Phasic ejection click

Phasic ejection click

Phasic ejection click is the click in pulmonary stenosis when the stiff valve opens, it varies with respiration and is better heard in expiration. It is the only right sided event which is better heard in expiration.

Phasic ejection click is usually associated with post stenotic dilatation of pulmonary artery. In contrast to the phasic pulmonary ejection click, the pulmonary vascular ejection clicks heard in other situations in which the pulmonary artery is dilated, does not vary significantly with respiration. Aortic ejection click is also non phasic with little variation with respiration [1].

Mechanism of phasic ejection click: During inspiration the systemic venous return increases and enhances the right ventricular filling. This elevates the right ventricular end diastolic pressure causing a cephalad excursion of the pulmonary valve at the end of diastole. Hence the opening movement during systole is less as the valve is already partially domed at the end of diastole.

In expiration the right ventricular end diastolic pressures are lower and presystolic doming of pulmonary valve does not occur. Hence the systolic excursion of pulmonary valve is more in systole and produces a prominent click. The click is nearer to first heart sound in inspiration, apparently fusing with it and moves away from the first heart sound in expiration.

Phasic ejection clicks arising from the dilated aorta can be heard in Tetralogy of Fallot. Just like the phasic ejection click of valvar pulmonary stenosis, it is better heard in expiration. Phasic ejection click in Tetralogy of Fallot can be heard best in the second right intercostal space (aortic area), though it may be heard in pulmonary area (second left intercostal space) and at the apex. In Tetralogy of Fallot there is no pulmonary ejection click as the pulmonary stenosis is infundibular in location [2].

References

1. William R. Jacobs. Chapter 28. Ejection Clicks. In Walker HK, Hall WD, Hurst JW, editors. Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition. Boston: Butterworths; 1990.
2. Satpathy M, Mishra BR. Clinical Diagnosis of Congenital Heart Disease. New Delhi, India: Jaypee Brothers Medical Publishers Pvt. Ltd; 2008. p 262.