Effects of nibentan on the endocardial muscle action potential
| Control | 10−8 M | 10−7 M | 10−6M | 5 × 10−6 M | |
|---|---|---|---|---|---|
| CL 2000 ms | |||||
| MDP (−mV) | 83 ± 1 | 83 ± 2 | 85 ± 1 | 86 ± 1 | 86 ± 1 |
| APA (mV) | 105 ± 1 | 104 ± 2 | 105 ± 1 | 105 ± 1 | 105 ± 2 |
| Vmax (V/s) | 169 ± 7 | 165 ± 27 | 165 ± 17 | 177 ± 25 | 107 ± 14* |
| APD50 (ms) | 155 ± 7 | 153 ± 4 | 171 ± 4* | 189 ± 4* | 189 ± 4* |
| APD90 (ms) | 204 ± 6 | 204 ± 4 | 220 ± 5* | 249 ± 6* | 249 ± 8* |
| Sl3 (mV/s) | 1143 ± 41 | 1212 ± 44 | 1168 ± 65 | 1038 ± 60 | 1028 ± 62 |
| CL 1000 ms | |||||
| MDP (−mV) | 84 ± 2 | 84 ± 2 | 86 ± 1 | 86 ± 2 | 87 ± 2 |
| APA (mV) | 103 ± 1 | 103 ± 2 | 105 ± 1 | 105 ± 2 | 103 ± 1 |
| Vmax(V/s) | 182 ± 10 | 176 ± 28 | 180 ± 22 | 154 ± 17 | 79 ± 11* |
| APD50 (ms) | 142 ± 4 | 144 ± 6 | 157 ± 3* | 172 ± 3* | 171 ± 4* |
| APD90(ms) | 190 ± 4 | 187 ± 7 | 206 ± 4* | 230 ± 4* | 229 ± 6* |
| Sl3 (mV/s) | 1204 ± 66 | 1180 ± 39 | 1167 ± 43 | 1063 ± 47 | 1021 ± 74 |
| CL 500 ms | |||||
| MDP (−mV) | 84 ± 1 | 84 ± 2 | 84 ± 1 | 85 ± 1 | 87 ± 2 |
| APA (mV) | 102 ± 1 | 103 ± 2 | 101 ± 1 | 102 ± 1 | 103 ± 1 |
| Vmax (V/s) | 178 ± 10 | 168 ± 25 | 170 ± 20 | 157 ± 21 | 72 ± 11* |
| APD50 (ms) | 114 ± 4 | 119 ± 3 | 120 ± 3* | 140 ± 3* | 142 ± 4* |
| APD90 (ms) | 157 ± 4 | 159 ± 4 | 166 ± 3* | 195 ± 3* | 195 ± 6* |
| Sl3 (mV/s) | 1169 ± 42 | 1182 ± 23 | 1074 ± 36 | 1043 ± 51 | 1030 ± 91 |
MDP, maximum diastolic potential; APA, action potential amplitude; Vmax, maximum rate of rise of phase 0; APD50and APD90, APD at 50% and 90% of full repolarization, respectively; Sl3, slope of phase 3. Values are mean ± S.E.M. (n = 6).
* P < .05 compared with control at the same CL.