Augmentation of left ventricular (LV) contractility and heart rate (HR) by sympathetic nerve stimulation and amelioration of heart failure by vagal nerve stimulation has been reported. However, the effects of concomitant electrical stimulation of both sympathetic and parasympathetic cardiac nerves in tissues such as those of the cardiac plexus remain unclear. This study sought to assess acute changes in cardiac function and hemodynamics in response to endovascular cardiac plexus stimulation (CPS).
Twelve dogs received endovascular CPS via a bipolar catheter within the right pulmonary artery. Stimulation frequency (20 Hz) and pulse width (4 milliseconds) were fixed; voltage varied (range, 15–60 V).
Results fell into three categories: 1, no response (n = 4); 2, an increase in systemic arterial pressure that was dependent on electrode placement (n = 4); and 3, a very reproducible and stable increase in aortic pressure (n = 4). In the third group, mean systolic aortic pressures, maximum value of the first derivative of LV pressure, and LV stroke work increased with stimulation (P < 0.02 for all parameters) as did cardiac output, end-systolic elastance, and preload recruitable stroke work (P = 0.03). Systemic and pulmonary vascular resistance, central venous pressure, pulmonary arterial pressure, and HR remained unchanged (P > 0.05).
In contrast to conventional inotropic agents, endovascular CPS induced significant and selective increases in LV contractility without increasing HR. Efforts to optimize electrode placement and fixation will improve the reproducibility of endovascular CPS treatment.
From the Departments of *Biomedical Engineering and †Molecular Cardiology, Lerner Research Institute, and ‡Cardiovascular Medicine, Miller Family Heart & Vascular Institute, Cleveland Clinic, Cleveland, OH USA; and §Global Cardiovascular Innovation Center, Cleveland, OH USA.
Accepted for publication August 8, 2012.
Supported by the Global Cardiovascular Innovation Center, a Wright Mega-Center of Innovation, and the State of Ohio’s Third Frontier Program, Cleveland, OH USA.
Disclosure: The authors declare no conflict of interest.
Address correspondence and reprint requests to Kiyotaka Fukamachi, MD, PhD, Department of Biomedical Engineering/ND20, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH 44195 USA. E-mail: firstname.lastname@example.org.