Yong-Giun Kim1, Gi-Byoung Nam2, Min Soo Cho3, Gyung-Min Park1, Minsu Kim4, Ji Hyun Lee5, Ki Won Hwang6, Jun Kim3, Kee-Joon Choi3, You-Ho Kim3. 1. Division of Cardiology, Department of Internal Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, South Korea. 2. Division of Cardiology, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea. Electronic address: gbnam@amc.seoul.kr. 3. Division of Cardiology, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea. 4. Division of Cardiology, Department of Internal Medicine, Chungnam National University Hospital, Chungnam National University School of Medicine, Daejeon, South Korea. 5. Division of Cardiology, Cardiovascular Center, Seoul National University Bundang Hospital, Seongnam, South Korea. 6. Division of Cardiology, Pusan National University Yangsan Hospital, Pusan National University of Medicine, Yangsan, South Korea.
Abstract
BACKGROUND: Fasciculoventricular (FV) bypass tracts (BTs) are the rarest form of ventricular preexcitation. Although they are not involved in clinically significant reentrant tachycardia, they may cause diagnostic and therapeutic confusion if not properly understood. This study aimed to assess the impact of FV BTs on the diagnosis and treatment of concomitant arrhythmias and cardiac diseases. METHODS: Twenty-two patients with FV BTs who underwent electrophysiologic (EP) study were evaluated. The prevalence of concomitant arrhythmias and cardiac diseases in FV BTs was evaluated. The mechanisms of concomitant arrhythmias were determined by EP study and cardiac diseases were diagnosed by echocardiography. RESULTS: One patient had FV BT with complete infra-Hisian atrioventricular (AV) block that mimicked a slow ventricular escape rhythm. Two patients had FV BT with atrial fibrillation or atrial flutter, which was misinterpreted as AV BT requiring emergency DC cardioversion. Eight patients had accompanying AV BTs. In 2 patients with AV BTs, unnecessary RF application was delivered after successful ablation of AV BT because conduction through a FV BT was mistaken for conduction through a residual AV BT. Five patients had no concomitant arrhythmia; however, two of them had hypertrophic cardiomyopathy with symptoms requiring beta-blocker. Patients had not been prescribed beta-blockers to avoid a proarrhythmic response before the EP study because the FV BTs mimicked AV BTs. CONCLUSION: FV BTs were frequently accompanied by AV BTs or other arrhythmias and cardiac diseases. They may cause misdiagnosis and inappropriate therapy and even unnecessary RF delivery when misinterpreted as AV BTs.
BACKGROUND:Fasciculoventricular (FV) bypass tracts (BTs) are the rarest form of ventricular preexcitation. Although they are not involved in clinically significant reentrant tachycardia, they may cause diagnostic and therapeutic confusion if not properly understood. This study aimed to assess the impact of FV BTs on the diagnosis and treatment of concomitant arrhythmias and cardiac diseases. METHODS: Twenty-two patients with FV BTs who underwent electrophysiologic (EP) study were evaluated. The prevalence of concomitant arrhythmias and cardiac diseases in FV BTs was evaluated. The mechanisms of concomitant arrhythmias were determined by EP study and cardiac diseases were diagnosed by echocardiography. RESULTS: One patient had FV BT with complete infra-Hisian atrioventricular (AV) block that mimicked a slow ventricular escape rhythm. Two patients had FV BT with atrial fibrillation or atrial flutter, which was misinterpreted as AV BT requiring emergency DC cardioversion. Eight patients had accompanying AV BTs. In 2 patients with AV BTs, unnecessary RF application was delivered after successful ablation of AV BT because conduction through a FV BT was mistaken for conduction through a residual AV BT. Five patients had no concomitant arrhythmia; however, two of them had hypertrophic cardiomyopathy with symptoms requiring beta-blocker. Patients had not been prescribed beta-blockers to avoid a proarrhythmic response before the EP study because the FV BTs mimicked AV BTs. CONCLUSION: FV BTs were frequently accompanied by AV BTs or other arrhythmias and cardiac diseases. They may cause misdiagnosis and inappropriate therapy and even unnecessary RF delivery when misinterpreted as AV BTs.