Unruptured Sinus of Valsalva Aneurysms Manifesting as Complete Heart Block

Introduction

Sinus of Valsalva aneurysms are usually unilateral and the most common clinical presentation is subsequent to aneurysmal rupture. However, in rare cases they present as bilateral lesions, and are infrequently diagnosed unruptured. We present a rare case of bilateral unruptured sinus of Valsalva aneurysms.

Case Report

A 27-year-old male patient presented with complaints of recurrent episodes of dizzy spells for 1 year and two episodes of syncope on the day of admission, suggestive of Stokes-Adams attacks. The patient did not have any other cardiac symptoms. There was no significant past medical illness.

On admission, he was experiencing bradycardia with a heart rate of 50 beats·min⁻¹. Blood pressure was 120/70 mm Hg in the right upper limb in a supine posture. Auscultation revealed a short early diastolic murmur in the aortic area. The rest of the examination was unremarkable. An initial electrocardiogram showed a complete atrioventricular block with a regular ventricular escape rhythm of right bundle branch block morphology (Figure 1A).

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Figure 1.

(A) Twelve-lead electrocardiogram at presentation showing complete heart block with a regular ventricular escape rhythm of right bundle branch block morphology with a heart rate of 47 beats·min⁻¹. (B) Twelve-lead electrocardiogram after recovery to sinus rhythm showing a heart rate of 71 beats·min⁻¹ and left bundle branch block.

Temporary transvenous pacing was performed by right femoral vein puncture. The patient spontaneously reverted to sinus rhythm with a left bundle branch block after 48 hours (Figure 1B). Transthoracic echocardiography revealed mild aortic regurgitation. There were two aneurysms (Figure 2 and 3) arising from the right and left aortic sinuses. The right sinus aneurysm was penetrating into the interventricular septum and the left sinus aneurysm was protruding into the left atrium (Figure 2 and 3).

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Figure 2.

Echocardiogram in parasternal long axis view showing large left SVA protruding into the left atrium.

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Figure 3.

Echocardiogram in an apical four-chamber view showing a large left SVA protruding into the left atrium and a smaller right SVA penetrating into the interventricular septum.

An aortogram demonstrated the presence of two large unruptured sinus of Valsalva aneurysms (SVAs) arising from the right and left coronary sinuses (Figure 4 and 5). The left coronary sinus aneurysm was large and the right coronary sinus aneurysm was smaller, burrowing into the interventricular septum. An aortic root angiogram also showed moderate aortic regurgitation. A left ventricular angiogram showed a dilated left ventricle with normal function. The patient was advised to undergo a repair of the SVAs with aortic valve replacement. However, he refused surgery, was discharged, and subsequently was lost to follow-up.

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Figure 4.

Aortogram in a 30° right anterior oblique view showing the unruptured large left SVA.

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Figure 5.

Aortogram in a 60° left anterior oblique view showing a large unruptured left SVA and a smaller unruptured right SVA.

The presence of bilateral unruptured SVAs involving left and right sinuses, manifesting as a transient complete heart block, makes this a very unusual presentation of an uncommon disease.

Discussion

SVA is a rare congenital anomaly caused by a defect of continuity between the aortic media and the annulus fibrosis. ¹ SVA was first described by Hope in 1837. ² Although the true incidence is unknown, unruptured SVAs are rarely encountered clinically. Among patients undergoing cardiopulmonary bypass, the incidence of SVA has been reported to be 0.1% to 1.5%. ¹ The anomaly is more common in the Oriental population compared to Caucasians. SVAs are most frequently located in the right coronary sinus (67% to 77%) with 15% originating in the non-coronary sinus and rare reports of isolated left SVAs. ³

The majority of cases of SVA are congenital. Involvement of multiple coronary sinuses is rare and often associated with a secondary etiology. ⁴ Secondary causes of SVA include atherosclerotic disease, Marfan's syndrome, syphilis, bacterial endocarditis, and cystic medial necrosis trauma (deceleration injury). Rare association with polycystic kidney, Behcet's disease, and tuberculosis has also been reported. ¹ A review of the literature revealed very rare case reports of SVAs arising from the right and left sinuses of Valsalva, ⁴ and triple aneurysms arising from all three sinuses. ⁵

The most common clinical manifestation of SVA is rupture into the right ventricle, although rupture into the right atrium, left ventricle, interventricular septum, pleural space, pulmonary artery, and pericardium can also occur. ¹

The pattern of presentation does, however, vary widely, and unruptured aneurysms are often ‘silent’ or present only with vague non-specific symptoms. Rare manifestations include cerebrovascular accidents, myocardial ischemia, mitral incompetence, right ventricular outflow tract obstruction, left ventricular outflow tract obstruction, and atrial fibrillation. ⁶

Cardiac conduction disturbance due to SVA can occur at several levels, ^7–8 including sinoatrial conduction disruption and various levels of his bundle block. Transient atrioventricular block and persistent complete atrioventricular block are also reported.

In our patient, the unruptured right SVA had extended into the interventricular septum and presumably, through transient compression, had compromised normal atrioventricular (A-V) node/His bundle function resulting in complete heart block.

Conclusion

We conclude from this case and a review of the literature that the presence of bilateral unruptured SVAs involving the right and left sinuses is rare. Moreover, presentation as a transient complete heart block is very rare and merits reporting.