Faculty Bibliography

BACKGROUND:Radiofrequency (RF) catheter ablation has provided an effective method for treating drug-refractory symptomatic atrial fibrillation. Recently, a cryoablation balloon approach has also received approval. The purpose of this study was to compare RF catheter ablation to cryoablation for the treatment of atrial fibrillation with respect to safety, immediate efficacy, and effects on procedural and fluoroscopy times. In addition, actual procedural costs were compared. METHODS:This study was approved by the Winthrop University Hospital Institutional Review Board to retrospectively examine cryoablation with the Arctic Front Cardiac CryoAblation balloon catheter (Medtronic, Inc) and compare it to RF catheter ablation for the treatment of drug-refractory symptomatic atrial fibrillation. Patient and procedural characteristics as well as immediate success were compared. Immediate failure was defined as incomplete pulmonary vein isolation of all veins. RESULTS:A total of 124 procedures (62 RFs and 62 cryoablations) were performed from December 2010 through July 2012. The cryoablation procedure took longer to perform than RF (171 ± 61 minutes vs 126 ± 49 minutes, respectively; P<.0001). There was no difference in fluoroscopy times between the two groups (29 ± 20 minutes for RF vs 32 ± 18 minutes for cryoablation; P=.39). The infusion of protamine following procedures was much more common in the cryoablation group (30 patients vs 2 patients in the RF group; P<.0001). The immediate success rate was 93.5% with RF ablation vs 96.7% with cryoablation (P=NS). There was not a significant difference in complications between the two approaches. The cost for each procedure was $24,391.88 ± 4826.77 for RF and $31,874.02 ± 8349.70 for cryoablation (P<.0001). CONCLUSION/CONCLUSIONS:Cryoablation provides an additional and alternative approach to RF ablation for the treatment of symptomatic drug-refractory atrial fibrillation with comparable immediate success and complications. It is synergistic with RF and permits the ability to tackle the entire gamut of atrial fibrillation (ie, paroxysmal and persistent). This study showed no decrease in procedural or fluoroscopy times with our early experience. One significant limitation with cryoablation is the cost. Cryoablation resulted in over $7000 extra cost to the hospital per procedure. The clinical benefits achieved by this additional cost warrant further investigation.

A case report of a patient with a high defibrillation threshold at initial implantation that was improved by the insertion of a shocking coil in the left lateral cardiac vein is discussed.

The use of serial electrophysiology studies to guide antiarrhythmic drug therapy in patients with ventricular tachycardia is both costly and time consuming. Intravenous procainamide administered during of the initial electrophysiology study has previously been shown to be useful in predicting the efficacy of oral antiarrhythmic medications (type I and III). The purpose of this study is to confirm that ventricular tachycardia suppression after intravenous procainamide correlates with suppression on oral class III antiarrhythmic medications (amiodarone and sotalol). This study included all patients with sustained ventricular tachycardia who underwent an initial electrophysiology study including an acute suppression trial with intravenous procainamide and a subsequent restudy on oral amiodarone or sotalol. The response to intravenous procainamide was then compared with these type III antiarrhythmic medications. Between January 1993 and May 1995, 360 patients underwent electrophysiology studies for suspected or documented ventricular arrhythmias. One hundred patients (28%) had an inducible sustained ventricular tachycardia, and 26 patients received both intravenous procainamide and subsequently oral amiodarone or sotalol. Acute infusion of procainamide provided a highly specific method for predicting suppression of oral amiodarone and sotalol (82% and 100% respectively). However, several patients who were not suppressed by intravenous procainamide were suppressed by oral sotalol resulting in lower overall predictive accuracy 12/15 (80%) for amiodarone vs. 5/11 (45%) for sotalol treated group. We conclude that the acute infusion of procainamide may help to predict ventricular tachycardia suppression after oral amiodarone and sotalol. A larger prospective trial is warranted to confirm this finding

The purpose of this study was to evaluate the efficacy, safety, and tolerance of pindolol as initial therapy for vasovagal syncope. Head-up tilt table testing (HUT) was performed on 192 patients for syncope or near-syncope of unknown cause. Forty-four (23%) patients had a positive HUT for vasovagal syncope, and 28 (64%) received oral pindolol as initial therapy. Three patients were lost to follow-up; of the remaining 25 patients (mean age 60 +/- 22 years), 15 were women, 14 had syncope, and 11 had near-syncope. At 14 +/- 6 months' follow-up, 16 (64%) patients were without recurrence or side effects from pindolol. Of the 9 patients who stopped taking pindolol, 3 were switched to another regimen for recurrent symptoms, 2 stopped because of side effects, and 4 did not comply with the regimen. In conclusion, pindolol appears to be safe and effective as initial treatment for vasovagal syncope

The need for thoracotomy has previously limited the use of the implantable cardioverter-defibrillator. Prior investigators have shown the efficacy and reduced risk of the transvenous implantable cardioverter-defibrillator. In this study, we report our experience with the transvenous implantable cardioverter-defibrillator as a first-line system. Thirty-four patients with mean age 63.2 +/- 10.3 years and mean ejection fraction 32.6 +/- 11.4% underwent implantation of a transvenous cardioverter-defibrillator using an Endotak lead with or without a subcutaneous patch. Twenty-one patients received a biphasic device and the remainder a monophasic device. Thirty-three of 34 patients (97%) were successfully implanted. The mean defibrillation threshold was than < or = 15.3 +/- 3.6J. Overall, 25 of 34 (74%) patients were implanted with a single endocardial lead alone. In the group receiving a biphasic device 19 of 21 (90%) were successfully implanted with a single endocardial lead alone whereas in the group receiving a monophasic device only 6 of 12 (50%) were successfully implanted with single endocardial lead alone (p < 0.05). There were no serious complications. One postoperative death was a result of end-staged congestive heart failure. We conclude that the transvenous implantable cardioverter-defibrillator is safe and efficacious and that incorporation of biphasic waveform may lead to higher rates of implantation of single transvenous lead alone without the need for subcutaneous patch

Electromagnetic interference can cause implanted devices (pacemakers and defibrillators) to malfunction. This article reviews four cases of device interference and provides a review of the literature, and our recommendations for managing these problems

Most applications of radiofrequency (RF) catheter ablation for treatment of ventricular tachycardia (VT) have been as a treatment of last resort. The purpose of this study was to determine the efficacy and safety of RF catheter ablation as the primary treatment for symptomatic single morphology VT. Eleven of 81 patients (14%) with inducible sustained monomorphic VT underwent RF ablation as the primary treatment. One of these 11 patients had successful RF ablation of bundle branch reentry VT and was excluded from this series. The remaining 10 patients had a mean age of 58 +/- 19 years (range 20 to 73 years), were mostly men (7 of 10 patients), and all presented with documented evidence of symptomatic sustained monomorphic VT, at a mean cycle length of 340 +/- 60 milliseconds (ms) (range 250 to 430 ms). Six patients had coronary artery disease (CAD), one had surgical repair for tetralogy of Fallot, one had surgical repair of a ventricular septal defect, and two had a normal cardiac substrate. The VT origin was mapped using a combination of activation mapping, mid-diastolic potentials, pace mapping, and concealed entrainment. A mean of 5 +/- 3 (range 2 to 11) RF applications were administered to the putative VT foci. Eight of 10 (80%) clinical VTs were successfully ablated. There were no serious complications. Patients with VT originating from the left ventricle were offered implantable cardioverter-defibrillator back-up; however, only one patient accepted this option. At a mean follow-up of 12 +/- 7 months, only one patient had a possible arrhythmia recurrence