Myocardial infarct associated with a partial thickness left atrial tear in a dog with mitral insufficiency

Retrospective evaluation of the ST segment electrocardiographic features in 180 healthy dogs

OBJECTIVES

Normal features of the ST segment are poorly characterised in dogs. This study aimed to describe ST segment characteristics in a population of healthy dogs.

MATERIALS AND METHODS

Medical records were reviewed to identify healthy dogs that underwent an electrocardiogram. Several ST segment qualitative parameters were evaluated: presence/absence of deviation, type of deviation (depression/elevation) and morphological patterns of depression (horizontal, downsloping, upsloping and sagging) and elevation (horizontal, concave and convex). Moreover, the amplitude of ST segment depression/elevation was measured. The potential effect of sex, bodyweight, age and somatotype on the presence/absence of ST segment deviation was evaluated through binary logistic regression.

RESULTS

One hundred and eighty dogs were enrolled. The deviation was evident in 43 of 180 dogs (23.9%), among which 36 showed depression and seven showed elevation. The median depression amplitude was 0.1 (range 0.05 to 0.3) mV. The mean elevation amplitude was 0.136 ±0.055 mV. Concerning depression morphology, the horizontal pattern was overrepresented, followed by the downsloping and upsloping ones. Concerning elevation morphology, all dogs showed a concave pattern. No meaningful effect of sex, bodyweight, age and somatotype on the presence/absence of ST segment deviation was documented.

CLINICAL SIGNIFICANCE

Normal features of canine ST segment were described and made available for clinical use.

Retrospective evaluation of clinical signs, clinical course, and prognosis between dogs with left atrial rupture secondary to myxomatous mitral valve disease and those with neoplastic cardiac tamponade (2015-2019): 70 cases

OBJECTIVE

To describe the clinical signs, clinical course, and prognosis of suspected left atrial rupture (LAR) secondary to myxomatous mitral valve disease (MMVD) in dogs and to compare them with dogs with suspected neoplastic cardiac tamponade (NCT).

DESIGN

Retrospective study from November 2015 to October 2019 SETTING: An out-of-hours Emergency Animal Hospital.

ANIMALS

Twenty-three dogs with LAR secondary to MMVD (LAR group) and 47 dogs with NCT (NCT group).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The following were the characteristics of the study population (LAR group vs NCT groups) with P < 0.05 as the significance threshold: male sex, 83% vs 66%; median age, 11.9 vs 12.5 years; and median weight, 3.8 vs 6.4 kg (P < 0.001). Chihuahuas and Miniature Dachshunds were overrepresented in the LAR and NCT groups, respectively. Statistically different clinical findings between the 2 groups were as follows (LAR vs NCT): pulmonary edema, 43% vs 0%; pericardial thrombus, 70% vs 6% (P < 0.001); ineffectiveness of pericardiocentesis (whether aspiration of pericardial fluid was successful or not), 58% vs 2% (P < 0.001); mortality rate within 48 hours of visiting hospital, 35% vs 9% (P < 0.01). No significant difference was observed in survival time after discharge between the 2 groups.

CONCLUSIONS

The proportion of dogs with a diagnosis of LAR secondary to MMVD in dogs with cardiac tamponade was higher than the previously reported rate. Furthermore, the frequency of pulmonary edema, ineffectiveness of pericardiocentesis, and short-term mortality rate was higher in the LAR group than in the NCT group.

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

A 14-year-old mixed-breed dog with a 2-year history of myxomatous mitral valve disease was examined for collapse and lethargy. At the presentation, pale oral mucous membranes, rapid and weak femoral pulses, and muffled heart sounds with a moderate left apical systolic murmur were revealed. Echocardiographic examination showed pericardial effusion with organized echogenic material originating from the left atrial wall. Tamponade of the right atrium and severe left atrial enlargement were also observed. Multiple views of the left atrium and left auricle allowed to visualize a hyperechoic mass adherent to the endocardium of the left atrial wall. Contrast-enhanced ultrasonography study allowed to rule out active intrapericardial hemorrhages, and echo-guided pericardiocentesis was performed. No recurrence of pericardial effusion was observed, but the dog suddenly died after 10 days. The postmortem examination confirmed multifocal left atrial thrombosis attached to the endomyocardial tears.