Pacing For Complete Atrioventricular Block Research Articles

Comparison of 1st and 2nd generation leadless pacemaker in sinus rhythm patients with chronic ventricular pacing for complete atrioventricular block

Abstract Funding Acknowledgements Type of funding sources: None. Background Leadless pacemakers (LPMs) represent a seductive alternative to conventional pacing. First generation of Micra transcatheter pacing system was able to provide single-chamber VVI(R) pacing mode only, with a potential risk of pacemaker syndrome in sinus rhythm patients. A 2nd generation system (AV) now provides atrioventricular synchrony through atrial mechanical sensing capability (VDD mode). Purpose We sought to compare VR and AV systems in patients with sinus rhythm and chronic ventricular pacing for complete atrioventricular block. Methods All consecutive patients implanted with an LPM in our department for complete atrioventricular block were retrospectively screened. Patients with atrial fibrillation, sinus dysfunction, or ventricular pacing burden <20% at 1-month post-implantation were excluded. Results A total of 80 patients – 35 VR (2015-2020) and 45 AV (2020-2021) – were included. VR and AV patients had similar baseline characteristics, except for that VR patients being older (82±8 versus 77±9 years, p=0.01). Mean ventricular pacing burden was 75% in the VR and 79% in the AV group (p=0.63). In AV patients, median atrioventricular synchronous beats rate was 77%, 67% having a >66% rate. An E/A ratio <1 as measured on echocardiography was the only independent predictor of accurate atrial mechanical tracking (adjusted OR=13, p=0.006). One-year survival rate was 86% in the VR group and 95% in the AV group (adjusted p=0.21). Two patients in the VR and 0 in the AV group eventually developed pacemaker syndrome in the 1st year post-implantation (p=0.07). Conclusion In sinus rhythm patients with chronic ventricular pacing for complete atrioventricular block implanted with an LPM, atrial mechanical sensing algorithm allowed significant atrioventricular synchrony in most patients, and was associated with no occurrence of – otherwise rare – pacemaker syndrome.

Preimplant Left Ventricular End‐Diastolic Dimension and Body Weight Independently Associate With Paced QRS Duration in Patients Receiving Right Ventricular Apical Pacing for Complete Atrioventricular Block

Paced QRS duration, a good marker of ventricular asynchrony while pacing, has been accepted as a valuable predictor of new-onset heart failure in patients receiving right ventricular apical pacing. But nowadays we have little evidence for predicting paced QRS duration before the implantation. There might be relationships between paced QRS duration and demographic characteristics, clinical features such as comorbidities, native QRS duration, or preimplant cardiac size. The purpose of this article was to identify potential predictors of paced QRS duration in patients receiving right ventricular apical pacing for complete atrioventricular block. One hundred seventy patients with right ventricular apical pacing for complete atrioventricular block were divided into 2 groups according to whether the paced QRS duration was longer than 170 ms or not. Demographic characteristics, clinical features, electrocardiogram and echocardiography before implantation, and electrocardiogram immediately after implantation, were retrospectively recorded. Preimplant left ventricular end-diastolic dimension (LVEDD) and body weight were found to be independently associated with the paced QRS duration. Although both of them had low sensitivity and specificity in predicting paced QRS duration longer than 170 ms, the specificity could increase to 81.2% when they were combined. Both preimplant LVEDD and body weight independently associate with paced QRS duration in patients receiving apical pacing for complete atrioventricular block. Although whether they really have an effect on new-onset heart failure still needs to be verified, and these findings might be a good indication.

Para-Hisian Pacing for a Pediatric Patient with a Congenitally Corrected Transposition of the Great Arteries (SLL)

We report a pediatric patient with a congenitally corrected transposition of the great arteries (ccTGA)(SLL) in which permanent para-Hisian pacing (PPHP) could improve dyssynchrony-associated systemic ventricular (SV) dysfunction resulting from permanent morphologic left ventricular pacing for complete atrioventricular block. Since, in patients with ccTGA(SLL), an elongated His-bundle runs medially toward the upper septum to the site of the fibrous continuity between the right-sided mitral valve and pulmonary artery, the His-bundle may easily be captured by a pacing lead, unlike in normal hearts. Thus, PPHP may be an effective therapeutic strategy for the treatment of dyssynchrony-associated SV dysfunction associated with ccTGA (SLL).

Permanent pacing for complete atrioventricular block after nonsurgical (alcohol) septal reduction in patients with obstructive hypertrophic cardiomyopathy

Nonsurgical septal reduction is a newly developed, catheter-based therapeutic option for patients with drug-refractory obstructive hypertrophic cardiomyopathy. A circumscribed septal infarction is generated to reduce the left ventricular outflow tract gradient. The spontaneous regression of complete atrioventricular block after the procedure and the main complication of the intervention are examined, and treatment with permanent pacing is evaluated.

Cardiovascular response to exercise in pacemaker implanted patients with fixed heart rate.

Cardiovascular response to supine exercise was studied in 11 patients with chronic ventricular pacing for complete atrioventricular block whose heart rate was fixed during exercise, and compared with 11 age- and sex-matched normal subjects. Oxygen uptake increased linearly with increasing work rate, and attained maximum values of 15.7 +/- 0.7 and 29.5 +/- 1.1 ml/min.kg, respectively. In both groups, cardiac output increased in association with oxygen uptake, although the maximum value in the patients was less than one half that in the controls (6.8 +/- 0.5 and 15.1 +/- 0.3 l/min). Stroke volume, however, could change in patients, as in the controls under similarly increased afterloads (maximum values were 96 +/- 7 and 93 +/- 3 ml/beat, respectively). During exercise, the systolic arterial pressure elevated to a similar extent in both groups (221 +/- 14 and 235 +/- 12 mmHg, respectively). The increase in stroke volume in the patients was achieved by complete systolic emptying and the Frank-Starling mechanism. It is considered that in patients with ventricular pacing, exercise can produce an increase in stroke volume when myocardial function is not impaired.