HEMODYNAMIC-EFFECTS OF WITHDRAWAL OF DIGITOXIN THERAPY IN PATIENTS WITH IDIOPATHIC DILATED CARDIOMYOPATHY IN SINUS RHYTHM

While digitalis therapy is generally accepted for patients with idiopathic dilated cardiomyopathy (IDC) and atrial fibrillation, its value for IDC patients in sinus rhythm is controversial. To determine the hemodynamic effects of long-term digitoxin (D) in combined medication, 16 patients (age: 54 +/- 14 y) with IDC, NYHA II-III, were analyzed with (serum concentration: 20.1 +/- 7.8 ng/ml) vs without D at rest and exercise using echocardiography and Swan-Ganz catheter. No change with vs without D was found for clinical NYHA stage, exercise duration (11.3 +/- 4.8 vs 11.1 +/- 4.2 min), blood pressure, and heart rate at rest and exercise. At rest, mean VCF was higher with than without D (0.92 +/- 0.29 vs 0.79 +/- 0.26 circ/s; p < 0.05) at comparable LV dimensions. Mean pulmonary artery pressure (PAP) was lower with than without D after 2 min (28 +/- 10 vs 33 +/- 12 mmHg; p < 0.01) and 4 min (33 +/- 11 vs 38 +/- 10 mmHg; p < 0.01) of exercise, a more pronounced increase of cardiac output with vs without D during exercise did not reach significance. Hemodynamic effects of D therapy were more pronounced in those patients with well maintained as compared to those with highly impaired LV function, and more pronounced during exercise than at rest. Blood-gas analysis indicated lower base excess and pH-values in PA at end of exercise (p < 0.05) and recovery (p < 0.01) without than with D. We conclude that for patients with IDC in sinus rhythm, NYHA II-III, a positive inotropic D effect is observed even in combined long-term medication. It is more pronounced in patients with less severely impaired LV function and during exercise, and does not influence clinical NYHA staging.