Ventricular rate control in chronic atrial fibrillation during daily activity and programmed exercise: a crossover open-label study of five drug regimens
Ramin Farshi, MDa,
Deborah Kistner, RNa,
Jonnalagedda S. M. Sarma, PhD, FACCa,
Jeffrey A. Longmate, PhD* and
Bramah N. Singh, MD, PhD, FACCa
a Division of Cardiology, West Los Angeles VA Medical Center, UCLA School of Medicine, Los Angeles, California, USA
* City of Hope Medical Center, Duarte, California, USA
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Figure 1 Circadian distribution of hourly mean VR in patients with CAF as influenced by various treatment regimens (Dig + dilt = digoxin + diltiazem; Dig + atn = digoxin + atenolol). The "hour of the day" refers to a 24 h clock with hour 0 being midnight. All regimens exhibited significant circadian variation of VR (p < 0.001). Digoxin and diltiazem given alone had similar overall rates during the 24 h. Compared with digoxin, atenolol alone and digoxin + atenolol markedly attenuated the circadian rhythmicity. Note that beta-blockade tended to shift the peak ventricular rate to a later time in the afternoon and the combination of digoxin and atenolol was the most effective regimen in reducing the ventricular rate in atrial fibrillation. See text for details.
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Figure 2 Cosinor modeling of the circadian pattern of VR in patients with CAF for comparison of the effects of different treatments on the phase of the circadian patterns. The 24-h VR data of each subject were fitted to a cosine curve through a nonlinear regression analysis. The hourly mean VR data and the corresponding cosine curves of 4 cases representing typical, best, borderline accepted and rejected fits are presented. The time of peak ventricular rate from midnight was calculated from the estimated phase of the cosine fit. See Table 2 and the text for details.
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Figure 3 Effect of various pharmacologic regimens on exercise-induced VR in patients with CAF. There was a linear trend in increases in VR on all 5 regimens. The mean VR on digoxin + atenolol treatment was the lowest and was significantly lower than those on digoxin, diltiazem and digoxin + diltiazem. See text for details.
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