Echocardiographic predictors of the acute hemodynamic response after upgrading to conduction system pacing

Abstract

Background

Conduction system pacing (CSP) is an alternative to right ventricular pacing (RVP) that may enhance cardiac function and haemodynamic parameters in certain patients. In this sub-study of Physiological versus Right Ventricular Pacing Outcome Trial, NCT06052475, a randomised trial of upgrading patients during box change, we examine the haemodynamic improvements from RVP to CSP and investigate whether these can be predicted by echocardiographic biomarkers.

Methods

A total of 20 patients participated in this sub-study, of whom 80% were male, with a mean age of 74.4 ± 7.9 years. Multiple high-precision, non-invasive, beat-by-beat systolic pressures were measured while switching between RVP and CSP using the Nexfin system. The improvement in cardiac function was predicted from baseline echocardiographic biomarkers and linear regression. All transthoracic echocardiography parameters were evaluated in comparison with the RVP baseline.

Results

The mean improvement in systolic blood pressure (SBP) when switching from RVP to CSP was 0.4 ± 2.2 mmHg. The acute systolic response differed; 10 patients (50%) presented a modest response in SBP, with changes ranging from 0.05 to 2 mmHg. Only 1 patient (10%) experienced a significant increase in SBP of more than 5 mmHg. A total of 8 patients (40%) revealed a slight reduction in SBP, ranging from –0.3 to –2 mmHg. No significant correlation was observed between haemodynamic improvement and the selected echocardiographic parameters (left ventricular ejection fraction, p=0.259; left ventricular end systolic volume, p=0.896; left ventricular end diastolic volume, p=0.758; stroke volume index, p=0.232).

Conclusion There was substantial variability in the haemodynamic improvements observed with upgrading from RVP to CSP, and no echocardiographic predictor was identified.