Artificial intelligence software standardizes electrogram-based ablation outcome for persistent atrial fibrillation.

INTRODUCTION: Multiple groups have reported on the usefulness of ablating in atrial regions exhibiting abnormal electrograms during atrial fibrillation (AF). Still, previous studies have suggested that ablation outcomes are highly operator- and center-dependent. This study sought to evaluate a novel machine learning software algorithm named VX1 (Volta Medical), trained to adjudicate multipolar electrogram dispersion. METHODS: This study was a prospective, multicentric, nonrandomized study conducted to assess the feasibility of generating VX1 dispersion maps. In 85 patients, 8 centers, and 17 operators, we compared the acute and long-term outcomes after ablation in regions exhibiting dispersion between primary and satellite centers. We also compared outcomes to a control group in which dispersion-guided ablation was performed visually by trained operators. RESULTS: The study population included 29% of long-standing persistent AF. AF termination occurred in 92% and 83% of the patients in primary and satellite centers, respectively, p = 0.31. The average rate of freedom from documented AF, with or without antiarrhythmic drugs (AADs), was 86% after a single procedure, and 89% after an average of 1.3 procedures per patient (p = 0.4). The rate of freedom from any documented atrial arrhythmia, with or without AADs, was 54% and 73% after a single or an average of 1.3 procedures per patient, respectively (p < 0.001). No statistically significant differences between outcomes of the primary versus satellite centers were observed for one (p = 0.8) or multiple procedures (p = 0.4), or between outcomes of the entire study population versus the control group (p > 0.2). Interestingly, intraprocedural AF termination and type of recurrent arrhythmia (i.e., AF vs. AT) appear to be predictors of the subsequent clinical course. CONCLUSION: VX1, an expertise-based artificial intelligence software solution, allowed for robust center-to-center standardization of acute and long-term ablation outcomes after electrogram-based ablation.

Prognostic value of left ventricular reverse remodeling and performance improvement after cardiac resynchronization therapy: A prospective study.

BACKGROUND: The present study was designed to evaluate the respective value of left ventricular (LV) reverse remodeling (changes in LV end-systolic volume relative to baseline (ΔLVESV)) or LV performance improvement (ΔLV ejection fraction (ΔLVEF) or ΔGlobal longitudinal strain (GLS)) to predict long-term outcome in a prospective cohort of consecutive patients receiving routine cardiac resynchronization therapy (CRT). METHODS: One hundred and seventy heart failure patients (NYHA classes II-IV, LVEF ≤ 35%, QRS width ≥ 120 ms) underwent echocardiography before and 9 months after CRT. The relationships between ΔLVESV, ΔLVEF, ΔGLS and outcome (all-cause mortality and/or CHF hospitalization, overall mortality, cardiovascular mortality, CHF hospitalization) were investigated. RESULTS: During a median follow-up of 32 months, 20 patients died and 27 were hospitalized for heart failure. ΔLVESV, ΔLVEF or ΔGLS were significantly associated with all-cause mortality or CHF hospitalization (adjusted hazard's ratio (HR) per standard deviation 0.58 (0.43-0.77), 0.39 (0.27-0.57) or 0.55 (0.37-0.83) respectively, all p < 0.01) and all other endpoints (all p < 0.01). Patients with ΔLVESV≥15%, ΔLVEF ≥ 10% and ΔGLS ≥ 1% had a reduced risk of mortality or CHF hospitalization (adjusted HR=0.25 (0.12-0.51), p < 0.001, adjusted HR = 0.26 (0.13-0.54), p < 0.001 and adjusted HR 0.38 (0.19-0.75), p = 0.006 respectively). Overall performance of multivariate models was better using ΔLVESV or ΔLVEF compared with ΔGLS. Interobserver agreement was excellent for ΔLVESV (Intraclass correlation coefficient - ICC-0.91) and ΔGLS (ICC 0.90) but modest for ΔLVEF (ICC 0.76) in a sample of 20 patients from the study population. CONCLUSIONS: LV reverse remodeling assessed by ΔLVESV is a strong and reproducible predictor of outcome following CRT. Compared with ΔLVESV, ΔLVEF and ΔGLS have important shortcomings: poorer reproducibility or lower predictive value.

Prognostic importance of postoperative QRS widening in patients with heart failure receiving cardiac resynchronization therapy.

BACKGROUND: Landmark reports have suggested that patients with QRS widening immediately after cardiac resynchronization therapy (CRT) experienced less frequently reverse left ventricular remodeling during follow-up. OBJECTIVE: We sought to investigate the relationship between postoperative QRS widening relative to baseline and mortality in a prospective cohort of heart failure patients receiving CRT. METHODS: A 12-lead electrocardiogram was recorded for 237 heart failure patients (New York Heart Association class II to IV, left ventricular ejection fraction ≤35%, and QRS width ≥120 ms) before and immediately after CRT device implantation. The relationships between QRS widening, all-cause and cardiovascular mortality, and echocardiographic response to CRT were studied. RESULTS: During a median follow-up of 24 months, 39 patients died. Fifty patients (21%) experienced QRS widening after CRT [QRS(+) group]. During follow-up, all-cause mortality was higher in QRS(+) patients than in QRS(-) patients (36-month survival free from death 81% ± 7% vs 64% ± 16%; log rank, P = .029). After adjustment for important prognostic confounders, QRS(+) patients remained associated with an excess overall mortality (adjusted hazard ratio [HR] 2.67; 95% confidence interval 1.07-6.65; P = .035) and cardiovascular mortality (adjusted hazard ratio 3.63; 95% confidence interval 1.13-11.65; P = .03). QRS(+) patients were less frequent responders to CRT than were QRS(-) patients (20 [47%] vs 136 [83%]; P < .0001). CONCLUSION: Postoperative QRS widening relative to baseline after CRT is associated with a considerable increased mortality risk during follow-up. Whether QRS narrowing should be achieved to optimize CRT placement, and thereby increase the rate of CRT responders and improve outcome, deserves further research.

[Implantation of a pacemaker through persistent left superior vena cava]. / Implantación de un marcapaso a través de una vena cava superior izquierda persistente: utilidad del registro de actividad eléctrica endocavitaria.

Persistent left superior vena is a relatively rare congenital variant. It is, however, the most common variation of the thoracic venous system. Prevalence is estimated in about 0.6 to 1.0% during pacemaker placement. This finding, often incidental, can difficult the lead progression through the left jugular or subclavian routes. This report describes a case of successful pacemaker implantation through a persistent left superior vena. Technical difficulties were overcome using the pacemaker electrode as unipolar lead. Endocavitary ECG recording helped us to guide the lead through the tortuous anatomy. A stable lead position was finally achieved by means of the active fixation system of the pacemaker electrode.

Relationship between two-dimensional speckle-tracking septal strain and response to cardiac resynchronization therapy in patients with left ventricular dysfunction and left bundle branch block: a prospective pilot study.

BACKGROUND: Previous studies have demonstrated variable patterns of longitudinal septal deformation in patients with left ventricular (LV) dysfunction and left bundle branch block. This prospective single center study was designed to assess the relationship between septal deformation patterns obtained by two-dimensional speckle-tracking echocardiography and response to cardiac resynchronization therapy (CRT). METHODS: One hundred one patients with New York Heart Association class II to IV heart failure, LV ejection fractions ≤ 35%, and left bundle branch block underwent echocardiography before CRT. Longitudinal two-dimensional speckle-tracking strain analysis in the apical four-chamber view identified three patterns: double-peaked systolic shortening (pattern 1), early pre-ejection shortening peak followed by prominent systolic stretch (pattern 2), and pseudonormal shortening with a late systolic shortening peak and less pronounced end-systolic stretch (pattern 3). CRT response was defined as a relative reduction in LV end-systolic volume of ≥ 15% at 9-month follow-up. CRT super-response was defined as an absolute LV ejection fraction of ≥ 50% associated with a relative reduction in LV end-systolic volume of ≥ 15% and an improvement in New York Heart Association functional class. Cardiac death or hospitalization for heart failure during follow-up was systematically investigated. RESULTS: Ninety-two percent of patients with pattern 1 or 2 were responders to CRT compared with 59% with pattern 3 (P < .0001). Thirty-six percent of patients with pattern 1 were super-responders compared with 15% of those with pattern 2 and 12% of those with pattern 3 (P = .037). The improvement in LV volumes, LV ejection fraction, and global longitudinal strain after CRT was better in patients with pattern 1 or 2 compared with those with pattern 3 (P < .0001 for all). Eighteen-month outcomes were excellent in patients with pattern 1 or 2, with event-free survival of 95 ± 3% compared with 75 ± 7% in patients with pattern 3 (P = .010). CONCLUSIONS: Septal deformation strain pattern 1 or 2 is highly predictive of CRT response. Further studies are needed to identify predictors of "nonresponse" in patients with a pattern 3.

Interference between pacemaker and video capsule endoscopy.

The wireless capsule video endoscopy is useful in patients with occult blood loss, but is contraindicated in patients with cardiac pacemaker (PM). No case of interference has been published. We report the case of a patient with a PM implanted in the abdominal wall. After capsule ingestion, cardiac monitoring showed no modification of the PM compartment (VOO, unipolar mode) but the capsule recording reveal more than 3 hours of loss of image. The wireless capsule endoscopy is safe in patients with PMs in VOO mode. Nevertheless important interference was noted in the recording when the capsule was near the PM.

Mechanisms of onset of atrial fibrillation: a multicenter, prospective, pacemaker-based study.

The aim of this study was to analyze the onset mechanisms of atrial tachyarrhythmias using a dedicated diagnostic system in 83 recipients of DDDR pacemakers implanted for standard clinical indications. The pulse generator was programmed in DDD mode, at 60 beats/min, and the diagnostic instrument was programmed to document atrial tachyarrhythmic episodes at rates >200 beats/min. Onset mechanism was defined as the combination of ambient rhythm and trigger. Various underlying rates and rhythms patterns, including tachycardia, increasing frequency of premature atrial complex (PAC), underlying heart rate increase, restart, and no specific underlying rhythm, and various triggers, including single, multiple, or short runs of PACs, sudden rate decrease, and sudden onset of atrial tachyarrhythmia were included in the combined classification. Atrial tachyarrhythmic episodes were documented on one follow-up interrogation in 48 of the 83 patients. The pacing indications consisted of high degree atrioventricular block in 19 patients, bradycardia-tachycardia syndrome in 22, and isolated sinus node dysfunction in 6 patients. The onset mechanisms of 318 episodes were recorded and analyzed. A variety of triggers were observed in 33 of the 48 patients, and 39 patients had various ambient rhythms. Among 20 documented onset mechanisms, the most common were increasing frequency of PAC + short runs (17%), no specific ambient rhythm + sudden onset (24%), and increasing frequency of PAC + sudden onset (12%). There were wide intra- and interpatient variations in onset mechanisms, suggesting that state-of-the-art pacemakers should represent versatile diagnostic tools and offer flexible pacing methods to refine the management of atrial tachyarrhythmias.

Implantación de un marcapaso a través de una vena cava superior izquierda persistente: Utilidad del registro de actividad eléctrica endocavitaria / Implantation of a pacemaker through persistent left superior vena cava

La presencia de una vena cava superior izquierda persistente es una variante congénita poco frecuente. Es, sin embargo, la anomalía más común del sistema venoso torácico. Su prevalencia ha sido estimada en 0.6 a 1.0% durante la implantación de marcapasos. Este hallazgo, frecuentemente incidental, puede dificultar la progresión del electrodo del marcapaso a través de los abordajes yugular o subclavio izquierdos. En este reporte presentamos la exitosa implantación de un marcapaso a través de una vena cava superior izquierda persistente. Las dificultades técnicas durante el procedimiento fueron resueltas usando el cable del marcapaso a manera de electrodo unipolar. El registro del electrograma endocavitario nos ayudó a guiar el electrodo a través de la anatomía difícil. Una posición estable final se logró mediante la utilización de un sistema de fijación activa.

Persistent left superior vena is a relatively rare congenital variant. It is, however, the most common variation of the thoracic venous system. Prevalence is estimated in about 0.6 to 1.0% during pacemaker placement. This finding, often incidental, can difficult the lead progression through the left jugular or subclavian routes. This report describes a case of successful pacemaker implantation through a persistent left superior vena. Technical difficulties were overcome using the pacemaker electrode as unipolar lead. Endocavitary ECG recording helped us to guide the lead through the tortuous anatomy. A stable lead position was finally achieved by means of the active fixation system of the pacemaker electrode.