P wave dispersion in obese dogs with and without mitral valve disease

Dispersão da onda P em cães obesos apresentando ou não doença valvar mitral

ABSTRACT:

Pwave dispersion (P_d) is an electrocardiographic index defined as the difference between the minimum and maximum Pwave duration in multiple leads. The augmentation of P_d reflects the discontinuous and inhomogeneous atrial depolarization resulting from cardiac and non-cardiac conditions. In humans, an increased P_d is associated with the development of cardiac arrhythmias, particularly atrial fibrillation. To investigate P_d in obese dogs, we enrolled 76 dogs, which were classified in four distinct categories according to body condition and the existance of valve insufficiency: obese dogs (O), dogs with both obesity and cardiac disease (O+CD), lean dogs with cardiac disease (CD) and healthy controls (H). To be included in the study, all dogs underwent an electrocardiographic and echocardiographic assessment. We reported significantly higher P_d in the animals included in categories O, O+CD and CD (18.0±7.6ms, 16.1±4.4ms, 12.1±4.3ms, respectively) as compared to the healthy subjects (7.3±2.2ms). Also, significant correlations between P_d and both the body mass index and body fat percentage were documented for the obese dogs. However, no association between P_d and LA/Ao could be identified in patients belonging to the O, O+CD and H categories. Thus, we have demonstrated that obese dogs, regardless of their valvular competency status, present high P_d values, suggesting an impaired propagation of atrial electrical impulse.

Key words:
mitral degeneration; P wave indices; adiposity; obesity; left atrial size