All drugs increased the variability of ventricular response in respect to baseline ( as an example , rMSSD : baseline 171 47 milliseconds , carvedilol 229 58 milliseconds ; P < 0.05 vs. baseline , metoprolol 226 66 milliseconds ; P < 0.05 vs. baseline , verapamil 228 84 ; P < 0.05 vs. baseline , diltiazem 256 87 milliseconds ; P < 0.05 vs. baseline and all other drugs ) .