Seasonal variation of right heart function in elite skiers-racers: an echocardiographic study.

Purpose: To examine seasonal variation of the right heart (RH) structure and function in elite skiers-racers.

Methods: The same group of 16 male was recruited into the study in the period of preparation for national competitions. The study was carried out at the hospital in Sykyvkar, the European North of Russia, which is located near 62° NL and 51° EL.

Effect of atrial artificial electrical stimulation on depolarization and repolarization and hemodynamics of the heart ventricle in rainbow trout Oncorhynchus mykiss.

The spatial-temporal organization of the activation, repolarization and hemodynamics of the heart ventricle in rainbow trout, Oncorhynchus mykiss, adapted to a temperature of 5-7 °C, were studied from the normal sinus rhythm (21.6 ± 4.9 bpm) to the highest possible heart rhythm (HR) (60 bpm), during which deterioration of the contractile activity of the myocardium occurred.

Acute effects of pacing site on repolarization and haemodynamics of the canine ventricles.

Aims: To determine the repolarization duration gradients in different ventricular regions at atrial and ventricular pacing and to test the hypothesis that acute haemodynamic response to ventricular pacing is related to the lead position with respect to repolarization gradients.

Methods And Results: Repolarization durations estimated as activation-recovery intervals (ARIs) were measured from unipolar electrograms recorded in the subepicardial (Epi), mid-myocardial (Mid), and subendocardial (Endo) layers of the apical and basal parts of the right ventricle (RV) and left ventricle (LV) of 15 healthy dogs under atrial and ventricular pacing. Cardiac haemodynamic variables were measured as well.