[show abstract][hide abstract] ABSTRACT: BACKGROUND: -Atrial tachycardias (AT) during or after ablation of AF frequently pose a diagnostic challenge. We hypothesized that both the patterns and timing of coronary sinus (CS) activation could facilitate AT mapping. METHODS AND RESULTS: -140 consecutive post-persistent AF ablation patients with sustained AT were investigated by conventional mapping. CS activation pattern was defined as "chevron" or "reverse chevron" when the activations recorded on both the proximal and distal CS dipoles were latest or earliest, respectively. The local activation of mid-CS was timed with reference to Ppeak-Ppeak (P-P) interval in lead V1. A ratio, mid-CS activation time to AT cycle length, was computed. Out of 223 diagnosed ATs, 124 were macroreentrant (56%) and 99 were centrifugal (44%). When CS activation was "chevron"/"reverse chevron" (n = 44, 20%), macroreentries were mostly roof-dependent. With reference to P-P interval, mid-CS activation timing showed specific consistency for peritricuspid and perimitral AT. Proximal to distal CS activation pattern and mid-CS activation at 50-70% of the P-P interval (n = 30, 13%) diagnosed peritricuspid AT with 81% sensitivity and 89% specificity. Distal to proximal CS activation and mid-CS activation at 10-40% of the P-P interval (n = 44, 20%) diagnosed perimitral AT with 88% sensitivity and 75% specificity. CONCLUSIONS: -The analysis of the patterns and timing of CS activation provides a rapid stratification of most likely macroreentrant ATs and points towards the likely origin of centrifugal ATs. It can be included in a stepwise diagnostic approach to rapidly select the most critical mapping maneuvers.
Circulation Arrhythmia and Electrophysiology 04/2013; · 5.95 Impact Factor
[show abstract][hide abstract] ABSTRACT: BACKGROUND: -A majority of patients undergoing ablation of ventricular tachycardia (VT) have implanted devices precluding substrate imaging with delayed-enhancement magnetic resonance imaging (MRI). Contrast-enhanced multi-detector computed tomography (MDCT) can depict myocardial wall thickness with submillimetric resolution. We evaluated the relationship between regional myocardial wall thinning (WT) imaged by MDCT and arrhythmogenic substrate in post-infarction VT. METHODS AND RESULTS: -We studied 13 consecutive post-infarction patients undergoing MDCT before ablation. MDCT data was integrated with high-density 3D-electroanatomic maps acquired during sinus rhythm (endocardium: 509±291 points/map, epicardium: 716±323 points/map). Low-voltage areas (<1.5 mV) and local abnormal ventricular activities (LAVA) during sinus rhythm were assessed with regard to the WT. A significant correlation was found between the areas of WT<5mm and endocardial low-voltage (correlation-R=0.82, p=0.001), but no such correlation was found in the epicardium. The WT<5mm area was smaller than the endocardial low-voltage area (54cm2 [Q1-Q3: 46-92] versus 71cm2 [Q1-Q3: 59-124], p=0.001). Among a total of 13,060 electrograms reviewed in the whole study population, 538 LAVA were detected and analyzed. LAVA were located within the WT<5mm (469/538 [87%]) or at its border (100% within 23mm). Very late LAVA (>100ms after QRS complex) were almost exclusively detected within the thinnest area (93% in the WT<3mm). CONCLUSIONS: -Regional myocardial WT correlates to low-voltage regions and distribution of LAVA critical for the generation and maintenance of post-infarction VT. The integration of MDCT WT with 3D-electroanatomic maps can help focus mapping and ablation on the culprit regions, even when MRI is precluded by the presence of implanted devices.
Circulation Arrhythmia and Electrophysiology 03/2013; · 5.95 Impact Factor
[show abstract][hide abstract] ABSTRACT: MDCT/MRI Fusion for the Guidance of VT Ablation. Background: Delayed enhancement (DE) MRI can assess the fibrotic substrate of scar-related VT. MDCT has the advantage of inframillimetric spatial resolution and better 3D reconstructions. We sought to evaluate the feasibility and usefulness of integrating merged MDCT/MRI data in 3D-mapping systems for structure-function assessment and multimodal guidance of VT mapping and ablation. Methods: Nine patients, including 3 ischemic cardiomyopathy (ICM), 3 nonischemic cardiomyopathy (NICM), 2 myocarditis, and 1 redo procedure for idiopathic VT, underwent MRI and MDCT before VT ablation. Merged MRI/MDCT data were integrated in 3D-mapping systems and registered to high-density endocardial and epicardial maps. Low-voltage areas (<1.5 mV) and local abnormal ventricular activities (LAVA) during sinus rhythm were correlated to DE at MRI, and wall-thinning (WT) at MDCT. Results: Endocardium and epicardium were mapped with 391 ± 388 and 1098 ± 734 points per map, respectively. Registration of MDCT allowed visualization of coronary arteries during epicardial mapping/ablation. In the idiopathic patient, integration of MRI data identified previously ablated regions. In ICM patients, both DE at MRI and WT at MDCT matched areas of low voltage (overlap 94 ± 6% and 79 ± 5%, respectively). In NICM patients, wall-thinning areas matched areas of low voltage (overlap 63 ± 21%). In patients with myocarditis, subepicardial DE matched areas of epicardial low voltage (overlap 92 ± 12%). A total number of 266 LAVA sites were found in 7/9 patients. All LAVA sites were associated to structural substrate at imaging (90% inside, 100% within 18 mm). Conclusion: The integration of merged MDCT and DEMRI data is feasible and allows combining substrate assessment with high-spatial resolution to better define structure-function relationship in scar-related VT. (J Cardiovasc Electrophysiol, Vol. pp. 1-8).
Journal of Cardiovascular Electrophysiology 11/2012; · 3.48 Impact Factor
[show abstract][hide abstract] ABSTRACT: Atrial fibrillation (AF) ablation has evolved to the treatment of choice for patients with drug-resistant and symptomatic AF. Pulmonary vein isolation at the ostial or antral level usually is sufficient for treatment of true paroxysmal AF. For persistent AF ablation, drivers and perpetuators outside of the pulmonary veins are responsible for AF maintenance and have to be targeted to achieve satisfying arrhythmia-free success rate. Both complex fractionated atrial electrogram (CFAE) ablation and linear ablation are added to pulmonary vein isolation for persistent AF ablation. Nevertheless, ablation failure and necessity of repeat ablations are still frequent, especially after persistent AF ablation. Pulmonary vein reconduction is the main reason for arrhythmia recurrence after paroxysmal and to a lesser extent after persistent AF ablation. Failure of persistent AF ablation mostly is a consequence of inadequate trigger ablation, substrate modification or incompletely ablated or reconducting linear lesions. In this review we will discuss these points responsible for AF recurrence after ablation and review current possibilities on how to overcome these limitations.
[show abstract][hide abstract] ABSTRACT: BACKGROUND: Inferolateral early repolarization (ER) and Brugada syndrome manifest with J waves. Isoproterenol suppresses recurrent ventricular arrhythmias while reducing J waves in both disorders. OBJECTIVE: To characterize the effect of isoproterenol on J waves. METHODS: We analyzed the impact of isoproterenol on J waves in 20 patients with Brugada-type electrocardiogram (Br group) and 38 patients with ER (ER group). RESULTS: In the ER group, J waves were present in inferior leads in 32 patients (84%) and in lateral leads in 23 patients (61%). Isoproterenol increased the heart rate by 75 beats/min in the ER group and by 71 beats/min in the Br group (P = .20). The incidences of persistent (≤0.05-mV decrease), decreased, and normalized J waves (residual J wave ≤0.05 mV) were 20%, 80%, and 0% for Br group patients and 29%, 8%, and 63% for ER group patients, respectively (P <.001). Within the ER group, inferior J waves persisted in 34% of the cases, decreased in 9%, and normalized in 56% whereas lateral J waves always normalized (P <.001). Baseline QRS width was broader in ER group patients with persistent J waves (90 ms vs 80 ms; P = .003) and was unchanged with isoproterenol (90 ms; P = .19), whereas it decreased in the remaining patients (75 ms; P <.001). CONCLUSIONS: J-wave syndromes have distinct regional sensitivity to beta-adrenergic stimulation. J waves may persist in a subset of patients with precordial and inferior J waves but never in lateral location. This heterogeneous response to isoproterenol may indicate distinctive mechanisms for Brugada and ER patterns, including depolarization abnormalities or ion channel sensitivity.
Heart rhythm: the official journal of the Heart Rhythm Society 08/2012; · 4.56 Impact Factor
[show abstract][hide abstract] ABSTRACT: Catheter ablation of ventricular tachycardia (VT) is effective and particularly useful in patients with frequent defibrillator interventions. Various substrate modification techniques have been described for unmappable or hemodynamically intolerable VT. Noninducibility is the most frequently used end point but is associated with significant limitations, so the optimal end point remains unclear. We hypothesized that elimination of local abnormal ventricular activities (LAVAs) during sinus rhythm or ventricular pacing would be a useful and effective end point for substrate-based VT ablation. As an adjunct to this strategy, we used a new high-density mapping catheter and frequently used epicardial mapping.
Seventy patients (age, 67±11 years; 7 female) with VT and structurally abnormal ventricle(s) were prospectively enrolled. Conventional mapping was performed in sinus rhythm in all, and a high-density Pentaray mapping catheter was used in the endocardium (n=35) and epicardially. LAVAs were recorded in 67 patients (95.7%; 95% confidence interval, 89.2-98.9). Catheter ablation was performed targeting LAVA with an irrigated-tip catheter placed endocardially via a transseptal or retrograde aortic approach or epicardially via the subxiphoid approach. LAVAs were successfully abolished or dissociated in 47 of 67 patients (70.1%; 95% confidence interval, 58.7-80.1). In multivariate analysis, LAVA elimination was independently associated with a reduction in recurrent VT or death (hazard ratio, 0.49; 95% confidence interval, 0.26-0.95; P=0.035) during long-term follow-up (median, 22 months).
LAVAs can be identified in most patients with scar-related VT. Elimination of LAVAs is feasible and safe and is associated with superior survival free from recurrent VT.
[show abstract][hide abstract] ABSTRACT: Background—Catheter ablation of ventricular tachycardia (VT) is effective and particularly useful in patients with frequent defibrillator interventions. Various substrate modification techniques have been described for unmappable or hemodynamically intolerable VT. Non-inducibility is the most frequently used endpoint but is associated with significant limitations such that the optimal endpoint remains unclear. We hypothesized that elimination of local abnormal ventricular activities (LAVA) during sinus rhythm or ventricular pacing would be a useful and effective endpoint for substrate-based VT ablation. As an adjunct to this strategy, we used a new high density mapping catheter and frequently employed epicardial mapping. Methods and Results—Seventy patients (67±11 y, 7 female) with VT and structurally abnormal ventricle(s) were prospectively enrolled. Conventional mapping was performed in sinus rhythm in all while a high density PentarayTM mapping catheter was used in the endocardium (n=35) and epicardially. LAVA were recorded in 67 patients [95.7%, 95% confidence interval (CI; 89.2%, 98.9%)]. Catheter ablation was performed targeting LAVA using an irrigated-tip catheter placed endocardially via a transeptal or retrograde aortic approach or epicardially via the sub-xiphoid approach. LAVA were successfully abolished or dissociated in 47 of 67 patients [70.1%, 95% CI (58.7%, 80.1%)]. In multivariate analysis, LAVA elimination was independently associated with a reduction in recurrent VT or death [hazard ratio 0.49, 95% CI (0.26, 0.95), P=0.035] during long-term follow-up (median 22 months). Conclusions—LAVA can be identified in most patients with scar-related VT. Elimination of LAVA is feasible and safe and associated with superior survival free from recurrent VT.