Tricuspid regurgitation is a heart condition where the tricuspid valve, located in the heart, does not close completely. This incomplete closure allows some blood to flow backward into the right upper chamber of the heart each time it beats. This backward flow occurs when the heart’s lower right chamber contracts to pump blood forward. While a small amount of backward flow can be harmless, significant tricuspid regurgitation can make the heart work harder over time.
The Tricuspid Valve and Its Function
The tricuspid valve is one of four valves within the heart, serving as a one-way gate between the heart’s right upper chamber, the right atrium, and the right lower chamber, the right ventricle. This valve features three flaps of tissue, referred to as leaflets or cusps. With each heartbeat, these leaflets open to allow deoxygenated blood to flow from the right atrium into the right ventricle. They then close tightly to prevent blood from flowing backward into the atrium when the ventricle contracts. This ensures efficient blood movement towards the lungs to pick up oxygen.
Pinpointing the Sound Location
When the tricuspid valve does not close properly, the backward blood flow creates a heart murmur. This murmur is often heard most clearly at a specific chest location. Healthcare professionals typically listen along the lower left side of the breastbone, known as the lower left sternal border. The sound is commonly identified around the fourth or fifth intercostal space, corresponding to the tricuspid valve’s anatomical position.
Listening for this murmur involves using a stethoscope. Placing it over the lower left sternal border allows the clinician to detect the characteristic whooshing sound caused by turbulent blood flow through the leaky valve. The intensity and characteristics of the sound at this location provide clues about tricuspid regurgitation. Its localization helps distinguish it from other heart sounds.
Characteristics of the Murmur
The tricuspid regurgitation murmur is typically holosystolic, meaning it occurs throughout ventricular contraction. It often presents as a high-pitched, blowing sound. The murmur’s intensity commonly increases with inspiration.
This phenomenon, where the murmur becomes louder during inhalation, is known as Carvallo’s sign. It involves increased venous return to the right side of the heart during inspiration. As more blood flows into the right atrium and ventricle, the amount that leaks backward through the incompetent tricuspid valve also increases, intensifying the murmur. This helps differentiate tricuspid regurgitation murmurs from those originating from the left side of the heart, which do not typically increase with inspiration.
Confirming the Diagnosis
While a heart murmur at the lower left sternal border indicates tricuspid regurgitation, a definitive diagnosis requires further evaluation. Echocardiography is the primary diagnostic tool to confirm tricuspid regurgitation and assess its severity. This imaging technique uses sound waves to create detailed pictures of the heart in motion.
Echocardiography allows providers to visualize the tricuspid valve’s structure and function, observe blood flow, and precisely measure backward leakage. It can reveal valve leaflet abnormalities, assess heart chamber size, and determine heart pressure. This helps classify tricuspid regurgitation severity.