Weak heart muscle is also known as systolic failure that occurs due to poor contractibility of left ventricles. Poor left ventricle contraction leads to reduced ejection fraction, thus, pumping oxygenated blood to the rest of the body is reduced. As a compensatory mechanism, the left ventricles remodel and ventricular dilatation takes place that leads to progression of systolic heart failure. Heart failure can also occur when the ventricles are stiff and not able to relax, termed as diastolic heart failure.
The normal ejection fraction of heart is about 55-70%; however, in systolic heart failure reduced ejection fraction of less than 40% is mostly seen in patients younger than 65 years. The common causes include cardiomyopathies (diseases of the heart muscle) and coronary artery disease (leading to irreversible damage to the heart muscle).(1)
What Are The Symptoms Of A Weak Heart Muscle?
The symptoms of heart failure are associated with congestion and fluid retention that cause shortness of breath and edema. The reduced ejection fraction leads to decreased blood flow at the time of high demand (as in increased physical activity) that manifests as early fatigue with prolonged exhaustion after heavy physical activity, unrelated to shortness of breath. When the disease has progressed, the cardiac output at rest is lower than normal. When there is extreme cardiac output reduction, it becomes life threatening and is termed as cardiogenic shock.(1)
Shortness of breath or exertional dyspnea is a very common symptom of heart failure or weak heart muscle. However, dyspnea is a common symptom of pulmonary disease; therefore, it is not specific to heart failure. Orthopnea (shortness of breath while lying down) is also a specific symptom of heart failure, though lacks in sensitivity. Paroxysmal nocturnal dyspnea (shortness of breath at night time) is another symptom of heart failure, which has greater sensitivity. It is caused due to increase in pressure of left ventricular filling. Furthermore, it can also lead to ischemic chest pain at night.
Generalized fatigue is another common symptom of chronic heart failure. It is caused by anomaly in skeletal muscle function and structure, due to premature lactase release, and impaired muscle blood flow. The deficiency in cerebral blood flow with changes in sleep pattern may lead to increased sleepiness and confusion in cases of severe chronic heart failure.
Swelling is another common symptom of weak heart muscle. It is most prominent in feet and ankles. Although, swelling is not specific to heart failure as it can be seen in liver distension, ascites, right heart failure, loss of appetite and bowel edema too. There also might be increase in weight due to fluid retention, although weight loss and cardiac cachexia are seen in some patients.(1)
The physical signs of heart failure include tachycardia, pulmonary crepitations, jugular venous distension, displaced apex beat and a third heart sound. These signs may also be present in other disease conditions, which may not be specific to the disease.
Complications of heart failure might include arrhythmias (both atrial and ventricular), stroke, thromboembolism, pulmonary congestion, pulmonary hypertension, respiratory muscle weakness, muscle wasting, hepatic congestion, hepatic dysfunction, malabsorption and sudden death.(2)
Atrial fibrillation is present in about 10-50% of all patients with chronic heart failure that can either be a cause or consequence of heart failure. Patients suffering from heart failure along with atrial fibrillation are at increased risk of developing stroke and other thromboembolisms. Ventricular arrhythmias are mostly found in patients with end stage heart failure.(1)
Approximately 2% patients with congestive heart failure suffer from stroke and thromboembolism (deep vein thrombosis, pulmonary embolism), annually. The risk factors associated with thromboembolic complications are low cardiac output, atrial fibrillation, persistence of sinus rhythm, and regional wall motion abnormalities. The risk of thromboembolism increases with the severity of cardiac failure and is related to left atria and left ventricular dilatation.
The mortality and morbidity of patients with symptomatic chronic systolic heart failure is about 20-30% one year mortality for mild to moderate heart failure and more than 50% one year mortality for severe heart failure.
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