Indicators of arrhythmogenesis in dogs with Pulmonary Hypertension

Pulmonary hypertension (PH) is a multifactorial syndrome that leads to cardiac muscle overload and distension. This generates right ventricular remodeling associated with sudden death (SCD) caused by ventricular arrhythmias. Electrocardiogram (ECG) is an important but simple tool for diagnosing arrhythmias allowing the early detection of SCD in ventricular remodeling due to PH through the measurement of the QT and T-peak T-end (TpTe) intervals which represent total ventricular electric activity and whose alteration may suggest a predisposition to SCD. This study aims to determine the role of arrhythmogenesis indicators in canine PH.Methods: Retrospective cardiologic evaluation of 53 dogs with PH (n=23 diagnosed with post-PH, and n=30 diagnosed with pre-PH), and 21 healthy (Control) dogs were used in this study. ECG records were used to determine, rhythm, heart rate, QRS duration, QRS dispersion, QT interval then corrected for heart rate (QTc); QT dispersion interval, QT interval variance (QTv), TpTe interval, and TpTe/QT. Prognostic and survival information were also recorded for the PH group. Results: QRS dispersion was significatively different (p 0.035) in dogs with PH compared with the healthy animals and when a cut-off value of 16.5 was applied there was a median survival time of 278 days in dogs with QRSdisp >16.5. QT, QTc, TpTe failed to demonstrate arrhythmogenic risk in dogs with PH. Conclusions: Dogs with post-PH showed a higher arrhythmogenic risk compared to animals with pre-PH and control animals. QRS dispersion may be used as an indicator of arrhythmogenesis in dogs with PH.