Left atrial remodeling and reduced atrial pump function after chronic right ventricular apical pacing in patients with preserved ejection fraction

Comparison between left bundle branch area pacing and right ventricular pacing: ventricular electromechanical synchrony and risk of atrial high-rate episodes

Background

The electromechanical dyssynchrony associated with right ventricular pacing (RVP) has been found to have adverse impact on clinical outcomes. Several studies have shown that left bundle branch area pacing (LBBAP) has superior pacing parameters compared with RVP. We aimed to assess the difference in ventricular electromechanical synchrony and investigate the risk of atrial high-rate episodes (AHREs) in patients with LBBAP and RVP.

Methods

We consecutively identified 40 patients with atrioventricular block and no prior atrial fibrillation. They were divided according to the ventricular pacing sites: the LBBAP group and the RVP group (including the right ventricular apical pacing (RVA) group and the right side ventricular septal pacing (RVS) group). Evaluation of ventricular electromechanical synchrony was implemented using electrocardiogram and two-dimensional speckle tracking echocardiography (2D-STE). AHRE was defined as event with an atrial frequency of ≥176 bpm lasting for ≥6 min recorded by pacemakers during follow-up.

Results

The paced QRS duration of the LBBAP group was significantly shorter than that of the other two groups: LBBAP 113.56 ± 9.66 ms vs. RVA 164.73 ± 14.49 ms, p < 0.001; LBBAP 113.56 ± 9.66 ms vs. RVS 148.23 ± 17.3 ms, p < 0.001. The LBBAP group showed shorter maximum difference (TDmax), and standard deviation (SD) of the time to peak systolic strain among the 18 left ventricular segments, and time of septal-to-posterior wall motion delay (SPWMD) compared with the RVA group (TDmax, 87.56 ± 56.01 ms vs. 189.85 ± 91.88 ms, p = 0.001; SD, 25.40 ± 14.61 ms vs. 67.13 ± 27.40 ms, p < 0.001; SPWMD, 28.75 ± 21.89 ms vs. 99.09 ± 46.56 ms, p < 0.001) and the RVS group (TDmax, 87.56 ± 56.01 ms vs. 156.46 ± 55.54 ms, p = 0.003; SD, 25.40 ± 14.61 ms vs. 49.02 ± 17.85 ms, p = 0.001; SPWMD, 28.75 ± 21.89 ms vs. 91.54 ± 26.67 ms, p < 0.001). The interventricular mechanical delay (IVMD) was shorter in the LBBAP group compared with the RVA group (-5.38 ± 9.31 ms vs. 44.82 ± 16.42 ms, p < 0.001) and the RVS group (-5.38 ± 9.31 ms vs. 25.31 ± 21.36 ms, p < 0.001). Comparing the RVA group and the RVS group, the paced QRS duration and IVMD were significantly shorter in the RVS group (QRS duration, 164.73 ± 14.49 ms vs. 148.23 ± 17.3 ms, p = 0.02; IVMD, 44.82 ± 16.42 ms vs. 25.31 ± 21.36 ms, p = 0.022). During follow-up, 2/16 (12.5%) LBBAP patients, 4/11 (36.4%) RVA patients, and 8/13 (61.5%) RVS patients had recorded novel AHREs. LBBAP was proven to be independently associated with decreased risk of AHREs than RVP (log-rank p = 0.043).

Conclusion

LBBAP generates narrower paced QRS and better intro-left ventricular and biventricular contraction synchronization compared with traditional RVP. LBBAP was associated with a decreased risk of AHREs compared with RVP.

Echocardiographic Evaluation of the Effect on Left Ventricular Function Between Left Bundle Branch Pacing and Right Ventricular Pacing

Purpose

The purpose of this study was to assess the left ventricular function effects of permanent left bundle branch pacing (LBBP) versus traditional right ventricular pacing (RVP).

Patients and Methods

Consecutive patients receiving pacemaker implantation were included and divided into left bundle branch block (LBBB) group and right ventricular pacing (RVP) group. Baseline characteristics were collected, and they received 1-year follow-up. Electrocardiogram (ECG) characteristics and pacing parameters were assessed before and after implantation. Cardiac function parameters such as left ventricular ejection fraction (LVEF) and tricuspid regurgitation (TR) were recorded and compared.

Results

Of 78 patients included, 45 patients received LBBP (mean age, 72.7 ± 12.2 years; male, 55.6%) and 33 patients underwent RVP (mean age 72.9 ± 11.8 years; male, 63.6%). The pacing parameters were satisfactory during the implantation and remained stable during mid-term follow-up. During the follow-up period, LBBP patients had a greater decrease in LVEDD and LVESD. The TR in the LBBP group was significantly improved as compared to the RVP group (P=0.016).

Conclusion

Permanent LBBP achieves favorable cardiac hemodynamic effects with good stability and safety. LBBP may reduce severe TR at 1-year follow-up, and LBBP may be an option for patients with severe TR.

Pacing of Specialized Conduction System

Right ventricular pacing for bradycardia remains the mainstay of pacing therapy. Chronic right ventricular pacing may lead to pacing-induced cardiomyopathy. We focus on the anatomy of the conduction system and the clinical feasibility of pacing the His bundle and/or left bundle conduction system. We review the hemodynamics of conduction system pacing, the techniques to capture the conduction system and the electrocardiogram and pacing definitions of conduction system capture. Clinical studies of conduction system pacing in the setting of atrioventricular block and after AV junction ablation are reviewed and the evolving role of conduction system pacing is compared with biventricular pacing.

The PhysioVP-AF study, a randomized controlled trial to assess the clinical benefit of physiological ventricular pacing vs. managed ventricular pacing for persistent atrial fibrillation prevention in patients with prolonged atrioventricular conduction: design and rationale

AIMS

In patients with prolonged atrioventricular (AV) conduction and pacemaker (PM) indication due to sinus node disease (SND) or intermittent AV-block who do not need continuous ventricular pacing (VP), it may be difficult to determine which strategy to adopt. Currently, the standard of care is to minimize unnecessary VP by specific VP avoidance (VPA) algorithms. The superiority of this strategy over standard DDD or DDD rate-responsive (DDD/DDDR) in improving clinical outcomes is controversial, probably owing to the prolongation of the atrialventricular conduction (PR interval) caused by the algorithms. Conduction system pacing (CSP) may offer the most physiological-VP approach, providing appropriate AV conduction and preventing pacing-induced dyssynchrony.

METHODS AND RESULTS

PhysioVP-AF is a prospective, controlled, randomized, single-blind trial designed to determine whether atrial-synchronized conduction system pacing (DDD-CSP) is superior to standard DDD-VPA pacing in terms of 3-year reduction of persistent-AF occurrence. Cardiovascular hospitalization, quality-of-life, and safety will be evaluated. Patients with indication for permanent DDD pacing for SND or intermittent AV-block and prolonged AV conduction (PR interval > 180 ms) will be randomized (1:1 ratio) to DDD-VPA (VPA-algorithms ON, septal/apex position) or to DDD-CSP (His bundle or left bundle branch area pacing, AV-delay setting to control PR interval, VPA-algorithms OFF). Approximately 400 patients will be randomized in 24 months in 13 Italian centres.

CONCLUSION

The PhysioVP-AF study will provide an essential contribution to patient management with prolonged AV conduction and PM indication for sinus nodal disease or paroxysmal 2nd-degree AV-block by determining whether CSP combined with a controlled PR interval is superior to standard management that minimizes unnecessary VP in terms of reducing clinical outcomes.

Atrial Pacing Affects Left Atrial Morphological and Functional Parameters Early after Pacemaker Implantation

Background and Objectives: Chronic atrial stimulation might impair left atrial (LA) function. We aimed to assess the impact of atrial pacing burden on LA volumetric and functional parameters after implantation of a dual-chamber pacemaker. Materials and Methods: The prospective study included 121 subjects with sinus node disease (SND) or atrioventricular block (AVB) that received a dual-chamber pacemaker. After device implantation, the subjects were divided into three groups: (1) SND with a lower rate (LR) set to 60 bpm and rate response enabled; (2) AVB with an LR set to 60 bpm and no rate response; and (3) AVB with an LR set to 40 bpm and no rate response. Subjects were followed at one and three months. Two subsets of patients with high and low atrial pacing burdens accompanied by low ventricular pacing percentage were analyzed. LA function was evaluated with volumetric and strain parameters from transthoracic echocardiography. Results: The high atrial low ventricular pacing group consisted of 38 subjects, and the low atrial low ventricular group consisted of 22 subjects. When looking at the change in volumetric parameters, we observed a tendency for volumes to increase in both groups; however, only minimal LA volume reached statistical significance at three months in the high atrial pacing group. A trend towards the lowering of an active emptying fraction at one month (p = 0.076) became significant at three months (p = 0.043), and was also only observed in the same group. Moreover, a decrease in the tendency to reach statistical significance at three months for reservoir and contractile strain parameters and stiffness index was only observed in the high atrial pacing group. Meanwhile, in the low atrial pacing burden group, all parameters remained significantly unchanged. Conclusions: The burden of right atrial pacing in patients with preserved left ventricular function negatively influences functional and morphologic LA parameters. Moreover, negative effects take place soon after pacemaker implantation and appear to be sustained.

New-onset atrial fibrillation following left bundle branch area pacing vs. right ventricular pacing: a two-centre prospective cohort study

AIMS

To investigate whether left bundle branch area pacing (LBBAP) can reduce the risk of new-onset atrial fibrillation (AF) compared with right ventricular pacing (RVP).

METHODS AND RESULTS

Patients with indications for dual-chamber pacemaker implant and no history of AF were prospectively enrolled if they underwent successful LBBAP or RVP. The primary endpoint was time to the first occurrence of AF detected by pacemaker programming or surface electrocardiogram. Follow-up at clinic visit was performed and multivariate Cox regression models were applied to evaluate the effect of LBBAP on new-onset AF. The final analysis included 527 patients (mean age 65.3 ± 12.6, male 47.3%), with 257 in the LBBAP and 270 in the RVP groups. During a mean follow-up of 11.1 months, LBBAP resulted in significantly lower incidence of new-onset AF (7.4 vs. 17.0%, P < 0.001) and AF burden (3.7 ± 1.9 vs. 9.3 ± 2.2%, P < 0.001) than RVP. After adjusting for confounding factors, LBBAP demonstrated a lower hazard ratio for new-onset AF compared with RVP {hazard ratio (HR) [95% confidence interval (CI)]: 0.278 (0.156, 0.496), P < 0.001}. A significant interaction existed between pacing modalities and the percentage of ventricular pacing (VP%) (P for interaction = 0.020). In patients with VP ≥ 20%, LBBAP was associated with decreased risk of new-onset AF compared with RVP [HR (95% CI): 0.199 (0.105, 0.378), P < 0.001]. The effect of pacing modalities was not pronounced in patients with VP < 20% [HR (95% CI): 0.751 (0.309, 1.823), P = 0.316].

CONCLUSION

Left bundle branch area pacing demonstrated a reduced risk of new-onset AF compared with RVP. Patients with a high ventricular pacing burden might benefit from LBBAP.

Pacing of Specialized Conduction System

Right ventricular pacing for bradycardia remains the mainstay of pacing therapy. Chronic right ventricular pacing may lead to pacing-induced cardiomyopathy. We focus on the anatomy of the conduction system and the clinical feasibility of pacing the His bundle and/or left bundle conduction system. We review the hemodynamics of conduction system pacing, the techniques to capture the conduction system and the electrocardiogram and pacing definitions of conduction system capture. Clinical studies of conduction system pacing in the setting of atrioventricular block and after AV junction ablation are reviewed and the evolving role of conduction system pacing is compared with biventricular pacing.

Occurrence of persistent atrial fibrillation during pacing for sinus node disease: The influence of His bundle pacing versus managed ventricular pacing

INTRODUCTION

In patients with sinus node disease (SND), the dual-chamber pacemaker (PM) is programmed in DDDR mode with an algorithm to avoid unnecessary right ventricular (RV) pacing. This pacing mode may prolong PR interval with consequently atrioventricular (AV) asynchrony which is associated with a higher risk of atrial fibrillation (AF). We evaluate whether preserving AV synchrony by setting a fixed AV delay during physiological RV pacing, that is, His bundle pacing (HBP), could reduce the risk of AF occurrence in comparison with a standard pacing mode with an algorithm to avoid unnecessary RV pacing (DDD-VPA).

METHODS AND RESULTS

We collected retrospective data from 313 consecutive patients who had undergone PM for SND. The first occurrence of persistent AF (>7 consecutive days) as a function of the pacing mode was evaluated. HBP and DDD-VPA were implemented in 82 and 231 patients, respectively. Persistent AF occurred in 128 (40.9%) patients over a median follow-up of 70 months (67-105). The DDD-VPA pacing mode was significantly correlated with the occurrence of persistent AF only when the basal PR was long (>180 ms). The risk of persistent AF was significantly lower in patients on HBP than in those on DDD-VPA, adjusted HR = .57 (95% CI, .36- .89, p=.014). Other independent predictors of persistent AF occurrence were: A history of AF (HR = 3.91; 95% CI, 2.48-6.19, p = .001), age, and long PR interval (HR = 2.98; 95% CI, 2.00-4.43, p=.001).

CONCLUSION

In SND patients and long basal PR interval, the HBP may reduce the risk of persistent AF in comparison with the DDD-VPA.

Development of New-Onset or Progressive Atrial Fibrillation in Patients With Permanent HIS Bundle Pacing Versus Right Ventricular Pacing: Results From the RUSH HBP Registry

Background

Conventional right ventricular pacing (RVP) has been associated with an increased incidence of atrial fibrillation (AF). We sought to compare the occurrence of new‐onset AF and assessed AF disease progression during long‐term follow‐up between His bundle pacing (HBP) and RVP.

Methods and Results

We included patients undergoing initial dual‐chamber pacemaker implants at Rush University Medical Center between January 1, 2016, and June 30, 2019. A total of 360 patients were evaluated, and 225 patients (HBP, n=105; RVP, n=120) were included in the study. Among the 148 patients (HBP, n=72; RVP, n=76) with no history of AF, HBP demonstrated a lower risk of new‐onset AF (adjusted hazard ratio [HR], 0.53; 95% CI, 0.28–0.99; P=0.046) compared with traditional RVP. This benefit was observed with His or RVP burden exceeding 20% (HR, 0.29; 95% CI, 0.13–0.64; P=0.002), ≥40% (HR, 0.31; P=0.007), ≥60% (HR, 0.35; P=0.015), and ≥80% (HR, 0.40; P=0.038). There was no difference with His or RV pacing burden <20% (HR, 0.613; 95% CI, 0.213–1.864; P=0.404). In patients with a prior history of AF, there was no difference in AF progression (P=0.715); however, in a subgroup of patients with a pacing burden ≥40%, HBP demonstrated a trend toward a lower risk of AF progression (HR, 0.19; 95% CI, 0.03–1.16; P=0.072).

Conclusions

HBP demonstrated a lower risk of new‐onset AF compared with RVP, which was primarily observed at a higher pacing burden.

Relationship between right ventricular pacing and non-sustained ventricular arrhythmias in patients with dual-chamber pacemaker and normal range left ventricular ejection fraction

Background

Right ventricular pacing (RVP) increases heart failure, AF, and death rates in pacemaker patients and ventricular arrhythmias (VAs) in defibrillator patients. However, the impact of RVP on VAs burden and its clinical significance in pacemaker patients with normal range LVEF of > 50–55% remains unknown. We sought to evaluate the relationship of RVP and VAs and its clinical impact in a pacemaker patient population.

Methods

Records of 105 patients who underwent denovo dual-chamber pacemaker implant or a generator change (Medtronic™ or Boston Scientific™) for AV block and sinus node disease at a tertiary care center between September 1, 2015, and September 1, 2016, were retrospectively reviewed.

Results

Data from 105 patients (51% females, mean age 76 ± 1 years, mean LVEF 61 ± 0.7%) without history of VAs (98.2%) were reviewed over 1044 ± 23 days. Dependent patients (100% RVP) exhibited the lowest VAs burden when compared to < 100% RVP (isolated PVCs, PVC runs of < 4 beats, and NSVT; p ≤ 0.001). Patients with < 1% RVP also exhibited low VA burden with intermediate RVP (1–99.9%) being most arrhythmogenic for PVC runs (p = 0.04) and for isolated PVCs (p = 0.006). Antiarrhythmics/beta and calcium channel blockers use and stress tests performed to evaluate VAs which were positive requiring intervention did not differ significantly. Burden of > 1/h of PVC runs and increasing PVC runs/h were significantly associated with hospitalization (p = 0.04) and all-cause mortality (p = 0.03), respectively.

Conclusions

In pacemaker patients with normal range LVEF (> 50–55%), 100% RVP is associated with the lowest burden of NSVT. Furthermore, patients with < 1% RVP also exhibit low VA burden; however, intermittent RVP seems to significantly correlate with non-sustained VAs.

A novel risk model for very late return of atrial fibrillation beyond 1 year after cryoballoon ablation: the SCALE-CryoAF score

PURPOSE

Cryoballoon ablation (CBA) is an effective technique for pulmonary vein isolation (PVI). To date, there are no risk models to predict very late recurrence of atrial fibrillation (VLRAF) after CBA.

METHODS

Retrospective analysis of a single-center database was performed. Inclusion criteria included PVI using CBA for atrial fibrillation (AF) without additional ablation targets, follow-up > 365 days, and no recurrent AF between 90 and 365 days after procedure. The primary endpoint was recurrent AF > 30 s > 12 months post-CBA. A risk model was created using clinical variables.

RESULTS

Of 674 CBA performed from 2011 to 2016, 300 patients (200 male, 62.0 ± 9.9 years) met inclusion criteria. Of these, 159 (53.0%) patients had paroxysmal AF. Patients had an average of 9.5 ± 2.7 cryoballoon freezes, and no patients required additional radiofrequency ablation lesion sets. Over a follow-up of 995 ± 490 days, 77/300 (25.7%) patients exhibited VLRAF. Univariate and multivariate analyses demonstrated that Structural heart disease (1 point), Coronary artery disease (3 points), left Atrial diameter > 43 mm (1 point), Left bundle branch block (3 points), Early return of AF (4 points), and non-paroxysmal AF (3 points) were risk factors for VLRAF. Combining these variables into a risk model, SCALE-CryoAF, (min 0; max 15) predicted VLRAF with an area under the curve of 0.73.

CONCLUSION

SCALE-CryoAF is the first risk model to specifically predict first recurrence of AF beyond 1 year, VLRAF, after CBA. Model discrimination demonstrates that SCALE-CryoAF predicts VLRAF after CBA significantly better than other risk models for AF recurrence.

Left Atrial Function Is Improved in Short-Term Follow-Up after Catheter Ablation of Outflow Tract Premature Ventricular Complexes

Background: Association of premature ventricular complexes (PVC) with left ventricular systolic dysfunction (LVSD) and efficacy of catheter ablation treatment have been demonstrated in studies. The role of left atrial (LA) mechanics in the etiopathogenesis of PVC-induced cardiomyopathy (PVC-CMP) as well as changes in LA mechanics with catheter ablation have not been studied before. Methods: A total number of 61 patients (Mean Age 43 ± 3) with idiopathic outflow tract (OT) PVCs undergoing radiofrequency catheter ablation (RFCA) were enrolled. ECG, 24 h Holter, and echocardiographic evaluation with left ventricular (LV) diastolic functions and LA volumetric assessments were performed before and three months after RFCA. Results: Along with a marginal increase in left ventricle ejection fraction (LVEF), improvement in diastolic functions and left atrial mechanics were observed in the study (LVEF 53 ± 7 versus 57 ± 6, p < 0.01) in short-term follow-up. The frequency of LV diastolic dysfunction (LVDD) decreased with catheter ablation (n = 5 to 0, p = 0.02). The overall LA function improved. Left atrium passive and overall emptying fraction (LAEF) increased significantly (0.32 ± 0.04 to 0.41 ± 0.04, p < 0.05 and 0.62 ± 0.04 to 0.65 ± 0.004, p < 0.05, respectively). Active LAEF decreased significantly (0.29 ± 0.005 to 0.24 ± 0.006, p < 0.05). Conclusions: The results of this study are indicative of “PVC-induced atriomyopathy” which responds to RFCA in short-term follow-up. Atrial dysfunction might play a role in symptoms and etiopathogenesis of LVSD.

Long-term follow-up results of the pacing to avoid cardiac enlargement (PACE) trial

AIMS

We report the results of long-term follow-up of the Pacing to Avoid Cardiac Enlargement (PACE) trial, a prospective, double-blinded, randomized, multicentre study that confirmed the superiority of biventricular (BiV) pacing compared with right ventricular apical (RVA) pacing in prevention of LV adverse remodelling and deterioration of systolic function at 1 and 2 years.

METHODS AND RESULTS

Patients with bradycardia and preserved LVEF were randomized to receive RVA (n = 88) or BiV pacing (n = 89). Co-primary endpoints were LV end-systolic volume (LVESV) and LVEF measured by echocardiography. There were 149 patients who had extended follow-up, with a mean duration of 4.8 ± 1.5 years (2.5-7.8 years). The primary endpoint analyses were performed in 146 patients (74 in the RVA group and 72 in the BiV group). In the RVA pacing group, the LVEF decreased while the LVESV increased progressively at follow-up, but remained unchanged in the BiV pacing group. The differences in LVEF between the RVA and BiV groups were -6.3, -9.2, and -10.7% at 1-year, 2-year, and long-term follow-up, respectively (all P < 0.001). The corresponding differences in LVESV were +7.4, +9.9, and +13.1 mL, respectively (all P < 0.001). The deleterious effects of RVA pacing consistently occurred in all the pre-defined subgroups. Furthermore, patients with RVA pacing had a significantly higher prevalence of heart failure hospitalization than the BiV group (23.9% vs. 14.6%, log-rank χ²  = 7.55, P  = 0.006).

CONCLUSION

Left ventricular adverse remodelling and deterioration of systolic function continued at long-term follow-up in patients with RVA pacing; this deterioration was prevented by the use of BiV pacing. Also, heart failure hospitalization was more prevalent in the RVA pacing group.

Frequent premature ventricular complex is associated with left atrial enlargement in patients with normal left ventricular ejection fraction

BACKGROUND

Premature ventricular complex (PVC) has been regarded as benign; however, when frequent, the arrhythmia can induce left ventricular (LV) systolic dysfunction. Meanwhile, the influence of PVCs on cardiac structural remodeling and functional change before occurrence of overt systolic heart failure has not been fully described. In this study, we attempted to identify early cardiac structural/functional manifestations of frequent PVCs in patients with normal LV systolic function.

METHODS

A total of 146 patients (age: 55 ± 15 years, 48 males) with frequent PVCs observed on 24-hour Holter monitoring (>10/h) and normal LV ejection fraction (LV EF ≥ 55% on echocardiography) were enrolled. Clinical characteristics and echocardiographic parameters of the patients were compared with those of an age-/sex-matched control group (n = 292, age: 55 ± 15 years, 96 males).

RESULTS

Patients with frequent PVCs had significantly larger left atrial volume index (LAVI [28 ± 9 mL/m(2) vs. 24 ± 7 mL/m(2) ]), along with larger LV end-diastolic dimension (49.4 ± 4.4 mm vs. 48.5 ± 3.9 mm), lower LV EF (63 ± 7% vs. 66 ± 6%), and lower peak systolic mitral annular velocity (7 ± 2 cm/s vs. 8 ± 2 cm/s; P < 0.05 for all), whereas other clinical characteristics were similar. In particular, in patients with frequent PVCs, LAVI showed linear correlation with PVC burden (R = 0.30, P < 0.001), and, in a multiple regression model, PVC burden independently estimated LAVI, even after controlling for age, sex, comorbidities, and systolic function (β = 0.309, P < 0.001).

CONCLUSION

Frequent PVC is associated with LA enlargement in patients with normal LV EF. Atrial anatomical remodeling may precede LV geometry change and systolic dysfunction in patients with frequent PVCs.

Hisian area and right ventricular apical pacing differently affect left atrial function: an intra-patients evaluation

AIMS

Right ventricular apex (RVA) pacing has adverse effects on left atrial (LA) function and may contribute to atrial arrhythmias. The effects of Hisian area (HA) pacing on LA function are still lacking. The objective of this study is to assess the left ventricular (LV) electromechanical activation/relaxation, systolic (S), diastolic (D) phases, and their effects on LA function during pacing from HA and RVA.

METHODS AND RESULTS

Thirty-seven patients with normal cardiac function underwent permanent HA pacing. In all patients, a RVA backup lead was added. The patients first underwent 3 months of HA pacing, followed by 3 months of RVA pacing. After each 3-month period, we compared by echocardiography: S-D LV electromechanical delay (S-D EMD), S-D intra-LV dyssynchrony, LV S-D phases, and their function evaluated by myocardial performance index (MPI) and mitral annular tissue Doppler early diastolic velocity (E'), pulmonary arterial systolic pressure (PASP), and LA function (LA phasic volumes and their emptying fraction). Right ventricular apex compared with HA pacing increased S-D EMD (P < 0.001) and intra-LV dyssynchrony (P < 0.001). As a consequence, a significant longer LV isovolumetric contraction time (P < 0.001) and LV isovolumetric relaxation time (P = 0.05) were measured during RVA compared with HA pacing, whereas LV ejection time was shorter (P = 0.033). Moreover, HA pacing resulted in significantly better MPI (P = 0.039), higher value of E' (P = 0.049), and lower PASP (P < 0.001). Finally, RVA compared with HA pacing was associated to higher LA volumes pre-atrial contraction (P = 0.001) and minimal volume (P = 0.003) with reduction in passive emptying fraction (P < 0.001) and total emptying fraction (P = 0.005).

CONCLUSION

Hisian area compared with RVA pacing resulted in a more physiological LV electromechanical activation/relaxation and consequently better LA function.