Faculty Bibliography

BACKGROUND:Case reports have described the coexistence of ventricular tachycardia (VT) and supraventricular tachycardia in the same patient. This study examines the frequency of dual atrioventricular nodal (AVN) physiology, AVN echo beats, and atrioventricular nodal reentrant tachycardia (AVNRT) in patients with VT. METHODS:Programmed atrial and ventricular stimulation was performed in 132 consecutive patients referred for electrophysiologic study of symptomatic VT. Of the 132, 99 patients had structural heart disease, and 33 patients had idiopathic ventricular tachycardia (IVT). RESULTS:Among the 33 patients with IVT, 23 had dual AVN physiology. Compared with patients with structural heart disease undergoing VT ablation, dual AVN pathways (70% vs 27%, P < .0001), dual AVN pathways with echo beats (24% vs 8%, P = 0.03), and AVNRT (21% vs 1%, P = .0002) were more common in patients with IVT. CONCLUSION/CONCLUSIONS:Dual AVN physiology and AVNRT appear to be associated with IVT. This finding suggests that patients with IVT should undergo a complete electrophysiologic evaluation, and the diagnosis of coexistent AVNRT should be considered in this population.

OBJECTIVE:Various approaches to pulmonary vein (PV) isolation have shown variable efficacy in patients with paroxysmal atrial fibrillation (AF). The purpose of this study is to report the efficacy and safety of routine isolation of all PVs using an endpoint of bi-directional electrical block. MATERIALS AND METHODS/METHODS:This study included 85 consecutive patients who underwent PV isolation for symptomatic paroxysmal AF. Complete isolation of all PVs was confirmed by demonstration of bi-directional block: (a) loss of all PV potentials, and (b) failure to capture the left atrium by pacing 10-14 bipolar pairs of electrodes on a circumferential catheter placed at the entrance of the PV at 10 mA with 2 ms pulse width. Induction of AF by burst pacing was attempted after PV isolation. RESULTS:Freedom from symptomatic or asymptomatic AF (detected by event recorder or Holter monitor) was present in 85% and 76% of patients at 6 and 12 months. Additional mitral isthmus or posterior left atrial lines were performed in seven patients with inducible atrial arrhythmias after PV isolation. Atrial tachycardia occurred in three of these patients during long-term follow-up and in two of the 78 patients without additional ablation. CONCLUSION/CONCLUSIONS:The use of bi-directional block circumferentially across all PV ostia as an electrophysiological endpoint may improve results of PV isolation for paroxysmal AF. Avoidance of routine additional left atrial ablation lines may decrease the risk of atrial tachycardia and esophageal fistula.

Implantable cardioverter-defibrillator (ICD) shocks diminish patients' quality of life, increase health care resource utilization, and may lead to other adverse sequelae. Better understanding of the factors that lead to ICD therapies, and better strategies to avoid unnecessary therapies, are needed to optimize patient outcomes. Data from major randomized clinical trials involving the use of ICDs and cardiac resynchronization therapy-defibrillator devices were reviewed to determine control group mortality rates, control group sudden death rates, and the frequency of appropriate and inappropriate ICD therapies. In all studies that classified deaths, appropriate ICD therapies outnumbered control group sudden cardiac deaths by a factor of 2 to 3. Some of these episodes can be explained by device programming, by the treatment of potentially unsustained tachycardias, and by errors of episode classification. Another underexplored possibility is that device therapy is proarrhythmic. Reasons for frequent therapies and methods to prevent them are discussed, as well as the notion of device proarrhythmia and the potentially detrimental effects of ICD shocks. These issues clearly affect the overall benefit of device therapy and have important implications for patient management and health care delivery.

OBJECTIVE:The purpose of this study was to evaluate a novel disposable lead-free radiation protection drape for decreasing radiation scatter during electrophysiology procedures. BACKGROUND:In recent years, there has been an exponential increase in the number of electrophysiology (EP) procedures exposing patients, operators and laboratory staff to higher radiation doses. METHODS:The RADPAD was positioned slightly lateral to the incision site for pectoral device implants and superior to the femoral vein during electrophysiology studies. Each patient served as their own control and dosimetric measurements were obtained at the examiner's elbow and hand. Radiation badge readings for the operator were obtained three months prior to RADPAD use and three months after introduction. RESULTS:Radiation dosimetry was obtained in twenty patients: 7 electrophysiology studies, 6 pacemakers, 5 catheter ablations, and 2 implantable cardioverter-defibrillators. Eleven women and nine men with a mean age of 63 +/- 4 years had an average fluoroscopy time of 2.5 +/- 0.42 minutes per case. Mean dosimetric measurements at the hand were reduced from 141.38 +/- 24.67 to 48.63 +/- 9.02 milliroentgen (mR) per hour using the protective drape (63% reduction; p < 0.0001). Measurements at the elbow were reduced from 78.78 +/- 7.95 mR per hour to 34.50 +/- 4.18 mR per hour using the drape (55% reduction; p < 0.0001). Badge readings for three months prior to drape introduction averaged 2.45 mR per procedure versus 1.54 mR per procedure for 3 months post-initiation (37% reduction). CONCLUSION/CONCLUSIONS:The use of a novel radiation protection surgical drape can significantly reduce scatter radiation exposure to staff and operators during a variety of EP procedures.

The case of an 87-year-old woman with a significant history of coronary artery disease illustrates the challenge associated with intractable ventricular tachycardias, and demonstrates the various options available for terminating and controlling the potentially fatal arrhythmia. A favorable outcome was obtained using advanced cardiac life support guidelines, current pharmacological regimens, ventricular burst pacing with overdrive suppression, intra-aortic balloon counterpulsation, coronary revascularization and implantable cardioverter-defibrillator insertion. These modalities, as well as other therapeutic alternatives, are discussed in the management of incessant ventricular tachycardia