Background: Though spontaneous closure of isolated congenital ventricular septal defects in humans is very common, it has been rarely reported in dogs. Case presentation: A 4 month old Havanese dog and a 4.5 month old Chihuahua x Jack Russell terrier cross were presented for murmur evaluation to the authors’ institution. Both puppies were clinically healthy and had a loud systolic murmur on the right hemithorax. Echocardiography in both dogs revealed a small, isolated, restrictive perimembranous congenital ventricular septal defect. No echocardiographic signs of left ventricular volume overload or pulmonary hypertension were present. Re-check auscultation in both dogs revealed the absence of a murmur, and echocardiography showed no flow through the interventricular septum. In the 9 kg Havanese dog and the 4 kg mixed breed dog, spontaneous closure occurred at 13–17 months and 12–30 months, respectively. Conclusions: In both dogs the spontaneous closure of a congenital perimembranous ventricular septal defect took place in a young adult age. The mechanism of closure remains unclear.

In this multicenter, prospective, observational study, abdominal aortic flow was examined with pulsed-wave Doppler ultrasound in dogs with a left-to-right shunting patent ductus arteriosus (PDA) and in apparently healthy dogs. Forty-eight dogs with a PDA and 35 controls were included. In the dogs with a PDA, 37/48 had hemodynamically significant PDAs (hsPDAs) while 11/48 had non-hsPDAs, based on the presence or absence of echocardiographic signs of left-sided volume overload, respectively. In 12 dogs (4/35 control dogs, 7/37 dogs with an hsPDA and 1/11 dogs with a non-hsPDA), the diastole was too short to visualize the end-diastolic flow. Antegrade end-diastolic flow was observed in 30/35 controls and 6/11 dogs with a non-hsPDA. Absent end-diastolic flow was observed in 1/35 control dogs and 3/11 dogs with a non-hsPDA. Retrograde end-diastolic flow was observed in 30/37 dogs with an hsPDA and 1/11 dogs with a non-hsPDA. Twenty-one dogs (15 with an hsPDA and 6 with a non-hsPDA) were reassessed after PDA closure, and, in 19/21, end-diastolic flow was visualized: 17/19 showed an antegrade flow, 1/19 an absent flow and 1/19 a retrograde flow. Sensitivity and specificity of retrograde end-diastolic flow for detection of hsPDAs were 100% and 90%, respectively. In conclusion, ultrasonographic assessment of abdominal aortic flow was feasible in dogs with PDA. However, end-diastolic flow was not always visualized. The presence of a retrograde end-diastolic flow was an accurate finding for discriminating hsPDAs and non-hsPDAs.