From the Guidelines
Blowing, holosystolic heart murmurs are primarily caused by conditions such as mitral regurgitation, tricuspid regurgitation, and ventricular septal defects, which allow blood to flow between cardiac chambers throughout systole, as noted in the most recent guidelines 1.
Causes of Holosystolic Murmurs
The main causes of these murmurs include:
- Mitral regurgitation, where the mitral valve fails to close properly, allowing blood to leak backward from the left ventricle into the left atrium during systole 1
- Tricuspid regurgitation, which involves a similar mechanism but affects the tricuspid valve between the right atrium and ventricle 1
- Ventricular septal defects, which create abnormal openings in the wall separating the ventricles, allowing blood to shunt from the higher-pressure left ventricle to the lower-pressure right ventricle throughout systole 1 These murmurs are characterized as "blowing" due to their auditory quality and "holosystolic" because they span the entire systolic period, beginning with the first heart sound (S1) and continuing through the second heart sound (S2).
Differentiation and Symptoms
The intensity and radiation pattern of these murmurs can help differentiate between causes:
- Mitral regurgitation typically radiates to the axilla
- Tricuspid regurgitation increases with inspiration
- Ventricular septal defects often radiate to the right sternal border Associated symptoms depend on the severity of the underlying condition and may include fatigue, shortness of breath, reduced exercise tolerance, and in advanced cases, signs of heart failure, as discussed in the context of congenital heart disease in adults 1.
From the Research
Causes of Blowing, Holosystolic Heart Murmurs
- Tricuspid regurgitation (TR) is a common cause of blowing, holosystolic heart murmurs, and it can be associated with poor outcome and predicts poor survival, heart failure, and reduced functional capacity 2.
- TR can be caused by various factors, including:
- Prosthetic valve dysfunction
- Left heart disease
- Right ventricular (RV) dysfunction and dilation
- Persistent pulmonary hypertension
- Chronic atrial fibrillation
- Organic (mainly rheumatic) tricuspid valve disease 2
- Ischemic mitral regurgitation can also lead to TR, which may be a direct consequence of right-sided ischemic disease 3.
- The severity of TR can be accompanied by larger tricuspid valve diameter, greater leaflet tethering, worse right ventricular function, and higher right ventricular pressure 3.
- Mitral valve disease can also contribute to the development of TR, and the incidence of TR is higher in patients with rheumatic mitral valve disease than in those with degenerative mitral regurgitation 2.
- TR can appear many years after mitral valve surgery and may not resolve after correcting the mitral valve lesion 2.