1Universitätsklinikum Tübingen Innere Medizin III, Kardiologie und Kreislauferkrankungen Tübingen, Deutschland; 2Kardiologie Nürnberg Dr. Sandrock & Partner Nürnberg, Deutschland; 3Universitätsklinikum Tübingen Kardiopathologie Tübingen, Deutschland; 4Ostalb-Klinikum Aalen Innere Medizin II, Kardiologie und Angiologie Aalen, Deutschland
Aims: Arrhythmia-induced tachycardiomyopathy (TCM) is commonly encountered in clinical practice. Diagnostic and prognostic parameters for clinical outcome are largely unknown. Thus, the aim of this study was to prospectively identify prognostic parameters for diagnosis and therapeutic outcome in patients with suspected TCM with a focus on specific findings in endomyocardial biopsy specimen.
Methods and Results: In this prospective, observational study (EMPATHY study, ClinicalTrials.gov: NCT03418467) 54 patients with newly diagnosed HFrEF due to suspected TCM and planned endomyocardial biopsy were enrolled after valvular or ischemic heart disease had been ruled out. The main outcome was defined as recovery of left ventricular ejection fraction (LVEF). At baseline mean LVEF was 32.1% (±9.5) and showed a recovery to 44.6% (±9.1) at follow-up. Increase in LVEF recovery correlated well with CRP levels (p<0.05) at study entry. Classical risk factors, however, including troponin I, creatine kinase, and NTpro-BNP had no significant prognostic value. While bioptic specimen showed increased leukocyte recruitment and fibrosis, neither of them was predictive for LVEF recovery potential. Analysis of mitochondrial distribution in cardiomyocytes, however, showed an enrichment of mitochondria at the intercalated discs (EMID-sign) in 50% of endomyocardial biopsies and the intensity of the EMID-sign was found to be predictive of LVEF recovery (p<0.05). EMID-sign intensity furthermore correlated with LV fibrosis and NTpro-BNP levels.
Conclusion: With this prospective observational study we provide novel histological and clinical biomarkers in patients with suspected TCM that help to identify subgroups with unfavorable prognosis at the time of initial contact.