Study session step 1 of 13

**Cardiac output:** CO = HR × SV. Normal 4–8 L/min. SV depends on **preload** (end-diastolic volume, Frank-Starling), **afterload** (TPR, aortic pressure), and **contractility** (inotropy — catecholamines, digoxin).

**Cardiac cycle phases (Wiggers):** 1. Isovolumetric contraction — all valves closed. 2. Systolic ejection — aortic valve opens. 3. Isovolumetric relaxation — all valves closed. 4. Rapid/slow filling; atrial contraction. S1 = mitral/tricuspid close. S2 = aortic/pulmonic close. S3 (rapid filling, HF/volume overload). S4 (stiff ventricle, HFpEF).

**Murmurs:** • Aortic stenosis — crescendo-decrescendo systolic at RUSB, radiates to carotids; parvus et tardus pulse. • Aortic regurgitation — decrescendo diastolic at LUSB; wide pulse pressure (water-hammer). • Mitral regurgitation — holosystolic blowing at apex. • Mitral stenosis — opening snap + diastolic rumble; often rheumatic.

**Ischemic heart disease:** • Stable angina — demand ischemia, relieved by rest/NTG. • Unstable angina — plaque rupture, no necrosis. • NSTEMI — subendocardial necrosis, troponin+. • STEMI — transmural; ST elevation; requires PCI < 90 min door-to-balloon per ACC/AHA.

**Heart failure:** HFrEF (EF ≤40%) vs. HFpEF (preserved). Guideline therapy GDMT: ACEi/ARB/ARNI + β-blocker (carvedilol, metoprolol succinate, bisoprolol) + MRA + SGLT2i.

**Hypertension (JNC 8 / ACC 2017):** normal <120/80; stage 1 130–139/80–89. Thiazides, CCBs, ACEi/ARB first-line. Special populations: ACEi preferred in diabetes/CKD; CCB or thiazide preferred in Black patients.