Effect of Transmural Differences in Excitation-Contraction Delay and Contraction Velocity on Left Ventricle Isovolumic Contraction: A Simulation Study.

Recent studies have shown that left ventricle (LV) exhibits considerable transmural differences in active mechanical properties induced by transmural differences in electrical activity, excitation-contraction coupling, and contractile properties of individual myocytes. It was shown that the time between electrical and mechanical activation of myocytes (electromechanical delay: EMD) decreases from subendocardium to subepicardium and, on the contrary, the myocyte shortening velocity (MSV) increases in the same direction. To investigate the physiological importance of this inhomogeneity, we developed a new finite element model of LV incorporating the observed transmural gradients in EMD and MSV.

Ventricular dyssynchrony assessment using ultra-high frequency ECG technique.

Purpose: The aim of this proof-of-concept study is to introduce new high-dynamic ECG technique with potential to detect temporal-spatial distribution of ventricular electrical depolarization and to assess the level of ventricular dyssynchrony.

Methods: 5-kHz 12-lead ECG data was collected. The amplitude envelopes of the QRS were computed in an ultra-high frequency band of 500-1000 Hz and were averaged (UHFQRS).

Variability of phase shift between blood pressure and heart rate fluctuations: a marker of short-term circulation control.

Background: We postulated that the variability of the phase shift between blood pressure and heart rate fluctuation near the frequency of 0.10 Hz might be useful in assessing autonomic circulatory control.

Methods And Results: We tested this hypothesis in 4 groups of subjects: 28 young, healthy individuals; 13 elderly healthy individuals; 25 patients with coronary heart disease; and 19 patients with a planned or implanted cardioverter-defibrillator (ICD recipients).

Heart rate and increased intravascular volume.

The objective was to establish whether an intravascular volume increase leads to a heart rate (HR) increase without increased sympathetic tonus. HR changes at rest and at deep breathing (6/min - simulated increase of atrial filling pressure) were measured in patients after heart transplantation. Evaluation of dependency of HR changes on breathing depth was done through a new time series methodology.

Pericardial abscess--a rare complication of sepsis.

Pericardial abscess is a very rare complication of sepsis. Authors describe the case of a 69-year-old woman. In her case staphylococcus sepsis led to pericardial abscess.