†Patient's consent obtained to publish clinical information, images and video.
A 27 yr old male† presented with worsening dyspnoea and palpitations to the department of Cardiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India, in March 2016. Echocardiography revealed a 2.0 cm × 2.0 cm-sized rounded ball thrombus moving inside the left atrium like a ricocheting ball ([Figure 1] & Video 1, Video 2). Whenever the ball thrombus was coming in contact with the mitral valve, it was being pushed towards the posterolateral wall of the left atrium by motion of the pliable mitral leaflets during systole. It was again bouncing back towards the mitral valve during diastole and then momentarily obstructing the mitral orifice and then again repeating the same cycle (Video 1 & Video 2). A diagnosis of 'severe mitral stenosis with ball thrombus' was made. He was treated with urgent mitral valve replacement and the ball thrombus was removed. Histopathological examination of the ball thrombus showed characteristic 'Lines of Zahn' (laminations of alternating layers of red blood cells and platelet mixed with fibrin), confirming it as thrombus [Figure 2]. At two years of follow up, the patient was doing well with normal prosthetic valve function without any further thrombus formation.
Figure 1: (A & B) Transthoracic echocardiogram in apical four-chamber and in parasternal long-axis views demonstrating free floating ‘left atrial ball thrombus’ (pointed arrow) and ‘mitral stenosis’ (block arrow).