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This study reports on predictors for successful radiofrequency (RF) ablation of idiopathic ventricular tachycardia (VT) in 48 patients--35 with right ventricular (RV) outflow tract and 13 with left ventricular VT. In RV outflow tract idiopathic VT, RF ablation was successful in 29 of 35 patients (83%). The following information allowed differentiation between patients with and without a successful RF ablation:1 induced VT morphology (O vs 3); presence of delta wave-like beginning of the QRS (2 vs 3) andor = 11 of 12 leads showing a "match" between the clinical VT and the pacemap (28 vs 1). Endocardial activation times were not different between both groups (-15 +/- 18 vs -4 +/- 5 ms). In left ventricle idiopathic VT, RF ablation was successful in 12 of 13 patients (92%). In patients who underwent successful ablation, 1 VT morphology was induced and no delta wave-like beginning of the QRS was present; a correlation between clinical VT and the pacemapor = 11 of 12 leads was found and the endocardial activation time preceded the QRS (range of -5 to -58 ms [mean -30 +/- 14]). Purkinje activity was observed in 5 of 7 patients with an idiopathic VT originating from the inferoposterior region but not from the inferoapical region of the left ventricle. Four patients (14%) with RV outflow tract idiopathic VT had recurrence during a mean follow-up of 2 to 50 months (mean 30 +/- 12). Thus, (1) in RV outflow tract idiopathic VT a good pacemap was more important than an early endocardial activation time; (2) an optimal pacemap as well as an early endocardial activation time were important predictors for successful ablation of the left ventricle idiopathic VT; (3) Purkinje activity was recorded in VTs arising in the inferoposterior region of the left ventricle; and (4) factors for unsuccessful ablation for idiopathic VT were1 induced VT morphology, a delta wave-like beginning of the QRS, and a VT/pacemap correlation11 of 12 leads. Idiopathic VT can be successfully ablated with both immediate and long-term success.

Ablation of an Anterior Fascicular Idiopathic VT. Introduction: Idiopathic ventricular tachycardia (VT) originating in or close to the anterior fascicle of the left bundle is rare. A patient with no structural heart disease and VT with a right bundle branch block configuration and right-axis deviation underwent an electrophysiologic examination. Methods and Results: Both endocardial activation mapping during VT and pacemapping were performed via a transseptal approach to localize the site of origin of the VT. Endocardial recordings of the His bundle and the posterior and anterior fascicles of the left bundle branch revealed an origin of the VT in or close to the anterior fascicle. The Purkinje potential at that site preceded the QRS complex by 20 msec, with pacemapping showing an optimal match between the paced rhythm and the clinical VT. RF energy delivered at this site terminated the VT. A left anterior nemiblock appeared after RF ablation. Ten months later, the patient is free from recurrences of VT. Conclusions: Idiopathic VT originating in or close to the anterior fascicle was cured by RF ablation. A Purkinje potential preceding the QRS during tachycardia and an optimal pacemap were used to guide RF ablation.

OBJECTIVE: To determine the features that distinguish bundle branch reentry (BBR) ventricular tachycardia from a supraventricular tachycardia with aberration on the 12 lead electrocardiogram (ECG). PATIENTS: Three patients in whom premature beats (2 cases) or sustained tachycardia (2 cases) showed a QRS configuration identical to that observed during sinus rhythm. INTERVENTIONS: Programmed electrical stimulation. RESULTS: These arrhythmias were ventricular in origin and caused by a BBR mechanism, as suggested by the following data obtained during electrophysiological study: (a) an H-V interval shorter during tachycardia than during sinus rhythm; (b) A-V dissociation; (c) activation of the right bundle branch before activation of the bundle of His. The ECG of all 3 patients showed right bundle branch block with very prolonged QRS duration (0.16 to 0.20 s). Characteristically, all 3 had prolonged H-V interval during sinus rhythm. All patients had had a previous myocardial infarction and had a dilated left ventricle. CONCLUSION: The presence of (a) wide complex extrasystoles or tachycardia with a QRS morphology identical to that of sinus rhythm; (b) A-V dissociation; and (c) a very prolonged QRS duration (0.16 s or more) is suggestive of ventricular tachycardia caused by bundle branch reentry.

Ablation of Pacemaker Circus Movement Tachycardia. Introduction: Treatment of pacemaker circus movement tachycardia (PCMT) in patients with very long VA conduction times may present a problem. Methods and Results: PCMT occurred in a 46-year-old woman with an uncommon AV nodal reentrant tachycardia who developed 2:1 AV block after fast pathway radiofrequency catheter (RF) ablation performed at another institution. Due to the long VA conduction time, PCMT could not be prevented by reprogramming the pacemaker or by the addition of antiarrhythmic drugs. Cure of the PCMT was obtained after selective RF ablation of the slow AV nodal pathway. Conclusion: RF ablation of the retrograde conduction offers another alternative for treatment of PCMT.

Supernormal Conduction. This report describes a patient with tachycardia-dependent left bundle branch block (LBBB) and atrial extrasystoles, some of which were followed by an unexpectedly narrow QRS complex. His-bundle recordings and premature atrial stimulation were performed to analyze the mechanism underlying the normalized intraventricular conduction of some of the early atrial impulses. The results suggested the presence of supernormal conduction in the left bundle branch (LBB), because(1) the HV interval was identical in LBBB complexes and in early narrow QRS complexes; (2) during single lest stimulation using different paced atrial cycle lengths, there was a well-defined range of H1, H2, intervals resulting in normalization of intraventricular conduction; and (3) atrial pacing with a cycle length of 500 msec resulted in alternation between wide and narrow QRS complexes. These findings rule out alternative mechanisms that could explain the unexpectedly normal intraventricular conduction of early impulses.

A 66-year-old woman with a history of typical atrial flutter and atrial fibrillation was referred to our institution for radiofrequency ablation. In 1997, her atrial flutter was successfully ablated. During the next 4 years, she remained free of both arrhythmias. In 2001, the patient presented again with atrial fibrillation. During the subsequent electrophysiological study, the index arrhythmia was an incessant atrial tachycardia (AT), 170 bpm (Figure 1, left). A 3-dimensional electroanatomic map (CARTO; Biosense Webster, Inc) of the right atrium (RA) during tachycardia clearly demonstrated a tachycardia originating in the left atrium (LA) (Figure 2). Mapping of the LA …

Recently, several studies of cryoablation using balloon technology versus radiofrequency ablation of the pulmonary veins have shown that cryoablation of paroxysmal atrial fibrillation (PAF) promises to be an effective therapy with success rates similar to that of radiofrequency ablation. Cryothermal energy is known to be safer than other energy sources. The most frequently occurring complication of cryoablation by using a balloon is phrenic nerve palsy, which often occurs by positioning the balloon deep in a pulmonary vein (PV). We report a case of a 65-year old man with PAF in whom we performed a successful PV isolation using a 23-mm cryoballoon (Arctic Front, Medtronic Inc, Quebec Canada). The application of cryothermal energy in the left inferior PV [LIPV] was relatively deep in the PV (Figure 1A, arrows pointing to balloon [BL]). Temperatures reached 64°C. Four days after the procedure, the patient presented at the hospital with hemoptysis. A thoracic computed tomography (CT) scan showed no abnormalities. Bronchoscopy showed an erosion with blood effusion (diameter 3 to 4 mm) on the ventral side at the division of

Purpose Catheter-based cryoablation (cryo) has proven to be as effective as radiofrequency energy (RF) ablation for the treatment of arrhythmias. Nevertheless, the duration of cryoapplications has been reported as being significantly longer than RF applications. Methods Thirty-seven consecutive patients (28 men; mean age 59 ± 14 years) with typical atrial flutter (AFL) underwent cryo of the cavotricuspid isthmus (CTI). Applications of 1 min were delivered with a 10-French, 10-mm tipped catheter (CryoCor™). If bidirectional CTI block was not obtained after 12 1-min applications, applications of 3 min were selectively delivered to areas of conduction breakthrough. The endpoint of the procedure was creation of bidirectional CTI block and non-inducibility of AFL. Results A median of 7 (range 3 to 12) 1-min applications were given along the CTI with a mean temperature of −88.6 ± 2.3°C. Mean fluoroscopy and procedure time were 27 ± 14 min and 110 ± 28 min respectively. Five patients required additional 3-min applications; in one patient an overextended ablation catheter prevented the completion of the index-procedure. The acute success rate of the index-procedure was 97%. In 12/24 patients, two with AFL recurrence, resumption of CTI conduction was found 4 months post-ablation. In all patients bidirectional CTI block was re-obtained after a median of one 1-min application. No additional AFL recurrences occurred, after a mean follow-up of 37 ± 3 (range 30 to 44) months. Conclusions Cryo of AFL can successfully be performed using the same application duration as used for RF ablation. Both acute and long-term results are comparable to RF ablation. AFL recurrences occurred in only a minority of patients with resumption of CTI conduction.

Objective Recent literature has shown that common type atrial flutter (AFL) can recur late after cavotricuspid isthmus (CTI) catheter ablation using radiofrequency energy (RF). We report the long term outcome of a large group of patients undergoing CTI ablation using cryothermy for AFL in a single center. Methods Patients with AFL referred for CTI ablation were recruited prospectively from July 2001 to July 2006. Cryoablation was performed using a deflectable, 10.5 F, 6.5 mm tip catheter. CTI block was reassessed 30 min after the last application during isoproterenol infusion. Recurrences were evaluated by 12-lead ECG and 24 h Holter recording every clinic visit (1/3/6/9 and 12 months after the procedure and yearly thereafter) or if symptoms developed. Results The 180 enrolled patients had the following characteristics: 39 women (22%), mean age 58 years, no structural heart disease in 86 patients (48%), mean left atrium diameter 44 ± 7 mm and mean left ventricular ejection fraction 57 ± 7%. The average number of applications per patient was 7 (3 to 20) with a mean temperature and duration of −88°C and 3 min, respectively. Acute success was achieved in 95% (171) of the patients. There were no complications. After a mean follow-up of 27 ± 17 (from 12 to 60) months, the chronic success rate was 91%. The majority of the recurrences occurred within the first year post ablation. One hundred and twenty three patients had a history of atrial fibrillation (AF) prior to CTI ablation and 85 (69%) of those remained having AF after cryoablation. In 20 of 57 (35%) patients without a history of AF prior to CTI ablation, AF occurred during follow-up. Conclusions This prospective study showed a 91% chronic success rate (range 12 to 60 months) for cryoablation of the CTI in patients with common type AFL and ratified the frequent association of AF with AFL.