Chapter 21: Heart Failure – Drug Classes & Management

Chapter 21 focuses on the comprehensive pharmacologic management of heart failure (HF), a critical and rapidly increasing health problem defined by the heart’s inability to deliver sufficient blood supply, resulting from either systolic dysfunction (HFrEF, reduced ejection fraction) or diastolic dysfunction (HFpEF, preserved ejection fraction). The therapeutic objectives are centered on reducing morbidity, enhancing patient survival, and improving quality of life by interrupting the harmful compensatory neurohormonal mechanisms, such as the activation of the Renin-Angiotensin-Aldosterone System (RAAS) and the Sympathetic Nervous System (SNS). First-line therapy for patients with HFrEF involves combining an Angiotensin-Converting Enzyme Inhibitor (ACE-I) or Angiotensin Receptor Blocker (ARB) with an evidence-based beta blocker (carvedilol, metoprolol succinate, or bisoprolol), particularly after stabilizing any acute decompensation. ACE-I and ARBs block the RAAS cascade, leading to vasodilation and reduced preload and afterload. A more recent strategy involves the Angiotensin Receptor-Neprilysin Inhibitor (ARNI), such as sacubitril/valsartan, which is recommended to replace ACE-I or ARBs in symptomatic Stage C HFrEF patients (NYHA Class II or III) to further reduce mortality, requiring a 36-hour washout period if transitioning from an ACE-I. Diuretics are crucial for symptom management by addressing volume overload and fluid retention (e.g., dyspnea, peripheral edema), with loop diuretics being preferred for marked retention or renal impairment. Other key treatments include aldosterone antagonists (spironolactone) to decrease morbidity and mortality in specific HFrEF patients, and the hydralazine/isosorbide dinitrate combination, which is an important vasodilator alternative, particularly for African-American patients. Digoxin is primarily used to improve symptoms and reduce hospitalizations, though it does not affect overall mortality rates. A newer option, Ivabradine, is indicated for stable HFrEF patients in sinus rhythm with a resting heart rate of 70 bpm or higher, working by selectively inhibiting the I f current to reduce heart rate. The text stresses the importance of monitoring for adverse effects like hypotension, hyperkalemia (especially with RAAS inhibitors), and angioedema, alongside nonpharmacologic interventions such as strict dietary sodium restriction (2 to 3 g daily) and adherence to prescribed aerobic activity.