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BACKGROUND Left ventricular (LV) mechanical discoordination, often referred to as dyssynchrony, is often observed in patients with heart failure regardless of QRS duration. We hypothesized that different myocardial substrates for LV mechanical discoordination exist from (1) electromechanical activation delay, (2) regional differences in contractility, or(More)
Experimental action potential (AP) recordings in isolated ventricular myoctes display significant temporal beat-to-beat variability in morphology and duration. Furthermore, significant cell-to-cell differences in AP also exist even for isolated cells originating from the same region of the same heart. However, current mathematical models of ventricular AP(More)
The ionization and UV-visible spectral properties of some harmala alkaloids have been investigated spectrophotometrically. Harmaline and harmine were found to have pKa values of 9.55 +/- 0.04 and 7.45 +/- 0.03, respectively. The ionization of harmalol was characterized by two processes which could be spectrophotometrically isolated from one another,(More)
Differences in mRNA expression levels have been observed in failing versus non-failing human hearts for several membrane channel proteins and accessory subunits. These differences may play a causal role in electrophysiological changes observed in human heart failure and atrial fibrillation, such as action potential (AP) prolongation, increased AP(More)
Variability in the action potential of isolated myocytes and tissue samples is observed in experimental studies. Variability is manifested as both differences in the action potential (AP) morphology between cells (extrinsic variability), and also 'intrinsic' or beat-to-beat variability of repolarization (BVR) in the AP duration of each cell. We studied the(More)
Abnormal left-right motion of the interventricular septum in early systole, known as septal flash (SF), is frequently observed in patients with left bundle branch block (LBBB). Transseptal pressure gradient and early active septal contraction have been proposed as explanations for SF. Similarities in timing (early systole) and location (septum) suggest that(More)
AIMS It is unclear how the position of the left ventricular (LV) lead relative to a scar affects the haemodynamic response in patients with dyssynchronous heart failure receiving cardiac resynchronization therapy. We investigated this complex interaction using a computational model. METHODS AND RESULTS The CircAdapt computational cardiovascular system(More)
Rapid leftward septal motion (RLSM) during early left ventricular (LV) diastole is observed in patients with pulmonary arterial hypertension (PAH). RLSM exacerbates right ventricular (RV) systolic dysfunction and impairs LV filling. Increased RV wall tension caused by increased RV afterload has been suggested to cause interventricular relaxation(More)