Quantification of left atrial contractile function using two-dimensional speckle tracking echocardiography in horses after conversion of atrial fibrillation to sinus rhythm.

This research sought to determine the contractile function of the left atria in horses after conversion of atrial fibrillation to sinus rhythm using two-dimensional speckle tracking echocardiography. The research further sought to demonstrate the potential utility of speckle tracking to identify left atrial dysfunction in Warmblood horses.

Research Methodology

• The study sample consisted of nineteen Warmblood horses who had atrial fibrillation (AF) and were successfully cardioverted to a regular heart rhythm. The methods of cardioversion used were either transvenous electrical cardioversion (TVEC) or medication using quinidine sulfate (QS).
• Echocardiographic examinations were conducted on these horses at different time points, specifically at 24 hours, 72 hours, and 1 to 6 months after successful cardioversion.
• The team utilized both standard 2-dimensional echocardiography (2DE) and 2D speckle tracking analyses (2DST) to measure key variables related to the size and functional state of the left atria. These include variables like global longitudinal strain (S), longitudinal strain rate (SR) and active left atrial fractional area change (FAC).

Findings of the Study

• The results showed that global S and SR, as well as active LA FAC identified cases with LA dysfunction after TVEC and QS cardioversion. These metrics were useful in demonstrating left atrial functional recovery over time.
• The agreement (consistency in observation) between active LA FAC and global S and SR to diagnose atrial dysfunction was substantial to fair 24 hr post cardioversion. However, this consistency waned with the passage of time.

Significance and Conclusions of the Study

• The key takeaway from this study is that two-dimensional speckle tracking echocardiography (2DST) is a valuable tool for quantifying left atrial contractile dysfunction in horses after they have been cardioverted from atrial fibrillation to a regular sinus rhythm.
• By detecting left atrial dysfunction early, better prognosis and appropriate follow up treatment can be offered to horses suffering from AF.