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Ventricular fibrillation triggered by a ruptured sinus of Valsalva aneurysm

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A 40 year old Japanese man fainted suddenly while fishing and was brought to hospital. He fainted again in the outpatient department. Electrocardiography showed ventricular fibrillation (fig 1A), and sinus rhythm was recovered by defibrillation with 200 J. He had no history of syncope or life threatening arrhythmias. A grade V/VI continuous murmur was accompanied by a diastolic thrill along the left sternal border. Electrocardiography showed negative T waves in leads II, III, aVF, and V4–6. Transoesophageal echocardiography with colour Doppler imaging showed an aneurysm of the right coronary sinus of Valsalva, which displaced towards the right ventricle, and had systolic–diastolic turbulent flow from the aorta into the right ventricle (fig 2).

Figure 1

(A) After an extrasystole, electrocardiography shows ventricular fibrillation. (B) Sustained polymorphic ventricular tachycardia was readily induced by double extrastimuli delivered from the right ventricle outflow tract in the control state.

Figure 2

Transoesophageal echocardiography with colour flow Doppler showing systolic–diastolic turbulent flow from the aorta into the right ventricle.

Catheterisation of the right heart revealed moderate increases of the pulmonary arterial and right ventricular systolic pressures. Blood oxygen saturation was increased by 12%, from 79.9% at the right atrium to 91.8% at the right ventricle. The left to right shunting rate was 42% and the pulmonary to systemic flow ratio was 1.7. Aortography revealed a jet of contrast medium flowing out of the right coronary sinus into the right ventricle.

The patient had surgery on the seventh hospital day. Intraoperatively, a strong thrill caused by the ruptured sinus of Valsalva aneurysm was palpated directly under the pulmonary arterial valve. The aneurysm was Konno I type with a diameter of 6–7 mm. A ventricular septal defect type I, 6–7 mm in diameter, was also found at the site. Postoperative electrophysiological examination showed that ventricular fibrillation was induced by continuous stimulation of the outflow route of the right ventricle (fig 1B). The postoperative course was favourable. Amiodarone 200 mg daily was initiated to prevent ventricular fibrillation.

Rupture of an aneurysm of the sinus of Valsalva is rare, accounting for only 0.26% of all surgical cases of congenital cardiac disease.1 Sinus of Valsalva aneurysm may result from a weak sinus of Valsalva wall. Recent studies have emphasised the wide variety of clinical manifestations of this lesion depending on its location and course.2 3 Because complications such as ventricular septal defect are relatively frequent, the aetiology is assumed to be congenital weakness of the sinus of Valsalva, except in cases resulting from inflammation, infection, or necrosis. The aetiology of the our case was assumed to be congenital because the patient was only 40 years old and had a ventricular septal defect; there were no inflammatory findings.

There have been two reported cases of ventricular fibrillation caused by rare mechanical complications in sinus of Valsalva aneurysms.4 5 In one report,4 the mechanism of ventricular fibrillation was myocardial ischaemia caused by compression of the left circumflex artery induced by a large aneurysm of the left sinus of Valsalva. In the other report,5 a ruptured aneurysm of the sinus of Valsalva had dissected into the ventricular septum and was complicated by ventricular fibrillation. No such complications were found in our patient. The origin of the aneurysm, the chamber into which it ruptured, and the association with a ventricular septal defect were typical for aneurysm of the sinus of Valsalva. However, the left to right shunting rate (42%) was enough to cause a rapid change in circulatory dynamics. Although ventricular fibrillation was easily induced by extrastimulation, our patient had no history of syncope or life threatening arrhythmias. These findings suggest that, in the absence of a rare mechanical complication, a ruptured aneurysm of the sinus of Valsalva may precipitate ventricular fibrillation because of an abrupt change in circulatory dynamics, if the patient has a tendency towards ventricular fibrillation. No other similar cases have been reported.

Acknowledgments

We thank the following physicians for their help in the management of this patient; Tatsuo Kaneko, Akihiko Nogami, Hiroshi Kamiyama, Shigeru Oshima, and Tadashi Suzuki.

References

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