Case Studies In Small Animal

Cardiovascular Medicine

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Case 38

Clinical Diagnoses

  1. Ostium secundum atrial septal defect (large)


bulletBrie, a 15 month old female standard poodle, presented to the UC Davis Cardiology Service for evaluation of a heart murmur.
bulletPhysical examination: HR 88bpm, regular rhythm, grade I-II/VI left basilar systolic murmur, split S2, femoral pulses strong and synchronous. Eupneic, normal bronchovesicular sounds all lung fields.
bulletRadiographs: Enlarged right heart with an enlarged main pulmonary artery. Pulmonary arteries and veins are prominent.
bulletEchocardiogram: Objective findings: IVSd 1.0 cm, EDD 3.1 cm, LVPWd 0.9 cm, IVSs 1.5 cm, ESD 2.4, LVPWs 1.1 cm, LA:AO 2.6/2.2 = 1.2, FS 25%, Aortic velocity 0.97 m/s, pulmonic velocity 1.54 m/s.
bulletSubjective findings: Large atrial septal defect in the upper interatrial septum and left-to-right shunting throughout diastole and most of systole readily visible on color and spectral Doppler. Moderate to severe right ventricular eccentric (volume overload) hypertrophy. Trivial to mild mitral valve insufficiency. Trivial tricuspid valve insufficiency. Trivial pulmonic insufficiency. A contrast echocardiogram identified a broad negative contrast region in the right atrium associated with left to right shunting at the atrial level and rare microbubbles identified in the left atrium.
bulletEchocardiographic shunt quantification: Pulmonic valve imaged from the right parasternal short axis view: pulmonic radius 1.13cm, VTI 24cm, HR 88bpm producing Qp of 8.5 L/min. Aortic valve imaged from the right parasternal short axis view: aortic radius 1.04cm, aortic flow assessed from the left apical four-chamber view with VTI 13.1cm, HR 99bpm producing Qs of 3.9 L/min. Qp:Qs = 2.2.
bulletECG: HR 72bpm, normal sinus rhythm, MEA - 120degrees, deep S waves in leads II, III and aVF (but lead I has deep Q rather than S waves), increased QRS duration 0.08sec. aberrant conduction consistent with right bundle branch block.
bulletConclusion: Large ostium secundum atrial septal defect (ASD) of mild-moderate size. Correction of this ASD either via surgery or via a transvascular device implantation may be considered.

Discharge Instructions

  1. Brie is a 15 month old intact female standard poodle who presented to the cardiology service for an exaggerated response to preanesthetic drugs. Your veterinarian diagnosed Brie with an atrial septal defect.
  2. On physical exam we found a soft murmur consistent with the above mentioned diagnosis. On echocardiogram we confirmed the presence of a mild to moderate-sized atrial septal defect.
  3. Dogs with small atrial septal defects live normal lives without any problems. Large atrial septal defects may result in right heart failure (abdominal fluid accumulation). Brie's defect is relatively large and may warrant the risk involved with surgical correction or transvascular occlusion.
  4. Recent studies on a family of Standard Poodles in Texas with ASDs have suggested an autosomal dominant mechanism of inheritance. If true, this would mean that at least one of Brie's parents also may have an ASD and that half of her offspring could also have ASDs. Please contact us if you are interested in screening her family members.
  5. Thank you bringing Brie to the UC Davis Cardiology Service.

Mark D. Kittleson, D.V.M., Ph.D. All rights reserved.