Funding Acknowledgements Type of funding sources: None. Background Cardiac resynchronization therapy (CRT) via permanent His bundle pacing (pHBP) has gained acceptance globally, but robust studies comparing pHBP-CRT with classic CRT are lacking. Purpose To compare the improvement in left ventricular ejection fraction (LVEF) after pHBP-CRT vs classic CRT. Methods Single-center study comparing a prospective series of pHBP-CRT with a historical series of CRT via classic biventricular pacing (BVP). Patients with non-ischemic cardiomyopathy, baseline LVEF <35%, left bundle branch block (LBBB), and CRT indications were selected. Results Fifty-one patients underwent classic CRT and 52 patients underwent pHBP-CRT (26.9% selective vs 73.1% non-selective HBP with LBBB correction). In 2 patients, pHBP was not possible: one of them cause of high thresholds and the other because QRS correction was lacking. The baseline characteristics are shown in Table 1. In the classic CRT group, 74.5% of patients were in sinus rhythm (SR) and 25.5% in atrial fibrillation (AF). In the pHBP group, 88.5% were in SR and 11.5% in AF (p=0.07). The median VP was 98.5% (94.3–100%) in the former group and 99% (98–100%) in the latter (p=0.484). Regarding LVEF, the primary objective of this study, in the classic CRT group, the median basal LVEF was 30% (29–35%) before implantation and 40% (35–48%) at follow-up. In the pHBP-CRT group, the median basal LVEF was 30% (28–34%) before implantation and 55% (45–60%) at follow-up (p=0.001). In the classic CRT group, the absolute increase in LVEF was >20%, 10–20%, and 5–10% in 19.6%, 31.4%, and 15.7% of patients, respectively. In the pHBP-CRT group, the absolute increase in LVEF was >20%, 10–20%, and 5–10% in 55.8%, 32.7%, and 7.7% of patients, respectively, (p=0.001). The characteristics of the basal and paced QRS, as well as the His thresholds, are shown in Table 2. Considering the secondary objective of our study, the median long-term (after a year) His recruitment threshold with LBBB correction was 1.25 (1–2.5) V at 0.4 ms in cases where pHBP-CRT was performed, compared to an LV coronary sinus threshold of 1.25 (1–1.75) V at 0.4 ms in cases where classic CRT was performed; there was no significant difference between the two groups (p=0.48). The basal QRS duration was similar in both groups; after CRT, the median paced QRS duration was 135 (120–145) ms for pHBP-CRT and 140 (130–150) ms for BVP-CRT (p=0.586). Considering the concept of effective QRS in patients who underwent pHBP CRT, the median paced QRS was 110 (110–120) ms (p=0.001) compared to the classic CRT. Conclusions The improvement in LVEF was superior in patients who underwent pHBP-CRT than in those that received classic CRT. The threshold levels after 1 year of follow-up period were similar for LBBB correction with pHBP or conventional BVP. Randomized prospective studies with larger populations and longer follow-up periods are needed to verify our results.
Funding Acknowledgements Type of funding sources: None. Background Although pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation, the percentage of patients in which a recurrence is detected is still high. This concern has increased the interest in finding new ablation techniques that could diminish recurrences. Purpose To determine if left atrial (LA) appendage isolation (LAAI) in addition to PVI is a safe procedure and if it entails an improvement in the recurrence of AF. Methods Single-center retrospective study including patients with paroxysmic (PxAF) or persistent (PsAF) AF referred to cryoballoon ablation (CAB), comparing patients in whom LAAI was performed with those in whom only PVI was performed. Results 131 patients (59.9 ± 12.3 years, 65.9% males) were referred to CAB in our center between 2017 and 2021. 103 patients (78.6%) had PxAF and 28 (21.4%) PsAF. Most patients had had AF for at least two years (65.6%), 12.2% between one and two years and 22.2% for less than one year. The median CHA2DS2-VASc score was 1 [0-2] and 72.5% had permanent anticoagulation indication. 90.1% had tried at least one antiarrhythmic drug (AAD) before the procedure (57.3% one AAD, the rest at least two AADs), being amiodarone (46.2%) and flecainide (46.2%) the most commonly used. Cardioversion prior to CAB was performed in 57.3% of patients. The most common anatomy was 4 independent pulmonary veins (81.7%), followed by left common trunk (10.7%). LAAI was performed in 41 patients (31.3%) and it was performed more frequently in patients with PsAF and permanent anticoagulation indication, as well as in hypertense patients with bigger LA diameter (Table 1). The rate of complications was low in both groups, highlighting the absence of periprocedural cardioembolic stroke (CES) and the low rate of CES in the follow-up (2.1%) (median time to the apparition of the CES 27 [20-27] months), with no statically significative differences between LAAI and PVI groups. During the 23 [13-37] months of follow-up, 32 patients (24.4%) had a recurrence after the 3-month blanking period (time to apparition of recurrence of 11 [6-21.75] months). There were no statically significant differences in the recurrences or in the complications between LAAI and PVI groups, neither in PxAF nor in PsAF patients (Table 2), although PxAF patients tended to have less recurrences when LAAI was performed (11.1% vs 25.0%, p=0.175). On the other hand, the 1-year success rate (defined as the absence of recurrence in the 12 months following the blanking period), was 80.2% (out of 96 patients who had at least 15-month follow-up), with no statically significative differences between LAAI and PVI groups (80.8% vs 80%, p=0.933). Conclusions LAAI is a safe procedure with a low rate of complications and no evidence of increased risk of CES in the follow-up. Although LAAI did not entail a lower recurrence rate, it could have a role in selected PxAF patients. Larger studies with longer follow-up are needed to confirm our data.
Funding Acknowledgements Type of funding sources: None. Introduction Electrocardiographic (ECG) parameters predictive of sudden death have been described in patients with ventricular dysfunction. Cardiac resynchronization therapy (CRT) in patients with left bundle branch block (LBBB), in addition to improve the left ventricular ejection fraction (LVEF), can correct part of them, which could have an important impact prognostic at follow-up. Repolarization changes in patients resynchronized via permanent His Bundle pacing (p-HBP) have not been described yet. Methods We designed a prospective descriptive study of patients with LBBB and CRT indication proposed for CRT by p-HBP. We analyzed different ECG patterns of sudden death (QT interval, corrected QT interval, QT interval dispersion, Tpeak-Tend, Tpeak-Tend dispersion, Tp-Te/QT ratio, rdT / JT index, T wave voltage, T wave duration) and the changes of them at 6-month follow-up after His resynchronization. Results We included 21 patients (57.1% male, 70 [63.5-80] years). 90.5% had hypertension, 57.1% diabetes mellitus and 66.7% dyslipidemia. 90.5% had structural heart disease (median LVEF 38 [30-52.5] %); 52.9 % had non-ischemic cardiomyopathy, being the principal cause of the dysfunction in these patients the dyssynchronipathy caused by LBBB. Other causes of cardiomyopathy were hypertensive cardiomyopathy (5.9%), valvulopathy (11.8%) and pacing induced cardiomyopathy (11.8%). 66.7% were resynchronized with dual chamber pacemakers, 28.6% with tricameral defibrillator and 4.8% with tricameral pacemaker. ECG parameters predictive of sudden death basally and at 6-month follow-up are summarized in table 1. All predictors improved in the follow-up with statically significant differences. Fig 1 shows basal (A) and 6-month follow-up (B) changes in repolarization parameters. Conclusion There is an improvement in the ECG parameters predictive of sudden death in patients with LBBB resynchronized via p-HBP. CRT through p-HBP could improve the risk of sudden death.
Funding Acknowledgements Type of funding sources: None. Introduction Permanent His bundle pacing (p-HBP) could be an alternative for cardiac resynchronization therapy (CRT), but an important limitation is that p-HBP cannot always correct the left bundle branch block (LBBB). The aim is to assess electrocardiographic (ECG) patterns of LBBB that can predict ECG response (QRS narrowing) to p-HBP. Methods Prospective descriptive study of patients with LBBB and CRT indication proposed for CRT by p-HBP. We analyzed the correlation between the different ECG patterns and the correction of LBBB. Results We included 70 patients. Once located His bundle electrogram, pacing at this level narrowed the QRS in 81.4% (n=57). We distinguished two ECG patterns in lead V1: QS or rS. Thirty-four patients (51.4%) presented QS pattern in lead V1 (Fig 1A), and in 94.1% of these correction of the LBBB was achieved (Fig 1B). The rS pattern was present in 36 patients and in 69.4% of these the correction of the LBBB was achieved. Differences between both groups were statistically significant (p=.008). The presence of QS pattern in V1 had a sensitivity of 56%, a specificity of 84.6% and a positive predictive value of 94.1% to predict LBBB correction. The AUC by a receiver operating characteristic analysis was .70±. In patients with rS pattern in lead V1, we analyzed the ratio between the descending and the ascending S wave component duration; the difference between patients in whom LBBB was corrected (ratio 0.742±0.124) and patients in whom it was not corrected (0.476±0.124) were statistically significant (p=.001). The AUC by a receiver operating characteristic analysis was .968 (very good predictor of LBBB correction). In this case, a ratio between the descending and the ascending S wave component duration≥0.64 (Fig 2C-D) showed a sensitivity of 92%, a specificity and a PPV of 100%, and a negative predictive value (NPV) of 83.3%. Related to the ratio between the ascending S wave component duration and the total QRS duration, it was 0.513±0.043 in patients with LBBB correction vs 0.60 ± 0.046 in those in whom it did not correct (P=.001). The AUC by a receiver operating characteristics analysis was .896 (good test to predict LBBB correction in patients with rS pattern in lead V1). We analyzed the ratio between the descending and the ascending S wave component duration in the global of patients, including those with QS pattern. Patients in whom it corrected the LBBB presented a ratio of 0.754±0.13 vs 0.459±0.081 in whom it did not correct (P<.001) (AUC .977). The ratio between the ascending S wave component duration and the total QRS duration in patients with LBBB correction was 0.542±0.003 vs 0.623±0.063 in whom it did not correct (P<.001) (AUC .84). Conclusions In patients with LBBB and CRT indication, the QS pattern in lead V1 predicts the correction of the QRS with HBP. In the case of rS pattern in lead V1, the ratio descending/ascending S wave component duration has a strong correlation with the LBBB correction.
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