@article {Raouf1472, author = {Wessam A Raouf and Khaled Shams and Amr Mansour}, title = {An unusual cause of tachyarrhythmia in an otherwise healthy young man}, volume = {103}, number = {18}, pages = {1472--1472}, year = {2017}, doi = {10.1136/heartjnl-2017-311485}, publisher = {BMJ Publishing Group Ltd}, abstract = {Clinical introduction A 32-year-old man referred to the cardiology clinic for palpitations was found to have paroxysmal supraventricular tachycardia (SVT) on 24-hour Holter monitoring. His~general and cardiac examinations were unremarkable. A transthoracic echocardiographic study to exclude structural heart disease was performed and showed an abnormal structure in relation to the right ventricular (RV) free wall; however, poor echocardiographic windows precluded proper characterisation. Cardiac MR~(CMR) was therefore performed. Cine images (figure 1 and online~supplementary~videos 1 and 2) demonstrated the abnormal structure. Dynamic pass of contrast (rest perfusion module) showed the sequence of intracavitary enhancement across different cardiac chambers in the horizontal long-axis plane (figure 1 and online~supplementary~video 3).Figure 1 Still frames from balanced steady state free precession images in the horizontal long-axis plane (A,B). Still frames from the dynamic pass of contrast in the horizontal long-axis and the short axis following contrast injection into the right arm (C,D). Images in the horizontal long-axis plane at the basal level using T2-weighted short-tau inversion recovery (E) and half Fourier single-shot turbo spin echo (F).Supplementary MaterialSupplementary data [cine_shax-ed.mp4] Supplementary MaterialSupplementary data [contrast.avi] Supplementary MaterialSupplementary data [4_chamber.avi] Question The abnormal structure is most likely which of the following?Pericardial cystRight atrial appendage aneurysmRight ventricular aneurysmJuxtaposed left atrial appendageAccessory right ventricular chamberQuestion}, issn = {1355-6037}, URL = {https://heart.bmj.com/content/103/18/1472}, eprint = {https://heart.bmj.com/content/103/18/1472.full.pdf}, journal = {Heart} }