First-in-human experience with occlusion of the superior vena cava to reduce cardiac filling pressures in congestive heart failure.

BACKGROUND: Acutely decompensated heart failure remains a major clinical problem. Volume overload promotes cardiac and renal dysfunction and is associated with increased morbidity and mortality in heart failure. We hypothesized that transient occlusion of the superior vena cava (SVC) will reduce cardiac filling pressures without reducing cardiac output or systemic blood pressure. The objective of this proof of concept study was to provide initial evidence of safety and feasibility of transient SVC occlusion in patients with acutely decompensated heart failure and reduced ejection fraction. METHODS AND RESULTS: In eight patients with systolic heart failure, SVC occlusion was performed using a commercially available occlusion balloon. Five minutes of SVC occlusion reduced biventricular filling pressures without decreasing systemic blood pressure or total cardiac output. In three of the eight patients, a second 10-minutes occlusion had similar hemodynamic effects. SVC occlusion was well-tolerated without development of new symptoms, new neurologic deficits, or any adverse events including stroke, heart attack, or reported SVC injury or thrombosis at 7 days of follow up. CONCLUSION: We report the first clinical experience with transient SVC occlusion as a potentially new therapeutic approach to rapidly reduce cardiac filling pressures in heart failure. No prohibitive safety signal was identified and further testing to establish the clinical utility of transient SVC occlusion for acute decompensated heart failure is justified.

Leadless pacing using induction technology: impact of pulse shape and geometric factors on pacing efficiency.

AIMS: Leadless pacing can be done by transmitting energy by an alternating magnetic field from a subcutaneous transmitter unit (TU) to an endocardial receiver unit (RU). Safety and energy consumption are key issues that determine the clinical feasibility of this new technique. The aims of the study were (i) to evaluate the stimulation characteristics of the non-rectangular pacing pulses induced by the alternating magnetic field, (ii) to determine the extent and impact of RU movement caused by the beating heart, and (iii) to evaluate the influence of the relative position between TU and RU on pacing efficiency and energy consumption. METHODS AND RESULTS: In the first step pacing efficiency and energy consumption for predefined positions were determined by bench testing. Subsequently, in a goat at five different ventricular sites (three in the right ventricle, two in the left ventricle) pacing thresholds using non-rectangular induction pulses were compared with conventional pulses. Relative position, defined by parallel distance, radial distance, and angulation between TU and RU, were determined in vivo by X-ray and an inclination angle measurement system. Bench testing showed that by magnetic induction for every alignment between TU and RU appropriate pulses can be produced up to a distance of 100 mm. In the animal experiment pacing thresholds were similar for non-rectangular pulses as compared with conventional pulse shapes. In all five positions with distances between 62 and 102 mm effective pacing was obtained in vivo. Variations in distance, displacement and angle caused by the beating heart did not cause loss of capture. At pacing threshold energy consumptions between 0.28 and 5.36 mJ were measured. Major determinants of energy consumption were distance and pacing threshold. CONCLUSION: For any given RU position up to a distance of 100 mm reliable pacing using induction can be obtained. In anatomically crucial distances, up to 60 mm energy consumption is within a reasonable range.

Intermittent Occlusion of the Superior Vena Cava Reduces Cardiac Filling Pressures in Preclinical Models of Heart Failure.

Congestion is a major determinant of clinical outcomes in heart failure (HF). We compared the acute hemodynamic effects of occlusion of the superior (SVC) versus the inferior vena cava (IVC) and tested a novel SVC occlusion system in swine models of HF. IVC occlusion acutely reduced left ventricular (LV) systolic and diastolic pressures, LV volumes, cardiac output (CO), and mean arterial pressure (MAP). SVC occlusion reduced LV diastolic pressure and volumes without affecting CO or MAP. The preCARDIA system is a balloon occlusion catheter and pump console which enables controlled delivery and removal of fluid into the occlusion balloon. At 6, 12, and 18 h, SVC therapy with the system provided a sustained reduction in cardiac filling pressures with stable CO and MAP. Intermittent SVC occlusion is a novel approach to reduce biventricular filling pressures in HF. The VENUS-HF trial will test the safety and feasibility of SVC therapy in HF.