Management of HFrEF (systolic dysfunction)

In most clinical situations, reducing afterload is the most effective way to manage heart failure with a reduced EF. Lowering vascular resistance and arterial blood pressure decreases the burden on the left ventricle and enhances contraction and ejection. Regardless of the baseline values, reducing blood pressure (while maintaining adequate tissue perfusion) is the mainstay of treatment of HFrEF. Therapeutic options include the following:

• ACE inhibitors. The most effective agents for reducing afterload are captopril, enalapril, lisinopril, and ramipril. They decrease clinical signs of CHF as well as rates of morbidity and mortality.

• β-Blockers. These drugs include carvedilol, bisoprolol, and metoprolol. They decrease mortality and hospitalization rates and, if not contraindicated, should be used in almost all CHF patients.

• Angiotensin II receptor blockers. Candesartan and valsartan may be used when hypotension from ACE inhibitors would not be tolerated.

• Amlodipine. Other calcium channel blockers should be avoided in CHF.

• Other afterload-reducing agents. These include hydralazine, clonidine, and, for patients intolerant of ACE inhibitors due to renal disease, α-adrenergic blockers (eg, prazosin, doxazosin).

• Treatment of anemia. Intravenous iron replacement may be used to treat anemia, but erythropoietin should be avoided.

• Lifestyle modification. Helpful lifestyle changes include smoking cessation, salt restriction, weight loss, exercise, and cardiac rehabilitation.

For patients with HFrEF, the contractility of the left ventricle can be enhanced with inotropic agents. Digoxin is reserved mainly for patients who remain symptomatic despite the use of diuretics and ACE inhibitors and for patients with CHF and atrial fibrillation requiring rate control. The other oral inotropic agents have not proved safe or effective in patients with chronic CHF; however, intravenous inotropic agents play a key role in treating hospitalized patients with worsening heart failure. Digoxin should not be used in patients with HFpEF (diastolic failure).

Management of HFpEF (diastolic dysfunction)

Heart failure with preserved EF can be improved by reducing preload, which in turn lowers filling pressures in the ventricle. Preload can be reduced by decreasing circulating blood volume, by increasing the capacitance of the venous bed, and by improving systolic function to empty the ventricle more effectively. Therapy for patients with HFpEF should focus on managing the contributing disease processes. For example:

• Hypertension may be managed with diuretics (spironolactone) and β-blockers.

• Atrial fibrillation is present in two-thirds of HFpEF patients. Consider treatment to control rate and rhythm.

• Cardiac ischemia is present in two-thirds of these patients. Consider use of PCI or CABG.

• Hyperlipidemia may be treated with statins in patients with HFpEF (they are not beneficial in HFrEF).

• Obesity may be managed with weight loss, exercise training, and cardiac rehabilitation.

Other approaches to CHF

Whenever possible, the underlying causes and/or contributing factors for CHF should be identified and addressed. Precipitating factors can include excessive salt or fluid intake, poor medication adherence, excessive activity, obesity, pulmonary infection or embolism, MI, renal disease, anemia, thyrotoxicosis, and arrhythmias.

Intermittent arrhythmias may seriously compromise ventricular function. Tachyarrhythmias may aggravate ischemia; bradyarrhythmias may decrease cardiac output and blood pressure further. As previously discussed, β-blockers should be considered for all patients with CHF for their effects on overall mortality, although they appear to be more effective in HFrEF than in HFpEF. Amiodarone was not found to be beneficial in the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT), and most other antiarrhythmic agents are contraindicated in CHF because they may decrease cardiac function and be paradoxically proarrhythmic. ICDs can be useful adjuncts to medical therapy in patients with CHF, cardiomyopathy, and an EF of 35% or less; and they improved mortality in both the MADIT II and SCD-HeFT trials. Biventricular pacing also improves mortality rates and decreases rehospitalization rates in patients with CHF and a wide QRS complex by improving contraction efficiency. Patients with heart block or other severe bradyarrhythmias may also require cardiac pacing.

Patients with a dilated cardiomyopathy and atrial fibrillation should receive anticoagulation therapy unless contraindications exist. Many physicians also prescribe anticoagulation for patients with a dilated cardiomyopathy, low EF, and normal sinus rhythm, if there are no contraindications. Options include warfarin, DAT, and newer agents such as dabigatran, apixaban, and rivaroxaban. Risk factors, cost, tolerability, and potential drug interactions should all be considered during agent selection.

Other measures that can help in managing CHF are restricting dietary sodium, avoiding fluid overload by carefully monitoring oral and intravenous fluid intake, controlling pain and anxiety, treating concomitant metabolic and pulmonary diseases, and providing supplemental oxygen to hypoxemic patients. Finally, all patients with CHF should receive an influenza vaccination and the pneumococcal vaccine.

Excerpted from BCSC 2020-2021 series: Section 1 - Update on General Medicine. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.