Chapter 15-10: Heart Failure (HF)

TEXTBOOK PRESENTATION

Patients classically have fatigue, dyspnea on exertion, orthopnea, paroxysmal nocturnal dyspnea, and edema. Often, there is an antecedent history of either MI or poorly controlled hypertension.

DISEASE HIGHLIGHTS

1. HF refers to any cardiac pathology that impairs left ventricular (LV) filling or ejection, which may arise from diseases or dysfunction of the myocardium, valves, or pericardium. The remainder of this discussion will focus on myocardial causes of HF. Valvular heart disease is discussed separately.

2. Affects 6.5 million patients in the United States and accounts for 900,000 hospitalizations and 75,000 deaths annually. At age 45, lifetime risk of heart failure is 27.4% in men and 23.8% in women. The risk of HFrEF is higher in men than in women although the risk of HFpEF is equal between genders.

3. Pathophysiologic classification: HF may occur in patients with impaired emptying (and an ejection fraction ≤ 40%) or impaired filling (with a preserved ejection fraction ≥ 50%). The distinction is important because both the etiologies and treatments of these 2 groups are different. HF may also be classified based on whether the primary process affects the LV or the right ventricle (RV).

   1. HFrEF

      1. Previously called systolic HF or systolic dysfunction, HFrEF accounts for approximately 50% of cases of HF.

      2. HFrEF develops when systolic dysfunction impairs LV emptying.

      3. CAD is the most common cause of HFrEF.

      4. Other common causes include long-standing hypertension and alcohol abuse.

      5. Less common causes include viral cardiomyopathy, postpartum cardiomyopathy, drug toxicity (eg, adriamycin), persistent tachycardia, and idiopathic cardiomyopathy.

   2. HFpEF

      1. Previously referred to as diastolic HF, HFpEF accounts for approximately 50% of all HF cases.

      2. HFpEF develops when an increase in myocardial muscle mass (thickness), infiltration, or fibrosis decreases LV compliance.

         1. Decreased LV compliance impairs LV filling.

         2. Note that although LV filling is compromised, contractility is preserved and the ejection fraction is normal.

      3. The most common cause of HFpEF is hypertension.

      4. Less common causes include

         1. Aortic stenosis

         2. Hypertrophic cardiomyopathy

         3. Infiltrative cardiomyopathies (eg, hemochromatosis, amyloidosis)

   3. The mortality in patients with HFrEF and HFpEF is similar.

   4. Patients with ejection fraction of 41–49% are classified as HFpEF, borderline. Their treatment and outcomes are similar to patients with HFpEF.

   5. Right- versus left-sided HF

      1. HF may involve the LV, the RV, or both.

      2. Common causes of LV failure include CAD, hypertension, and alcoholic cardiomyopathy.

      3. Common causes of RV failure include advanced LV failure and severe pulmonary disease, such as COPD (cor pulmonale).

      4. A key distinguishing feature between right- and left-sided HF is that pulmonary edema, common in LV failure, is not a feature of isolated RV failure.

      5. Peripheral edema, JVD, and fatigue may be seen in LV or RV failure.

   6. Progression

      1. HF triggers maladaptive neurohormonal changes including increased activation of the renin-angiotensin-aldosterone system and the sympathetic nervous system.

      2. These neurohormonal responses promote sodium retention, increase afterload, and contribute to volume overload and progressive HF.

      3. Therapies that interrupt these responses reduce mortality.

4. Classifications of HF

   1. New York Heart Association (NYHA)

      1. Functional ...