Canine Congestive Heart Failure Study Guide

Overview and Clinical Importance

Congestive heart failure (CHF) is a clinical syndrome that occurs when the heart can no longer pump sufficient blood to meet the body's metabolic demands, or can only do so at elevated filling pressures. In dogs, CHF most commonly results from myxomatous mitral valve disease (MMVD), accounting for approximately 75% of all canine heart disease cases. The second most common cause is dilated cardiomyopathy (DCM), which predominantly affects large and giant breed dogs. Understanding the pathophysiology, clinical presentation, diagnostic approach, and treatment of CHF is essential for NAVLE success and clinical practice.

Heart failure in dogs carries significant morbidity and mortality. Approximately 10% of dogs presented to primary care veterinary practices have heart disease, making cardiovascular conditions a major component of the NAVLE examination. Early recognition and appropriate staging of heart disease directly impacts treatment decisions and patient outcomes.

Pathophysiology of Congestive Heart Failure

Hemodynamic Basis

Heart failure develops when cardiac output becomes insufficient to meet tissue oxygen demands. The failing heart triggers compensatory mechanisms including: