Abstract P150: Age, Gender and Race Variations in QRS Duration in Patients With Atrial Fibrillation

Abstract

Background: Atrial fibrillation (AF) is associated with increased incidence of congestive heart failure (CHF). While patients with intraventricular conduction delay were shown to have increased risk of atrial fibrillation, recent analysis of a study revealed increased mortality among patients with QRS 90-119 ms and AF. The demographics of QRS duration (QRSD) in AF remain under-studied. Methods: A University-based EKG database was randomly searched for 150 total EKGs: 75 EKGs were with AF; another 75 were with sinus rhythm, as a control group. Demographics, heart rate and QRSD were documented. QRSDs were retrieved from the baseline electrocardiograms of patients included in both groups, and were compared using student’s T test. Further subgroup analyses based on age, gender and race were also performed. Results: The mean QRSD in AF group was 102 ± 22 ms compared to 92 ± 19 ms in SR group (P < 0.05). In patient’s < 65 years of age, QRSD in AF group was 96 ± 12 ms compared to 92 ± 19 ms in SR group (P = NS); however, In patient’s ≥ 65 years of age, QRSD in AF group was 107 ± 26 ms compared to 91 ± 18 ms in SR group (P < 0.05). In males, QRSD in AF group was 102 ± 22 ms compared to 89 ± 16 ms in SR group (P < 0.05); however, in females, QRSD in AF group was 94 ± 21 ms compared to 93 ± 20 ms in SR group (P = NS). In white patients, QRSD in AF group was 102 ± 20 ms compared to 90 ± 14 ms in SR group (P < 0.05); however, in black patients, QRSD in AF group was 104 ± 27 ms compared to 94 ± 23 ms in SR group (P = NS). Conclusion: The incidence of AF, approaching 6 million in the US, continues to rise in epidemic proportions, and is expected to double over the next few decades as the population ages. The poor rate control in AF, in addition to the loss of the atrial contraction, are two main factors thought to be responsible for symptoms and development of CHF. In our cohort, we demonstrated a significant association between AF and widened QRSD, previously shown to correlate with poor outcome in AF patients. In age analysis, the development of intraventricular conduction delay (IVCD) was significant only in the elderly with AF, who are known to be at higher risk of CHF. IVCD was also more common in white patients compared to black patients; of interest, white patients have been previously shown to develop CHF at an older age compared to black patients, suggesting that IVCD may play a role in the CHF mechanism in this subgroup with AF. In our cohort, males, but not females, had a significantly wider QRSD in AF compared to control. Our findings shed some light on a potentially new mechanism of added morbidity and mortality in AF patients, with higher prevalence in elderly white males, a subgroup which may benefit from early detection and treatment of AF and CHF. Further studies will help validate our findings in a larger cohort and in patients with CHF diagnosis.