From the Guidelines
The presence of an S4 heart sound is a significant indicator of diastolic dysfunction, particularly in patients with conditions like hypertension, coronary artery disease, or hypertrophic cardiomyopathy, as it represents the vibration of the ventricular wall when atrial contraction forces blood into a stiff, non-compliant ventricle 1. The relationship between an S4 heart sound and diastolic dysfunction is rooted in the pathophysiology of ventricular filling. In diastolic dysfunction, the ventricle becomes less compliant, making it harder for the ventricle to fill during diastole. This condition can be a result of various factors, including myocardial relaxation abnormalities, as noted in the study by the American Society of Echocardiography and the European Association of Cardiovascular Imaging 1.
Key points to consider in the relationship between S4 heart sound and diastolic dysfunction include:
- The S4 sound occurs late in diastole, just before the first heart sound (S1), and is best heard with the bell of the stethoscope at the apex of the heart with the patient in the left lateral decubitus position.
- The presence of an S4 typically indicates grade 1 (mild) diastolic dysfunction, where the ventricle requires higher filling pressures to achieve adequate filling.
- Management of diastolic dysfunction focuses on treating the underlying cause, controlling blood pressure, and managing volume status, with medications such as ACE inhibitors or ARBs, beta-blockers, and diuretics, along with lifestyle modifications including sodium restriction, regular exercise, and weight management.
- Reduced LV relaxation is one of the earliest manifestations of myocardial dysfunction, and patients with diastolic dysfunction may not be able to augment myocardial relaxation with exercise compared with normal subjects, as discussed in the study 1.
Therefore, the presence of an S4 heart sound should prompt further evaluation for diastolic dysfunction, including echocardiography to assess left ventricular diastolic function, as recommended by the American Society of Echocardiography and the European Association of Cardiovascular Imaging 1.
From the Research
Relationship between S4 Heart Sound and Diastolic Dysfunction
- The S4 heart sound is associated with diastolic dysfunction, as it is often heard in patients with conditions that lead to impaired ventricular filling, such as left ventricular hypertrophy and coronary artery disease 2, 3.
- Diastolic dysfunction is characterized by impaired ventricular relaxation and stiffness, leading to increased filling pressures and potentially resulting in heart failure 4, 5, 6.
- The presence of an S4 heart sound can be an indicator of diastolic dysfunction, as it is often heard in patients with conditions that lead to impaired ventricular filling 2, 3.
- Echocardiography is a useful tool in diagnosing diastolic dysfunction and can help identify the underlying cause of the condition, including the presence of an S4 heart sound 2, 5.
Diagnosis and Treatment of Diastolic Dysfunction
- Diastolic dysfunction can be diagnosed using a combination of physical examination, echocardiography, and other non-invasive tests 2, 5, 6.
- Treatment of diastolic dysfunction typically involves addressing the underlying cause of the condition, such as hypertension, coronary artery disease, or left ventricular hypertrophy 4, 2, 6.
- Medications such as angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, beta-blockers, and diuretics may be used to treat diastolic dysfunction, although the optimal treatment strategy is still being studied 4, 6, 3.