Left Atrial Rupture Secondary to Myxomatous Mitral Valve Disease in 11 Dogs

Abstract

The purpose of this retrospective study was to evaluate the long-term outcome in dogs with left atrial rupture secondary to myxomatous mitral valve disease. Eleven client-owned dogs met the inclusion criteria for the study. Median age was 11.6 yr (range, 8.3-17.8 yr), and median weight was 5.8 kg (range, 3.8-15.2 kg). Of the 11 dogs, 10 survived the initial 24 hr after diagnosis and 5 of the dogs were still alive at the conclusion of data collection. The median survival of all dogs was 203 days. Dogs with no previous history of congestive heart failure (CHF) at the time of diagnosis had a significantly longer median survival time (345 days) compared with dogs with a previous history of CHF (160 days, P = 0.0038). Outcome of dogs with myxomatous mitral valve disease presenting with left atria rupture was more favorable than previously reported, and dogs without previous CHF survived the longest.

Left Atrial Mural Thrombosis and Hemopericardium in a Dog with Myxomatous Mitral Valve Disease

“…Recently, thrombi attached to partial left atrial endocardial tears have been described in a dog with MMVD and myocardial infarct [ 8 ]. Pericardial effusion is usually associated with tumors or idiopathic pericardial effusion in dogs; less commonly, it is secondary to coagulopathy, local infections, congestive heart failure, or left atrial rupture [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 15 , 16 , 17 , 18 , 19 , 20 ]. Left atrial tears can occur in the lateral wall of the left atrium secondary to MMVD and cause pericardial effusion, cardiac tamponade, and sudden death in dogs [ 1 , 2 , 3 , 5 ].…”

“…Rarely, acquired atrial septal defects secondary to MMVD have been reported in dogs: fossa ovalis can be a site of tear as a consequence of mechanical trauma or increased atrial pressure [ 21 , 22 ]. The etiology of the left atrial tears in dogs affected by MMVD is unclear: Increased left atrial volume/pressure and mechanical trauma from high velocity mitral regurgitation jet represent predisposing factors for spontaneous tears [ 1 , 5 , 6 , 7 ]. The dog described in this report presented atrial thrombosis and hemopericardium secondary to left atrial rupture: Multiple left atrial tears with variable depths were able to cause both intracardiac and intrapericardial hemorrhages.…”

“…Left atrial rupture has been previously reported as an uncommon complication of severe myxomatous mitral valve disease (MMVD) in dogs [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ]. The etiology of left atrial rupture in dogs affected by MMVD can be multifactorial, however, endocardial splitting represents a predisposing factor in the development of this clinical condition [ 1 , 5 , 6 , 7 ]. Endocardial splitting can variably extend in depth into the myocardium with spontaneous tear of the endomyocardium [ 1 , 5 , 6 , 7 ].…”

“…The etiology of left atrial rupture in dogs affected by MMVD can be multifactorial, however, endocardial splitting represents a predisposing factor in the development of this clinical condition [ 1 , 5 , 6 , 7 ]. Endocardial splitting can variably extend in depth into the myocardium with spontaneous tear of the endomyocardium [ 1 , 5 , 6 , 7 ]. Therefore, dogs with endocardial splitting can develop complete endomyocardial rupture with hemopericardium [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ].…”

“…Endocardial splitting can variably extend in depth into the myocardium with spontaneous tear of the endomyocardium [ 1 , 5 , 6 , 7 ]. Therefore, dogs with endocardial splitting can develop complete endomyocardial rupture with hemopericardium [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ]. Conversely, an incomplete endocardial tear can result in intracardiac bleeding and thrombus formation, as previously reported in a dog [ 8 ].…”