective surgery + high risk -> consider stress test.
Emergency surgery -> proceed with medical optimization.

Final Words

Cardiology rewards pattern recognition. Master the EKG, practice with questions, and internalize the landmark trials - they are the foundation of every guideline recommendation. This guide covers the entire scope of clinical cardiology for medical students, residents, and board review. Updated 2026.

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