Haemodynamic consequences of targeted single- and dual-site right ventricular pacing in adults with congenital heart disease undergoing surgical pulmonary valve replacement

Abstract

AimsThe purpose of this study was to create an epicardial electroanatomic map of the right ventricle (RV) and then apply post-operative-targeted single- and dual-site RV temporary pacing with measurement of haemodynamic parameters. Cardiac resynchronization therapy is an established treatment for symptomatic left ventricular (LV) dysfunction. In congenital heart disease, RV dysfunction is a common cause of morbidity—little is known regarding the potential benefits of CRT in this setting.Methods and resultsSixteen adults (age = 32 ± 8 years; 6 M, 10 F) with right bundle branch block (RBBB) and repaired tetralogy of Fallot (n = 8) or corrected congenital pulmonary stenosis (n = 8) undergoing surgical pulmonary valve replacement (PVR) for pulmonary regurgitation underwent epicardial RV mapping and haemodynamic assessment of random pacing configurations including the site of latest RV activation. The pre-operative pulmonary regurgitant fraction was 49 ± 10%; mean LV end-diastolic volume (EDV) 85 ± 19 mL/min/m2 and RVEDV 183 ± 89 mL/min/m2 on cardiac magnetic resonance imaging. The mean pre-operative QRS duration is 136 ± 26 ms. The commonest site of latest activation was the RV free wall and DDD pacing here alone or combined with RV apical pacing resulted in significant increases in cardiac output (CO) vs. AAI pacing (P < 0.01 all measures). DDDRV alternative site pacing significantly improved CO by 16% vs. AAI (P = 0.018), and 8.5% vs. DDDRV apical pacing (P = 0.02).ConclusionSingle-site RV pacing targeted to the region of latest activation in patients with RBBB undergoing PVR induces acute improvements in haemodynamics and supports the concept of ‘RV CRT’. Targeted pacing in such patients has therapeutic potential both post-operatively and in the long term.

Pulmonary Right Ventricular Resynchronization in Congenital Heart Disease

“…Temporary RV-CRT was applied by atrial-synchronized RV free wall pacing in bipolar configuration from 2 closely spaced electrodes placed at the border between the inflow and outflow parts in the proximity of the tricuspid annulus. This region has been reported as the site of latest activation in the postrepair tetralogy of Fallot patients with RBBB 12 (Figure 1). Sensed (echocardiographic evaluation) or paced (catheterization) AV delays were set to achieve maximum shortening of the QRS complex through fusion of the intrinsic and paced ventricular depolarization waves.…”

“…RV or biventricular pacing improves short-term hemodynamics in both children and adults with congenital heart disease and RBBB. [8][9][10][11][12][13] The impact of RV-CRT on RV mechanics and contraction efficiency has, however, never been studied despite the fact that pulmonary RV dysfunction and failure are common sources of morbidity and reason for reinterventions in both pediatric and adult congenital heart disease. The present report gives insights into the potential role of RV-CRT in this specific patient group.…”

Branching out

“…On the other hand, several studies showed the strength of relatively simple measures of dyssynchrony, such as apical rocking and septal flash do improve prediction of CRT response [48][49][50] . Further improvements were made by using the analysis of strain patterns 51 , resulting in parameters such as CURE 52 , septal systolic rebound stretch 37,53 , and systolic stretch index 47 .…”

“…LBBB was present 50 . A study in patients with congenital heart disease and RBBB found that pacing from a site of late activation in the RV yielded superior haemodynamic benefit over RV apical pacing, underlining the importance of exploring alternative lead locations 51 . Pacing the RV from a site of late activation was also found to be beneficial in other studies 52,53 .…”

“…However, in one of these studies, the lead was not necessarily placed in a site of late activation 54 , while in the other study, a relatively short atrioventricular (AV) delay was used (70% of the intrinsic PR interval) 55 . The study by Plymen et al used a longer AV delay (close to 90% of the intrinsic PR interval), potentially yielding more fusion with the intrinsic activation wavefront and thus more effective resynchronization 51 .…”