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Patients with non-ischemic dilated cardiomyopathy and AF exhibit worse global longitudinal strain and reduced work index and constructive work of the myocardium compared to those without AF

Background: The presence of atrial fibrillation (AF) is known to be associated with reduced cardiac output due to ineffective atrial contraction during systole while recent research data shows that AF also contributes to adverse ventricular remodeling even if it is normofrequent. Likewise, AF and heart failure (HF) often co-exist while the presence of tachyarrhythmia may significantly contribute to myocardial dysfunction. Purpose: We hypothesized that the presence of AF in patients with non- ischemic dilated cardiomyopathy and left ventricular ejection fraction (LVEF) <50% will be associated with impaired global longitudinal strain (GLS) and advanced parameters of myocardial function such as global work index (GWI), global constructive work (GCW), global wasted work (GWW) and global work efficiency (GWE), compared to non- AF patients. Methods: Sixty consecutive patients (1:1 fashion enrollment of those with AF and without AF) with known non-ischemic dilated cardiomyopathy and LVEF <50% were included in the analysis. All patients underwent advanced echocardiography examination which was performed by a single sonographer with high expertise in transthoracic echo. Myocardial parameters including GLS, GWI, GCW, GWW, and GWE were measured. Echocardiographic examination was performed by using a commercially available ultrasound system. Results: A total of 30 patients with AF and 30 patients without AF were enrolled. The mean age of the analyzed population was 64.8 ± 13.0 years, 63.3% were male (N=38) and the average LVEF was 28 ± 9 %. Patients with AF did not significantly differ from those without AF with respect to age (64.9 vs. 64.6 years, p=0.920), LVEF (26.6 vs. 28.4 %, p=0.435), diastolic function as evidenced by E/e' ratio (15.4 vs. 16.2, p=0.645), systolic (117 vs. 124 mmHg, p=0.255) and diastolic blood pressure (77 vs. 79 mmHg, p=0.498), respectively. Equally so, both groups were similar concerning hemoglobin (135 vs. 140 g/L, p=0.261), serum creatinine (118 vs. 109 μmol/L, p=0.483), high- sensitivity cardiac troponin I (56 vs. 75 ng/L, p=0.389) and NT-proBNP (6420 vs. 8320 pg/mL, p=0.316). Patients with AF, compared to non-AF patients, had significantly lower GLS (-5.3±3.1 vs. -7.7±3.9 %, p=0.011), GWI (477±294 vs. 714±427 mmHg %, p=0.015), and GCW (753±355 vs. 1084±534 mmHg %, p=0.007). Both groups did not differ concerning GWW and GWE indices (p=0.100 and p=0.391, respectively). The main findings are summarized in Figure 1. Conclusions: AF is associated with a higher degree of myocardial dysfunction in patients with non- ischemic dilated cardiomyopathy as evidenced by a significant disturbance in advanced echocardiographic parameters of myocardial function, compared to those without AF. These findings are reinforced by the fact that both groups were well-balanced concerning baseline systolic and diastolic function and other relevant clinical parameters.

atrial fibrillation ; heart failure ; advanced echocardiography ; myocardial work ; dilated cardiomyopathy ; nonischemic cardiomyopathy ; global longitudinal strain ; GLS ; global work index ; GWI ; global constructive work (GCW), global wasted work (GWW), global work efficiency (GWE)

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