Use of advanced mapping systems to guide ablation in complex cases: experience with noncontact mapping and electroanatomic mapping systems.

OBJECTIVE: This report describes our experience with noncontact mapping and electroanatomic mapping in complex ablations, which are defined as ablations done after failure of conventional ablation. MATERIAL AND METHODS: Patients were included (N = 68; 49% with structural heart disease) in whom previous ablation failed and in whom a second procedure was done with advanced mapping. Non-contact mapping was used in 17 patients, electroanatomic mapping in 36, and both noncontact and electroanatomic mapping in 15. Arrhythmias included focal atrial tachycardia (n = 16), reentrant atrial tachycardia (n = 14), right ventricular outflow tachycardia (n = 10), post-myocardial infarction ventricular tachycardia (n = 9), and others (n = 19). RESULTS: Acute success at the second ablation was achieved in 79% of patients. At 20 +/- 9 months after the procedure, 69% of these patients reported having significantly fewer symptoms than before the second ablation, and 51% were free of symptoms. Only 16% were using antiarrhythmic medications. Complications included a small pericardial effusion in two patients, hypotension in one patient, and a femoral pseudoaneurysm in another. CONCLUSIONS: Advanced mapping is a useful and safe adjunct for catheter ablation after ablation has failed in patients with complex substrate.

Long-term outcome of patients who received implantable cardioverter defibrillators for stable ventricular tachycardia.

INTRODUCTION: Evidence is inconclusive concerning the role of implantable cardioverter defibrillators (ICDs) to treat patients with hemodynamically stable ventricular tachycardia (VT). The goal of this study was to estimate future risk of unstable ventricular arrhythmias in patients who received ICDs for stable VT. METHODS AND RESULTS: We reviewed complete ICD follow-up data from 82 patients (age 66.1 +/- 11.3 years; left ventricular ejection fraction 32.3%+/- 11.2%; mean +/- SD) who received ICDs for stable VT. During the follow-up period of 23.6 +/- 21.5 months (mean +/- SD), 15 patients (18%) died, and 10 (12%) developed unstable ventricular arrhythmia, 8 of whom had the unstable arrhythmia as the first arrhythmia after ICD placement. Estimated 2- and 4-year survival in the whole group was 80% and 74%, respectively. Estimated 2- and 4-year probability of any VT and unstable VT was 67% and 77% and 11% and 25%, respectively. There were no differences in age, ejection fraction, sex, underlying heart disease, cycle length, symptoms, baseline electrophysiologic study results, or QRS characteristics of qualifying VT between patients who developed unstable ventricular arrhythmia and patients who did not. Twenty-nine patients (35%) had at least one inappropriate shock, and 11 (13%) underwent further surgery for ICD-related complications. CONCLUSION: Patients who present with hemodynamically stable VT are at risk for subsequent unstable VT. ICD treatment offers potential salvage of patients with stable VT who subsequently develop unstable VT/ventricular fibrillation, although complications and inappropriate shocks are considerable. No predictors could be found for high and low risk for unstable arrhythmias. These findings support ICD treatment for stable VT survivors.

Long-term prognosis of inducible ventricular flutter: not an innocent finding.

BACKGROUND: The prognostic significance of ventricular flutter (VFL) induced during programmed electrical stimulation (PES) is currently unknown. METHODS: This study examined patients who had PES-induced VFL and assessed their long-term prognosis compared with patients who had inducible sustained monomorphic ventricular tachycardia (SMVT). RESULTS: Of 3414 patients undergoing PES, 74 (2%) had sustained VFL. They were compared with a group of 71 patients undergoing PES in the same time frame who had inducible SMVT. Patients with inducible VFL had a higher ejection fraction than patients with SMVT (0.39 vs 0.33; P =.05). More aggressive pacing was required for arrhythmia induction in patients with VFL, with more stimuli (2.7 +/- 0.5 vs 2.2 +/- 0.6; P <.01) and tighter S(2), S(3), and S(4) intervals. After a mean follow-up of 30 +/- 31 months, the mortality rate was 34% in patients with VFL and 30% in patients with SMVT (P =.41). No difference in the 2 groups in overall survival or a combined end point of sudden death or appropriate implantable cardioverter defibrillator shock was revealed with Kaplan-Meier analysis. CONCLUSION: The long-term prognosis of patients with inducible VFL is similar to that of patients with inducible SMVT, even when VFL is induced with a relatively aggressive protocol.

ST-segment deviation following implantable cardioverter defibrillator shocks: incidence, timing, and clinical significance.

ST-segment analysis is frequently used during surgical procedures, while ST deviation is considered a sign of myocardial injury. ST deviations were reported following transthoracic and epicardial electrical shocks. The prevalence, timing, and clinical significance of ST-segment deviation following endocardial ICD shocks are discussed in this article. Twenty-eight patients undergoing 125 shock episodes during ICD implantation or testing were included. A 12-lead ECG was recorded at baseline, continuously during the first 3-10 seconds, 1 minute after test shocks, 3-10 seconds and 1 and 5 minutes after each shock given to terminate VF. ST deviation was diagnosed when the ST-segment was displaced > or = 1 mm in at least one lead compared to baseline. ST-segment deviations were observed after 49 (39%) of all shock episodes in 17 (61%) of patients. ST elevation was observed after 30 (24%) of all shock episodes, and ST depression after 31 (25%). Following 13 shock episodes in seven patients, ST-elevation and depression were observed. ST depressions occurred more frequently after shocks given to terminate VF than after lower energy test shocks (28% vs 18% respectively, P = 0.045). However, there was no significant difference in the prevalence of ST elevations between the lower or higher energy shocks. No adverse clinical events were observed in patients with or without postshock ST-segment deviation. ST-segment deviation following endocardial ICD shocks is a frequent phenomenon, occurring acutely and resolving during the first few minutes postshock. It mayhave no prognostic implications.