Case report

A four-month-old female infant presented with increased sweating and respiratory distress for one week duration. Upon arrival at the emergency department, she was alert with good peripheral perfusion. However, she exhibited moderate respiratory distress. Cardiovascular examination identified a grade 4/6 ejection systolic murmur at the upper right sternal border. Abdominal examination revealed mild hepatomegaly. Other systemic evaluations were unremarkable. A chest radiograph revealed cardiomegaly with the evidence of pulmonary oedema. Transthoracic echocardiography demonstrated a bicuspid aortic valve with dysplastic leaflets. The z-score of the aortic annulus was −3 standard deviations. The peak systolic gradient across the aortic valve measured 79 mmHg. The left ventricle was hypertrophied with preserved systolic function. The findings of echocardiogram confirmed a diagnosis of severe aortic stenosis. Consequently, percutaneous transcatheter balloon valvuloplasty of the aortic valve was planned.

During the procedure, a 4 Fr introducer sheath was inserted via the right femoral artery, followed by the advancement of a 4 Fr right coronary catheter over a 0.035” × 180 cm hydrophilic guidewire to the ascending aorta. The hydrophilic guidewire was subsequently exchanged for a 0.014” × 182 cm intermediate support guidewire, which was manoeuvered across the aortic valve to the apical region of the left ventricle. After appropriate positioning, the 4 Fr right coronary catheter was withdrawn, and a Mini Tyshak 6 × 20 mm balloon (NuMED, New York, USA) was introduced and advanced to the aortic valve. The balloon was inflated to 4.5 ATM twice for 10 s using an insufflation syringe. During the intervention, the patient exhibited intermittent, non-sustained ventricular tachycardia, which was transient and spontaneously resolved. Post-procedure, the patient developed sinus bradycardia, with a heart rate of 50 beats per minute as observed on cardiac monitoring. She was initiated on a low-dose intravenous adrenaline infusion, which resulted in an increase in heart rate to 120 beats per minute. A repeated echocardiogram demonstrated residual aortic stenosis, with a peak gradient of 57 mmHg, but no evidence of aortic regurgitation. A 12-lead electrocardiogram revealed sinus rhythm with a heart rate of 110 beats per minute. The patient was discharged three days post-procedure with a scheduled follow-up in six weeks duration.

At the six-week follow-up, the infant remained clinically stable without any active complaints. A 12-lead electrocardiogram demonstrated bigeminy with a heart rate of 150 beats per minute (figure 1). Further analysis indicated that the premature ventricular contractions originated from the left mid-septal region and the left bundle of His, suggestive of inflammatory changes in the conductive pathway following percutaneous transcatheter balloon valvuloplasty for aortic stenosis. Echocardiographic assessment revealed residual aortic stenosis with a peak gradient of 50 mmHg, absence of aortic regurgitation, and normal left ventricle function. As the patient was asymptomatic, her caregivers were advised to closely monitor for any symptoms. Six weeks later, a 12-lead electrocardiogram demonstrated sinus rhythm with isolated premature ventricular contractions, indicating resolution of the inflammatory changes in the bundle of His (Figure 2). The patient continued to remain clinically stable, with adequate weight gain, reaching 6 kg at six months of age. Given the persistence of aortic valve pathology, she remains under cardiac surveillance and is anticipated to require aortic valve repair in the future.

Figure 1.

Displays an ECG taken during the six-week follow-up after PTBV of the aortic valve, revealing ventricular bigeminy. The premature ventricular contractions (PVCs) are unifocal, originating from the left ventricle, as indicated by the dominant R wave in lead V1.

Figure 2.

Presents an ECG recorded 12 weeks after PTBV of the aortic valve, demonstrating the occurrence of infrequent PVCs.