| Author/Editor | Vokač, Damijan | |
| Title | Elektrofiziološki efekti adenozina na humani monofazni potencijal | |
| Type | monografija | |
| Place | Zagreb | |
| Publisher | Sveučilište u Zagrebu, Medicinski fakultet | |
| Publication year | 1999 | |
| Volume | str. 81 | |
| Language | cro | |
| Abstract | Integrative effects of adenosine on human atrial and ventricular monophasic action potential (MAP) on different pacing rates and incremental doses were studied. BACKGROUND: Interaction of rate dependent and adenosine dependent duration shortening on human MAP, mainly determined by repolarization processes driven by potassium currents and influenced by cycle length or by action of hormones and drugs, were studied. In supraventricular nodal and atrial cells MAP duration besides rate dependent control also succumbs to acetylholine and adenosine operated channels. METHODS: MAPs from right atrium and right ventricular apex were recorded simultaneously parallel to intracavitary his electrocardiogram from 8 patients ages between 24 and 60 years (mean 37+/-12) during elective electrophysiology study. Standard Franz contact catheters were used. Incremental doses of adenosine boluses 1.0, 3.0 and 6.0 mg were applied via central vein catheter during different pacing cycle lengths: 800 ms, 600 ms and 500 ms. Atrial and ventricular MAPs were automatically analyzed for MAP duration at 100%, 90%, 70% and 50% repolarization time. Data were expressed in relative values as percent shortening of MAP duration from control value obtained before adenosine bolus. RESULTS: Adenosine caused brief and marked atrial MAP duration shortening after bolus with time constant of ( Tau = 3.85 +/- 1.25 sec) after maximal-effect. Significant shortening of atrial MAP duration were observed for all doses of adenosine on different pacing rates. On atrial MAPs marked statistically significant (p<0.001) effects on shortening were obtained. Mean atrial MAP 90% duration at 800 ms pacing cycle decreased from 274 +/- 70 msec to 198 +/- 75 and on 500 ms pacing cycle from 230 +/- 32 to 135 +/- 29 msec after 6.0 mg of adenosine. (Abstract truncated at 2000 characters) | |
| Descriptors | ADENOSINE ACTION POTENTIALS HEART ATRIUM HEART VENTRICLE MYOCARDIAL CONTRACTION ATRIAL FIBRILLATION HEART RATE ELECTROCARDIOGRAPHY |