What is the clinical evidence from this study?

Study design: Cross-Sectional. Population: Sick sinus syndrome with normal left ventricular function (n=14). Intervention: Acute right ventricular apical (RVA) and right ventricular outflow tract (RVOT) pacing vs. Baseline AAI pacing. Primary outcome: Wall motion score, longitudinal LV strain, and electromechanical delay.

May 7, 2008Open Access

Right ventricular outflow and apical pacing comparably worsen the echocardioghraphic normal left ventricle

Key Result

Acute right ventricular apical and outflow tract pacing comparably deteriorated wall motion score and longitudinal LV strain compared to baseline AAI pacing in 14 patients.

Study Design

Type

Cross-Sectional (n=14)

Structured PICO

Does acute right ventricular apical or outflow tract pacing worsen echocardiographic left ventricular function compared to baseline in patients with normal LV function?

Population

14 patients with a DDD-pacemaker (7 RVA, 7 RVOT) for sick sinus syndrome, normal left ventricular function, normal atrioventricular and intraventricular conduction, and no other cardiac abnormalities.

Intervention

Acute right ventricular apical (RVA) or right ventricular outflow tract (RVOT) pacing (DDD mode)

Comparator

Baseline intrinsic ventricular conduction (AAI pacing mode)

Outcome

Acute changes in wall motion score (WMS), longitudinal LV strain, and electromechanical delay assessed by echocardiographysurrogate

Acute right ventricular pacing, whether apical or outflow tract, comparably worsens echocardiographic parameters of left ventricular function in patients with normal baseline function.

Abstract

AIMS: A depressed left ventricular function (LVF) is sometimes observed during right ventricular apical (RVA) pacing, but any prediction of this adverse effect cannot be done. Right ventricular outflow tract (RVOT) pacing is thought to deteriorate LVF less frequently because of a more normal LV activation pattern. This study aims to assess the acute effects of RVA and RVOT pacing on LVF in order to determine the contribution of echocardiography for the selection of the optimum pacing site during pacemaker (PM) implantation. METHODS AND RESULTS: Fourteen patients with a DDD-pacemaker (7 RVA, 7 RVOT) and normal LVF without other cardiac abnormalities were studied. PM dependency, because of sick sinus syndrome with normal atrioventricular and intraventricular conduction, was absent in all, allowing acute programming changes. Wall motion score (WMS), longitudinal LV strain, and tissue Doppler imaging for electromechanical delay were assessed with echocardiography during AAI pacing constituting baseline and DDD pacing. The WMS was normal at baseline (AAI pacing) in all patients and LV dyssynchrony was absent. Acute RVA and RVOT pacing deteriorated WMS, electromechanical delay, and longitudinal LV strain, but no difference of the deterioration between both pacing sites was present and dyssynchrony did not emerge. CONCLUSION: Both acute RVA and RVOT pacing negatively affect WMS, longitudinal LV strain, and mechanical activation times, without clear differences between both pacing sites. Thus echocardiographic techniques do not facilitate the selection between RVOT and RVA pacing to exclude adverse effects on LVF during PM implantation in patients with a normal LVF.