Diagnostic Approach and Treatment Strategy in Tachycardia‐induced Cardiomyopathy

Background Due to the absence of differential guidelines for heart failure with tachyarrhythmia, it is difficult to diagnose tachycardia‐induced cardiomyopathy (TIC) at the initial visit. Furthermore, clinical outcomes of rate versus rhythm control in TIC are unclear. Hypothesis Because the etiology of TIC is different from dynamic cardiomyoplasty (DCMP), differential parameters may be present. Methods We assessed 21 patients with TIC (15 men; mean age, 50 ± 14 years) and 21 control patients with idiopathic DCMP. We assessed clinical courses, echocardiographic parameters, as well as outcomes by treatment. Results In the TIC group, the related tachyarrhythmias were atrial fibrillation (n = 12), atrial flutter (n = 5), atrial tachycardia (n = 3) and paroxysmal supraventricular tachycardia (n = 1). After treatment, all patients became asymptomatic and the ejection fraction (EF) improvement (ΔEF ≥15%) was observed in all patients (left ventricular ejection fraction [LVEF], 30 ± 11% initial versus 58 ± 6% last ). In the idiopathic DCMP group, no patient showed EF improvement (EF increase ≤ 5%), and 4 patients (19%) underwent heart transplantation. Left ventricle (LV) mass indices, volumes adjusted by BSA, and dimensions were smaller in the TIC group than in the idiopathic DCMP group. Of those, LV end‐diastolic dimension was the only independent predictor of TIC in multiple regression analysis (odds ratio [OR] 0.742 per 1 mm, 95% confidence ratio [CI] 0.618 to 0.891, p = 0.001). The Association of University Cardiologists (AUC) was 0.908 on receiver‐operating characteristic (ROC) curve analysis and LV end‐diastolic dimension ≤ 61% mm could predict TIC with a sensitivity of 100% and a specificity of 71.4%. After restoration of sinus rhythm (n = 8), one experienced recurrent TIC after discontinuation of amiodarone. After control of heart rate (n = 13), one experienced recurrent TIC due to poor control of heart rate (log‐rank test, p = 0.808). There were no differences in the echocardiographic parameters between the 2 groups before and after treatment except for the larger initial LV volumes in the rhythm control. Conclusions In patients presented as heart failure with tachyarrhythmia, initial echocardiographic parameters, especially LV end‐diastolic dimension, help to differentiate TIC from idiopathic DCMP. Rate control was as effective as rhythm control for EF improvement and prognosis. Copyright © 2008 Wiley Periodicals, Inc.