From the Guidelines
Abnormal heart sounds can be caused by various cardiac conditions, including valvular heart disease and heart failure.
Common Causes of Abnormal Heart Sounds
- Valvular abnormalities: such as mitral regurgitation, ventricular septal defect, or other conditions that affect the heart valves 1
- Cardiac enlargement or dysfunction: which can be caused by heart failure, myocardial infarction, or other conditions that impair the heart's ability to contract or relax 1
- Arrhythmias: such as supraventricular tachycardia, atrial fibrillation, or ventricular tachycardia, which can cause abnormal heart rhythms and sounds 1
Evaluation of Abnormal Heart Sounds
The evaluation of abnormal heart sounds typically involves a physical examination, electrocardiogram (ECG), and echocardiography to determine the underlying cause of the abnormal sound.
- Echocardiography is recommended for patients with diastolic or continuous heart murmurs, apical or left sternal edge holosystolic or late systolic murmurs, and for patients with midsystolic murmurs of grade 3 or greater intensity 1
- The ECG can help identify arrhythmias and other cardiac conditions that may be causing the abnormal heart sound 1
Importance of Accurate Diagnosis
Accurate diagnosis of the underlying cause of abnormal heart sounds is crucial to guide treatment and management.
- Untreated valvular heart disease or heart failure can lead to serious complications, such as heart failure, myocardial infarction, or even death 1
- Arrhythmias can also be life-threatening if left untreated, and prompt diagnosis and treatment are essential to prevent complications 1
From the Research
Abnormal Heart Sounds
Abnormal heart sounds can be caused by various factors, including:
- Vasodilation, which can lead to a narrow angle of divergence between the ventricular and arterial pressure decay curves, resulting in an absent or faint second heart sound 2
- Changes in vascular tone and elasticity, which can affect the second heart sound 2
- Abnormal activation of the septum, such as in left bundle branch block, which can transform the septum into a passive structure, resulting in a slower rise of left ventricular pressure and a longer isovolumic period, causing a small and delayed first sound 3
- Elevated left atrial pressure, stiffening of the mitral valve, and catecholamines, which can affect the first heart sound 3
- Heart failure, which can cause a third heart sound (S3) 4
- Cardiac conditions such as Rheumatic Heart Disease (RHD), which can cause murmurs in heart sounds 5
- Various clinical conditions that affect the timing, loudness, and pitch of diastolic heart sounds, such as coronary artery disease, cardiomyopathy, and valvular heart disease 6
Types of Abnormal Heart Sounds
Different types of abnormal heart sounds include:
- Murmurs, which can be systolic or diastolic, and can be caused by conditions such as RHD 5
- Extra heart sounds, such as the third heart sound (S3), which can be caused by heart failure 4
- Diastolic heart sounds, which can be caused by various clinical conditions, such as coronary artery disease, cardiomyopathy, and valvular heart disease 6