Immediate Amelioration of Mechanical Pulsus Alternans by Adaptive Servo-ventilation Therapy

Abstract

echanical pulsus alternans is sometimes seen inpatients with severe heart failure. This case reportdescribes a patient with medically refractory acute heartfailure due to severe left ventricular (LV) systolic dys-function withpulsusalternans,whereshort-termadaptiveservo-ventilation (ASV)therapyimmediatelyamelioratedthe mechanical pulsus alternans.A 52 year-old male was admitted to the hospitaldue to progressive exertional dyspnoea. Auscultationof the chest revealed fine crackles over both lungs.An S3 gallop rhythm and a grade 2/6 of pansystolicmurmur were audible at the apex. His blood pres-sure was 110/70mmHg and heart rate was 120bpm.Chest X ray showed cardiomegaly with bilateral pul-monary congestion. The electrocardiogram showed sinustachycardia with normal QRS duration. Blood exami-nation on admission revealed remarkable elevation inthe serum level of brain natriuretic peptide (BNP) of1740 pg/dl (<18.4pg/ml). Echocardiography showed aseverely dilated left ventricle (LV) with an ejection frac-tion of 15% (Movie 1). Estimated systolic pulmonaryartery pressure from tricuspid regurgitation velocity was64 mmHg. Initial treatment with angiotensin II recep-tor blockers, intravenous diuretics, and carperitide failedto provide a favourable response. Subsequently, intra-venous phosphodiesterase III inhibitor for three daysdid not improve his condition. Radial pulse revealedalternating strong and weak beats, indicating mechanicalpulsus alternans. Repeated echocardiography demon-strated alternating pulsed Doppler flow velocities acrossthe LV outflow tract (LVOT) with no significant change ofLV size and systolic function compared to the previousstudy (Fig. 1). Although oxygen saturation was preservedby