Clinical Characterization of Arrhythmia-Induced Cardiomyopathy in Patients With Tachyarrhythmia and Idiopathic Heart Failure.

BACKGROUND: Arrhythmia-induced cardiomyopathy (AIC) is a known entity, but prospective evidence for its characterization is limited. OBJECTIVES: This study aimed to: 1) determine the relative frequency of the pure form of AIC in the clinically relevant cohort of patients with newly diagnosed, otherwise unexplained left ventricular systolic dysfunction (LVSD) and tachyarrhythmia; 2) assess the time to recovery from LVSD; and 3) identify parameters for an early diagnosis of AIC. METHODS: Patients were prospectively included, underwent effective rhythm restoration, and were followed-up at 2, 4, and 6 months to evaluate clinical characteristics, biomarkers, and cardiac imaging including cardiac magnetic resonance imaging. Patients with recurred arrhythmia were excluded from analysis. RESULTS: 41 of 50 patients were diagnosed with AIC 6 months after rhythm restoration. Left ventricular (LV) ejection fraction increased 2 months after rhythm restoration from 35.4% ± 8.2% to 52.7% ± 8.0% in AIC patients vs 37.0% ± 9.5% to 43.3% ± 7.0% in non-AIC patients. From month 2 to 6, LV ejection fraction continued to increase in AIC patients (57.2% ± 6.1%; P < 0.001) but remained stable in non-AIC patients (44.0% ± 7.8%; P = 0.628). Multivariable logistic regression analysis revealed that lower LV end-diastolic diameter at baseline could be used for early diagnosis of AIC, whereas biomarkers and other morphological or functional parameters, including late LV gadolinium enhancement, did not show suitability for early diagnosis. CONCLUSIONS: We observed a high prevalence of AIC in patients with otherwise unexplained LVSD and concomitant tachyarrhythmia, suggesting that this condition may be underdiagnosed in clinical practice. Most patients recovered fast, within months, from LVSD. A low initial LV end-diastolic diameter may constitute an early marker for diagnosis of AIC.

Native T1 mapping for the diagnosis of cardiac amyloidosis in patients with left ventricular hypertrophy.

BACKGROUND: Cardiac magnetic resonance (CMR) with parametric mapping can improve the characterization of myocardial tissue. We studied the diagnostic value of native T1 mapping to detect cardiac amyloidosis in patients with left ventricular (LV) hypertrophy. METHODS: One hundred twenty-five patients with increased LV wall thickness (≥ 12 mm end-diastole) who received clinical CMR in a 3 T scanner between 2017 and 2020 were included. 31 subjects without structural heart disease served as controls. Native T1 was measured as global mean value from 3 LV short axis slices. The study was registered at German clinical trial registry (DRKS00022048). RESULTS: Mean age of the patients was 66 ± 14 years, 83% were males. CA was present in 24 patients, 21 patients had hypertrophic cardiomyopathy (HCM), 80 patients suffered from hypertensive heart disease (HHD). Native T1 times were higher in patients with CA (1409 ± 59 ms, p < 0.0001) compared to healthy controls (1225 ± 21 ms), HCM (1266 ± 44 ms) and HHD (1257 ± 41 ms). HCM and HHD patients did not differ in their native T1 times but were increased compared to control (p < 0.01). ROC analysis of native T1 demonstrated an area under the curve for the detection of CA vs. HCM and HHD of 0.9938 (p < 0.0001), which was higher than that of extracellular volume (0.9876) or quantitative late gadolinium enhancement (0.9406; both p < 0.0001). The optimal cut-off value of native T1 to diagnose CA was 1341 ms (sensitivity 100%, specificity 97%). CONCLUSION: Non-contrast CMR imaging with native T1 mapping provides high diagnostic accuracy to diagnose cardiac amyloidosis in patients with left ventricular hypertrophy.