From the Research
In Tetralogy of Fallot, split heart sounds are not typically a characteristic finding, as the pulmonary component of the second heart sound is often soft or absent due to right ventricular outflow tract obstruction. The classic auscultatory finding is a harsh systolic ejection murmur heard best at the left upper sternal border, caused by blood flowing through the narrowed pulmonary outflow tract 1. Other cardiac findings include a right ventricular heave and occasionally a diastolic murmur of pulmonary regurgitation after surgical repair. The absence of split S2 occurs because the pulmonary valve closure is delayed and softened by the increased resistance to right ventricular emptying, causing it to merge with or become inaudible compared to the aortic valve closure. This contrasts with normal cardiac physiology where S2 is typically split during inspiration as right-sided events are delayed relative to left-sided events. Understanding these auscultatory findings is important for clinical assessment of patients with Tetralogy of Fallot both before and after surgical correction.
Some key points to consider in the clinical assessment of Tetralogy of Fallot include:
- The presence of a harsh systolic ejection murmur, which is a characteristic finding in TOF 2
- The absence of split S2, which is due to the delayed and softened pulmonary valve closure 3
- The presence of a right ventricular heave, which is a sign of right ventricular hypertrophy 4
- The potential for diastolic murmurs of pulmonary regurgitation after surgical repair, which can indicate residual or recurrent disease 1
It is essential to note that the management of Tetralogy of Fallot has evolved over time, and current treatment strategies aim to improve long-term survival and reduce the risk of complications such as arrhythmias and sudden death 5. However, the significance of split heart sounds in TOF remains a topic of interest, and the absence of split S2 is a key finding that can aid in the diagnosis and clinical assessment of patients with this condition.