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Background Implantable cardioverter-defibrillators (ICDs) reduce mortality in patients at risk for sudden cardiac death. However, clinical trials report higher rates of appropriate ICD therapies in implanted patients than untreated patient mortality rates would predict. Objective This study sought to describe a newly recognized form of ventricular proarrhythmia related to the mechanical presence of the ICD. Methods Four ICD patients were referred for management of recurrent ventricular tachycardia (VT) refractory to medications and catheter ablation. All were treated with lead extraction and followed prospectively for arrhythmia recurrence. Results Two patients received ICDs for primary prevention because of a family history of sudden death and nonischemic cardiomyopathy, respectively. Episodes of VT with ICD therapies began 2 months and 1 year after implantation, and continued for 3 months and 5 years, respectively, until referral. Two secondary prevention ICD patients with ischemic cardiomyopathy developed incessant VT within 1 day and 3 days after implantation with multiple ICD shocks. VT was not suppressed by antiarrhythmic drugs, and catheter ablation failed in 2 patients. In all patients, spontaneous VT's had a QRS morphology similar to the paced morphology from the ICD leads, raising suspicion of lead-related proarrhythmia. After lead extraction, primary prevention ICD patients remained free of VT during follow-up periods of 17 and 21 months, and VT storm was controlled in the secondary prevention patients. Conclusions ICD leads can cause uncontrollable VT until the lead is extracted, suggesting a mechanical effect. In contrast to transient ectopy that occurs early after implantation, this proarrhythmia can be chronic. Recognition is important because lead extraction is curative and can prevent unnecessary ICD shocks, antiarrhythmic medications, and catheter ablation.

INTRODUCTION Radiofrequency (RF) ablation of the cavotricuspid isthmus (CTI) can be performed using different types of ablation catheter. Gold tip electrodes have the theoretical advantage of creating bigger lesions than standard platinum-iridium electrode. This prospective, randomized study compares the clinical efficacy of 8-mm gold tip catheter, externally irrigated and 8-mm platinum-iridium tip (Pt tip) catheters. METHODS AND RESULTS Sixty consecutive patients (51 men, 60 +/- 10 years) undergoing de novo CTI ablation for documented typical atrial flutter were randomized to one of the following ablation catheters: 8-mm gold tip catheter, an externally irrigated-tip (Irr. tip) catheter, or an 8-mm Pt tip catheter. The procedural endpoint was achievement of bidirectional isthmus conduction block with < or = 20 minutes of RF energy application. The latter was achieved equally with the 3 catheters (95% for gold tip, 100% for irrigated tip, 95% for Pt tip) and the durations of RF (10 +/- 6, 10 +/- 4, 13 +/- 8 minutes), fluoroscopy (12 +/- 6, 12 +/- 7, 15 +/- 12 minutes) and the procedure (34 +/- 23, 38 +/- 24, 40 +/- 30 minutes) were similar in all groups. The maximal targeted power could not be reached in at least one location in 40% of patients with gold tip and in 35% of patients with Pt tip catheters whereas it was always achieved with an Irr. tip catheter (P = 0.003, P = 0.008). The reduction in impedance during RF delivery was greater with Irr. tip (11 +/- 7 ohms) than with gold (7 +/- 4 ohms, P = 0.02) or Pt tip (5 +/- 3 ohms, P = 0.001) catheters. CONCLUSION This study demonstrates equivalent efficacies of gold, platinum-iridium and externally Irr. tip catheters for successful de novo ablation of the CTI.

Echocardiography is an essential tool in the evaluation of patients with cardiac emergencies and chest trauma. The objective of our study was to establish the feasibility and diagnostic accuracy of a portable satellite transmission system in the assessment of cardiac emergencies for the real-time support of mass casualty and humanitarian relief efforts. Twelve patients with various degrees of cardiac structural disease identified by conventional inhospital transthoracic echocardiography were transported to a remote portable field hospital where transthoracic echocardiography was performed with a handheld echocardiographic device. Images were then relayed by a commercial satellite to a level III trauma center where they were interpreted in real time by a cardiologist. Remote studies were recorded at the field hospital before satellite transmission and again on download at the receiving facility. The remotely acquired studies before and after satellite transmission were compared with each other and subsequently compared with conventional hospital transthoracic echocardiograms for technical quality and diagnostic accuracy using a blinded, single-reader, side-by-side comparison. Excellent agreement was found between the recorded field-site and satellite-transmitted images with an overall average of 95% concordance. When the field data acquired with the handheld device and satellite transmission were compared with conventional inhospital echocardiography, a high degree of agreement was demonstrated in overall technical quality (83%) and assessments of left ventricular ejection fraction (100%), pericardial effusion (100%), and left ventricular size (92%). This study demonstrates the feasibility and diagnostic accuracy of remote, real-time echocardiography using satellite transmission for mass casualty triage or humanitarian relief efforts.

The most common cardiac injuries in the United States are blunt trauma from motor vehicle accidents or low-velocity trauma from stabbings. During military conflict, high-velocity injuries, including gunshot wounds (GSW) and fragment injury from improvised explosive devices (IED), are relatively more common.This is a retrospective review of cases with high-velocity penetrating injury and suspected myocardial involvement during a 6-month period in Baghdad, Iraq, at a United States Army hospital during Operation Iraqi Freedom.Eleven cases survived to admission (GSW in 5, IED in 6). The mean age of the all-male cohort was 27 years (range, 3-54 years). Eight of the 11 patients (73%) were victims of polytrauma. The entrance involved the right ventricle (n = 3), right atrium (n = 2), left ventricle (n = 1), or mediastinum and pericardial reflections (n = 5). Echocardiography was performed in all 11 patients. In 7 patients, no foreign body was identifiable, and in 2 patients the foreign body was identified within the pericardial fat pad. Three patients were identified as having a suspected ventricular septal defect, ranging in size from 2 to 8 mm. The most common electrocardiographic abnormality was atrioventricular block and right bundle branch block. In 4 patients, the management of the chest injury was nonsurgical, and in 1 patient the treatment was a chest tube only. Four of the patients underwent median sternotomy, 1 underwent emergent lateral thoracotomy, and 1 underwent an infradiaphragmatic approach.This case series is too small to draw definitive conclusions; however, a multidisciplinary approach to high-velocity injuries with potential for cardiac involvement augments preoperative assessment for myocardial injury and may allow selective nonoperative management.