Autothreshold algorithm feasibility and safety in left bundle branch pacing.

AIMS: Autothreshold algorithms enable remote monitoring of patients with conventional pacing, but there is limited information on their performance in left bundle branch pacing (LBBP). Our objective was to analyse the behaviour of the autothreshold algorithm in LBBP and compare it with conventional pacing and manual thresholds during initial device programming (acute phase), after 1-7 days (subacute), and 1-3 months later (chronic). METHODS AND RESULTS: A prospective, non-randomized, single-centre comparative study was conducted. Consecutive patients with indication for cardiac pacing were enrolled. Implants were performed in the left bundle branch area or the right ventricle endocardium at the discretion of the operator. Left bundle branch pacing was determined according to published criteria. Autothreshold algorithm was activated in both groups whenever allowed by the device. Seventy-five patients were included, with 50 undergoing LBBP and 25 receiving conventional pacing. Activation of the autothreshold algorithm was more feasible in later phases, showing a favourable trend towards bipolar pacing. Failures in algorithm activation were primarily due to insufficient safety margins (82.8% in LBBP and 90% in conventional pacing). The remainder was attributed to atrial tachyarrhythmias (10.3% and 10%, respectively) and electrical noise (the remaining 6.9% in the LBBP group). In the LBBP group, there were not statistically significant differences between manual and automatic thresholds, and both remained stable during follow-up (mean increase of 0.50 V). CONCLUSION: The autothreshold algorithm is feasible in LBBP, with a favourable trend towards bipolar pacing. Automatic thresholds are similar to manual in patients with LBBP, and they remain stable during follow-up.

Septal fascicle involvement during a Purkinje-related ventricular tachycardia: Electroanatomic correlation using omnipolar technology.

Idiopathic verapamil-sensitive fascicular ventricular tachycardia (VT) is the most common form of Purkinje-related ventricular tachycardia (PRVT). Left septal fascicle (LSF) involvement and its connections with the other fascicles, have been recently reported as a pathophysiologic mechanism for this form of PRVT. We describe a case of idiopathic PRVT with LSF involvement using omnipolar technology (OT) mapping in relation to a false tendon. Ablation in the area with concealed fusion entrainment did not terminate the tachycardia. However, radiofrequency application in the area of LSF with manifest fusion entrainment, resulted in immediate tachycardia termination. Six months follow-up showed no tachycardia recurrence.

Ablation with zero-fluoroscopy of premature ventricular complexes from aortic sinus cusps: A single-center experience.

BACKGROUND: Catheter ablation of premature ventricular complexes from aortic sinus cusps (ASC-PVC) is a complex procedure that conventionally requires coronary catheterization (CC) to localize coronary artery ostium (CAO). Little published information is available on the mapping and ablation with zero-fluoroscopy (ZF) of ASC-PVC. The aim of the study was to determine the efficacy and safety of ASC-PVC ablation with a ZF approach guided by 3D intracardiac echocardiography integration in the electroanatomical mapping system (ICE 3D-EAM). METHODS: This observational study included one patient cohort treated conventionally and another treated with ICE 3D-EAM-guided ZF ablation. Clinical, efficacy, and safety outcomes were evaluated acutely and at 3 months follow-up. RESULTS: The study included 21 patients with ASC-PVC: 10 in the ZF group (age 49 ± 16 years, 60% males) and 11 in the control group (age 47 ± 15 years, 27% males). Fluoroscopy was not required for any patient in the ZF group. Acute success was obtained in 80% of the ZF group vs 55% of the control group (P = .36). The recurrence rate was 30% in the ZF group vs 27% in the control group (P = 1). One nonsevere complication was observed in the ZF group (P = .48). CONCLUSIONS: ZF catheter ablation of ASC-PVC guided by ICE 3D-EAM is feasible, effective, and safe.

Perfil clínico de la miocardiopatía arritmogénica del ventrículo derecho con afección asociada del izquierdo / Clinical profile of arrhythmogenic right ventricular cardiomyopathy with left ventricular involvement

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Taquicardia ventricular diagnosticada por ecocardiografía: ¿fallan los criterios diagnósticos clínicos y electrocardiográficos? / Echocardiographic diagnosis of ventricular tachycardia: is there a problem with clinical and electrocardiographic diagnostic criteria?

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Ablation of frequent PVC in patients meeting criteria for primary prevention ICD implant: Safety of withholding the implant.

BACKGROUND: Premature ventricular complex (PVC) ablation has been shown to improve left ventricular ejection fraction (LVEF) and New York Heart Association functional class in patients with left ventricular dysfunction. Both are considered key variables in predicting risk of sudden cardiac death. OBJECTIVE: The objective of this study was to assess whether ablation might remove the primary prevention (PP) implantable cardioverter-defibrillator (ICD) indication in patients with frequent PVC. METHODS: Sixty-six consecutive patients with PP-ICD indication and frequent PVC [33 (50%) men; mean age 53 ± 13 years; 11 (17%) with ischemic heart disease] underwent PVC ablation. The ICD was withheld and the indication was reevaluated at 6 and 12 months. RESULTS: LVEF progressively improved from 28% ± 4% at baseline to 42% ± 12% at 12 months (P < .001). New York Heart Association functional class improved from 2 patients with NYHA functional class I (3%) at baseline to 35 (53%) at 12 months (P < .001). The brain natriuretic peptide level decreased from 246 ± 187 to 176 ± 380 pg/mL (P = .004). The PP-ICD indication was removed in 42 patients (64%) during follow-up, from 38 (92%) of them at 6 months, showing an independent association with baseline PVC burden and successful sustained ablation. In patients with successful sustained ablation, a cutoff value of 13% PVC burden had a sensitivity of 100% and a specificity of 93% (area under the curve 99%) for removing ICD indication postablation. No sudden cardiac deaths or malignant ventricular arrhythmias were observed. CONCLUSION: In patients with frequent PVC and PP-ICD indication, ablation improves LVEF and, in most cases, allows removal of the indication. Withholding the ICD and reevaluating within 6 months of ablation seems to be a safe and appropriate strategy.