Speckle tracking-derived left atrial strain rate – undervalued and useful predictor of adverse events

Abstract

Abstract Background Strain rate reflects the rate of change of the distance between two points of the myocardium occurring in the cardiac cycle. It is a time-dependent parameter requiring higher temporal resolution than standard strain assessment. Because of this limitation, speckle tracking-derived left atrial (LA) strain rate analysis is of less interest in the literature. Purpose To analyze the prognostic value of LA strain rate during 2-years follow-up in patients with atrial fibrillation (AF). Methods The prospective study involved 80 patients with nonvalvular AF scheduled for elective electrical cardioversion (mean age 63.5±13 years, 60% male). All patients underwent echo before cardioversion and 24 hours after conversion to sinus rhythm. We analyzed standard echocardiographic parameters. Using the speckle-tracking method, we assessed LA strain rate during ventricular systole LA-SSR, in the early stage of ventricular diastole LA-ESR, and during atrial active pump phase LA-ASR. The last one is possible to measure only in the sinus rhythm. The analysis included 4-chamber and 2-chamber views. The clinical endpoint was predefined as AF recurrence. Results Median time of the current AF episode was 2.1 (IQR 0.5–5) months. Standard echo measurements revealed a median left ventricular ejection fraction of 55% (IQR 46–58) and the median of LA volume indexed to body surface area 42 ml/m2 (IQR 33–51). The successful cardioversion rate was 90%. During follow-up, we noticed AF recurrence in 49 (68%) patients. The median time-to-event was 2 (IQR 1 to 6.9) months. Receiver operating characteristic curve analysis revealed that LA-SSR <−0.73 s–1 (AUC=0.745; p=0.0004) and LA-ESR >−1 s–1 (AUC=0.703; p=0.0015) assessed during AF as well as LA-ESR >−0.88 s–1 (AUC=0.644; p=0.04) and LA-ASR >−1 s–1 (AUC=0.837; p<0.0001) measured in sinus rhythm were the optimal cut-off values for predicting AF recurrence. The figure presents Kaplan-Meier survival analysis for AF recurrence. Conclusions Speckle tracking-derived LA strain rate predicts the recurrence of AF after successful electrical cardioversion. Funding Acknowledgement Type of funding sources: None.