Chronic Heart Failure PDF

Chronic Heart Failure (See also Harrison’s Principles of Internal Medicine, 17th Edition, Chapter 227) Definition Heart failure (HF) o An abnormality of cardiac structure or function that prevents the heart from ejecting or filling, causing dyspnea, fatigue, weakness...

Chronic Heart Failure (See also Harrison’s Principles of Internal Medicine, 17th Edition, Chapter 227) Definition Heart failure (HF) o An abnormality of cardiac structure or function that prevents the heart from ejecting or filling, causing dyspnea, fatigue, weakness and circulatory congestion Chronic HF o Heart failure that develops or progresses slowly and in which vascular congestion is common but arterial pressure is well maintained until very late o Exacerbations are precipitated by infection, tachycardia, non-compliance with medications, emotional stress, and arrhythmias. Refractory HF o Inadequate response to usual treatment Forms of HF Systolic versus diastolic failure o Systolic failure: inability of the ventricle to contract normally, with symptoms resulting from inadequate cardiac output ƒ Ejection fraction 50% o Systolic and diastolic failure coexist in most patients with HF. Low-output versus high-output HF o Low-output HF: cardiac output at rest 3.5 L/min per m2 or upper limit of normal (before development of HF) ƒ Seen in hyperthyroidism, anemia, pregnancy, arteriovenous fistulas, beriberi, and Paget’s disease, usually with underlying heart disease Left-sided versus right-sided HF o Left-sided HF: left ventricle is hemodynamically overloaded and/or weakened, resulting in pulmonary congestion (dyspnea, orthopnea). o Right-sided HF: abnormality primarily affecting right ventricle, resulting in edema, congestive hepatomegaly and systemic venous distention Copyright © The McGraw-Hill Companies, Inc. All rights reserved. www.harrisonspractice.com 2 Chronic Heart Failure Epidemiology All types of HF o In the U.S. ƒ Affects 4.5 million patients ƒ About 0.5 million new cases annually ƒ 1 million hospital admissions annually ƒ >50,000 deaths annually o Increasing in prevalence and incidence in North America and Europe o More common in elderly persons Diastolic HF o More common in women than men o Seen especially in elderly women with hypertension Risk Factors Hypertension Coronary artery disease Diabetes mellitus Dilated or hypertrophic cardiomyopathy Valvular heart disease Cardiotoxins Etiology Ventricles respond to chronic hemodynamic overload with development of hypertrophy. Chronic pressure overload leads to development of concentric ventricular hypertrophy. o Ratio between wall thickness and ventricular cavity size increases. When elevated stroke volume is required for prolonged periods (e.g., valvular regurgitation, high-output states), the ventricle dilates and develops eccentric hypertrophy o Ratio between wall thickness and ventricular cavity diameter remains relatively constant In both eccentric hypertrophy and concentric hypertrophy, wall tension is initially maintained. o Cardiac function may remain stable for years; initially, progression of HF is usually slow, then accelerates. o Ultimate deterioration of myocardial function (or new insult, such as MI) leads to HF. ƒ The ventricle dilates, and the ratio between wall thickness and cavity size decreases, increasing stress on the myocardium. ƒ The ventricle undergoes remodeling to more spherical shape, further increasing stresses on the wall and sometimes causing mitral regurgitation, which may initiate a vicious circle. ƒ Endogenous neurohormonal systems are activated, and cytokines appears to be involved. Symptoms & Signs Symptoms Dyspnea with exertion (early) or at rest (late) Orthopnea o Dyspnea when recumbent; relief with sitting upright or use of several pillows Copyright © The McGraw-Hill Companies, Inc. All rights reserved. www.harrisonspractice.com Chronic Heart Failure 3 Paroxysmal nocturnal dyspnea o Attacks of severe shortness of breath and coughing at night; usually awakens patient o Coughing and wheezing often persist even with sitting upright. o Cardiac asthma: nocturnal dyspnea, wheezing and cough due to bronchospasm Fatigue and weakness Abdominal symptoms o Anorexia o Nausea o Abdominal pain and fullness Cerebral symptoms o Altered mental status due to reduced cerebral perfusion ƒ Confusion ƒ Difficulty concentrating ƒ Impaired memory ƒ Headache ƒ Insomnia ƒ Anxiety Nocturia Physical findings Pulmonary rales with or without expiratory wheeze Lower-extremity edema Hydrothorax (pleural effusion) Ascites o Most common in constrictive pericarditis and tricuspid valve disease Congestive hepatomegaly o Positive abdominojugular reflux Jugular venous distention Third and fourth heart sounds: often present but not specific Elevated diastolic arterial pressure Depression Sexual dysfunction Findings in late/severe HF o Pulsus alternans ƒ Regular rhythm with alternation in strength of peripheral pulses ƒ Most common in cardiomyopathy, hypertensive, and ischemic heart disease o Diminished pulse pressure o Jaundice o Decreased urine output o Cardiac cachexia Differential Diagnosis Pulmonary disease with dyspnea o Obstructive airway disease o Diffuse parenchymal lung disease o Pulmonary vascular occlusive disease o Disease of chest wall and respiratory muscles o Cardiac asthma: wheezing secondary to bronchospasm occurring at night Copyright © The McGraw-Hill Companies, Inc. All rights reserved. www.harrisonspractice.com 4 Chronic Heart Failure Other conditions leading to peripheral edema o Varicose veins, cyclic edema, or gravitational effects: no jugular venous hypertension o Renal disease: abnormal renal function tests, urinalysis o Elevation of venous pressure is uncommon. Hepatic cirrhosis o Enlargement of liver o Ascites o Normal jugular venous pressure o Negative abdominojugular reflux Diagnostic Approach Approach to patient o Detailed clinical examination o Two-dimensional echocardiography with Doppler flow studies o Electrocardiography (ECG) o Chest radiography o Brain natriuretic peptide (BNP) measurement Framingham criteria for diagnosis of congestive heart failure (CHF) o To establish a clinical diagnosis of CHF by these criteria, at least 1 major and 2 minor criteria are required. o Major criteria ƒ Paroxysmal nocturnal dyspnea ƒ Neck vein distention ƒ Rales ƒ Cardiomegaly ƒ Acute pulmonary edema ƒ S3 gallop ƒ Increased venous pressure ƒ Positive hepatojugular reflux o Minor criteria ƒ Extremity edema ƒ Night cough ƒ Dyspnea on exertion ƒ Hepatomegaly ƒ Pleural effusion ƒ Vital capacity reduced by one-third from normal ƒ Tachycardia (≥120 beats/min) o Major or minor criterion ƒ Weight loss ≥4.5 kg over 5 days of treatment Laboratory Tests ECG o Aids in determining etiology; e.g. abnormal Q waves in old MI, left ventricular hypertrophy in hypertension BNP measurement o >200 pg/mL supports diagnosis o