Search

Background and Aims Accelerated atrial pacing offers potential benefits for patients with heart failure with preserved ejection fraction (HFpEF) and atrial fibrillation (AF), compared with standard lower-rate pacing. The study investigates the relationship between atrial pacing rate and left-heart filling pressure. Methods Seventy-five consecutive patients undergoing catheter ablation for AF underwent assessment of mean left atrial pressure (mLAP) and atrioventricular (AV) conduction delay (PR interval) in sinus rhythm and accelerated atrial pacing with 10 bpm increments up to Wenckebach block. Computer simulations (CircAdapt) of a virtual HFpEF cohort complemented clinical observations and hypothesized the modulating effects of AV coupling and atrial (dys)function. Results In the study cohort, 49(65%) patients had a high HFpEF likelihood (H2FPEF ≥ 5.0), and 28(37%) an elevated mLAP ≥ 15 mmHg at sinus rhythm. Optimal pacing rates of 100 [70–110]bpm (median [IQR]) significantly reduced mLAP from 12.8 [10.0–17.4]mmHg in sinus rhythm (55 [52–61]bpm) to 10.4 [7.8–14.8]mmHg (P <.001). Conversely, higher pacing rates (130 [110–140]bpm) significantly increased mLAP to 14.7 [11.0–17.8]mmHg (P <.05). PR interval and, hence, AV conduction delay prolonged incrementally with increasing pacing rates. Simulations corroborated these clinical findings, showing mLAP reduction at a moderately increased pacing rate and a subsequent increase at higher rates. Moreover, simulations suggested that mLAP reduction is optimized when AV conduction delay shortens with increasing rate. Conclusions Accelerated pacing acutely reduces left-heart filling pressure in patients undergoing AF catheter ablation and computer simulations with HFpEF features, suggesting it as a potential therapeutic strategy to alleviate congestion symptoms. Virtual HFpEF patient cohorts hypothesize that AV sequential pacing may further optimize this therapy's beneficial effects. [ABSTRACT FROM AUTHOR]

Background Left bundle branch area pacing (LBBAP) has been introduced as an alternative to biventricular pacing in cardiac resynchronization therapy (CRT). Several studies describe echocardiographic reverse remodelling after LBBAP. Reverse electrical remodelling after LBBAP has not yet been described. Case summary A 77-year-old female with non-ischaemic heart failure with reduced ejection fraction [left ventricular ejection fraction (LVEF) 30–35%], left bundle branch block (QRS duration 164 ms), and symptomatic atrial fibrillation irresponsive to pharmacological therapy was evaluated for CRT with LBBAP and atrioventricular node ablation. Successful LBBAP implantation resulted in confirmed left bundle branch capture. Immediately after implantation, paced QRS duration was 194 ms with a long stimulus-V6RWPT (time to peak R wave in V6) of 93 ms, suggesting distal conduction system disease. Patient showed an echocardiographic improvement (LVEF 35–50%) and improvement in symptoms (NYHA class III to NYHA class II) at 1-year follow-up. Moreover, an improvement in conduction delays was found present. Paced QRS duration improved to 159 ms and stimulus-V6RWPT improved to 78 ms. This improvement might be due to reverse electrical remodelling. Discussion This case demonstrates that LBBAP can induce reverse electrical remodelling, even in the presence of distal conduction system disease. With the current availability of different pacing strategies in CRT (i.e. biventricular CRT, LBBAP, and left bundle branch-optimized CRT), more research on patient selection and pacing strategy selection is needed. [ABSTRACT FROM AUTHOR]

Aims Focus of pacemaker therapy is shifting from right ventricular (RV) apex pacing (RVAP) and biventricular pacing (BiVP) to conduction system pacing. Direct comparison between the different pacing modalities and their consequences to cardiac pump function is difficult, due to the practical implications and confounding variables. Computational modelling and simulation provide the opportunity to compare electrical, mechanical, and haemodynamic consequences in the same virtual heart. Methods and results Using the same single cardiac geometry, electrical activation maps following the different pacing strategies were calculated using an Eikonal model on a three-dimensional geometry, which were then used as input for a lumped mechanical and haemodynamic model (CircAdapt). We then compared simulated strain, regional myocardial work, and haemodynamic function for each pacing strategy. Selective His-bundle pacing (HBP) best replicated physiological electrical activation and led to the most homogeneous mechanical behaviour. Selective left bundle branch (LBB) pacing led to good left ventricular (LV) function but significantly increased RV load. RV activation times were reduced in non-selective LBB pacing (nsLBBP), reducing RV load but increasing heterogeneity in LV contraction. LV septal pacing led to a slower LV and more heterogeneous LV activation than nsLBBP, while RV activation was similar. BiVP led to a synchronous LV–RV, but resulted in a heterogeneous contraction. RVAP led to the slowest and most heterogeneous contraction. Haemodynamic differences were small compared to differences in local wall behaviour. Conclusion Using a computational modelling framework, we investigated the mechanical and haemodynamic outcome of the prevailing pacing strategies in hearts with normal electrical and mechanical function. For this class of patients, nsLBBP was the best compromise between LV and RV function if HBP is not possible. [ABSTRACT FROM AUTHOR]