HF pathophysiology

cardiac diastole

chambers relaxed, blood flows in

atrial systole, ventricular diastole

atria contract, push blood into ventricles

atrial diastole, ventricular systole

after atria relax, ventricles contract, push blood out of heart

ejection fraction

blood pumped out/blood in chamber

cardiac output definition & equation

amount of blood ejected by heart

CO = HR x SV

SV

blood volume ejected during systole

preload

volume of blood in ventricles at end of diastole

high preload = high ionotropy

ionotropy

force of myocardial contraction

afterload

resistance LV must overcome to pump blood out of the heart

can be caused by valve issues

MVO2

amount of O2 used by heart muscles

how does increased preload impact SV and contractility? (Frank Starling Curve)

increased preload → increased stroke volume → increased contractility

as afterload increases, what happens to SV? (Frank Starling Curve)

SV decreases

How do the Frank Starling curves differ between someone with HF and someone without?

HF has much lower range of SV (y-axis)

HF curve always falls under no HF curve

goals of HF therapy (in terms of preload and afterload)

increase preload to increase stroke volume

decrease afterload so blood travels to the rest of the body more easily

systolic dysfunction

enlarged ventricles fill with blood, less blood gets pumped out

heart not working well as a pump

diastolic dysfunction

stiff ventricles fill w/ less blood → less blood gets pumped out

myocyte hypertrophy and stiffening

how does myocardial injury cause HF?

myocardial injury activates hemodynamic & neurohormonal compensatory responses → ventricular remodeling → progressive systolic & diastolic dysfunction

nonmodifiable risk factors for HF

age (older adults)

genetics (FH cardiomyopathy)

disease states risk factors for HF

ASCVD

HTN

diabetes

thyroid dysfunction

obesity

lifestyle risk factors for HF

cigarettes

EtOH

sedentary

medications w/ negative inotropic effect (risk factors for HF)

antiarrhythmics (disopyramide, dronedarone, flecainide, propafenone, sotalol)

beta-blockers

non-DHP CCBs (verapamil, diltiazem)

cardiotoxic medications (risk factors for HF)

chemotherapy agents

alcohol

Na & H2O retention meds (risk factors for HF)

COX-2 inhibitors

glucocorticoids

NSAIDs

thiazolidinedones (pioglitazone, rosiglitazone)

meds w/ uncertain mechanism that are risk factors for HF

DPP4 inibitors

TNF-alpha inhibitors

Stage A HF

at risk of HF

no sxs, has risk factors

Stage B HF

pre-HF

no sxs of HF but has either:

• structural heart disease

• risk factors and high BNPs or troponin

high BNP indicates what

may have HF

Stage C HF

symptomatic HF

structural heart disease w/ current or previous sxs

Stage D HF

advanced HF

sxs that interfere with daily life and cause recurrent hospitalizations

common signs of HF

jugular venous distension (JVD)

cardiomegaly

common symptoms of HF

dyspnea & subtypes (orthopnea, paroxysmal nocturnal dyspnea)

exercise intolerance

fatigue

swollen ankles

less common signs of HF

peripheral or pulmonary edema

pulmonary crackles

weight gain

cachexia

hepatomegaly / ascites

less common sxs of HF

anorexia

poor appetite

nausea

bloating

weight gain/loss

depression

ECHO

ultrasound of heart to diagnose HF

HFrEF

LVEF ≤40%

HFpEF

LVEF ≥50%

Class I symptoms

mild

no limitations to physical activity

Class II symptoms

mild

slight limitation of physical activity

Class III symptoms

moderate

comfortable at rest → less than ordinary activity causes fatigue

Class IV symptoms

severe

sxs at rest → can’t carry out physical activity without discomfort