176-73: Findings of Endomyocardial biopsy in patients with suspected tachycardiomyopathy

Abstract

Introduction: Patients who present with severely reduced unclear left ventricular ejection fraction and supraventricular tachycardias including atrial fibrillation are still a challenge in clinical practice. Specifically, it is not clear which patients benefit from an aggressive restoration of sinus rhythm including ablation therapy. In the current study we investigated findings in endomyocardial biopsies from patients with supraventricular tachycardia and with recent onset heart failure due to cardiomyopathy of unclear etiology. Methods and Results: 31 patients with new onset heart failure and unclear severely reduced ejection fraction were included in the study. 15 patients presented with suspected tachycardiomyopathy and 16 presented with suspected dilated cardiomyopathy (mean age 64 years, mean left ventricular ejection fraction 29%). In all patients endomyocardial biopsies were performed according to clinical indication. All patients received heart failure therapy due to the current guidelines. In the tachcardiomyopathy group 7 patients underwent an ablation of atrial fibrillation or atrial flutter and in 8 a rhythm control was achieved by cardioversion and antiarrhythmic therapy including amiodaron and betablocker. Whereas left ventricular ejection fraction improved from 29.2 to 44.5% in patients with tachycardiomypathy, patients with newly diagnosed dilated cardiomyopathy showed no relevant recovery (28.8 vs 31.4%). Interestingly all patients with suspected tachycardiomyopathy revealed enhanced expression of MHCII molecules and 93.3% enhanced numbers of CD68+ macrophages. In contrast, patients with newly diagnosed DCM revealed only in 31.3% enhanced MHCII expression and 18% increased numbers of CD68+ macrophages. No difference was observed regarding the amounts of CD3+ T cells. Conclusions: Tachycardiomyopathy is associated with a macrophage-dominated cardiac inflammation with enhanced expression of MHCII receptors. Thus, endomyocardial biopsy may be a valuable diagnostic tool predicting the recovery potential of left ventricular ejection fraction in patients with tachycardiomyopathy.