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BACKGROUND Conventional activation mapping is difficult without inducible, stable ventricular tachycardia (VT). METHODS AND RESULTS We evaluated 16 patients with drug refractory, unimorphic, unmappable VT. Nine patients had ischemic and 7 had nonischemic cardiomyopathy. All patients had implantable defibrillators and had experienced 6 to 55 VT episodes(More)
OBJECTIVES This study sought to characterize the electrocardiographic patterns predictive of left ventricular sites of origin of repetitive monomorphic ventricular tachycardia (RMVT). BACKGROUND RMVT typically arises from the right ventricular outflow tract (RVOT) in patients without structural heart disease. The incidence of left ventricular sites of(More)
Magnetic resonance imaging (MRI) generates potent electromagnetic forces in the form of a static, gradient, or pulsed radiofrequency magnetic field that can result in pacemaker malfunction. This report documents a case of rapid cardiac pacing during MRI in a patient with a dual chamber pacemaker. Although the mechanism of rapid cardiac pacing is unclear, it(More)
OBJECTIVES We sought to 1) correlate conduction block in the isthmus of the right atrium between the inferior vena cava and the tricuspid annulus with the efficacy of catheter ablation of type I atrial flutter, and 2) characterize the effects of ablative lesions on the properties of isthmus conduction. BACKGROUND There are few data on the mechanism of(More)
OBJECTIVES This study sought to document postoperative complications attributable to nonthoracotomy defibrillation lead systems in a large cohort. BACKGROUND The incidence of postoperative complications specifically associated with nonthoracotomy defibrillation lead systems is unknown. METHODS Postoperative lead-related complications were evaluated in(More)
Surface electrocardiographic criteria may be inadequate to distinguish some cases of atrioventricular (AV) nodal reentrant supraventricular tachycardia (SVT) from those with orthodromic SVT incorporating a posterior septal bypass tract (orthodromic SVT) because of similarities in P-wave morphology and timing during SVT. Invasive electrophysiologic studies(More)
Transient entrainment was demonstrated during 59 pacing events in 18 episodes of sustained uniform ventricular tachycardia (VT) while recording electrograms from the site of origin of tachycardia (LE-SOO). During entrainment, the morphology of the initial component of the LE-SOO was identical to the morphology observed during the tachycardia in 13 VTs(More)
The incidence and significance of fusion of the QRS complex during resetting of sustained ventricular tachycardias (VTs) was determined in 53 VTs induced by programmed stimulation in 46 patients with prior myocardial infarction. All 53 VTs were reset with one or two extrastimuli delivered at the right ventricular apex (RVA); 29 (54.7%) demonstrated fusion(More)
To determine the relation between the intraoperative defibrillation threshold and successful postoperative termination of induced ventricular fibrillation (VF) with the automatic implantable cardioverter defibrillator (AICD), 33 patients who underwent AICD implantation were studied. The defibrillation threshold, determined after at least 10 seconds of VF,(More)
Uniform success for ablation of focal atrial tachycardias has been difficult to achieve using standard catheter mapping and ablation techniques. In addition, our understanding of the complex relationship between atrial anatomy, electrophysiology, and surface ECG P wave morphology remains primitive. The magnetic electroanatomical mapping and display system(More)