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A bidomain reaction-diffusion model of the human heart was developed, and potentials resulting from normal depolarization and repolarization were compared with results from a compatible monodomain model. Comparisons were made for an empty isolated heart and for a heart with fluid-filled ventricles. Both sinus rhythm and ectopic activation were simulated.(More)
The boundary-element method (BEM) is widely used for electrocardiogram (ECG) simulation. Its major disadvantage is its perceived inability to deal with the anisotropic electric conductivity of the myocardial interstitium, which led researchers to represent only intracellular anisotropy or neglect anisotropy altogether. We computed ECGs with a BEM model(More)
BACKGROUND ST segment deviation conveys crucial information concerning diagnosis, therapy and prognosis during acute coronary syndromes, but the understanding of the genesis of different ST shift polarities and the rationale for optimal lead placement during ischemic monitoring are incomplete. PATIENTS AND METHODS Ninety-nine continuous recordings were(More)
To compare the effects of valsartan and amlodipine alone or in combination on plasma norepinephrine (NE) at rest and standing for 10 minutes in patients with hypertension, 47 patients with a sitting diastolic blood pressure (BP) (DBP)>95 mm Hg and<110 mm Hg were randomized in a double-blind fashion to either valsartan or amlodipine. During the first 4 weeks(More)
The simulation of the propagation of electrical activity in a membrane-based realistic-geometry computer model of the ventricles of the human heart, using the governing monodomain reaction-diffusion equation, is described. Each model point is represented by the phase 1 Luo-Rudy membrane model, modified to represent human action potentials. A separate longer(More)
Using wavelets, we computed the entropy of the signal at various frequency levels (wavelet time entropy) and, thus, find an optimal measure to differentiate normal states from ischemic ones. This new indicator is independent from the ST segment and yet provide a conclusive detection of the ischemic states.
BACKGROUND Myocardial ischemia, commonly defined as ST-segment elevation or depression on the electrocardiogram (ECG), is plagued by a large number of false positive events. OBJECTIVES To present a new method that attempts to distinguish between 'highly probable ischemia' and positional changes. METHODS Continuous three-lead orthogonal ECG monitoring(More)
The main goal of this study was to simulate clinical body surface potential maps, recorded during percutaneous transluminal coronary angioplasty protocols, using a realistic geometry computer heart model. Other objectives were to address the question of reciprocal ST-segment changes observed in the 12-lead electrocardiogram during ischemia and to verify the(More)
—We implemented a recent model of the human ven-tricular cell membrane in our existing human heart model comprising 12 million cells. Using an inhomogeneous torso model, a normal ECG was simulated, as well as ECGs for a membrane model with modified transient outward current. We also investigated the effect of cellular coupling in the heart on the action(More)
OBJECTIVE To determine the effects of 8 weeks of therapy with amlodipine, ramipril or telmisartan on the autonomic system over 24 h in hypertensives. METHODS After a placebo run-in, 57 patients were included in a prospective randomized open-label design protocol for therapy with amlodipine (5 mg for 4 weeks followed by 10 mg for 4 weeks, n = 22), or(More)