Chapter 11: Congestive Heart Failure and Management Drugs

Learning Objectives

Introduction

Congestive heart failure is the most common cause of hospitalization in the United States. The number of patients that carry the primary diagnosis of heart failure account for greater than 3 million visits per year. The burden of this disease and the cost of caring for these patients are staggering. Heart failure is the last destination and most common complication for the majority of heart diseases such as myocardial infarction, hypertension, valvular heart diseases, atherosclerosis, and congenital heart disease. Consequently, there are various types, stages, and pathogeneses of heart failure. Therefore, an understanding of the pathophysiology of this disease is essential in managing these patients.

Definition

When the ability of the heart to effectively pump blood to the rest of the body is compromised, this will result in a mismatch between supply and demand of the metabolizing tissues ­during ordinary activity.

Congestive heart failure can occur as a result of impaired cardiac contractility, which is known as systolic congestive heart failure. It can also result from increased myocardial stiffness or an inability of the heart to relax in the absence of reduced contractility, often known as heart failure with preserved ejection fraction (HFEF) or diastolic heart failure. High output cardiac failure is another entity characterized by elevated cardiac output in certain medical conditions such as Beriberi, hyperthyroidism, and systemic AV fistulas. Even though the resting cardiac index is elevated, symptoms of heart failure develop because of a failure to compensate for increased requirements. Table 11.1 lists the major causes of heart failure.

Causes of Heart Failure

Heart Failure Due to Impaired Cardiac Function

• Myocardial infarction

• Valvular dysfunction

• Hypertension

• Toxins

• Infections, such as sepsis and Chagas disease

• Arrhythmias

• Stress-induced cardiomyopathy

• Muscular dystrophies, such as Duchenne muscular dystrophy

• Autoimmune etiologies

• Endocrinopathies such as hyperthyroidism

• Glycogen storage diseases

• Alcohol-induced cardiomyopathy

• Myocarditis

• Chemotherapy-induced cardiotoxicity

Heart Failure Due to Impaired Relaxation of the Cardiac Muscle Is Also Known as Heart Failure with Preserved Ejection Fraction