Ablation around the PV ostia diminishes left atrial response to VS and decreases the atrial VW. The attenuated vagal response after ablation may contribute to the suppression of AF.
Background-The coexistence of atrial fibrillation (AF) and atrial flutter (AFL) is well recognized. AF precedes the onset of AFL in almost all instances. We evaluated the effect of 2 ablation strategies in patients with paroxysmal AF (PAF) and AFL. Methods and Results-Ninety-eight patients with PAF/AFL were prospectively recruited to undergo pulmonary vein cryoisolation (PVI). Those with at least 1 episode of sustained common-type AFL were assigned to cavotricuspid isthmus cryoablation followed by a 6-week monitoring period and a subsequent PVI (nϭ36; group I). Patients with PAF only underwent PVI (nϭ62; group II). The study included 76 men with a mean age of 50Ϯ10 years. Most patients (76 [78%]) had no structural heart disease. When the 2 groups were compared, residual AF after a blanking period of 3 months after PVI occurred in 24 patients (67%) in group I versus 7 (11%) in group II (PϽ0.05). Conclusions-In patients with PAF and no documented common-type AFL, PVI alone prevented the occurrence of AF in 82%, whereas in patients with AFL/PAF, cavotricuspid isthmus cryoablation and PVI were used successfully to treat sustained common-type AFL but appeared to be insufficient to prevent recurrences of AF. In this population, AFL can be a sign that non-pulmonary vein triggers are the culprit behind AF or that sufficient electrical remodeling has already occurred in both atria, and thus a strategy that includes substrate modification may be required.
Pulmonary vein cryoisolation is effective in 82% of patients with recent-onset PAF during a mean follow-up of 33 +/- 15 (range 15 to 60) months. If the arrhythmogenic PV is identified and isolated, the long-term outcome is excellent, indicating no need to isolate all PVs.
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.
A 74-year-old woman with a medical history of atrial fibrillation for 1 year presented with long-standing fatigue, dizziness, and shortness of breath. On physical examination, the patient had a blood pressure of 130/ 60 mm Hg and a heart rate of 24 beats per minute. The remaining physical examination was unremarkable. The ECG showed a complete atrioventricular block with a sinus rhythm of 100 beats per minute, a QT interval of 770 ms, a corrected QT interval of 486 ms, and a ventricular escape rhythm of 24 beats per minute. While being prepared for a pacemaker implantation, she had an episode of polymorphic ventricular tachycardia leading to ventricular fibrillation ( Figure). Prompt defibrillation was achieved with a monophasic shock of 360 J. A temporary pacemaker was inserted, and the implantation of a dual chamber rate-responsive pacemaker was completed without further problems. In patients with complete distal heart block, the escape rhythm is usually very slow. Significant bradycardia is known to increase the QT interval, with subsequent lengthening of the ventricular action potential duration. The latter increases the risk for an extrastimulus to cause ventricular premature activation. Furthermore, it is not uncommon for competing pacemaker cells to cause frequent ventricular premature beats. This substrate is ideal for the occurrence of a short-long-short sequence (Figure). The compensatory long cycle after a ventricular premature beat results in an excessive lengthening and an increased dispersion of an already abnormal local ventricular refractoriness. If a timely ventricular premature beat occurs, functional conduction block may produce reentrant excitation, leading to polymorphic ventricular tachycardia/fibrillation. Patients with chronic atrioventricular block usually die of ventricular arrhythmias. In patients with advance heart block, pacing needs to be performed without delay. DisclosuresNone.
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