High output heart failure caused by a large pelvic arteriovenous malformation

A 73-year-old woman was referred to our department due to mild breathlessness on exertion. She denied chest pains but occasionally had palpitations, which were not troublesome. She did not complain of fluid retention and nor did she have orthopnoea or paroxysmal nocturnal dyspnoea. Her previous medical history included abdominal aortic aneurysm (AAA) repair 15 years ago for infra renal aneurysm. On examination she was in atrial fibrillation with a rate of 64 bpm, was normotensive and with no pedal oedema. Cardiovascular examination revealed significantly raised JVP with systolic V waves, a pansystolic murmur at left lower sternal edge and systolic flow murmur in pulmonary area. Lung fields were clear with no added sounds. A continuous loud bruit was noted on examination of her lower abdomen. Routine blood tests showed she had normocytic anaemia with a haemoglobin level of 10.4 g/dl, but both liver and renal function tests were normal. Her electrocardiogram (ECG) revealed rate controlled atrial fibrillation with no ischaemic changes. Chest X-ray showed massive cardiomegaly (Figure 1a). Her transthoracic echocardiogram (Figure 2a) showed normal left ventricular systolic and diastolic function but dilatation of all four heart chambers with severe biatrial dilatation. There was moderate to severe tricuspid regurgitation with only mild pulmonary hypertension and no evidence of intra-cardiac shunting. Subsequently, her cardiac output evaluated by echocardiography was elevated at 9.8 L/min with cardiac index of 6.0 L/min/m (>3.9 L/min/m considered as high cardiac output). Further confirmation of her echocardiographic findings by invasive cardiac catheterization was not undertaken as the values obtained were definitive and not borderline, Doppler echocardiography has been validated against catheterderived parameters and serial assessment of cardiac output is more conveniently assessed noninvasively for elderly patients. Contrast CTscan of abdominal aorta and pelvic vessels was arranged (Figure 2b). This showed grossly enlarged iliac vessels forming a massive pelvic arteriovenous malformation. The inferior vena cava was dilated (3.8 cm diameter) with high attenuation consistent with high flow. The relationship of the arteriovenous malformation to her previous AAA surgery remained undetermined, as previous operation notes and imaging were unavailable. Despite treatment with salt restriction and loop diuretics, she suffered increasing breathlessness on minimal exertion and developed worsening pedal oedema. Further chest X-ray showed pulmonary oedema with bilateral pleural effusions (Figure 1b). In view of her frail condition and large size of the arteriovenous malformation, it was decided not to consider surgical correction. As an alternative, she underwent repeated courses of alcohol sclerotherapy administered percutaneously to embolize the fistula. Transiently, her symptoms improved and serial echocardiographic assessment of cardiac output revealed a reduction to a nadir of 5.4 L/min but eventually further deterioration ensued with recurrent DECLARATIONS