Echocardiographic indices of age- and gender-dependent cardiac remodeling over the adult lifespan in Irish Wolfhounds.

INTRODUCTION: Characterizing age- and gender-dependent cardiac remodeling over the adult lifespan in Irish Wolfhounds (IWs) by echocardiography. In people, a life-long cardiac remodeling process has been demonstrated.

ANIMALS, MATERIALS, METHODS: Irish Wolfhounds (56 males, 90 females) with no indication of cardiac disease at final assessment (>7.0 years old). For each dog, four transthoracic echocardiographic studies were analyzed. Left ventricular (LV) systolic and diastolic internal dimensions (LVIDs, LVIDd), LV fractional shortening (FS) and ejection fraction (EF), LV free wall and interventricular septal thickness, right ventricular diastolic dimension, and left atrial (LA) and right atrial systolic diameters were compared at time points in the following age categories (years): 1.0-2.5; 3.0-4.0; 4.5-6.0; and 7.0-10.5 and related to age, body weight, and heart rate.

RESULTS: Over the adult life course, males had statistically significant increases in LV internal dimensions, atrial diameters, and decreases of FS and EF. From youngest to oldest age of examination means ± standard deviations were as follows: LVIDs, 32.7 ± 2.9 vs. 36.5 ± 2.9 mm; LVIDd, 49.6 ± 4.7 vs. 53.4 ± 3.8 mm; right atrial diameter, 36.8 ± 3.3 vs. 42.6 ± 3.3 mm; LA, 49.0 ± 3.6 vs. 55.0 ± 3.7 mm; and FS, 34.6 ± 3.7 vs. 31.0 ± 3.2. In females, LV internal dimensions did not change significantly, increases in right atrial (38.1 ± 3.7 mm to 40.0 ± 5.2 mm) and LA diameter (48.8 ± 3.6 to 52.4 ± 4.3 mm) were attenuated, as were decreases of FS (33.4 ± 3.7 to 31.5 ± 4.4, p = 0.02). LV wall thicknesses did not significantly change in both genders.

DISCUSSION AND CONCLUSIONS: Over the adult life course, echocardiography demonstrated increasing LV dimensions in male IWs only. In both genders, FS and EF decreased, and atrial diameters increased. Females showed an attenuated remodeling process.