Optimized Multisite Ventricular Pacing in Postoperative Single-Ventricle Patients

Abstract

Ventricular dyssynchrony is associated with morbidity and mortality after palliation of a single ventricle. The authors hypothesized that resynchronization with optimized temporary multisite pacing postoperatively would be safe, feasible, and effective. Pacing was assessed in the intensive care unit within the first 24 h after surgery. Two unipolar atrial pacing leads and four bipolar ventricular pacing leads were placed at standardized sites intraoperatively. Pacing was optimized to maximize mean arterial pressure. The protocol tested 11 combinations of the 4 different ventricular lead sites, 6 atrioventricular delays (50–150 ms), and 14 intraventricular delays. Optimal pacing settings were thus determined and ultimately compared in four configurations: bipolar, unipolar, single-site atrioventricular pacing, and intrinsic rhythm. Each patient was his or her own control, and all pacing comparisons were implemented in random sequence. Single-ventricle palliation was performed for 17 children ages 0–21 years. Pacing increased mean arterial pressure (MAP) versus intrinsic rhythm, with the following configurations: bipolar multisite pacing increased MAP by 2.2 % (67.7 ± 2.4 to 69.2 ± 2.4 mmHg; p = 0.013) and unipolar multisite pacing increased MAP by 2.8 % (67.7 ± 2.4 to 69.6 ± 2.7 mmHg; p = 0.002). Atrioventricular single-site pacing increased MAP by 2.1 % (67.7 ± 2.4 to 69.1 ± 2.5 mmHg: p = 0.02, insignificant difference under Bonferroni correction). The echocardiographic fractional area change in nine patients increased significantly only with unipolar pacing (32 ± 3.1 to 36 ± 4.2 %; p = 0.02). No study-related adverse events occurred. Multisite pacing optimization is safe and feasible in the early postoperative period after single-ventricle palliation, with improvements in mean arterial pressure and fractional area shortening. Further study to evaluate clinical benefits is required.

A Review of Surgical Atrioventricular Block with Emphasis in Patients with Single Ventricle Physiology

“…These studies involve two ventricle physiology and do not exclusively include the complex anatomy and physiology found in congenital heart disease . Moreover, single ventricles are at risk of dysfunction and early failure even without the addition of pacing . The added stress of chronic pacing is likely to only hasten ventricular deterioration.…”

“…Optimization of lead location, specifically on the left apex or left mid lateral wall, has been shown to prevent LV function impairment in children . Adult studies have shown conversion to biventricular pacing to improve ventricular dysfunction in pacing induced dysfunction via early activation of late‐activating regions of myocardium and reduced ventricle oxygen demand . These studies involve two ventricle physiology and do not exclusively include the complex anatomy and physiology found in congenital heart disease .…”

“…18 Adult studies have shown conversion to biventricular pacing to improve ventricular dysfunction in pacing induced dysfunction via early activation of late-activating regions of myocardium and reduced ventricle oxygen demand. 22 These studies involve two ventricle physiology and do not exclusively include the complex anatomy and physiology found in congenital heart disease. 16 Moreover, single ventricles are at risk of dysfunction and early failure even without the addition of pacing.…”

“…16 Moreover, single ventricles are at risk of dysfunction and early failure even without the addition of pacing. [22][23][24] The added stress of chronic pacing is likely to only hasten ventricular deterioration. Thus, the model of pacing induced ventricular dysfunction and failure will likely be seen in the single ventricle population much like it has in the two ventricle population.…”

“…22 In single ventricle anatomy, temporary multisite pacing has been shown to improve hemodynamics in the postoperative setting in those with intact AV conduction. 22,23 Currently no universal recommendations for lead placement in single ventricle patients with surgical AV block. In fact, because of the complex nature of single ventricle anatomy, a single, universal optimal site may not exist.…”