Electrical modalities beyond pacing for the treatment of heart failure

In this review, we report on electrical modalities, which do not fit the definition of pacemaker, but increase cardiac performance either by direct application to the heart (e.g., post-extrasystolic potentiation or non-excitatory stimulation) or indirectly through activation of the nervous system (e.g., vagal or sympathetic activation). The physiological background of the possible mechanisms of these electrical modalities and their potential application to treat heart failure are discussed

The Effects of Inhomogeneities and Anisotropies on Electrocardiographic Fields: A Three-Dimensional Finite Element Study

The aim of this study was to quantify the effects of selected inhomogeneities and anisotropies on computed electric potential fields associated with the electrocardiographic forward problem. The model construction was based on the Utah Torso model and included geometry for major anatomical structures such as subcutaneous fat, skeletal muscle, and lungs, as well as for epicardial fatpads, major arteries and veins, and the sternum, ribs, spine and clavicles. Measured epicardial potentials served as the electrical source for solutions to the electrocardiographic forward problem computed using the finite element (FE) method. The geometry of the torso model for each simulation was constant but different combinations of conductivities were assigned to individual organs or tissues. Comparisons of different conductivity combinations followed one of two basic schemes: 1) a homogeneous torso served as the reference against which we compared simulations with a single organ or tissue assigned its ..

Acute electromechanical effects of atrioventricular coupled pacing in patients with heart failure.

BACKGROUND: Postextrasystolic potentiation (PESP) is a property of cardiac tissue whereby two closely timed depolarizations cause the subsequent contraction to be of increased magnitude. METHODS AND RESULTS: Ten subjects were studied in a single-blind study to evaluate the safety and performance of an atrioventricular coupled pacing (A-VCP) algorithm to produce sustained PESP among subjects with moderate heart failure. The primary end points were algorithm safety, patient perception, and cardiac function. The effects of A-VCP on cardiac function were assessed by comparing echocardiographic parameters before and after 15 to 20 minutes of A-VCP. A-VCP produced no arrhythmic episodes, ejection fraction increased by 8 ejection fraction points (31%) (P \u3c or = .001), end-systolic volume decreased by 10% (P \u3c or = .05), and a trend toward increasing end-diastolic volume was observed (P = .084). Stroke volume increased by 43% (P \u3c or = .001), and the pulse rate decreased by 41% (P \u3c or = .001) during A-VCP. This resulted in decreased cardiac output of 15% (P \u3c or = .05). Six of the 10 subjects felt no effects from A-VCP, and four subjects felt a change with A-VCP turned on. CONCLUSION: Short-term A-VCP was found to be safe and well tolerated in a majority of patients. Hemodynamic effects were mixed with improved ejection fraction and stroke volume but decreased cardiac output