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Background And Aim Of The Study: Pacing-induced mitral regurgitation contributes to the 'pacemaker syndrome', which usually is observed with ventricular (V) pacing, but has also been reported with atrioventricular (AV) sequential pacing. Effects of different pacing modes on 3-D kinematics of the mitral apparatus are incompletely understood.
Methods: Radio-opaque markers were placed on the left ventricular (LV) and mitral apparatus including the annulus, leaflets and papillary muscles of eight sheep. Hemodynamic and 3-D dynamic marker geometry were obtained one week later with biplane videofluoroscopy (60 Hz) during atrial (pacing site = left atrium), AV-sequential (140 ms interval) and (anterolateral LV epicardial) ventricular pacing.
Results: Compared with A-pacing (*p <0.05): 1) The regurgitant fraction increased with both AV- and V-pacing (A: 6 +/- 3%, AV: 13 +/- 3%*, V: 15 +/- 2%*); 2) AV and V-pacing delayed closure at the leaflet center (A: 21 +/- 10 ms, AV: 52 + 5 ms*, V: 92 +/- 6 ms*) and posterior commissure (A: 17 +/- 10 ms, AV: 46 +/- 8 ms*, V: 94 +/- 6 ms*). V-pacing delayed valve closure at the anterior commissure (A: 27 +/- 9 ms, V: 94 +/- 6 ms*); 3) The end-diastolic leaflet opening angle was greater with AV- and V-pacing (anterior mitral leaflet (AML): A: 32 +/- 2 degrees, AV: 41 +/- 4 degrees*, V: 46 +/- 4 degrees*; posterior mitral leaflet (PML): A: 56 +/- 4 degrees, AV: 62 +/- 3 degrees*, V: 68 +/- 3 degrees*); 4) 'Effective' end-diastolic PML midline length was reduced with AV- and V-pacing (A: 11.2 +/- 0.7 mm, AV: 10.0 +/- 0.4 mm*, V: 10.2 +/- 0.3 mm*), as was the distance from each papillary muscle (PM) tip to the AML edge ('effective' chordal length) close to the commissures (anterior PM-AML: A: 31.5 +/-1.8 mm, AV: 30.5 +/- 1.9 mm*, V: 29.7 +/- 1.8 mm*; posterior PM-AML: A: 33.7 +/- 1.8 mm, AV: 33.1 +/- 1.9 mm*, V: 32.8 +/- 1.9 mm*).
Conclusion: Both ventricular and AV-sequential-pacing resulted in a more widely opened valve at end-diastole and leaflet dyssynchrony with delayed mitral valve closure and early systolic mitral regurgitation. These alterations which result in pacing-induced mitral regurgitation may be clinically important in patients with impaired LV function.
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Eur J Heart Fail
September 2025
Cardiology Department, University Medical Centre Ljubljana, Ljubljana, Slovenia.
Aims: There is a lack of data from randomized clinical trials comparing treatment outcomes between conduction system pacing (CSP) modalities and biventricular pacing (BVP) in symptomatic patients with refractory atrial fibrillation (AF) scheduled for atrioventricular node ablation (AVNA). The CONDUCT-AF investigates whether CSP is non-inferior to BVP in improving left ventricular ejection fraction (LVEF) and clinical outcomes in heart failure (HF) patients with symptomatic AF undergoing AVNA.
Methods: This study is an investigator-initiated, prospective, randomized, multicentre clinical trial conducted across 10 European centres, enrolling 82 patients with symptomatic AF, HF with reduced LVEF, and narrow QRS.
Heart Rhythm O2
August 2025
Department of Cardiology, Rouen University Hospital, UNIROUEN, INSERM U1096, Rouen, France.
Background: A high burden of right ventricular pacing (RVP) increases the risk of hospitalization because of heart failure. Data on predictive factors for high burden of RVP in patients with permanent pacemaker implantation (PPI) after transcatheter aortic valve replacement (TAVR) are limited.
Objective: This study aimed to identify predictors of high RVP burden in patients with current indications for PPI after TAVR.
Heart Rhythm O2
August 2025
Department of Cardiology, Triemli Hospital Zürich, Zürich, Switzerland.
Background: Leadless pacemakers (LPs) can reduce long-term complications compared with conventional devices. However, previous studies have primarily focused on single chamber right ventricular LPs.
Objective: This study aimed to evaluate the implantation, safety, and device performance characteristics in a first real-world European use of an active fixation atrial LP for either dual chamber or single chamber pacing.
Can J Cardiol
September 2025
Department of Cardiology, Ningbo No.2 Hospital, Ningbo, Zhejiang, China.
Background: During the electrode screwing process in left bundle branch pacing (LBBP), the significance of the S wave in lead V6 remains elusive. Our study analyzes the change of the S wave in lead V6 under different patterns of capture and explores its mechanisms.
Methods: This study included 243 cases with criterion of selective LBBP (SLBBP), we performed continuous pacing technique and classified the electrophysiological characteristics observed during the screwing process into four patterns: left ventricular septal pacing (LVSP), non-selective LBBP (NSLBBP) in low output and in the lower output, selective LBBP.
IEEE J Biomed Health Inform
September 2025
Identifying the onset of the QRS complex is an important step for localizing the site of origin (SOO) of premature ventricular complexes (PVCs) and the exit site of Ventricular Tachycardia (VT). However, identifying the QRS onset is challenging due to signal noise, baseline wander, motion artifact, and muscle artifact. Furthermore, in VT, QRS onset detection is especially difficult due to the overlap with repolarization from the prior beat.
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