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Introduction/objectives Whether a brachymorphic conformation may lead to electrocardiographic peculiarities diverging from generic reference intervals (RIs) cited in textbooks remains to be established. Therefore, this study aimed at evaluating electrocardiographic variables in one of the most common brachymorphic breed, namely the French Bulldog (FB). Animals, materials and methods Medical records were retrospectively reviewed to identify healthy FBs ≥1-year-old that underwent an electrocardiogram. The Mann–Whitney U test or the Student's t-test was used to compare continuous variables among male and female dogs, while the χ2 test was used for categorical variables. Spearman's correlation coefficients between electrocardiographic measurements and age and body weight were also calculated. Moreover, electrocardiographic RIs were determined. Results Eighty healthy FBs were enrolled; their electrocardiographic variables fitted with generic RIs, with the exception of the QRS-complex mean electrical axis (QRS-MEA). The median QRS-MEA value was 43.5° (from −18° to +90°). A QRS-MEA shift was found in 24/80 (30%) dogs; in all cases, it was a left shift (median 26°, from −18° to +39°). Specifically, 20 dogs showed a slight left shift (from +39° to +14°), while four dogs showed a marked one (from +9° to −18°). No meaningful differences were found when comparing electrocardiographic variables between males and females. No significant correlations between electrocardiographic variables and age or body weight were found, with the exceptions of the P-wave amplitude, PQ-interval duration and QT-interval duration. Conclusions Healthy FBs can present a left shift of QRS-MEA. These data should be considered when interpreting FBs’ electrocardiograms.

Objectives To assess the ability of electrocardiography (ECG) to predict left ventricular hypertrophy (LVH) in the cat and to investigate the prognostic value of selected ECG variables in cats with LVH. Animals Fifty-seven privately owned cats: 22 clinically healthy cats and 35 cats with LVH. Material and methods This is a clinical cohort study. Echocardiographic diagnosis and surface ECG were available. Electrocardiography analysis included rhythm diagnosis and specific electrocardiographic measurements. In cats with LVH, cause of death and outcome data were recorded and analyzed using Kaplan–Meier curves. Results The presence of arrhythmia had sensitivity and specificity of 31% and 100%, respectively, for identifying LVH. Among ECG measurements, duration of QT interval (QT) and QT interval corrected for heart rate (QTc) was statistically different between healthy cats and cats with LVH (p = 0.007). Overall, the most accurate cutoffs to identify LVH were QT > 170 ms (sensitivity and specificity 48.3% and 91%, respectively) and QTc > 188 ms (sensitivity and specificity 62% and 77%, respectively). In healthy cats, the highest QT and QTc values were 180 ms and 200 ms, respectively. Mean survival time was 58 days and indeterminable for cats with QT > 180 ms and QT ≤ 180 ms, respectively (p = 0.042) and 125 days and indeterminable for cats with QTc > 200 ms and QTc ≤ 200 ms, respectively (p = 0.017). Conclusions Arrhythmias as well as prolonged QT and QTc are useful ECG parameters in identifying LVH and predicting survival in affected cats.