The auscultation of second heart sound reveals presence of the disease and its pathophysiology, conduction defects, ventricular function, and hemodynamics around the aortic and pulmonary valves. To understand the splitting of the second heart sound, it is useful to understand the concepts of hangout interval and ejection time. Differential diagnosis of S2 split include opening snap, third heart sound, and pericardial knock. Variations of second heart sound may involve intensity or variations of split. Variations of split can be single heart sound, wide split, wide fixed split, or paradoxical splitting.Interpretation of second heart sound in congenital heart disease provides information about the presence and position of semilunar valves.

Stent under expansion is one of the reasons compromising the outcomes of percutaneous coronary interventions. The most common cause of the stent under expansion is calcium deposited in the atherosclerotic plaque. Adequate plaque modification is the paramount before the placement of a stent, as the options to handle under expanded stent are limited and less effective. In this case report, we explore the usage of knuckle wire for the extrastent plaque modification, after being failed with routine methods of handling stent under expansion.