Influence of including or excluding endocardial borders on left ventricular wall thickness measurements in cats.

BACKGROUND

Consensus is lacking on which endocardial borders to include when measuring left ventricular wall thickness (LVWT) in cats.

HYPOTHESIS/

OBJECTIVES

The number of endocardial borders included can influence whether an individual cat is classified as having hypertrophic cardiomyopathy (HCM) or not.

ANIMALS: Fifty-two cats that previously were diagnosed as either healthy, equivocal for HCM, or having an HCM phenotype.

METHODS

Single-center retrospective cross-sectional study. Three observers measured LVWT using 4 different LVWT measurement protocols: leading edge-to-leading edge (L-L); leading edge-to-trailing edge, trailing edge-to-leading edge, and trailing edge-to-trailing edge for the interventricular septum and L-L and trailing edge-to-leading edge methods for the left ventricular free wall (LVFW). Measurements were made using stored echocardiographic images on 2 occasions by 2 observers. A Friedman test and post-hoc Wilcoxon signed rank test with Bonferroni correction were performed to detect differences between measurement techniques.

RESULTS

Interventricular septum (IVS) wall thickness was significantly larger for leading-edge-to-trailing-edge measurement (median and [interquartile range (IQR)]: 5.5 [3.8-7.2] millimeters) compared with other methods (P < .001). The trailing-edge-to-leading-edge method produced significantly smaller results (4.3 [IQR, 3.4-6.2] millimeters for the interventricular septum and 4.8 [IQR, 3.4-6.2] millimeters for the LVFW) compared with other methods (P < .001). Median IVS thickness measured as leading-edge-to-trailing-edge was 1.2 millimeters larger than when measured as trailing-edge-to-leading-edge.

CONCLUSIONS AND CLINICAL

IMPORTANCE

LVWT varies depending on the number of endocardial borders included. The number of endocardial borders included in LVWT measurements should be standardized.