In clinical use, digoxin and cibenzoline are prescribed together for the treatment of cardiac arrhythmias. They are mainly excreted unchanged in urine, and their rates of excretion are similar. It has therefore been suggested that the pharmacokinetics of digoxin can predict that of cibenzoline. The aim of this study was to examine the possibility of prediction of cibenzoline dose from that of digoxin. We retrospectively examined 141 Japanese inpatients who received treatment for atrial fibrillation after cardiac surgery in the National Cardiovascular Center from April 2000 to December 2002. We found that CIBCL/F increased in proportion to DxCL/F. We obtained and evaluated a formula to predict cibenzoline dose from that of digoxin. If the dosage predicted from the formula was administered, about 70% patients could be maintained within the therapeutic range. The formula obtained in this study, which can predict cibenzoline dose from that of digoxin, should thus be very valuable in clinical practice.
We encountered a pre-operative patient with hypertrophic cardiomyopathy who needed a careful evaluation of heart failure by Doppler echocardiography. On echocardiographic examination, mitral inflow showed an abnormal relaxation pattern, suggesting normal left atrial pressure. However the pulmonary capillary wedge pressure by a Swan-Ganz catheter was elevated. In echocardiographic parameters, mitral E velocity to mitral annular E velocity ratio(E/E') suggested high left atrial pressure. Doppler echocardiographic evaluation of heart failure needs to be performed carefully, especially in patients with hypertrophic cardiomyopathy and advanced diastolic left ventricular relaxation.