Electrocardiographic, echocardiographic, and left atrial strain imaging features of a dog with atrial flutter and third-degree atrioventricular block

Abstract

A 14-year-old American Staffordshire terrier was presented for episodes of exercise-induced syncope. At admission, atrial flutter coupled to third-degree atrioventricular block was diagnosed electrocardiographically. On the second day of hospitalization, surface electrocardiogram revealed spontaneous conversion to sinus rhythm with persistence of atrioventricular block. Complete transthoracic echocardiograms were performed after each electrocardiographic examination. The combined use of conventional echocardiography with tissue Doppler imaging-based modalities allowed to investigate the atrial electromechanical correlation and function during typical atrial flutter and after its resolution.

Left Atrial Tachycardia and Third-Degree Atrioventricular Block in a Dog

“…Cases have been reported of dogs with atrial standstill confined to the LA 7 and with atrial dissociation during sinus rhythm. 8 Doppler echocardiographic profiles associated with such rhythm disturbances have been documented, [7][8][9] whereas changes like those noted in the present case have not. Atrial fibrillation that is confined to one atrium has been documented in humans, including with Doppler echocardiographic confirmation as in the present case.…”

Echocardiographic predictors of first onset of atrial fibrillation in dogs with myxomatous mitral valve disease

“…In dogs with MMVD, PALS progressively decreases while heart failure class advances and LA dilatation becomes worse. 16,18 Moreover, lower PALS values indicate increased risk of cardiac death in dogs with MMVD. 17 Therefore, PALS is a valuable echocardiographic variable to noninvasively assess LA mechanical dysfunction in dogs with cardiac disease.…”

“…In contrast, the STE‐derived deformation technique is more reproducible and clinically useful. In dogs with MMVD, PALS progressively decreases while heart failure class advances and LA dilatation becomes worse 16,18 . Moreover, lower PALS values indicate increased risk of cardiac death in dogs with MMVD 17 .…”

“…[10][11][12][13] Left atrial tissue Doppler imaging and STE also have been applied in both clinically healthy dogs and dogs with MMVD. [14][15][16][17][18][19] In particular, LA STE-derived strain has been shown to decrease progressively as the disease advances, 15 and it is a predictor of cardiac death in dogs with MMVD. 17 Our aim was to evaluate the clinical usefulness of several indices of LA and left ventricular (LV) morphology and function to predict the future occurrence of AF in a population of dogs with naturally occurring MMVD.…”

“…Among these, advanced echocardiographic techniques such as LA tissue Doppler imaging and LA speckle tracking echocardiography (STE) have been shown to be valuable tools for predicting AF occurrence in humans with cardiac disease or normally‐structured hearts 10‐13 . Left atrial tissue Doppler imaging and STE also have been applied in both clinically healthy dogs and dogs with MMVD 14‐19 . In particular, LA STE‐derived strain has been shown to decrease progressively as the disease advances, 15 and it is a predictor of cardiac death in dogs with MMVD 17 …”