Aortic root abscess presenting as alternating bundle branch block: Infective endocarditis of bicuspid aortic valve

Abstract

Bicuspid aortic valve is the most common congenital cardiac malformation, affecting 1%–2% of the population. Among various complications, incidence of infective endocarditis (IE) in the bicuspid aortic valve population is high with higher rate of periannular extension resulting in conduction disturbances. Here we are reporting a rare case of infective endocarditis of bicuspid aortic valve presented with alternating bundle branch block.

1. Case report

A 45-year old man admitted with staphylococcal infective endocarditis of bicuspid aortic valve with aortic root abscess. He had one week history of persistent high grade fever with chills. 12 lead Electrocardiogram (ECG) showed new onset complete RBBB with prolonged PR interval (Fig. 1A). Transthoracic echocardiography showed bicuspid aortic valve with evidence of aortic root abscess (Fig. 2A and B). On second day, ECG showed LBBB morphology with features of A-V dissociation followed by alternating bundle branch block (Fig. 1B). Troponin-I was negative. It was decided to insert temporary pacemaker immediately followed by emergency aortic valve replacement with aortic root abscess debridement. But patient developed asystole while transferring him to cathlab for temporary pacemaker insertion and could not be revived.

Fig. 1.

(A): 12 lead Electrocardiogram of the patient taken in emergency department showing right bundle branch block with first degree atrio-ventricular block (PR interval 400 mSec). (B): 12 lead Electrocardiogram of the patient taken 48 h of admission showing left bundle branch block morphology with features of A-V dissociation.

Fig. 2.

(A): Transthoracic 2-D echocardiography image, parasternal long axis view showing echo-lucent area (arrow) in aortic root suggestive of aortic root abscess. (B): Transthoracic 2-D echocardiography image, modified parasternal short axis view showing echo-lucent area (arrow) in aortic root suggestive of aortic root abscess.

2. Discussion

Among the various complications of bicuspid aortic valve including aortic stenosis, aortic regurgitation, aortic dissection, the incidence of infective endocarditis in the bicuspid aortic valve population is reported to be as high as 10 to 30% in some series. However, the actual incidence is likely to be lower. Viridans streptococci and staphylococci accounts for two third of cases. Patients with infective endocarditis of bicuspid aortic valve are younger (fourth and fifth decades), having strong male predominance and has a higher incidence of valve perforation, valve destruction, heart failure and valvular, perivalvular or myocardial abscess formation including periannular complications.¹ Development of perivalvular abscess results in its rapid progression into the His bundle or the AV node in 45% of total patients resulting in bundle-branch or AV blocks.² Aortic valve endocarditis complicated with a perivalvular abscess has high mortality rate requiring urgent surgical treatment. Hence early diagnosis and surgical treatment of a perivalvular abscess are essential to decrease mortality and improving survival rate.

Conflicts of interest

All authors have none to declare.