The effects of heart rate on myocardial velocity and atrio-ventricular displacement during exercise with and without beta-blockade: a tissue Doppler echocardiographic study.
BACKGROUND
Colour tissue Doppler echocardiography (TDE) allows an objective assessment of regional myocardial function. Peak systolic velocity (PSV) and A-V plane displacement (AVPD) obtained from colour TDE correlate well with changes in cardiac wall motion and can discriminate ischemic areas during stress echocardiography. During exercise, the relationship between PSV and AVPD depends on several factors besides ischemia and should be considered when performing exercise stress echocardiography.


OBJECTIVE
To investigate the relation between PSV, AVPD and heart rate (HR) during semi-upright exercise with and without beta-blockade.


METHODS
Twelve healthy men underwent semi-upright exercise stress echocardiography with and without beta-blockade on two separate occasions. Standard echocardiographic projections were used for the stress echocardiography. Grey-scale echocardiographic pictures containing colour TDE information were obtained at rest and during a two-stage exercise test, and the images were analyzed off-line. The PSV and AVPD were measured at four points at the base of the left ventricle at the septum and lateral, inferior and anterior walls.


RESULTS
PSV, AVPD and HR gradually increased during exercise. The increases in PSV and AVPD were linearly correlated with the increase in HR. The increases in PSV were significantly lower during exercise with beta-blockade than without beta-blockade (P<0.05). This was not observed in AVPD, as increments were not affected by beta-blockade.


CONCLUSIONS
These data showing a relationship between HR and PSV, and a significantly lower PSV with beta-blockade at a given HR, suggest that PSV is influenced by HR and myocardial contractility, both of which are augmented by physical exercise-induced sympathetic stimulation.
Quintana
Miguel
M
Departments of Clinical Physiology and Cardiology, Huddinge University Hospital, Karolinska Institute, 141 86 Stockholm, Sweden. miguel.quintana@labmed.ki.se
Gustafsson
Thomas
T
Sundblad
Patrick
P
Langanger
Jenny
J
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000328:Adult; D016279:Atrial Function, Left / Q000502:physiology; D018618:Echocardiography, Doppler, Color / Q000379:methods; D025401:Echocardiography, Stress; D004562:Electrocardiography; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008790:Metoprolol / Q000494:pharmacology; D009200:Myocardial Contraction / Q000502:physiology*; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging*; D016277:Ventricular Function, Left / Q000502:physiology
D000319:Adrenergic beta-Antagonists; D008790:Metoprolol