Significance of inducibility of atrial fibrillation after pulmonary vein isolation in patients with healthy left atrium substrate.

BACKGROUND: The significance of the inducibility of atrial fibrillation (AF) after pulmonary vein isolation (PVI) in patients with AF remains disputable and polarizing. Therefore, we investigated the prognostic value of the inducibility of AF on long-term outcome after PVI in patients without low-voltage left atrial (LA) substrate. METHODS: Two hundred forty-five patients (mean age 59+/-9years, 72% male) without LA low-voltage areas (defined as electrogram amplitudes <0.5 mV) undergoing first PVI procedure were included in the study. Following successful PVI, inducibility was assessed by burst pacing from coronary sinus with a cycle length (CL) of 300, 250, and 200 ms or the shortest CL resulting in 1:1 atrial capture. During the follow-up period of up to 3 years, the rhythm outcome was monitored by serial 7-days Holter electrocardiogram. RESULTS: AF was induced in 38 patients (16%). Atypical atrial flutter was observed in six patients (2%), while typical flutter in three cases (1%). Within the first 3 months, early recurrence was diagnosed in 39 patients (16%), while late recurrence was detected in 58 patients (24%) after a mean AF free survival of 28 ± 1 months. While there was no impact on early recurrence, AF inducibility affected long-term recurrence (31 ± 1 vs 23 ± 3 months; P = .001). In multivariate analysis, AF inducibility (hazard ratio [HR] 2.14; 95% confidence interval [CI], 1.03-4.45; P = .041) and persistent type of AF (HR 2.17; 95%CI, 1.06-4.47; P = .034) were associated with late AF recurrence. CONCLUSION: In patients without low-voltage substrate undergoing PVI, AF inducibility is a significant predictor of long-term outcome. The pathomechanisms of this phenomenon must be further studied to be addressed by additional treatment.

Agreement between gadolinium-enhanced cardiac magnetic resonance and electro-anatomical maps in patients with non-ischaemic dilated cardiomyopathy and ventricular arrhythmias.

AIMS: We sought to investigate the overlap between late gadolinium enhancement (LGE) in cardiac magnetic resonance (CMR) and electro-anatomical maps (EAM) of patients with non-ischaemic dilated cardiomyopathy (NIDCM) and how it relates with the outcomes after catheter ablation of ventricular arrhythmias (VA). METHODS AND RESULTS: We identified 50 patients with NIDCM who received CMR and ablation for VA. Late gadolinium enhancement was detected in 16 (32%) patients, mostly in those presenting with sustained ventricular tachycardia (VT): 15 patients. Low-voltage areas (<1.5 mV) were observed in 23 (46%) cases; in 7 (14%) cases without evidence of LGE. Using a threshold of 1.5 mV, a good and partially good agreement between the bipolar EAM and LGE-CMR was observed in only 4 (8%) and 9 (18%) patients, respectively. With further adjustments of EAM to match the LGE, we defined new cut-off limits of median 1.5 and 5 mV for bipolar and unipolar maps, respectively. Most VT exits (12 out of 16 patients) were found in areas with LGE. VT exits were found in segments without LGE in two patients with VT recurrence as well as in two patients without recurrence, P = 0.77. In patients with VT recurrence, the LGE volume was significantly larger than in those without recurrence: 12% ± 5.8% vs. 6.9% ± 3.4%; P = 0.049. CONCLUSIONS: In NIDCM, the agreement between LGE and bipolar EAM was fairly poor but can be improved with adjustment of the thresholds for EAM according to the amount of LGE. The outcomes were related to the volume of LGE.

Individually tailored vs. standardized substrate modification during radiofrequency catheter ablation for atrial fibrillation: a randomized study.

Aims: This randomized single-centre study sought to compare the efficacy and safety of pulmonary vein isolation (PVI) plus voltage-guided ablation vs. PVI with or without linear ablation depending on the type of atrial fibrillation (AF). Methods and results: Overall, 124 ablation-naive patients with paroxysmal or persistent AF were randomized to PVI with (persistent AF) or without (paroxysmal AF) additional linear ablation (control group) vs. PVI plus ablation of low-voltage areas (LVAs) irrespective of AF type. Bipolar voltage mapping was performed during stable sinus rhythm. An LVA consisted of ≥ 3 adjacent mapping points that each had a peak-to-peak amplitude ≤0.5 mV. After a mean follow-up of 12 ± 3 months, significantly more patients in the LVA ablation group were free from atrial arrhythmia recurrence >30 s off antiarrhythmic drugs (AADs) after a single procedure (primary endpoint) compared with control group patients [40/59 (68%) vs. 25/59 (42%), log-rank P = 0.003]. Arrhythmia-free survival on or off AADs was found in 33/59 control group patients (56%) and in 41/59 LVA ablation group patients (70%) (adjusted log-rank P = 0.10). During the 7 day Holter monitoring period at 12 months, significantly more patients in the LVA ablation group were free from arrhythmia recurrence on or off AADs [45/50 (90%) vs. 33/46 (72%), P = 0.04]. No between-group differences were observed regarding procedure duration, fluoroscopy time, and major complications. Conclusion: In this single-centre study, individually tailored substrate modification guided by voltage mapping was associated with a significantly higher arrhythmia-free survival rate compared with a conventional approach applying linear ablation according to AF type.

Prospective, multicenter validation of a clinical risk score for left atrial arrhythmogenic substrate based on voltage analysis: DR-FLASH score.

BACKGROUND: Left atrial (LA) low-voltage areas (LVAs) are frequently observed in patients with atrial fibrillation (AF) and may predict AF recurrence after catheter ablation. OBJECTIVE: The aim of this study was to develop and validate a clinical tool to identify LVAs that are associated with AF recurrence after pulmonary vein isolation (PVI). METHODS: In a cohort of 238 patients, voltage maps were created during LA procedures. LVAs were defined as areas with electrogram amplitudes <0.5 mV. On the basis of regression analysis, predictors of LA substrate were identified. These parameters were used to establish a dedicated risk score (DR-FLASH score, based on diabetes mellitus, renal dysfunction, persistent form of AF, LA diameter >45 mm, age >65 years, female sex, and hypertension). This risk score was then prospectively validated in a multicenter cohort of 180 patients. The association of the score with long-term recurrence of atrial arrhythmias after circumferential PVI was tested in a retrospective cohort of 484 patients. RESULTS: The DR-FLASH score effectively identified LVA substrate (C statistic = 0.801, P < .001). In the prospective multicenter validation cohort, the predictive value of the DR-FLASH score was confirmed (C statistic = 0.767, P < .001). The probability for the presence of LA substrate increased by a factor of 2.2 (95% confidence interval [CI] 1.6-2.9, P < .001) with each point scored. Furthermore, the risk of AF recurrence after PVI increased by a factor of 1.3 (95% CI 1.1-1.5, P < .001) with every additional point and was almost 2 times higher in patients with a DR-FLASH score >3 (odds ratio 1.7, 95% CI 1.1-2.8, P = .026). CONCLUSION: The DR-FLASH score may be useful to identify patients who may require extensive substrate modification instead of PVI alone.

Catheter ablation of ventricular tachycardia and mortality in patients with nonischemic dilated cardiomyopathy: can noninducibility after ablation be a predictor for reduced mortality?

BACKGROUND: Data on outcomes after catheter ablation of ventricular tachycardia (VT) in patients with nonischemic dilated cardiomyopathy (NIDCM) are insufficient. We aimed to investigate the effects of successful catheter ablation of VT on cardiac mortality in patients with NIDCM. METHODS AND RESULTS: One hundred two patients with NIDCM (86 men; mean age, 58.8±15.2 years; mean ejection fraction, 33.3±11.9%) underwent VT ablation. After catheter ablation, a programmed ventricular stimulation to test for success was performed. Complete VT noninducibility was achieved in 62 (61%) patients and partial success or failure in 32 (31%) patients. During 2 years of follow-up, VT recurrence was observed in 33 patients (53%) without inducible VTs and in 24 patients (75%) with inducible VT inducible (P=0.041). VT inducibility was associated with higher VT recurrence (adjusted hazard ratio, 1.84; 95% confidence interval, 1.08-3.13; P=0.025). The primary end point of all-cause mortality was reached in 9 patients (15%) with noninducible VTs versus 11 patients (34%) with inducible sustained VTs (P=0.026). VT inducibility was associated with all-cause mortality (adjusted hazard ratio, 2.73; 95% confidence interval, 1.003-7.43; P=0.049). CONCLUSIONS: In patients with NIDCM and recurrent sustained VTs, a complete ablation of all inducible VTs may be achieved in 60% of the cases. The complete noninducibility may be a preferable end point of ablation because it was associated with better long-term success. Importantly, if possible to achieve through ablation, a complete VT noninducibility was associated with reduction of the likelihood for all-cause mortality in patients with NIDCM.

Differentiating the origin of outflow tract ventricular arrhythmia using a simple, novel approach.

BACKGROUND: Numerous electrocardiographic (ECG) criteria have been proposed to identify localization of outflow tract ventricular arrhythmias (OT-VAs); however, in some cases, it is difficult to accurately localize the origin of OT-VA using the surface ECG. OBJECTIVE: The purpose of this study was to assess a simple criterion for localization of OT-VAs during electrophysiology study. METHODS: We measured the interval from the onset of the earliest QRS complex of premature ventricular contractions (PVCs) to the distal right ventricular apical signal (the QRS-RVA interval) in 66 patients (31 men aged 53.3 ± 14.0 years; right ventricular outflow tract [RVOT] origin in 37) referred for ablation of symptomatic outflow tract PVCs. We prospectively validated this criterion in 39 patients (22 men aged 52 ± 15 years; RVOT origin in 19). RESULTS: Compared with patients with RVOT PVCs, the QRS-RVA interval was significantly longer in patients with left ventricular outflow tract (LVOT) PVCs (70 ± 14 vs 33.4±10 ms, P < .001). Receiver operating characteristic analysis showed that a QRS-RVA interval ≥49 ms had sensitivity, specificity, and positive and negative predictive values of 100%, 94.6%, 93.5%, and 100%, respectively, for prediction of an LVOT origin. The same analysis in the validation cohort showed sensitivity, specificity, and positive and negative predictive values of 94.7%, 95%, 95%, and 94.7%, respectively. When these data were combined, a QRS-RVA interval ≥49 ms had sensitivity, specificity, and positive and negative predictive values of 98%, 94.6%, 94.1%, and 98.1%, respectively, for prediction of an LVOT origin. CONCLUSION: A QRS-RVA interval ≥49 ms suggests an LVOT origin. The QRS-RVA interval is a simple and accurate criterion for differentiating the origin of outflow tract arrhythmia during electrophysiology study; however, the accuracy of this criterion in identifying OT-VA from the right coronary cusp is limited.

Early referral for ablation of scar-related ventricular tachycardia is associated with improved acute and long-term outcomes: results from the Heart Center of Leipzig ventricular tachycardia registry.

BACKGROUND: The effects of time to referral for catheter ablation (CA) of scar-related ventricular tachycardia (VT) on acute success, VT recurrence, and cardiac mortality are unclear. METHODS AND RESULTS: We investigated 300 patients after CA of sustained VT. CA was performed within 30 days after the first documented VT in 75 (25%) patients (group 1), between 1 month and 1 year in 84 (28%) patients (group 2), and >1 year after the first VT occurrence in 141 (47%) patients (group 3). The end points were noninducibility of any VT after CA (acute success), VT recurrence and cardiac mortality after 2 years. Acute success was achieved in 66 (88%) patients in group 1, 68 (81%) in group 2, and in 99 (70.2%) in group 3 (P=0.008). During the 2-year follow-up period, VT recurred in 28 (37.3%) patients in group 1, 52 (61.9%) patients in group 2, and 91 (64.5%) patients in group 3 (P<0.0001). Recurrence-free survival was higher in group 1, as compared with group 2 (hazard ratio [HR], 1.85; P=0.009) and group 3 (HR, 2.04; P=0.001). No survival difference was observed between groups 1 and 2 (HR, 0.85; P=0.68) and groups 1 and 3 (HR, 1.13; P=0.73). ß-blocker therapy, VT of ischemic origin, and complete success were associated with VT-free survival. VT recurrence (HR, 1.91; P=0.037) predicted cardiac mortality. CONCLUSIONS: CA of scar-related VT performed within 30 days after the first documented VT was associated with improved acute and long-term success. VT recurrence, but not the early referral for CA, was associated with cardiovascular mortality.

Treatment with novel oral anticoagulants in a real-world cohort of patients undergoing cardiac rhythm device implantations.

AIMS: The safety and efficacy of novel oral anticoagulants in patients with atrial fibrillation undergoing pacemaker or implantable cardioverter-defibrillator interventions have not been clearly defined. Therefore, we compared the incidence of bleeding and thrombo-embolic complications following cardiac rhythm device (CRD) implantations under dabigatran vs. rivaroxaban in a real-world cohort. METHODS AND RESULTS: We analysed 176 consecutive procedures performed in 93 patients treated peri-interventionally with dabigatran and 83 patients with rivaroxaban, respectively. Post-operative bleeding complications and thrombo-embolic events occurring within 30 days were compared. There were no significant differences in baseline characteristics between patients in the dabigatran and the rivaroxaban group. Most of the patients in both the groups received dual chamber or cardiac resynchronization devices (71 vs. 78%) as opposed to single-chamber systems (29 vs. 22%). In the dabigatran group, two (2%) bleeding complications (two pocket haematomas) were observed in comparison with four (5%, three pocket haematomas and one pericardial effusion) in the rivaroxaban group (P = 0.330). Three complications in the rivaroxaban group necessitated surgical intervention as opposed to none in the dabigatran group (P = 0.064). One case of a transient ischaemic attack occurred in the dabigatran group (P = 0.343). CONCLUSION: Bleeding and thrombo-embolic complications in patients treated with dabigatran or rivaroxban are rare. Further and larger studies are warranted to define the optimal anticoagulation management in patients with a need for oral anticoagulation and CRD interventions.

Long-term efficacy of single procedure remote magnetic catheter navigation for ablation of ischemic ventricular tachycardia: a retrospective study.

BACKGROUND: Remote magnetic navigation (RMN) aims to reduce some inherent limitations of manual radiofrequency (RF) ablation. However, data comparing the effectiveness of both methods are scarce. This study evaluated the acute and long-term success of RMN guided versus manual RF ablation in patients with ischemic sustained ventricular tachycardia (sVT). METHODS: One hundred two consecutive patients (age 68 ± 10 years, LVEF 32 ± 12%, 88 men) with ischemic sVT were ablated with RMN (Stereotaxis; 49%) or manually (51%) using substrate and/or activation mapping (Carto) and open-irrigated-tip catheters. All received implantable defibrillators or loop recorders. Acute success was defined as noninducibility of any sVT at the end of the ablation procedure and long-term success as freedom from VT upon follow-up. RESULTS: There was no difference in the baseline characteristics between the groups. Three patients died in hospital. Acute success rate was similar for RMN and manual ablation (82% vs 71%, P = 0.246). RMN was associated with significantly shorter fluoroscopy time (13 ± 12 minutes vs 32 ± 17 minutes, P = 0.0001) and RF time (2337.59 ± 1248.22 seconds vs 1589.95 ± 1047.42 seconds, P = 0.049), although total procedure time was similar (157 ± 40 minutes vs 148 ± 50 minutes, P = 0.42). There was a nonsignificant trend toward better long-term success in RMN group: after a median of 13 (range 1-34) months, 63% in the RMN and 53% in the manual ablation group were free from VT recurrence (P = 0.206). CONCLUSION: RMN guided RF ablation of ischemic sustained VT is equally efficient compared with manual ablation in terms of acute and long-term success rate. These results are achieved with a significantly reduced fluoroscopy time and shorter RF time.