Adequacy of Preoperative Digitalis Therapy in Controlling Ventricular Rate in Postoperative Atrial Fibrillation

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Abstract
Fa 53 unselected patients with mitral valve disease who underwent mitral valve surgery and developed atrial fiorillation in the immediate postoperative period, the ventricular rates were measured immediately before and after the onset of atrial fibrillation. Patients were divided into three groups: those who received no digitalis at all; those who were maintained on digitalis prior to the operation and in whom treatment with digitalis was was discontinued several days before the onset of the arrhythmia; and those who were maintained on conventional doses of digitalis up to the onset of the arrhythmia. Results of the study indicated that the mean ventricular rates at the time of the onset of atrial fibrillation were 163 beats per minute in group A, 138 in group B, and 121 in group C. Differences between the three groups were statistically significant at the 0.001 level. It was shown that the mean ventricular rate in patients receiving digitalis maintenance was still significantly higher than control rates in sinus rhythm. In half of the patients in group C inadequate control of ventricular rates was observed during atrial fibrillation. In half of this subgroup (one quarter of group C) excessive ventricular rates and high requirements for additional digitalis needed to bring ventricular rates under control suggested a virtually non-existent digitalis effect.