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
HF: General appearance & vitals
#Mild/moderate HF: No distress at rest. Systolic BP may be high. #Severe HF: Orthopnea, labored breathing, SOB. Systolic BP probably low, possibly decreased pulse pressure. May be tachycardic.
HF: Jugular vein exam
Estimation of right atrial pressure. With patient lying recumbent & head tilted at 45º, estimate height of the venous blood column above sternal angle in centimeters & add 5.
HF: pulmonary exam
Crackles result from movement of fluid into alveoli from intravascular space. May not be present in chronic HF.
When present in patient without lung disease, CRACKLES ARE SPECIFIC FOR HEART FAILURE!
HF: cardiac exam
Essential, but may not provide useful info re: HF severity!
#PMI displaced laterally below 5th intercostal space if cardiomegaly is present #S3 most common in volume overload with tachycardia & tachypnea, often in hemodynamic instability #S4 isn't specific, but often presents with diastolic dysfunction #Possible mitral/tricuspid regurg murmurs
HF: abdomen exam
Hepatomegaly is important sign in HF!
Lifestyle measures to help control HF
1) Exercise: routine modest exercise may result in reduced HF symptoms
2) Diet: Restriction of Na recommended for ALL HF patients (2-3 grams/day)
Vasodilators for the treatment of acute HF
Nitroglycerin
Nitroprusside
Nesiritide
Inotropes for the treatment of acute HF
Dobutamine
Milirinone
Dopamine
Vasoconstrictors for treatment of acute HF
Dopamine (for hypotension)
Epinephrine
Phenylephrine
Vasopressin
These two diseases are responsible for 50% of the cor pulmonale in North America:
1) COPD
2) Chronic bronchitis
What is the basic mechanism behind cor pulmonale?
Increased pressure in pulmonary capillary bed increases workload of right ventricle, which then dilates & fails.
What is the most common cause of RIGHT heart failure? (Hint: not a lung disease…)
LEFT heart failure!
Signs & symptoms of cor pulmonale
#Dyspnea: result of increased work of breaking bc of decreased lung elasticity, altered respiratory mechanics, or inefficient ventilation # Elevated JVP, hepatomegaly, LE edema
Treatment for cor pulmonale:
#Treat underlying pulmonary disease #Decrease work of breathing #Oxygenate #Diuretics
