Global longitudinal strain assessment of systolic dysfunction in Doberman Pinschers with ventricular arrhythmias and normal echocardiographic measurements.

BACKGROUND

Dilated cardiomyopathy (DCM) in Doberman Pinschers (DPs) often initially manifests as ventricular arrhythmias (stage B1) without echocardiographic evidence of cardiac remodeling (stage B2). Global longitudinal strain (GLS) is a sensitive echocardiographic variable for detecting early systolic dysfunction.

HYPOTHESIS/

OBJECTIVES

To assess whether GLS detects systolic dysfunction in DPs with arrhythmogenic stage B1 and to evaluate the association between arrhythmic burden and GLS.

ANIMALS: Sixty-three DPs with arrhythmogenic stage B1 DCM and 63 control DPs.

METHODS

Retrospective case-control study. Stage B1 was defined as ≥300 ventricular premature complexes (VPCs) within 24 h or >50 VPCs on two 24-h Holter recordings within 1 year, with otherwise normal echocardiographic measurements. Forty-three dogs had "last-normal" (LN) examinations 6-12 months before arrhythmia onset. GLS was measured using 2-dimensional speckle-tracking echocardiography (STE) from left apical 2-, 3-, and 4-chamber views. Stage B1 dogs were subclassified into low-grade (LGvpc) and high-grade (HGvpc) groups based on arrhythmic burden.

RESULTS

GLS was lower in stage B1 dogs (mean ± SD, -16.80% ± 2.71%) compared to controls (-20.22% ± 1.90%; P = .044). Stage B1 dogs had lower GLS compared to their LN examinations (mean difference, -2.45%; 95% CI, -3.67% to -1.24%; P < .001). Dogs in the HGvpc group had lower GLS (-15.45% ± 2.79%) than LGvpc dogs (-18.39% ± 1.51%; mean difference, -2.94%; 95% CI, -4.28% to -1.60%; P < .001).

CONCLUSIONS

GLS detects systolic dysfunction in DPs with arrhythmogenic stage B1 DCM despite normal conventional echocardiographic measurements. Higher arrhythmic burden is associated with more severe systolic dysfunction.