A decade of catheter ablation of cardiac arrhythmias in Sweden: ablation practices and outcomes.

AIMS: Catheter ablation is considered the treatment of choice for many tachyarrhythmias, but convincing 'real-world' data on efficacy and safety are lacking. Using Swedish national registry data, the ablation spectrum, procedural characteristics, as well as ablation efficacy and reported adverse events are reported. METHODS AND RESULTS: Consecutive patients (≥18 years of age) undergoing catheter ablation in Sweden between 01 January 2006 and 31 December 2015 were included in the study. Follow-up (repeat ablation and vital status) was collected through 31 December 2016. A total of 26 642 patients (57 ± 15 years, 62% men), undergoing a total of 34 428 ablation procedures were included in the study. In total, 4034 accessory pathway/Wolff-Parkinson-White syndrome (12%), 7358 AV-nodal re-entrant tachycardia (21%), 1813 atrial tachycardia (5.2%), 5481 typical atrial flutter (16%), 11 916 atrial fibrillation (AF, 35%), 2415 AV-nodal (7.0%), 581 premature ventricular contraction (PVC, 1.7%), and 964 ventricular tachycardia (VT) ablations (2.8%) were performed. Median follow-up time was 4.7 years (interquartile range 2.7-7.0). The spectrum of treated arrhythmias changed over time, with a gradual increase in AF, VT, and PVC ablation (P < 0.001). Decreasing procedural times and utilization of fluoroscopy with time, were seen for all arrhythmia types. The rates of repeat ablation differed between ablation types, with the highest repeat ablation seen in AF (41% within 3 years). The rate of reported adverse events was low (n = 595, 1.7%). Death in the immediate period following ablation was rare (n = 116, 0.34%). CONCLUSION: Catheter ablations have shifted towards more complex procedures over the past decade. Fluoroscopy time has markedly decreased and the efficacy of catheter ablation seems to improve for AF.

An easy-to-use, operator-independent, clinical model to predict the left vs. right ventricular outflow tract origin of ventricular arrhythmias.

AIMS: To identify clinical characteristics able to predict a left ventricular outflow tract (LVOT) origin in outflow tract ventricular arrhythmias (OTVAs). METHODS AND RESULTS: We included 117 consecutive patients (training sample) with successful radiofrequency ablation of OTVA in one centre. A predictive model for LVOT origin was obtained using clinical data. The model was prospectively validated in a second population (testing sample) of 143 patients from two additional centres. In training sample, mean age was 54 ± 17 years, 72 patients (61%) were male, and 63 (54%) had cardiovascular risk factors. Sixty (51%) patients had LVOT origin. Independent predictors for LVOT origin were the presence of hypertension [odds ratio (OR) 2.17, confidence interval (CI) 0.91-6.20, P = 0.09], male gender (OR 4.83, 95% CI 1.89-12.33, P < 0.001), and age >50 years (OR 4.46, 95% CI 1.57-12.7, P = 0.005). A simple score was constructed with these three variables to predict LVOT origin (mean predicted probability of 15% for score 0, 26% for score 1, 60% for score 2, and 87% for score 3, P < 0.001) and reached 80% sensitivity and 75% specificity. The score was validated in the testing sample and was not inferior to previously described electrocardiogram algorithms. CONCLUSION: Patients currently referred for OTVA ablation are older, more frequently men, and with a higher probability for LVOT origin than previously described. A LVOT origin is associated with the presence of hypertension, male gender, and older age, and can be anticipated by using a simple clinical score.

Scar dechanneling: new method for scar-related left ventricular tachycardia substrate ablation.

BACKGROUND: Ventricular tachycardia (VT) substrate ablation usually requires extensive ablation. Scar dechanneling technique may limit the extent of ablation needed. METHODS AND RESULTS: The study included 101 consecutive patients with left ventricular scar-related VT (75 ischemic patients; left ventricular ejection fraction, 36 ± 13%). Procedural end point was the elimination of all identified conducting channels (CCs) by ablation at the CC entrance followed by abolition of residual inducible VTs. By itself, scar dechanneling rendered noninducibility in 54.5% of patients; ablation of residual inducible VT increased noninducibility to 78.2%. Patients needing only scar dechanneling had a shorter procedure (213 ± 64 versus 244 ± 71 minutes; P = 0.027), fewer radiofrequency applications (19 ± 11% versus 27 ± 18%; P = 0.01), and external cardioversion/defibrillation shocks (20% versus 65.2%; P < 0.001). At 2 years, patients needing scar dechanneling alone had better event-free survival (80% versus 62%) and lower mortality (5% versus 11%). Incomplete CC-electrogram elimination was the only independent predictor (hazard ratio, 2.54 [1.06-6.10]) for the primary end point. Higher end point-free survival rates were observed in patients noninducible after scar dechanneling (log-rank P = 0.013) and those with complete CC-electrogram elimination (log-rank P = 0.013). The complications rate was 6.9%, with no deaths. CONCLUSIONS: Scar dechanneling alone results in low recurrence and mortality rates in more than half of patients despite the limited ablation extent required. Residual inducible VT ablation improves acute results, but patients who require it have worse outcomes. Recurrences are mainly related to incomplete CC-electrogram elimination.

Impact of earliest activation site location in the septal right ventricular outflow tract for identification of left vs right outflow tract origin of idiopathic ventricular arrhythmias.

BACKGROUND: The earliest activation site (EAS) location in the septal right ventricular outflow tract (RVOT) could be an additional mapping data predictor of left ventricular outflow tract (LVOT) vs RVOT origin of idiopathic ventricular arrhythmias (VAs). OBJECTIVE: The purpose of this study was to assess the impact of EAS location in predicting LVOT vs RVOT origin. METHODS: Macroscopic and histologic study was performed in 12 postmortem hearts. Electroanatomic maps (EAMs) from 37 patients with outflow tract (OT) VA with the EAS in the septal RVOT were analyzed. Pulmonary valve (PV) was defined by voltage scanning after validation of voltage thresholds by image integration. EAM measurements were correlated with those of macroscopic/histologic study. RESULTS: A cutoff value of 1.9 mV discriminated between subvalvular and supravalvular positions (90% sensitivity, 96% specificity). EAS ≥1 cm below PV excluded RVOT site of origin (SOO). According to anatomic findings (distance PV-left coronary cusp = 5 ± 3 vs PV-right coronary cusp = 11 ± 5 mm), EAS-PV distance was significantly shorter in VAs arising from left coronary cusp than from the other LVOT locations (4.2 ± 5.4 mm vs 9.2 ± 7 mm; P = .034). The 10-ms isochronal longitudinal/perpendicular diameter ratio was higher in the RVOT vs the LVOT SOO group (1.97 ± 1.2 vs 0.79 ± 0.49; P = .001). An algorithm based on EAS-PV distance and the 10-ms isochronal longitudinal/perpendicular diameter ratio predicted LVOT SOO with 91% sensitivity and 100% specificity. CONCLUSION: An algorithm based on the EAS-PV distance and the 10-ms isochronal longitudinal/perpendicular diameter ratio accurately predicts LVOT vs RVOT SOO in outflow tract VAs with EAS in the septal RVOT.

Mapping data predictors of a left ventricular outflow tract origin of idiopathic ventricular tachycardia with V3 transition and septal earliest activation.

BACKGROUND: The proximity of the outflow tracts (OTs) frequently results in an overlap in surface electrocardiographic features of ventricular arrhythmias originating from this anatomic region, particularly when the transition occurs in lead V3. In addition, no reliable criteria to discriminate between a right ventricular OT (RVOT) and a left ventricular OT (LVOT) site of origin (SOO) are derived from intracardiac mapping. METHODS AND RESULTS: A series of 15 patients underwent ablation because of OT ventricular arrhythmias having a V3 transition, and a septal earliest activation on the RVOT was included in the study. Electrocardiographic and mapping data were collected to analyze accuracy in predicting the RVOT versus the LVOT SOO of the ventricular arrhythmia. A 10-ms isochronal map area in the RVOT was smaller in the RVOT SOO group (1.2 [0.4-2.1] versus 3.4 [2.4-3.9] cm2, respectively; P=0.004) and had a shorter perpendicular diameter (13 [7-17] versus 28 [20-29] mm; P=0.001) and a higher longitudinal/perpendicular axis ratio (1.04 [0.95-1.11] versus 0.49 [0.44-0.57]; P=0.001). A 10-ms isochronal map area>2.3 cm2 predicted an LVOT origin with 85.7% sensitivity and 87.5% specificity, whereas a longitudinal/perpendicular axis ratio<0.8 predicted an LVOT origin with 100% sensitivity and 100% specificity. Electrocardiography-derived parameters showed lower values of sensitivity and specificity. The distal coronary sinus activation mapping did not permit distinction between RVOT and LVOT SOO. CONCLUSIONS: The 10-ms isochronal map area and the longitudinal/perpendicular axis ratio accurately predict the RVOT versus the LVOT SOO in patients with OT ventricular arrhythmias, a V3 transition, and a septal earliest activation.

Displacement of the target ablation site and ventricles during premature ventricular contractions: relevance for radiofrequency catheter ablation.

BACKGROUND: During premature ventricular contractions (PVCs), a spatial displacement of the ventricles and the target ablation site with respect to the sinus rhythm (SR) position is observed during mapping and ablation. OBJECTIVES: To analyze this displacement and its relevance for image integration and PVC ablation. METHODS: The electroanatomical activation maps (EAMs) of 55 consecutive patients who underwent PVC ablation were analyzed. Spatial displacement between each point position during PVC and SR was obtained. RESULTS: A total of 6923 points from 71 EAMs were analyzed. Overall, the median distance between the point position during SR and PVC for all the points was 9.42 mm (interquartile range [IQR]: 6.19-12.85). The EAM points from the right ventricle showed more displacement than did those from the left ventricle: 10.35 mm (IQR: 7.16-13.95) vs 7.62 mm (IQR: 5.20-10.81); P <.001. The ventricular end-diastolic volume of the EAM during SR was greater than that during PVC (median difference: 9.75 [IQR: 0.37-19.67] mL; P = .002). A shorter coupling interval of the PVC was associated with greater spatial displacement (r = -.521; P <.001), higher end-diastolic volume reduction with respect to the SR beat (r = -.718; P = .001), and worse image integration (mean point-to-surface distance between EAM and 3-dimensional computed tomography-derived structure; r = -.642; P = .018). CONCLUSIONS: There is a significant spatial displacement between the point position in SR and PVC, mainly in the right ventricle. This displacement increases with the shortening of the PVC coupling interval and can result in poorer image fusion and difficult catheter navigation/positioning for ablation.

Combined endocardial and epicardial catheter ablation in arrhythmogenic right ventricular dysplasia incorporating scar dechanneling technique.

BACKGROUND: Ventricular tachycardia (VT) ablation in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) has a low success rate. A more extensive epicardial (Epi) arrhythmogenic substrate could explain the low efficacy. We report the results of combined endocardial (Endo) and Epi VT ablation and conducting channel (CC) elimination. METHODS AND RESULTS: Eleven consecutive patients with ARVD/C were included in the study. A high-density 3D Endo (321±93 sites mapped) and Epi (302±158 sites mapped) electroanatomical voltage map was obtained during sinus rhythm to define scar areas (<1.5 mV) and CCs inside the scars, between scars, or between the tricuspid annulus and a scar. The end point of the ablation procedure was the elimination of all identified CCs (scar dechanneling) and the abolition of all inducible VTs. The mean procedure and fluoroscopy time were 177±63 minutes and 20±8 minutes, respectively. Epi scar area was larger in all cases (26±18 versus 94±45 cm(2), P<0.01). The combined Endo and Epi VT ablation eliminated all clinical and induced VTs, and the addition of scar dechanneling resulted in noninducibility in all cases. Seven patients continued on sotalol. During a median follow-up of 11 months (6-24 months), only 1 (9%) patient had a VT recurrence. There was a single major bleeding event that did not preclude a successful procedure. CONCLUSIONS: Combined Endo and Epi mapping reveals a wider Epi VT substrate in patients with ARVD/C with clinical VTs. As a first-line therapy, combined Endo and Epi VT ablation incorporating scar dechanneling achieves a very good short- and midterm success rate.

Long-term arrhythmia variability after monomorphic ventricular tachycardia in patients with an implantable cardioverter defibrillator.

BACKGROUND: Arrhythmia burden in patients receiving an implantable cardioverter defibrillator (ICD) after monomorphic ventricular tachycardia (mVT) is higher than in patients with other indications. We investigated the long-term arrhythmia profile in this subset of patients. METHODS: Fifty-two patients with an ICD implanted after mVT were followed up for at least 3 months. The cycle lengths (CLs) of the tachycardias recovered from the device memory were compared with the CL of the index arrhythmia. Morphological analysis of the intracardiac electrograms was performed and the response to antitachycardia pacing (ATP) was also assessed. RESULTS: A total of 833 mVT episodes with intracardiac electrograms occurred during the follow-up (3-58 months; mean: 30.3 months) in 41 of the 52 patients analyzed. mVTs with different CLs as compared with the index mVT were found in 26 (50.0%), and at least two different mVT morphologies were observed in 28 (53.8%) patients. Multiple mVT morphologies were predictive of lower ATP efficacy (95.6%, 85.0%, and 70.3% in the patients with 1, 2, and 3 or more mVT morphologies, respectively; P < 0.0001) and a higher shock burden (4.2%, 19.3%, and 24.7% in the patients with 1, 2, and 3 or more mVT morphologies, respectively; P < 0.0001). CONCLUSION: A high mVT burden was demonstrated with marked variability of the arrhythmias as concerns both CL and morphology in patients with an ICD implanted for mVT. Multiple mVT morphologies during the follow-up were predictive of lower ATP efficacy and a higher shock burden.

[Cryoballon isolation of the pulmonary veins in atrial fibrillation: mid-term results after the first 55 patients]. / Pitvarfibrilláció kezelése a pulmonalis vénák krioballon-izolációjával: Középtávú eredmények az elsô 55 beteg alapján.

UNLABELLED: Several transcatheter techniques based on radiofrequency energy were elaborated for the treatment of atrial fibrillation through the last decade. Recently, similar success rates with a better safety profile concerning life threatening complications were reported with the novel methode of cryoballon isolation of the pulmonary veins. This paper summarizes our initial experience with cryoballon ablation after the first 55 patients. METHOD: [corrected] Symptomatic patients refractory to aniarrhythmic medication mostly with paroxysmal atrial fibrillation without significant structural heart disease were enrolled. Cannulation and isolation of all pulmonary veins were attempted using a 28 mm double-wall cryoballon inflated at the ostium of the vein and abolishing eletrical activity of atrial tissue around its perimeter by freezing to -70 C. Intravenous heparin during and oral anticoagulant after the procedure was administered. Conventional ECGs, Holter ECGs and transtelephonic ECG recordings were used through 6 months follow-up for rhythm monitoring. RESULTS: In 55 patients enrolled (18 female; age: 56 + or - 33,64 years) 165 out ot 192 (86%) pulmonary veins were successfully isolated. All pulmonary veins were isolated in 37 patients (67%). Procedure time was 155.67 + or - 100.66 min, while fluoroscopy time was 34.04 + or - 31.89 min. In 34 patients with 6 months follow-up 24 (70%) either remained free of arrhythmia (17 patients) or had a significant decrease in arrhythmia burden (7 patients). CONCLUSION: Based on our initial experience, cryoballon isolation of pulmonary veins appears to be a more simple procedure with similar efficacy to radiofrequency ablation in the treatment of atrial fibrillation.

[Multiple obliterative vascular disease. Challenge in diagnosis and in treatment]. / Multiplex obliteratív érbetegség. Kihívás a diagnosztikában és a kezelésben.

UNLABELLED: Currently, peripheral arterial disease is an underdiagnosed disorder. Several modifiable and non-modifiable risk factors have role in its development and progression. As system disorder it might be a part and an important predictor of fatal cardio- and cerebrovascular events. CASE REPORT: The authors describe the case of a 73-year-old male with multilocational vascular disorder, with simultaneously occurring carotid disease, critical limb ischaemia with aorto-bifemoral bypass, multiple infarction with mechanical complication, inoperable coronary disease and with implantable cardioverter defibrillator for ventricular arrhythmia. CONCLUSION: Peripheral arterial disease affects the whole vascular system and can progress into serious cardiac and cerebral manifestations causing the patient's death inspite of comprehensive treatment.

Radiofrequency catheter ablation of premature ventricular complexes improved left ventricular function in a non-responder to cardiac resynchronization therapy.

Frequent premature ventricular complexes (PVCs) have been demonstrated to cause tachycardiomyopathy in some individuals with a structurally normal heart. We report a patient with severe congestive cardiomyopathy which did not respond to cardiac resynchronization therapy (CRT). Ambulatory monitoring and interrogation of the device memory revealed frequent monomorphic PVCs that were considered a potential cause of the failure of CRT. Radiofrequency ablation of the focus at the postero-inferior left ventricle eliminated the arrhythmia, with a resultant rapid improvement in the clinical status and echo parameters. As PVCs are often associated with severe heart failure, the presence of frequent extrasystoles may be an underrecognized cause of a non-response to resynchronization therapy.