Derivações precordiais em felinos saudáveis: caracterização do eletrocardiograma de 12 derivações

Abstract

The 12-lead electrocardiogram is a widely used diagnostic tool in human and canine patients. Its purpose is to increase the stratification of arrhythmias and conduction disorders, suggest cardiac remodeling, identify repolarization disorders, provide risk criteria and predictors of clinical outcome and mortality. The study of the electrocardiographic characterization of the precordial system proposed by Wilson modified by Kraus (2002) and Santilli (2019) remains unexplored in cats, as well as electrical remodeling markers that can contribute to the clinical, diagnostic, and prognostic stratification of domestic felines. The objective of this study was to characterize the normality indices of the 12-lead electrocardiogram (V1-V6), associated with the criteria of repolarization (TpTf and TpTf/QT) and ventricular (RPT) activation in domestic cats. 144 cats were evaluated, and a total of 37 met the inclusion criteria and had a 12-lead ECG recorded with the right precordial lead (V1) positioned in the fifth right intercostal space (5thrICS) and the left precordial leads (V2-V6 ) positioned in the sixth left intercostal space. Of these, 17 cats were also evaluated with the recording of the V1 positioned in the first right intercostal space (1strICS) for comparison. P-wave duration, QRS complex, PQ, QT, RPT, TpTf, TpTf/QT intervals, amplitude of P, Q, R, S, T waves and ST segment were evaluated in DII and precordial variations (V1- V6). When positioned on the 1strICS, most cats presented a negative P wave and revealed a median of the R/S<1, while the P wave was positive in V2-V6 and predominantly positive in the V1-5thrICS, with the median of the R/S>1 from V1-5thrICS and V2 to V6. A significant difference was observed between the RPT of V1-1strICS with V1- 5thrICS, DII and V3-V6. In conclusion, as in dogs and humans, placement of lead V1 at the location of the 1strICS produced a more consistent ECG pattern of right atrial and ventricular depolarization for most cats. The left precordials showed a positive pattern similar to the other species. Normality values were generated for the new researched ECG variables. Further studies are needed to determine the clinical and prognostic usefulness of RPT, TpTf and TpTf/QT and 12-lead ECG in feline heart disease.