Heart murmurs are abnormal sounds heard during a heartbeat cycle and can indicate various underlying cardiac conditions. These murmurs are often classified based on their timing within the cardiac cycle, their intensity, and quality (Figure). Systolic murmurs occur between the S1 and S2 heart sounds and are commonly associated with conditions such as aortic stenosis or mitral regurgitation, whereas diastolic murmurs occur between the S2 and S1 heart sounds and may signal issues like patent ductus arteriosus. Recognizing the characteristics of murmurs, including their location, timing, radiation, and intensity, is crucial for accurate diagnosis and appropriate management of cardiovascular diseases.
Among these, aortic stenosis manifests as a harsh systolic murmur typically heard at the right upper sternal border, indicative of obstruction in the outflow tract. Patent ductus arteriosus presents with a continuous machinery-like murmur, reflecting persistent fetal circulation between the aorta and pulmonary artery. Ventricular septal defects produce a holosystolic murmur best heard at the lower left sternal border, denoting abnormal communication between the ventricles. Hypertrophic cardiomyopathy, characterized by asymmetric septal hypertrophy, generates a systolic ejection murmur intensified with maneuvers that decrease preload. Pulmonary stenosis produces a systolic ejection murmur over the left upper sternal border due to obstruction in the pulmonary outflow tract. Mitral regurgitation yields a holosystolic murmur radiating to the axilla, arising from retrograde flow from the left ventricle into the left atrium.
In the diagnostic arsenal for evaluating heart murmurs, cardiac catheterization, chest X-rays, electrocardiogram (ECG), and echocardiogram play crucial roles in providing comprehensive insights into cardiac structure and function. Cardiac catheterization offers direct visualization of coronary arteries, cardiac chambers, and pressures, aiding in the diagnosis of congenital anomalies like ventricular septal defects or valvular disorders such as aortic stenosis. Chest X-rays provide valuable anatomical information, detecting cardiomegaly, pulmonary congestion, or signs of pulmonary hypertension. ECGs assess electrical activity, identifying rhythm abnormalities and ischemic changes indicative of underlying heart disease. Echocardiography, a non-invasive imaging modality, offers real-time visualization of cardiac chambers, valves, and blood flow patterns, facilitating the diagnosis of conditions like mitral regurgitation or hypertrophic cardiomyopathy. Integrating these diagnostic modalities enables clinicians to accurately characterize heart murmurs, guiding appropriate treatment strategies and improving patient outcomes.
By: Pilar Mallent, Mateo Perez and Carolina Pobes
