Fluoroless Catheter Ablation of Cardiac Arrhythmias: A 5-Year Experience.

BACKGROUND: Catheter ablations have been traditionally performed with the use of fluoroscopic guidance, which exposes the patient and staff to the inherent risks of radiation. We have developed techniques to eliminate the use of fluoroscopy during cardiac ablations and have been performing completely fluoroless catheter ablations on our patients for over 5 years. METHODS: We present a retrospective analysis of the safety, efficacy, and feasibility data from 500 consecutive patients who underwent nonfluoroscopic catheter ablation, targeting a total of 639 arrhythmias, including atrioventricular reciprocating tachycardia (AVRT), atrioventricular nodal reentrant tachycardia (AVNRT), atrial tachycardia (AT), atrial fibrillation (AF), premature ventricular contractions (PVCs), and ventricular tachycardia (VT). We perform fluoroless ablations using intracardiac electrograms, electroanatomic mapping, and for most cases intracardiac echocardiography. Our experience includes exclusively endocardial cardiac ablations. RESULTS: The mean follow-up was 20.5 months. Recurrence rate for AVRT was 6.5%, for AVNRT 2.5%, for macro-reentrant AT 6.4%, for focal AT 5.4%, for AF 22.6%, for PVC 6.7%, and for VT 21.4%. Major complications occurred in five patients (1.0%); minor complications occurred in three patients (0.6%). No deaths occurred. Fluoroscopy was used in one instance, for 0.3 minutes, to confirm venous access. CONCLUSIONS: Completely fluoroless catheter ablations may be routinely performed for all endocardial ablations without compromising safety, efficacy, or procedural duration.

Time-limited cryomapping during tachycardia: improved long-term outcomes for cryoablation of AVNRT.

PURPOSE: Cryothermal ablation (CTA) for atrioventricular nodal reentrant tachycardia (AVNRT) is considered safer than radiofrequency ablation (RFA) since it eliminates the risk of inadvertent AV block. However, it has not been widely adopted due to high late recurrence rate (LRR). In an effort to improve LRR, we evaluated a new approach to cryothermal mapping (CTM): "time to tachycardia termination" (TTT). METHODS: This single-center study had 88 consecutive patients who underwent CTA using TTT for AVNRT. The CTA catheter was positioned in sinus rhythm at the posteroseptal tricuspid annulus, and then AVNRT was induced. The CTA target site was identified by prompt tachycardia termination in ≤20 s during CTM. Procedural success was defined as no inducible AVNRT and ≤1 single AV nodal echoes. RESULTS: Acute procedural success was achieved in 87 of 88 patients (98.9 %) and was similar to prior studies for both CTA and RFA. No permanent AV block was observed. LRR was 3.7 % at a mean follow-up of 19.7 months. LRR was equivalent to that commonly reported for RFA and improved when compared to conventional CTA. CONCLUSION: TTT for CTA of AVNRT provides enhanced safety and similar long-term efficacy when compared to RFA. Based upon this experience, TTT provides an enhancement to conventional CTA that appears to result in improved long-term outcomes. In light of these findings, it seems reasonable to undertake additional randomized trials to determine whether RFA or CTA using TTT is the optimal approach for the catheter ablation of AVNRT.

Nonfluoroscopic catheter ablation of cardiac arrhythmias in adults: feasibility, safety, and efficacy.

BACKGROUND: Catheter ablations are traditionally performed using fluoroscopic guidance, exposing both patients and medical staff to the risks of radiation. Nonfluoroscopic catheter ablation has been used successfully to treat limited types of arrhythmias in children, but whether this approach has broad application in adults is uncertain. The purpose of this study was to evaluate the feasibility, safety, and efficacy of fluoroless catheter ablation in adults being treated for a range of arrhythmias. METHODS AND RESULTS: Retrospective analysis was performed in 2 patient groups (both n = 60): (1) the nonfluoroscopy (NF) group consisting of consecutive adult patients, in which catheter positioning was accomplished exclusively with intracardiac electrograms (IE), electroanatomic mapping (EAM), and intracardiac echocardiography (ICE); and (2) the fluoroscopy (F) group, in which catheter positioning was additionally guided by fluoroscopy. The patients in the F group were selected to match the types of arrhythmias in the NF group. All ablation procedures were performed by one operator. The total procedure time did not differ between groups for any specific type of arrhythmia ablated. Acute procedural success was similar in both groups (NF, 59/60 [98%] and F, 60/60 [100%]). The complications were limited to a groin pseudoaneurysm in the NF group, and pericardial effusion and groin hematoma in the F group. CONCLUSION: Catheter ablations were efficiently and effectively performed in adults with a variety of arrhythmias using only IE, EAM, and ICE for catheter guidance. This nonfluoroscopic technique was feasible, posed no additional safety concerns, and should be readily implementable in most electrophysiology laboratories.

Observations on the safety and effectiveness of dofetilide in patients with paroxysmal atrial fibrillation and normal left ventricular function.

Dofetilide is currently recommended as second-tier therapy to maintain sinus rhythm in patients with paroxysmal atrial fibrillation (PAF) and normal left ventricular function, yet limited data support this recommendation. We examined the safety and efficacy of dofetilide in this setting through a retrospective chart review. We evaluated patients who had symptomatic PAF, normal left ventricular function, and no significant valvular disease. The end points were complete suppression of symptomatic PAF and subjective symptomatic improvement with dofetilide treatment. Over a 3-year period, 34 patients who had failed previous antiarrhythmic therapy were included. Of these, 3 discontinued dofetilide treatment before discharge. Of the remaining 31 who continued treatment after discharge, it was eventually discontinued in 13. At 12 months, symptomatic improvement was observed in 18 of 31 patients, 6 of whom remained asymptomatic. Treatment with dofetilide in this study was successful in less than 1 in 5 patients. Despite careful precautions, serious proarrhythmias, the major limiting side effect of dofetilide, still occurred during long-term follow-up.

Ventricular tachycardia induced by biventricular pacing in patient with severe ischemic cardiomyopathy.

INTRODUCTION: Cardiac resynchronization therapy (CRT) is a new alternative which affords symptomatic improvement in two-thirds of patients who exhibit medically refractory congestive heart failure (CHF) as well as significant prolongation of the QRS duration (>135 msec). As more experience with CRT accrues, unexpected complications of this promising therapy may become apparent. Herein, we describe a patient with severe ischemic cardiomyopathy and refractory CHF who developed incessant ventricular tachycardia (VT) after the initiation of biventricular pacing. The patient is a 75-year-old man who suffered an inferior myocardial infarction 6 years before presenting for CRT. He underwent a three-vessel CABG in 1997. Subsequently, episodes of near syncopal sustained VT developed, for which he received a dual chamber ICD. In 2001 he developed refractory CHF and ECG revealed LBBB with a QRS duration of 195 msec. Shortly after the initiation of biventricular pacing, the patient developed multiple episodes of drug resistant monomorphic VT that could be terminated only transiently by ICD therapies. Ultimately, the only intervention, which proved to be effective in eliminating VT episodes, was inactivation of LV pacing. Despite subsequent therapeutic regimen of sotalol, lidocaine, tocainide, and quinidine all subsequent attempts to reactivate LV pacing resulted in prompt VT recurrence. CONCLUSION: This case represents a clear example of CRT induced proarrhythmia, which required inactivation of LV pacing for effective acute management. Such an intervention should be considered in CRT patients who exhibit a notable increase in drug refractory VT episodes.

Brugada syndrome: an unusual cause of convulsive syncope.

A patient who presented with a new apparent seizure was found to have abnormal electrocardiographic findings, with classic features of the Brugada syndrome. He had spontaneous episodes of nonsustained ventricular tachycardia, easily inducible ventricular fibrillation at electrophysiological study in the absence of structural heart disease, and a negative neurological evaluation. These findings suggested that sustained ventricular arrhythmias known to be associated with the Brugada syndrome and resultant cerebral hypoperfusion, rather than a primary seizure disorder, were responsible for the event. Patients with the Brugada syndrome often present with sudden death or with syncope resulting from ventricular arrhythmias. In consideration of its variability in presentation sometimes mimicking other disorders, primary care physicians and internists should be aware of its often transient electrocardiographic features.