Improvement in exercise capacity despite cardiac deterioration: Noninvasive assessment of long-term therapy with amrinone in severe heart failure

Seven patients with severe congestive heart fallure (CHF) were treated with oral amrinone for a mean duration of 39 weeks (range 16 to 72). During the first week of therapy, exercise capacity as assessed on a treadmill using the Naughton protocol, increased substantially from 7.6 ± 4.2 to 12.1 ± 4.4 minutes (p < 0.01). At an early period of follow-up (8 to 12 weeks), a further significant increase in exercise capacity to 14.7 ± 5.0 minutes (p < 0.05) was demonstrated, while at a later follow-up exercise capacity had decreased to 11.4 ± 6.8 minutes (p < 0.05). This was still significantly greater than prior to amrinone therapy (p < 0.01). Left ventricular ejection fraction was increased from 14 ± 4 to 19 ± 4% (p < 0.05) during the first week of therapy, but was not significantly different from control at the early and late periods of follow-up. Left ventricular end-diastolic dimension index increased from control value of 43 ± 5 to 47 ± 7 mm/m² (p < 0.01) at the late period of follow-up. Thus long-term amrinone therapy resulted in a substantial improvement in exercise capacity despite a slow, but progressive decline in cardiac performance.