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Atrial Rupture 99

DIAGNOSIS These may relieve left heart failure signs PROGNOSIS & OUTCOME
(dyspnea) but are eventually followed by • Generally poor, but some dogs have survived
Diagnostic Overview
VetBooks.ir Left atrial rupture is suspected when an old abdominocentesis may be required in addi- • Survival has been observed for several months Diseases and Disorders
right heart failure signs (ascites), and periodic
with intensive vasodilator therapy.
tion to optimal diuretic therapy.
dog of a predisposed breed with mitral regur-
gitation and significant cardiomegaly has sudden
collapse and signs of hypotensive or cardiogenic • Epicardial perforations causing survivable if an atrial septal defect develops.
hemopericardium usually are small and
shock. A working clinical diagnosis is established located in the caudal wall of the left atrium PEARLS & CONSIDERATIONS
with echocardiography that demonstrates near the left atrial appendage. Therapy
pericardial effusion and a blood clot adjacent includes partial pericardiocentesis if there is Comments
to the left atrium in a patient with a perforating significant tamponade (Caution: in some • The chief radiographic signs are marked
split. In patients with acquired atrial septal patients, the epicardial clot dislodges, and enlargement of the cardiac silhouette and a
defect, Doppler echocardiography reveals left- hemorrhage becomes brisk, requiring urgent large left atrium.
to-right blood flow through the split-induced surgical intervention or euthanasia), vasodila- • The chief echocardiographic signs are peri-
atrial septal defect. tors, and surgical closure of the perforation cardial effusion and a blood clot near the
site. left atrium. Hemopericardium due to other
Differential Diagnosis causes typically is chronic in nature, larger
• Other myocardial disease Acute General Treatment in volume, and is not associated with a blood
• Atrial neoplasm • Therapy for acute severe congestive heart clot at this site.
• Neoplastic pericardial effusion failure (p. 408) • If the animal is hemodynamically stable and
• Idiopathic pericardial effusion • Pericardiocentesis (p. 1150) may be consid- a blood clot is on the left atrium, there is
• Congenital atrial septal defect ered when there is hemopericardium and merit in not removing the hemopericardium
significant tamponade; the owner should be so that counterpressure is maintained on the
Initial Database warned that intractable atrial hemorrhage is left atrium until vasodilator therapy can be
• Auscultation to identify loud systolic murmur possible, and a plan (including whether to initiated and/or preparations can be made
in mitral valve area; occasionally, the murmur proceed to thoracotomy and code designation for surgery.
may be very soft if severe tamponade and/ in the case of cardiac arrest) should be • Acquired atrial septal defects are small, and
or hypotension is/are present. finalized before beginning the procedure. detection with Doppler echocardiography
• Thoracic radiographs to detect large, globoid • Thoracotomy and suture closure of epicardial may require searching the dorsocaudal aspect
cardiac silhouette plus left atrial enlargement perforation of the right atrium.
• Electrocardiogram to identify arrhythmias
such as atrial premature beats or atrial fibril- Chronic Treatment Technician Tips
lation and conduction abnormalities such As appropriate for advanced myxomatous mitral • Dogs at greatest risk of atrial rupture are
as wide, notched P waves. valve disease (p. 409); may include those with degenerative valve disease (i.e.,
• Furosemide 1-2 mg/kg PO q 12h, adjusted small-breed dogs), which are generally less
ADVANCED OR CONFIRMATORY TESTING as needed, if congestive heart failure is present likely to develop idiopathic or neoplastic
• Two-dimensional (2D) echocardiography to • Pimobendan 0.25 mg/kg PO q 12h if pericardial effusion.
detect pericardial effusion (hemopericardium) congestive heart failure is present • In a small-breed dog with a murmur typical
and a laminar blood clot, usually near the • Enalapril 0.5 mg/kg PO q 12h if congestive of mitral regurgitation, presenting with signs
left atrium in the long-axis view when heart failure is present typical of pericardial effusion and cardiac
epicardial perforation has occurred • Amlodipine 0.05-0.2 mg/kg PO q 12-24h tamponade, keep atrial rupture on the dif-
• Color Doppler echocardiography of atrial if more vasodilator effect is needed ferential list.
septum to detect left-to-right shunt when • Surgical creation of an atrial septal defect to
atrial septal perforation has occurred decompress the left atrium Client Education
• Circumferential suture of the mitral annulus Avoid stress and hyperactivity. Teach owner to
TREATMENT to reduce mitral regurgitation monitor respiratory rate at home to detect
progressive congestive heart failure.
Treatment Overview Possible Complications
• Treatment depends on the location and depth • Additional atrial hemorrhage SUGGESTED READING
of the rupture. Nonperforating (partial) left • Death if intractable atrial hemorrhage causes Buchanan JW: Spontaneous left atrial rupture in
atrial ruptures usually cannot be confirmed critical cardiac tamponade dogs. Adv Exp Med Biol 22:315-324, 1972.
antemortem; treatment consists of standard
therapy for congestive heart failure. Recommended Monitoring AUTHOR: James W. Buchanan, DVM, M Med Sci,
• Acquired atrial septal defects are endomyo- Periodic radiographs or echocardiogram to DACVIM
EDITOR: Meg M. Sleeper, VMD, DACVIM
cardial ruptures of the interatrial septum. monitor atrial size and hemopericardium

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