Effects of Maintenance Digoxin Therapy on Systolic Time Intervals and Serum Digoxin Concentrations

Abstract

SUMMARYSystolic time intervals (STI) and serum digoxin concentrations (SDC) were measured in eight patients with compensated atherosclerotic and/or hypertensive heart disease who received oral digoxin 0.25 mg/day or 0.5 mg/day for alternate two-week periods without a loading dose. Control data were obtained both before and after the four weeks of treatment. After 13 days treatment with digoxin, 0.5 mg/day, there was a significant decrease in total electromechanical systole corrected for heart rate (QS2i), pre-ejection period (PEP), pre-ejection period corrected for heart rate (PEP,) Methods Eight patients, all in normal sinus rhythm, with compensated atherosclerotic and/or hypertensive heart disease were studied. Four patients were male and four patients were female. Ages ranged from 35 years to 68 years. Five patients were receiving maintenance doses of digoxin, orally, at the time of selection for the study. Digoxin was discontinued at least two weeks prior to the first control observation. In all patients, SDC at the time of the first control observation was less than 0.4 ng/ml. Diuretics, antihypertensive agents, and sedatives were continued in unchanged doses. Patients taking diuretics received supplemental oral potassium chloride. The purpose of the study was fully explained to each patient and written informed consent was obtained.The initial evaluation of each patient included determinations of blood urea nitrogen, serum creatinine, sodium, potassium, chloride, carbon dioxide combining power, calcium, carotene, and thyroxine. The results of these studies were all within the normal range. Chest X-rays and 12-lead electrocardiograms were compatible with the clinical diagnoses.Two sets of control observations (Cl and C2) were obtained two weeks before starting digoxin. Four of the patients then received digoxin 0.25 mg/day for two weeks

Modulation of plasma adrenomedullin by epinephrine infusion during head up tilt

“…LVET and PEP corrected for heart rate and gender (LVETi and PEPi, respectively) were calculated from regression equations for normal subjects (Weissler and Garrard 1971). For detailed analysis of systolic time intervals see (Carliner et al 1974). Finally, in situations of increased inotropy, such as during epinephrine infusion, systolic time intervals corrected for heart rate may mask the associated inotropic effect (see Krzeminski et al 2009).…”

Pharmacokinetics and Echocardiographic Effects of Digoxin in Low Birth Weight Infants with Left-to-Right Shunting due to Patent Ductus arteriosus

“…However, Karliner et al (23), were unable to detect significant changes in L VSTI until 13 days of maintenance digoxin therapy had elapsed in adults, and Davidson and Gibson (24) were unable to demonstrate a correlation between digoxin concentration and LVSTI following acute administration of digoxin. Our inability to detect changes in LVSTI might be attributed to technical factors at high resting heart rates or simply to a lack of effect of digoxin on LVSTI.…”

Long‐term antiarrhythmic therapy with N‐acetylprocainamide

“…Had PEP/LVET reduction during initial NAPA therapy represented a direct myocardial action, one might have expected that this effect would have persisted even when placebo period PEP/ LVET was normalized (as has been shown for other positive inotropic drugs). 2,9 The apparent dependence of this effect on the status of underlying myocardial function suggests that the initial reduction of PEP/LVET represents an indirect effect of NAPA on myocardial performance. Thus, NAPA might cause peripheral vasodilatation which could reduce afterload in patients with compromised cardiac function and cause stroke volume to increase.…”