Heart failure is a very common disease and affects approximately 1-2 percent of the adult population in developed countries. The prevalence of congestive heart failure rises to about 10% among the population over 70 years of age. Projection in the United States shows that heart failure will increase by more than 40% by the year 2030, resulting in over eight million people with heart failure.
What is mild congestive heart failure?
Clinical studies have shown that approximately 50% of patients with heart failure have a relatively normal or slightly reduced heart function. A popular method of evaluating heart function is by calculating an ejection fraction. This is usually done by obtaining an echocardiogram and measuring how much blood is pumped with each contraction divided by the total amount of blood contained in the left ventricle. Some patients with heart failure and normal pump function can have an ejection fraction of greater than 50% or preserved ejection fraction. This is known as diastolic dysfunction, which is a condition in which the heart does not relax normally. Some patients with slightly reduced pump function, also known as mild systolic dysfunction, can have an ejection fraction in the range of 40- 49% or heart failure with mid-range ejection fraction.
When compared to heart failure patients with reduced ejection fraction (ejection fraction < 40%), patients with preserved or mid-range ejection fraction are predominantly elderly women with more comorbidities such as hypertension, atrial fibrillation, and diabetes type 2.
What are the symptoms of mild congestive heart failure?
The patient may experience bouts of fluid retention and weight gain, shortness of breath on exertion, and decreased exercise tolerance. Some patients may have significant problems with swelling of their legs. This may lead the patient to depression and frustration because they can no longer do their regular activities and are having to rely more on their families. Sometimes the patient can feel the heart racing as a consequence of the heart function being reduced.
What is the prognosis if you have mild congestive heart failure?
As the population ages, the prevalence of heart failure with preserved ejection fraction and mid-range ejection fraction increases. In a U.S. study of heart failure hospitalization, patients with preserved (ejection fraction of 50% or greater) or mid-range ejection fraction (EF= 40-49%) accounted for more than 40% of all heart failure hospitalization. This is an increase of 10% over the previous decade. Heart failure hospitalizations strongly predict poor prognosis. The readmission rate and mortality within three months post-discharge reach 30% and 10% respectively and are similar to patients with reduced left ventricular ejection fraction (EF= less than 40%).
So there is a lot of variability in the prognosis of patients with mild congestive heart failure. But for the patient who has been admitted to the hospital, this is usually a marker of the severity of the illness and may prompt a physician to be more aggressive with medical therapy.
What is the treatment for mild congestive heart failure?
To date, there is a lack of evidence in the management of patients with heart failure with preserved or mid-range ejection fraction. No treatment has yet been shown to reduce morbidity and mortality in these patients. The management is usually limited to optimal treatment of comorbidities such as hypertension, atrial fibrillation, and coronary artery disease.
Elevated blood pressure is an extra load on the heart. In response, the left ventricle becomes thicker (LVH) and unfortunately stiffer. As the pressure rises in the heart, it also increases in the lungs, making the patient short of breath with minimal activity. There is solid evidence that improving one’s blood pressure can lead to the regression of LVH. Some medicines such as angiotensin II receptor blockers (ARBs), calcium channel blockers, and angiotensin-converting enzyme (ACE) inhibitors can lead to regression of hypertrophy and return the heart to a more normal thickness and function.
When the heart muscle is stiff, the heart needs more time to fill with blood. When the heart rate is fast and uncoordinated like sometimes in atrial fibrillation, the patient becomes very short of breath, even at rest. It is important to have a reasonably slow heart rate to allow for optimal filling. The medicines used most commonly to slow your heart rate are beta-blockers and calcium channel blockers. Sometimes in atrial fibrillation or flutter, we have to go a step further and proceed to cardioversion or ablation to return to a normal heart rhythm.
Coronary artery disease where a blockage in the artery causes significantly decreased blood flow can lead to varying levels of ischemia in the myocardium. Ischemia makes the heart muscle stiff and causes the patient to be short of breath during exercise. Medicines such as nitrates, beta-blockers, calcium antagonists, ranolazine, or interventions to reopen the arteries such as coronary stenting can relieve ischemia and the patient’s symptoms.
Usually, diuretics are recommended to alleviate symptoms of congestion. The management of fluid in the body is very important in patients who have heart failure, particularly if they have had a previous hospitalization for heart failure. In the Cardiomems-Heart failure postmarketing trial, patients with a device to measure pressure in the pulmonary artery where diuretics were used to keep the pressure close to normal were found to have 60% less chance of another admission for heart failure even if their heart function was normal (EF >50%) or mildly abnormal (EF = 41-50%).
The ACC/AHA guidelines have included the use of aldosterone receptor blockers in patients with heart failure and ejection fraction greater than 45%. Aldosterone is a hormone in the body that is thought to mediate hypertrophy or thickening of the heart muscle, fibrosis, and inflammation which contribute to the stiffening of the heart. Blocking aldosterone using spironolactone has been shown to reverse some of these findings with improvement of the filling of the heart as demonstrated by echocardiograms.
The clinical study TOPCAT sought to test the value of spironolactone as a treatment of patients with heart failure and preserved heart function (EF = 45% or greater). Treatment with spironolactone did not significantly reduce death from cardiac cause or heart failure hospitalization. However, there was a beneficial effect observed in patients enrolled with increased fluid status as reflected by an elevated natriuretic peptide (BNP). It is important to monitor the side effects of spironolactone in particular: the potassium level in the blood, the kidney function, and gynecomastia, or swelling of the breasts in men. This latter can be quite uncomfortable but reversible upon cessation of the drug. Bayer Pharmaceuticals is developing a new agent to block aldosterone without the side effect of spironolactone. It is called finerenone and will be tested in different clinical research sites across the world. It is thought to be more selective and effective than spironolactone.