New-Onset Cardiomyopathy With and Without Atrial Fibrillation
Background: Atrial fibrillation (AF) is the most common arrhythmia and is often associated with cardiomyopathy (CM) and heart failure. There has been little research performed to assess whether there are any differences in patient profile, comorbidities, presenting complaints, and electrocardiographic (ECG) or laboratory characteristics and outcomes between patients who have AF at presentation or preceding the diagnosis of new-onset CM (defined as left ventricular ejection fraction ≤ 40%) and patients who are diagnosed with new-onset CM without any preceding atrial dysrhythmias.
Purpose: To assess differences among patients with new-onset CM (LVEF ≤ 40%) with AF and without AF.
Methods: We used a balance research design to compare patients diagnosed with new-onset CM with AF (N = 196) and without AF (N = 197). Demographic characteristics, comorbidities, diagnosis, ECG characteristics, laboratory marker variables, and outcome data were described using appropriate descriptive statistics. The two groups of patients with and without AF were compared using chi-squared and independent t-test. An alpha of 0.05 was used for all statistical tests, and all statistical analysis was done using SAS version 9.4 (SAS Institute Inc., Cary, NC).
Results: Patients in the AF-CM group were older (73.51 vs 64.18 years; P < 0.001) and more likely to be male (63.3% vs 49.2%; P = 0.005), of Caucasian ethnicity (96.9% vs 76.7%; P < 0.001), and have a history of hypertension (70.4% vs 53.3%; P = 0.0005) or coronary artery disease (33.7% vs 20.8%; P = 0.0042). They were more likely to be diagnosed as an outpatient (35.7% vs 10.2%; P < 0.0001); if presenting to the hospital, they were much more likely to have congestive heart failure as their presenting complaint (61.1% vs 38.4%; P < 0.0001). They also were more likely to have low voltage on their presenting ECG compared to the control group (39% vs 27.6%; P = 0.0003). Troponin (0.91 vs 14.27; P = 0.0067) and brain natriuretic peptide (771.3 vs 1015.6; P = 0.021) values were significantly lower in the AF group. Patients in the AF-CM group showed an increased risk of death: 30.1% vs 20.8% (P = 0.0345).
Conclusion: Patients with atrial fibrillation and new-onset cardiomyopathy differ from patients without atrial fibrillation in demographic characteristics, comorbidities, venue of diagnosis, presenting complaints, ECG characteristics, laboratory markers, and prognosis. This may have implications for diagnosis, work-up, and treatment of these patients.