Aims: To profile the changes in non-invasive clinical, biochemical and imaging markers during withdrawal of therapy in patients with recovered dilated cardiomyopathy, providing insights into the pathophysiology of relapse.
Methods: Clinical, biochemical and imaging data from patients during phased withdrawal of therapy in the randomised or single-arm cross-over phases of TRED-HF were profiled. Clinical variables were measured at each study visit and imaging variables were measured at baseline, 16 weeks and 6 months.
Results: Amongst the 49 patients (35% women, mean age 53.6 years [standard deviation 11.6]) who withdrew therapy, 20 relapsed. Increases in mean heart rate (7.6 beats per minute [95% CIs 4.5,10.7]), systolic blood pressure (6.6mmHg [95% CI 2.7,10.5]) and diastolic blood pressure (5.8mmHg [95% CI 3.1,8.5]) were observed within 4-8 weeks of starting to withdraw therapy. A rise in mean LV mass (5.1g/m2 [95%CI 2.8,7.3]) and LV end-diastolic volume (3.9ml/m2 [95% CI 1.1,6.7]) and a reduction in mean LV ejection fraction (-4.2 [95% CI -6.6, -1.8]) were seen by 16 weeks, the earliest imaging follow-up. Plasma NT-pro-BNP fell immediately after withdrawing beta-blockers and only tended to increase 6 months after beginning therapy withdrawal (mean change in log NT-pro-BNP at 6 months: 0.2, 95% CI -0.1,0.4).
Conclusion: Changes in plasma NT-pro-BNP are a late feature of relapse, often months after a reduction in LV function. A rise in heart rate and blood pressure are observed soon after withdrawing therapy in recovered dilated cardiomyopathy, typically accompanied or closely followed by early changes in LV structure and function.