Supraventricular trigeminy in a dog with myxomatous mitral valve disease/Trigeminismo supraventricular em um cao com doenca mixomatosa da valva mitral

Supraventricular trigeminy is an uncommon cardiac impulse formation disturbance. Detecting and treating cardiac arrhythmias is an important therapeutic goal in cardiology. The aim of this note is to report an occurrence of supraventricular trigeminy in a dog with myxomatous mitral valve disease (MMVD). A 15-year-old intact male mongrel dog weighing 13kg and with a history of heart murmur, cough, dyspnea, and ascites was referred for cardiac evaluation. Echocardiographic findings were consistent with a diagnosis of myxomatous mitral and tricuspid valves disease with a severe hemodynamic compromise. Electrocardiography (ECG) revealed a sinus arrhythmia with isolated supraventricular premature complexes, supraventricular couplets, and periods of supraventricular trigeminy. Previous retrospective and prospective studies that evaluated cardiac arrhythmias in dogs have not reported supraventricular trigeminy. The present report showed that supraventricular trigeminy may occur in dogs with MMVD with severe hemodynamic compromise, probably related to atrial enlargement. In addition, this case reinforces the importance of performing ECG in dogs with MMVD, since it complements the echocardiogram and enables a better therapeutic approach. Key words: arrhythmia, canine, electrocardiography, endocardiosis. O trigeminismo supraventricular e um disturbio incomum de formacao do impulso eletrico cardiaco. Detectar e tratar arritmias cardiacas sao um importante objetivo terapeutico em cardiologia. O objetivo desta nota e relatar a ocorrencia de trigeminismo supraventricular em um cao com doenca mixomatosa da valva mitral (DMVM). Um cao sem raca definida, macho, inteiro, 15 anos de idade e 13kg foi levado para avaliacao cardiaca com um historico de sopro cardiaco, tosse, dispneia e ascite. Os achados ecocardiograficos foram compativeis com doenca mixomatosa de valvas mitral e tricuspide com comprometimento hemodinamico severo. A eletrocardiografia (ECG) revelou arritmia sinusal com presenca de complexos supraventriculares prematuros isolados, aos pares e periodos de trigeminismo supraventricular. O trigeminismo supraventricular nao e relatado em estudos retrospectivos e prospectivos que avaliaram arritmias cardiacas em um grande numero de caes. O presente relato evidencia que o trigeminismo supraventricular pode ocorrer em caes com DMVM e comprometimento hemodinamico severo, provavelmente relacionado a dilatacao atrial. Ainda, reforca a importancia da realizacao do ECG em ca