A holosystolic murmur describes a specific sound heard during a heart examination. It indicates a sound present throughout the entire period when the heart’s main pumping chambers, the ventricles, contract. This type of sound suggests blood is flowing unusually within the heart during this crucial phase of its cycle.
Understanding the Components
The term “holosystolic” is derived from two Greek roots: “holo,” meaning “whole” or “entire,” and “systolic,” referring to “systole.” Systole is the phase of the cardiac cycle when the heart muscle contracts, actively pumping blood out to the body and lungs. During this contraction, the ventricles eject blood into the aorta and pulmonary artery.
A holosystolic sound occurs throughout the entire duration of systole. This means the sound begins with the first heart sound (S1), signaling the start of ventricular contraction, and continues until the second heart sound (S2), which marks the end of this contraction.
Holosystolic Murmurs in Context
A heart murmur is an unusual sound, often described as a whooshing or swishing, heard during the heartbeat. These sounds arise from turbulent blood flow through the heart valves or nearby blood vessels. Murmurs are classified based on when they occur within the cardiac cycle, such as during systole (contraction), diastole (relaxation), or continuously.
A holosystolic murmur spans the entire period of ventricular contraction. Unlike other systolic murmurs that might appear only in early or late systole, a holosystolic murmur starts at the very beginning of systole and extends without interruption until the end. This consistent presence can sometimes obscure the normal heart sounds (S1 and S2), making them difficult to distinguish.
Common Causes and Associated Conditions
Holosystolic murmurs are caused by conditions that allow blood to flow abnormally between heart chambers or backward through a valve. Three common conditions are mitral regurgitation, tricuspid regurgitation, and ventricular septal defects.
Mitral regurgitation occurs when the mitral valve, located between the left atrium and left ventricle, does not close completely during systole. This incomplete closure allows blood to leak backward into the left atrium as the left ventricle contracts to pump blood to the body. The murmur often has a blowing quality and is typically heard loudest at the heart’s apex, sometimes radiating to the armpit.
Tricuspid regurgitation involves the tricuspid valve, situated between the right atrium and right ventricle. When this valve fails to close properly, blood leaks back into the right atrium during the right ventricle’s contraction. This murmur is commonly heard at the left lower sternal border and often becomes louder during inspiration, a distinguishing characteristic.
A ventricular septal defect (VSD) is a hole in the wall separating the heart’s two lower chambers, the ventricles. This defect allows blood to shunt from the higher-pressure left ventricle to the lower-pressure right ventricle during the entire systolic phase. The murmur is frequently heard at the left lower sternal border. Its intensity can vary, often being louder with smaller defects due to increased turbulence.
Detection and Further Evaluation
A holosystolic murmur is first detected by a healthcare provider using a stethoscope during a routine physical examination. The provider listens carefully for the murmur’s timing and assesses other characteristics such as its location, intensity, pitch, quality, and any areas to which the sound radiates. The intensity of a murmur is often graded on a scale from 1 to 6, with higher numbers indicating a louder sound.
If a holosystolic murmur is identified, further evaluation is recommended to determine its underlying cause and significance. The primary diagnostic tool is an echocardiogram, which uses sound waves to create detailed images of the heart’s structure and blood flow. This non-invasive test helps pinpoint the specific issue causing the murmur. Other tests, such as an electrocardiogram (ECG) to measure the heart’s electrical activity or a chest X-ray to check for heart enlargement, may also be performed. This investigation ascertains whether it is a benign finding or indicative of a more significant cardiac condition.