Correlation between Morris index on electrocardiography and left atrium measurements on the echocardiogram of dogs with myxomatous mitral valve disease

摘要

© 2022The Morris index is an electrocardiographic parameter that can suggest left atrial overload in humans when, in the evaluation of the first precordial lead, the negative deflection has a longer duration in the terminal portion of the P wave. We compared the presence of the Morris Index with values already established on the echocardiogram, namely, LA:Ao ratio and left atrial volume indexed to body weight by Simpson's biplanar method. Forty-seven dogs without left atrial remodeling (Group 1) and 53 dogs with remodeling (Group 2) were evaluated. The Morris Index proved to be a parameter of low sensitivity (49) and moderate specificity (61), with 55 accuracy and positive and negative predictive values of 59 and 51, respectively. The association between the variables was analyzed statistically by Fisher's test. There was a weak positive correlation between the Morris Index and the LA:Ao ratio. In contrast, there was no association between the index and atrial remodeling. In conclusion, taken alone, the Morris Index failed as a predictive marker of left atrial remodeling.