P5.11: Effect of Carotid Baroreceptor Activation on Ventricular Function and Central Arterial Hemodynamics: A Case Report Based on Invasive Pressure-Volume Loop Analysis

Abstract

Background Carotid baroreceptor activation (CBA) is being explored as anti-hypertensive therapy in patient with resistant hypertension. In this study, we demonstrate the effect of CBA on cardiac performance and central arterial hemodynamics based on invasive data measured in a 78 year old male patient with resistant hypertension who also showed clinical symptoms of heart failure. Materials and methods Measurements were performed upon implantation of a CBA device (CVRx, Minneapolis, Mn), with a pressure-volume catheter inserted via the groin and advanced into the left ventricle (LV). Pressure-volume loops were acquired at baseline and with CBA (Figure-left). Upon catheter pullback, pressure recordings were made (baseline and CBA) in the aortic root (Figure-right). A flow waveform was derived from the volume data, and combined with the aortic root pressure to assess wave reflection via wave decomposition.

Results CBA slowed heart rate from 64 to 46 bpm, reduced central systolic (from 165 to 107 mmHg) and pulse (92 to 56 mmHg) pressure, while stroke volume increased by about 30%. The LV end-diastolic pressure-volume relation was lowered (Figure-left), reducing end-diastolic pressure from about 19 to 13 mmHg. CBA lowered characteristic impedance by 40%, leading to a similarly large reduction in forward pressure wave amplitude (from 90 to 56 mmHg). Backward wave amplitude was lowered from 31 to 23 mmHg.

Conclusions This in vivo case report demonstrates not only profound favourable effects of CBA on LV afterload, but a concomitant effect on LV filling dynamics which might particularly be important in patients with heart failure.