Harrisons 234: Heart failure & cor pulmonale Flashcards
Heart failure: what is it?
Clinical syndrome of signs & symptoms arising from abnormality of heart structure & function.
Heart failure: why is it bad?
Because you kinda need your heart, and if it fails, that will suck!
Or because of “frequent hospitalizations, poor quality of life, and shortened life expectancy,” which is really what I said anyway.
Heart failure: some classic signs & symptoms
Signs: Edema, crackles
Symptoms: Dyspnea, fatigue
The incidence of HF seems to be rising. How come?
Because we’re doing better at fixing OTHER cardiac disorders, like MI & valve disease.
“current therapies for cardiac disorders…are allowing patients to survive longer.”
Heart failure patients are in 1 of 2 groups. What are those groups?
1) HF with depressed EF (systolic heart failure)
2) HF with preserved EF (diastolic heart failure)
What is the “line” for preserved vs. depressed EF?
40% is the magic number!
< 40% = depressed EF
≥ 40% = preserved EF
Some possible etiologies for depressed EF/systolic HF:
#CAD: myocardial infarct or ischemia #Nonischemic dilated cardiomyopathy: familial/genetic disorder, infiltrative disorder #Chronic pressure overload: HTN, obstructive valve disease, intracardiac (L-to-R shunting), extracardiac shunting #Toxic/drug induced damage: metabolic disorder, viral #Chagas disease #Chronic arrhythmia: tachy or brady
Some possible etiologies for preserved EF/diastolic HF:
#Pathologic hypertrophy: primary (hypertrophic cardiomyopathy) or secondary (hypertension) #Restrictive cardiomyopathy: infiltrative disorders, storage diseases #Aging #Fibrosis #Endomyocardial disorders #Pulmonary heart disease: cor pulmonale, pulmonary vascular disorders
HF patients are classified by objective assessment using what scale?
New York Heart Association (NYHA) Classes I-IV
NYHA Class I
No limitation of physical activity. Ordinary activity does not cause undue fatigue, palpitations, dyspnea, or angina.
NYHA Class II
Slight limitation of physical activity. Comfortable at rest. Ordinary activity results in fatigue, palpitation, dyspnea or angina.
NYHA Class III
Marked limitation of physical activity. Comfortable at rest. Less than ordinary activity causes fatigue, palpitation, dyspnea, & angina.
NYHA Class IV
Inability to carry on any physical activity without discomfort. Symptoms of HF or angina may be present at rest. Discomfort increases with any physical activity.
What is an index event in the context of HF?
“An event that either damages the heart muscle…or disrupts the ability of the myocardium to generate force.”
It can be abrupt, gradual, or hereditary.
Compensation mechanisms that keep HF patients asymptomatic:
1) Renin-angiotensin-aldosterone & adrenergic nervous systems
2) Increased myocardial contractility
3) Vasodilatory molecules (ANP, BNP, prostaglandins & nitric oxide)
“I’ll take HF for $200, Alex”
“Left ventricular remodeling”
“What is a series of adaptive changes within the myocardium?”
(You win!)
What causes LV remodeling?
1) Myocyte hypertrophy
2) Alterations of myocyte contractility
3) Loss of myocytes
4) beta-adrenergic desensitization
5) Abnormal myocardial metabolism & energetics
6) Reorganization of extracellular matrix so that it does not provide enough support to myocytes
Cardinal Symptoms of HF
#Fatigue #Shortness of breath
What’s the origin of the classic dyspnea in HF?
Biggest contributor: Pulmonary congestion with accumulation of interstitial or intra-alveolar fluid
Runner ups: reduction in lung compliance, increased airway resistance, respiratory muscle fatigue, anemia
Let’s talk about orthopnea! What IS it? Why is it a thing? How do we measure it?
What: dyspnea when patient lies down
Why: redistribution of fluid back into central circulation when the patient lies down, resulting in higher pulmonary capillary pressure
How measured: “How many pillows do you sleep on?”
Paroxysmal nocturnal dyspnea (PND): What, when, & why?
What: acute episodes of SOB & coughing that wake ya up. Coughing & wheezing continue after assuming upright position.
When: At night, about 1-3 hours after HS
Why: Increased pressure in bronchial arteries, leading to airway compression. Probably also that fluid redistribution thing.
Cheyne-Stokes respiration: What’s that?
Disordered breathing in which periods of apnea cycle with periods of hyperventilation.
Cheyne-Stokes respiration: Why does it happen?
Diminished sensitivity to PCO2 in respiratory center.
Apneic phase results in higher arterial PCO2, which stimulates respiratory center, which triggers hyperventilation. Resulting hypocapnia triggers more apnea…and on and on.
Other possible HF symptoms
#GI symptoms: anorexia, nausea, early satiety #Right upper quadrant pain (re: liver congestion) #Cerebral symptoms: confusion, disorientation & sleep/mood disturbances #Nocturia
