EFFECTS OF INTRAVENOUS DIGOXIN ON PULMONARY VENOUS AND TRANSMITRAL FLOWS IN PATIENTS WITH CHRONIC HEART-FAILURE OF DIFFERENT DEGREES

Acute effects of digoxin on diastole were evaluated noninvasively by combining data simultaneously obtained by Doppler echocardiograms (echo-Doppler) of transmitral and pulmonary venous flow curves in 38 patients with dilated and failing hearts, who had been stable for at least 7 days before the study. According to the resting ejection fraction (EF), patients were subdivided into Group 1 (EF < 30%: n = 20, mean EF values 23 +/- 8%) and Group 2 (EF greater-than-or-equal-to 30%: n = 18, mean EF values 40 +/- 3%). Significant differences were observed at rest between the two groups in both transmitral (shorter deceleration time and isovolumic relaxation time and increased peak E and E/A ratio in Group 1 vs. Group 2) and transpulmonary (reduced systolic forward component and systolic fraction of the flow curves in Group 1 compared with Group 2 and control subjects) parameters. Digoxin (1 mg subdivided into two doses, each infused over a 15-min period with 2 h between the doses) significantly modified the diastolic profile in Group 1 patients in the absence of statistically relevant changes in EF: a significant decrease of transmitral peak E (from 76 +/- 17 to 60 +/- 15 cm/s, p < 0.05) and E/A ratio (from 2.5 +/- 1 to 1.6 +/- 0.6; p < 0.05) and a significant lengthening of deceleration time (from 115 +/- 20 to 160 +/- 18 ms; p < 0.05) were detected. A simultaneous consistent decrease of the diastolic forward velocity (from 51 +/- 14 to 40 +/- 13 cm/s, p < 0.05) and an increase of the percent systolic fraction (from 31 +/- 5% to 41 +/- 8%; p < 0.05) of the pulmonary venous flow curves, compared with the control state (p<0.05), were also observed. No difference was detected in any of the echo-Doppler transmitral and transpulmonary vein flow parameters after digoxin in Group 2 of patients. Among patients with dilated and failing hearts, those with more advanced left ventricular systolic dysfunction (EF < 30%) exhibited a diastolic profile characterized by a restrictive transmitral filling pattern combined with a clear reduction of systolic fraction and with an increase in the diastolic forward component of the pulmonary venous flow curves. These patients show significant changes in diastolic parameters after digoxin injection, expressed by a trend toward a normalized transmitral filling flow pattern (significant decrease of peak E, E/A ratio, and significant lengthening of deceleration time) and toward a restoration of the amount of systolic left atrial filling at the pulmonary venous flow curves (significant increase in systolic fraction and significant decrease in the diastolic forward component). These changes are consistent with a reduction of left ventricular driving pressures. Conversely, patients with a lesser degree of systolic dysfunction exhibited a normal pulmonary venous flow profile together with a transmitral filling pattern of abnormal relaxation type: in these patients no changes were observed in any of the echo-Doppler transmitral and transpulmonary vein flow parameters after acutely injected digoxin.