Effects of Cardiac Resynchronization Therapy on the Arrhythmic Substrate in a Patient with Long QT and Torsades de pointes

• Published in: Journal of Arrhythmia Vol. 27; no. 4; pp. 332 - 337
• Main Authors: Masayasu Ikutomi, Masashiro Matsusita, Hiroyuki Arashi, Yuji Watari, Goro Endo, Jun-ichi Yamaguchi, Masao Yamasaki, Satoshi Ohnishi
• Format: Journal Article
• Language: Japanese
• Published: Japanese Heart Rhythm Society 2011
• ISSN: 1880-4276

We describe a patient with torsades de pointes (TdP) who was implanted with cardiac resynchronization therapy defibrillator (CRT-D). At the time of CRT-D implantation, left ventricular (LV) epicardial pacing exacerbated TdPs and developed into electrical storm, which was triggered even by biventricular pacing. We needed to inactivate the LV lead for 2 weeks. At the next device check testing of LV pacing still induced TdPs, whereas biventricular pacing did not. After starting the continuous biventricular pacing no ventricular arrhythmias happened, and furthermore the QT intervals prolonged by LV pacing were obviously shortened only after 2 weeks as ventricular systolic function recovered. Then even continuous LV alone pacing induced no TdP. These findings indicate novel electrical effects of cardiac resynchronization therapy. [Introduction] Cardiac resynchronization therapy (CRT) is an established therapy in selected symptomatic patients with systolic heart failure, improving symptoms and reducing mortality1,2). It is controversial at to whether CRT also reduces ventricular tachyarrhythmias3-5). The antiarrhythmic effects of CRT are reported in several small studies6,7) and are logically attributed to reverse anatomical remodelling8), with concomitant decrease in myocardial wall tension and neurohormonal activation9).