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We present a case of a 67-year-old female with a previous history of pulmonary vein isolation for paroxysmal atrial fibrillation who presented with supraventricular bigeminy with a constant coupling interval. The supraventricular bigeminy originated from the anterior mitral annulus with initial mapping suggestive of a focal mechanism. However detailed mapping using an ultrahigh resolution mapping system (with the manual shifting of the annotation window) revealed very low amplitude potentials connecting the previous sinus beat with continuous activation along the mitral annulus. Our observations were indicative of a re-entry mechanism underlying the supraventricular bigeminy.

BACKGROUND The presence of heart failure (HF) has been associated with poorer outcomes in patients undergoing catheter ablation (CA) for atrial fibrillation (AF). However, the effectiveness of CA amongst the subset of patients with tachycardia-induced cardiomyopathy (TIC) remains poorly defined. METHODS AND RESULTS In a retrospective analysis we compared outcomes of first-time CA for persistent AF in a cohort of patients with previously diagnosed TIC (n = 45; age 58 ± 8 years; 91% male) to those with structurally normal hearts (non-TIC; n = 440; age 55 ± 9 years; 95% male). TIC was defined as an impaired ventricular function (left ventricular ejection function [LVEF]

BACKGROUND Optimal procedure endpoints of catheter ablation for ventricular tachycardia (VT) are not defined and multiple repeat procedures are sometimes required. However, there are few studies to compare the details of repeat procedures to the initial procedure. The aim of this study is to compare the characteristics of clinical and induced VT throughout multiple procedures and clarify their relations. METHODS AND RESULTS Of 425 consecutive patients with structural heart disease who underwent catheter VT ablation, second, third and fourth procedures were performed in 101, 23, and 5 patients, respectively. Of 227 VTs that were induced during the second procedure, 68 (30%) VTs had previously been induced at the first procedure. In multivariable analysis, identification of an exit/isthmus site (HR = 0.29, P = 0.047), early termination of VT during radiofrequency application (HR 0.11, P = 0.037) and elimination of target VT at the end of first procedure (HR = 0.43, P = 0.036) were independently associated with noninducibility of the same VT at the second procedure. Over the course of multiple procedures the mean VT cycle length gradually lengthened (381 ± 107, 413 ± 111, 460 ± 124, 507 ± 99 milliseconds in first, second, third, and fourth procedure, respectively, P < 0.001) and more induced VTs became mappable (32%, 40%, 62%, and 70% in first, second, third, and fourth procedure, respectively, P < 0.001). CONCLUSIONS Identification and ablation of VT exit/isthmus, early termination of VT during radiofrequency application and elimination of targeted VT are associated with absence of that VT during a repeat procedure, and recurrences are then mostly due to new VTs or other VTs that were not induced at the first procedure.

VT Recurrence as Related to Scar Ablation Sites Introduction Magnetic resonance (MR)-imaging has shown that infarct scars causing ventricular tachycardia (VT) can extend deep to and beyond bipolar low-voltage areas (LVAs) and may be a source of ablation failure. We hypothesized that the size of the unipolar LVA “penumbra” beyond the overlying bipolar scar may predict outcome of endocardial VT ablation. Methods Twenty consecutive patients with ischemic cardiomyopathy who underwent endocardial VT ablation were retrospectively reviewed. Bipolar (30–500 Hz) LVA defined as

Criteria for Epicardial Origin in Ischemic VT. Objectives: We tested proposed algorithms for idiopathic and nonischemic tachycardias for their ability to identify epicardial LV-VT origins. Backgroud: Several ECG features have been reported to identify epicardial origins for left ventricular tachycardias (LV-VTs) in the absence of myocardial infarction. Only limited data exist in postinfarction patients. Methods: The QRS features of 24 VTs that were ablated from the epicardium and 39 left ventricular VTs ablated from the endocardium were retrospectively analyzed for various 12-lead ECG features previously reported. Results: No ECG feature consistently predicted an epicardial LV-VT origin in infarct-related tachycardias, with epicardial VTs showing slightly longer QRS durations (189 ± 32 ms in epicardial vs 179 ± 37 ms in endocardial, P = 0.28). Pseudo-delta duration was 38 ± 27 versus 47 ± 27 ms (P = 0.2), intrinsicoid deflection time 93 ± 35 versus 86 ± 32 ms (P = 0.4), shortest RS 97 ± 38 versus 99 ± 32 ms (P = 0.77), and median deflection index 0.82 ± 0.25 versus 0.87 ± 0.22 (P = 0.43). The finding of a Q wave in lead I and the absence of a Q wave in the inferior leads failed to predict an epicardial origin in superior LV-VT sites. Q waves in any inferior lead and aVR/aVL-ratio

Optimal procedure endpoints of catheter ablation for ventricular tachycardia (VT) are not defined and multiple repeat procedures are sometimes required. However, there are few studies to compare the details of repeat procedures to the initial procedure. The aim of this study is to compare the characteristics of clinical and induced VT throughout multiple procedures and clarify their relations.Of 425 consecutive patients with structural heart disease who underwent catheter VT ablation, second, third and fourth procedures were performed in 101, 23, and 5 patients, respectively. Of 227 VTs that were induced during the second procedure, 68 (30%) VTs had previously been induced at the first procedure. In multivariable analysis, identification of an exit/isthmus site (HR = 0.29, P = 0.047), early termination of VT during radiofrequency application (HR 0.11, P = 0.037) and elimination of target VT at the end of first procedure (HR = 0.43, P = 0.036) were independently associated with noninducibility of the same VT at the second procedure. Over the course of multiple procedures the mean VT cycle length gradually lengthened (381 ± 107, 413 ± 111, 460 ± 124, 507 ± 99 milliseconds in first, second, third, and fourth procedure, respectively, P0.001) and more induced VTs became mappable (32%, 40%, 62%, and 70% in first, second, third, and fourth procedure, respectively, P0.001).Identification and ablation of VT exit/isthmus, early termination of VT during radiofrequency application and elimination of targeted VT are associated with absence of that VT during a repeat procedure, and recurrences are then mostly due to new VTs or other VTs that were not induced at the first procedure.

VT Ablation in a Patient with Peripartum Cardiomyopathy A 38-year-old female with prior failed endocardial ablation for ventricular tachycardia (VT) was referred for further treatment. She had been diagnosed with peripartum cardiomyopathy 7 years before and had persistent left ventricular dysfunction with an ejection fraction of 20%. Epicardial voltage mapping showed extensive epicardial scar despite absence of endocardial scar. Five distinct VT morphologies were induced. Ablation was aided by electrogram characteristics, pace mapping, entrainment mapping, and establishing electrical inexcitability along areas of epicardial scar. After epicardial ablation no sustained VT was induced. She had been doing well without VT occurrence but died 1 year later unexpectedly at home.

Magnetic resonance (MR)-imaging has shown that infarct scars causing ventricular tachycardia (VT) can extend deep to and beyond bipolar low-voltage areas (LVAs) and may be a source of ablation failure. We hypothesized that the size of the unipolar LVA "penumbra" beyond the overlying bipolar scar may predict outcome of endocardial VT ablation.Twenty consecutive patients with ischemic cardiomyopathy who underwent endocardial VT ablation were retrospectively reviewed. Bipolar (30-500 Hz) LVA defined as1.5 mV and unipolar (0.5-500 Hz) LVA defined as8.3 mV were reviewed on an electroanatomic mapping system. VT isthmus sites were identified from entrainment mapping, VT termination by ablation, or pace-mapping with abolition of VT inducibility by ablation.All bipolar LVAs (70.5 ± 20 cm(2) ) had unipolar LVAs that surrounded the bipolar LVA (147 ± 47 cm(2) ). Only 58% of the induced VTs could be mapped and ablated. During a 3-month follow-up 8/20 patients had VT recurrence. The size of the LVA penumbra was not different for those with (88 ± 47 cm(2) ) versus without (69 ± 35 cm(2) ) recurrences. However, all (8/8) of the group that recurred had isthmus/exits in the bipolar LVA border compared to only 3/12 that did not recur (100% vs. 25%; P0.05). Furthermore, 5/8 patients who recurred harbored VT isthmuses in the unipolar LVA penumbra than 1/12 who did not recur (63% vs. 8%; P = 0.01).In ischemic cardiomyoapthy, unipolar LVA penumbra of varying size surrounds endocardial bipolar LVA, indicating intramural/epicardial scar. Although the size of this area did not predict early recurrence after endocardial ablation, frequent recurrences after VT ablation at scar periphery suggests deeper substrate toward the infarct border.

A 38-year-old female with prior failed endocardial ablation for ventricular tachycardia (VT) was referred for further treatment. She had been diagnosed with peripartum cardiomyopathy 7 years before and had persistent left ventricular dysfunction with an ejection fraction of 20%. Epicardial voltage mapping showed extensive epicardial scar despite absence of endocardial scar. Five distinct VT morphologies were induced. Ablation was aided by electrogram characteristics, pace mapping, entrainment mapping, and establishing electrical inexcitability along areas of epicardial scar. After epicardial ablation no sustained VT was induced. She had been doing well without VT occurrence but died 1 year later unexpectedly at home.

UNLABELLED PV and Linear Ablation for CFAEs. INTRODUCTION Linear ablations in the left atrium (LA), in addition to pulmonary vein (PV) isolation, have been demonstrated to be an effective ablation strategy in patients with persistent atrial fibrillation (PsAF). This study investigated the impact of LA linear ablation on the complex-fractionated atrial electrograms (CFAEs) of PsAF patients. METHODS AND RESULTS A total of 40 consecutive PsAF patients (age: 54 ± 10 years, 39 males) who underwent catheter ablation were enrolled in this study. Linear ablation of both roofline between the right and left superior PVs and the mitral isthmus line joining from the mitral annulus to the left inferior PV were performed following PV isolation during AF. High-density automated CFAE mapping was performed using the NAVX, and maps were obtained 3 times during the procedure (prior to ablation, after PV isolation, and after linear ablations) and were compared. PsAF was terminated by ablation in 13 of 40 patients. The mean total LA surface area and baseline CFAEs area were 120.8 ± 23.6 and 88.0 ± 23.5 cm(2) (74.2%), respectively. After PV isolation and linear ablations in the LA, the area of CFAEs area was reduced to 71.6 ± 22.6 cm(2) (58.7%) (P < 0.001) and 44.9 ± 23.0 cm(2) (39.2%) (P < 0.001), respectively. The LA linear ablations resulted in a significant reduction of the CFAEs area percentage in the region remote from ablation sites (from 56.3 ± 20.6 cm(2) (59.6%) to 40.4 ± 16.5 cm(2) (42.9%), P < 0.0001). CONCLUSION Both PV isolation and LA linear ablations diminished the CFAEs in PsAF patients, suggesting substrate modification by PV and linear ablations. (J Cardiovasc Electrophysiol, Vol. 23, pp. 962-970, September 2012).

Completion of Mitral Isthmus Ablation. Background: Although mitral isthmus (MI) ablation in atrial fibrillation (AF) patients has been shown to be an effective ablative strategy, the establishment of the bidirectional conduction block of the MI is technically challenging. We investigated the usefulness of a steerable sheath for MI ablation in patients with persistent AF and its impact on the clinical outcome of persistent AF ablation. Methods: A total of 80 consecutive patients undergoing MI ablation were randomized to 1 of the following 2 groups: group S (using a steerable long sheath) or group NS (using a nonsteerable long sheath). MI ablation was performed by using an open-irrigated ablation catheter with the guidance of a 3-dimensional mapping system. The endpoint of the MI ablation was the achievement of a bidirectional block. Results: Bidirectional block through the MI was achieved in 87.5% (70/80) of patients with 14.0 ± 6.7 minutes of radiofrequency application. The bidirectional block was more frequently achieved in patients in group S compared to group NS (97.5% (39/40) vs 77.5% (31/40), P = 0.02). Additionally, epicardial ablation within the coronary sinus was less frequently required in group S compared to group NS (12.5% (5/40) vs 72.5% (29/40), P < 0.0001). Atrial tachycardia after the procedure more frequently occurred in the patients in whom MI block had not been achieved during the initial procedure (40.0% (4/10) vs 10.0% (7/70), P = 0.04). Conclusions: The MI block could be achieved in the majority of patients by using a steerable sheath. An incomplete MI block increased the risk of AT following persistent AF ablation. (J Cardiovasc Electrophysiol, Vol. 22, pp. 1331-1338, December 2011)

Background: Recent evidence has suggested that the transient re-conduction of the isolated pulmonary vein (PV) induced by the intravenous injection of adenosine (dormant PV conduction) might predict the incidence of subsequent venous reconnection after the procedure, which is the main cause of the atrial fibrillation (AF) recurrence after PV isolation (PVI). We tested the hypothesis that the elimination of these dormant PV conductions by additional radiofrequency (RF) applications can improve the efficacy of the PVI. Methods and Results: One hundred forty-eight patients (124 males; mean age 53 ± 9 years) with drug-refractory AF underwent the PVI procedure. The standard PVI was performed in 94 patients (Group A), whereas the elimination of adenosine triphosphate (ATP)-induced dormant conduction using additional RF energy was performed in addition to the standard PVI in other 54 patients (Group B). Dormant conduction was observed in 56% of the patients (30/54) in Group B and 95% of these transient re-conductions were successfully eliminated by additional RF applications (mean: 1.5 ± 1.0 times). During the mean follow-up period of 20 months, recurrences of AF after the procedures were observed significantly less frequently in Group B (20%) than in Group A (40%) (P < 0.05). Conclusion: The use of additional RF applications to eliminate transient PV reconnection induced by ATP injection led to a reduction of AF recurrence after PVI, most likely due to the minimization of the subsequent PV reconnection.