Durability of output-dependent QRS transition and left bundle branch capture in left bundle branch area pacing.

BACKGROUND: Although output-dependent QRS transition is a specific indicator that confirms left bundle branch (LBB) capture during left bundle branch area pacing (LBBAP), its durability remains unclear. OBJECTIVE: To evaluate the presence of output-dependent QRS transition and capture thresholds of the LBB and left ventricular septal myocardium (LVS) immediately and up to 1 year after the LBBAP procedure. METHODS: We enrolled 129 patients with successful LBBAP who were available for 1-year follow-up postoperatively. Threshold testing was performed immediately after LBBAP on postoperative day 0 (POD-0), after three days (POD-3), 6 months (POD-180), and 1 year (POD-360). RESULTS: Output-dependent QRS transition persisted in 64 (88%) patients on POD-360, from amongst the 73 patients with output-dependent QRS transition on POD-0. In contrast, 55 (98%) of 56 patients without QRS transition on POD-0 did not exhibit QRS transition thereafter. LBB thresholds were slightly elevated on POD-360, albeit without statistical significance, compared to those on POD-0 (1.22 ± 1.00 vs. 1.43 ± 1.29 V at 0.4 ms, p=0.26). The LBB thresholds increased by ≥1.5 V in 7 (11%) patients. However, in 93% of patients with an LBB threshold of ≤2.5 V on POD-0, LBB capture was maintained at 2.5 V on POD-360. LVS thresholds were similar on POD-0 and POD-360 (0.81 ± 0.36 vs. 0.83 ± 0.24 V, p=1.0), and did not increase by ≥1.5 V in any patient. CONCLUSION: Output-dependent QRS transitions were highly reproducible after implantation. Furthermore, LBB thresholds remained stable in most cases during the first postoperative year.

Difference in risk factors of silent brain infarction between paroxysmal and persistent atrial fibrillation.

BACKGROUND: Although silent brain infarction is an independent risk factor for subsequent symptomatic stroke and dementia in patients with nonvalvular atrial fibrillation, little is known regarding differences in risk factors for silent brain infarction between patients with paroxysmal and persistent nonvalvular atrial fibrillation. METHODS: This study population consisted of 190 neurologically asymptomatic patients (mean age, 64 ± 11 years) with nonvalvular atrial fibrillation (119 paroxysmal, 71 persistent) who were scheduled for catheter ablation. All patients underwent brain magnetic resonance imaging to screen for silent brain infarction prior to ablation. Transthoracic and transesophageal echocardiography was performed to screen for left atrial abnormalities (left atrial enlargement, spontaneous echo contrast, or left atrial appendage emptying velocity) and complex plaques in the aortic arch. RESULTS: Silent brain infarction was detected in 50 patients (26%) [26 patients (22%) in paroxysmal vs. 24 patients (34%) in persistent, p = 0.09]. Multiple logistic regression analysis indicated that age and diabetes mellitus or chronic kidney disease (estimated glomerular filtration rate < 60 mL/min/1.73 m2) were associated with silent brain infarction in patients with paroxysmal nonvalvular atrial fibrillation (p < 0.05), whereas no modifiable risk factors of silent brain infarction were observed in patients with persistent nonvalvular atrial fibrillation. CONCLUSIONS: These findings suggest that intensive intervention for diabetes mellitus and renal impairment from the paroxysmal stage or ablation therapy at the time of paroxysmal stage to prevent progression to persistent nonvalvular atrial fibrillation may prevent silent brain infarction and consequently reduce the risk of future symptomatic stroke.

Successful catheter ablation improves exercise tolerance in persistent atrial fibrillation patients, especially those with reduced ventricular contraction, preserved atrial function, or a high CHADS2 score.

BACKGROUND: It has been reported that rhythm control for persistent atrial fibrillation (per-AF) patients by catheter ablation improves their exercise tolerance, subjective symptoms, and quality of life (QoL). However, clinical factors that can predict future improvement of exercise capacity after successful catheter ablation in per-AF patients are unclear. METHODS: This study consisted of 62 patients (mean age 65.6 ±â€¯8.7 years, 77% males) with per-AF who underwent catheter ablation from June 2017 to May 2018. All patients were subjected to extended pulmonary vein isolation. Exercise tolerance was evaluated using a symptom-limited cardiopulmonary exercise test before and 3 months after catheter ablation. Primary endpoints were QoL measurements using an original questionnaire and functional assessments performed at 3 months. RESULTS: The questionnaire revealed significant improvement in QoL after catheter ablation (minimal metabolic equivalents occurring symptoms: from 5.48 ±â€¯1.14 to 5.64 ±â€¯1.06; p = 0.01). Endurance exercise characteristics improved significantly after catheter ablation, demonstrated by a shift in anaerobic threshold (from 13.3 ±â€¯3.0 to 15.2 ±â€¯3.3 ml/kg/min; p < 0.001), peak oxygen uptake (from 19.1 ±â€¯4.6 to 22.5 ±â€¯5.0 ml/kg/min; p < 0.001), and minute ventilation vs carbon dioxide production slope (from 28.3 ±â€¯6.1 to 25.7 ±â€¯3.8; p < 0.001). Multivariate Cox regression analysis revealed that a decreased left ventricular ejection fraction, high left atrial appendage velocity, and high CHADS2 score were identified as independent predictors of anaerobic threshold and a peak value of oxygen uptake with more than 20% improvement. CONCLUSIONS: Catheter ablation for per-AF patients improves QoL and exercise tolerance. The effect was especially remarkable in patients with reduced ventricular function, those who had a preserved atrial function, or those at high risk of thromboembolism.

Utility of the combination of simple electrocardiographic parameters for identifying mid-septal pacing.

INTRODUCTION: The electrocardiograms (ECG) criteria to anchor the lead to the right ventricular septum have not been established. This study aimed to identify ECG criteria of pacing at the right ventricular mid septum (RVMS) and investigate whether the paced QRS duration (pQRSd) from the RVMS was narrow. METHODS AND RESULTS: In 42 patients, ECG pacing at the basal anterior wall (BA), mid-anterior wall (MA), apex (AP), and mid septum (MS) was recorded. The pacing sites were validated by using right ventriculography and computed tomography. We estimated the ECG parameters and compared them among the four pacing sites. The combination of simple four paced-ECG parameters could reliably confirm the pacing at the RVMS. The area under the receiver-operating characteristics curve for the number of positive findings among the following: (a) positive QRS in lead aVL, (b) QRS notching in lead I, (c) precordial leads transition at less than V5, and (d) presence of isoelectric QRS in the inferior leads was 0.95 (95% confidence interval, 0.91-0.98) and the number of positive findings (≥3) had a sensitivity of 83.3% and a specificity of 93.7% for discriminating MS from the other sites. The pQRSd with three or more positive findings was significantly narrower than that with less than three positive findings (≥3: 137.4 ± 9.2 ms, <3: 151.8 ± 13.1 ms, P ≤ .05). CONCLUSION: The combination of ECG parameters can help identify right ventricular mid-septal pacing. The use of these parameters may enable the implantation of the pacing lead in the RVMS accurately and obtain a narrower QRS duration.

Prognostic value of high-sensitive troponin T for predicting cardiovascular events after atrial fibrillation ablation.

BACKGROUND AND OBJECTIVES: This study aimed to evaluate the utility of high-sensitive troponin T (hs-TnT) for predicting AF recurrence and major adverse cardiovascular events (MACE) after AF ablation. METHODS AND RESULTS: A total of 227 consecutive patients with AF (mean age, 66 ± 10 years; persistent AF, n = 98) who underwent an initial ablation were enrolled. We measured hs-TnT before AF ablation and divided the patients into three groups according to the hs-TnT level: low, lesser than or equal to 0.005 µg/L (n = 54); medium, 0.006-0.013 µg/L (n = 127); and high, greater than or equal to0.014 µg/L (n = 46). We evaluated the composite endpoint of AF recurrence or MACE (including death, stroke, acute coronary syndrome, and heart failure hospitalization) after the ablation. The median hs-TnT level was 0.008 µg/L. The values of chronic kidney disease prevalence, CHA2 DS2 -VASc score, B-type natriuretic peptide level, and left atrial diameter were the highest in the high hs-TnT group among the three groups. During a mean follow-up of 15 ± 8 months, AF recurrence and MACE occurred in 56 (25%) and 9 (4%) patients, respectively. The high hs-TnT group had the highest incidence of AF recurrence and MACE among the three groups (high: 39% and 15%, medium: 22% and 2%, and low: 19% and 0%, respectively; log-rank P < .05). In multivariate analysis, hs-TnT greater than or equal to 0.014 µg/L and persistent AF were independent predictors of the composite endpoint. CONCLUSION: Hs-TnT may be a useful marker for predicting AF recurrence or MACE after AF ablation.

Efficacy of the current of injury in envisaging the dislodgement of leads implanted in the right atrial septum or the right ventricular septum.

BACKGROUND: The implantation of leads in the right atrial septum (RAS) or the right ventricular septum (RVS) is technically challenging, and dislodgement occurs occasionally. This study aims to determine a predictor for the dislodgement of leads implanted in the RAS or RVS. METHODS: This retrospective cohort study enrolled 137 consecutive patients who underwent the cardiac implantable electronic devices implantation, using active fixation leads in the RAS and RVS. We compared the pacing threshold, R- or P-wave amplitude, slew rate, and presence of the current of injury (COI) between dislodged and nondislodged leads. RESULTS: We performed lead fixation for 74 and 125 times in the RAS and RVS, respectively. Atrial lead dislodgement occurred five times (6.8%) intraoperatively and five times (6.8%) postoperatively, whereas ventricular lead dislodgement occurred eight times (6.4%) intraoperatively and three times (2.4%) postoperatively. Although there were no lead parameters that showed a significant difference common to RAS lead and RVS lead, the presence of the COI was significantly different between nondislodged and dislodged leads in both the RAS and RVS (atrial leads: 57.8% vs 0%, P < 0.001; ventricular leads: 67.5% vs 9.1%, P < 0.001). The positive predictive value of COI presence for predicting no lead dislodgement was 100% and 98.7% in the RAS and RVS, respectively. CONCLUSION: Lead dislodgement is more likely when the COI is absent; documentation of COI should be pursued during lead implantation in challenging sites as the RAS and RVS.

The usefulness of right ventriculography to aid anchoring a pacing lead to the right ventricular septum.

Aims: Although right ventricular septal pacing is thought to be more effective in minimizing pacing-induced left ventricular dysfunction, the accurate way to anchor the lead to the right ventricular septum (RVS) has not been established. Our aim was to clarify the usefulness of right ventriculography (RVG) to aid accurate anchoring of the lead to the RVS. Methods and results: Eighty-four patients who underwent pacemaker implantation were enrolled. We anchored the lead to the RVS by using an RVG image obtained at a 30° right anterior oblique view as a reference. We confirmed the actual lead position by performing computed tomography after the procedure and examined the characteristics of the paced QRS complex. Of the 81 patients, except 3 patients whose leads were anchored to the apex due to high pacing thresholds in the RVS, the leads were successfully anchored to the RVS in the 79 (98%) patients, and the number of leads placed in the high-, mid-, and low-RVS was 3 (4%), 58 (73%), and 18 (23%), respectively. The paced QRS duration in these 79 patients was 140 ± 13 ms. The paced QRS duration from mid-RVS was considerably narrower than that from high- or low-RVS (137 ± 12 ms vs. 146 ± 12 ms; P = 0.012). Conclusion: Right ventriculography was very useful in aiding accurate anchoring of the lead to the RVS. Further, pacing from mid-RVS may be more effective in minimizing the QRS duration than pacing from other RVS sites.