Cardiac MRI risk factors predict atrial arrhythmia development in repaired tetralogy of Fallot patients

Abstract

Abstract Background/Introduction Tetralogy of Fallot (TOF) patients with atrial arrhythmias (AA) experience greater morbidity and mortality than do their arrhythmia-free counterparts. Cardiac MRI (cMRI) has proven useful in elucidating risk factors for arrhythmia development in this population, but more work needs to be done to assess the efficacy of predicting AA onset. Purpose To evaluate demographic and clinical metrics, including those routinely assessed on cMRI, that predict AA onset in repaired TOF. Methods 175 repaired TOF patients ≥18 years of age and without prior AA undergoing initial cMRI between 2003 and 2020 were identified from a tertiary U.S. hospital database. Subsequent development of AA (specifically atrial fibrillation, atrial flutter, and atrial tachycardia) was evaluated by chart review and device checks (if present). Kaplan-Meier analysis was used to assess arrhythmia-free survival based on cMRI characteristics, and log-rank test used to compare differences in survival curves. Cutoff values for Kaplan-Meier analysis were the mean value (for the respective variable being measured) of our cohort at the time of their initial cMRI. Results Over a median follow-up of 3.3 years, 30 patients (17%) developed AA, including 16 with atrial fibrillation (53%), 20 with atrial flutter (67%), and 2 with atrial tachycardia (7%). Age at cMRI (p<0.01), history of hypertension (p=0.01), and time from birth to complete TOF repair (p<0.05) predicted AA. cMRI predictors included indexed right ventricular (RV) end diastolic and systolic volumes (both p<0.01), as well as indexed right atrial (RA) volume (p<0.05) and pulmonic regurgitation (PR) fraction (p<0.05). Indexed RV and RA volumes but not left sided chamber volumes predicted the development of atrial fibrillation. All Kaplan-Meier survival distributions were significantly different with the exception of those for right atrial volumes. Conclusions Our study suggests that RA and RV volumes may play a valuable role in predicting atrial arrhythmia onset in the repaired TOF population. Disease progression in a predominantly right-sided heart disease may play a role in predicting the onset of both “right sided” arrhythmias such as atrial flutter, as well as “left sided” arrhythmias such as atrial fibrillation. Additionally, the increased AA burden in patients with mild RV dilation seen in our study may suggest a potential benefit to early pulmonic valve replacement in this patient group. Funding Acknowledgement Type of funding sources: None. Clinical and cMRI CharacteristicsKaplan-Meier Survival Analysis