Sustained intraoperative bradycardia revealing Sengers syndrome.

Sir,

Hypertrophic cardiomyopathies (HCM) are uncommon disorders in childhood.[1] They are often asymptomatic and can present as cardiac arrest. During preanaesthetic assessment, if bilateral congenital cataracts are present, the clinician should suspect Sengers Syndrome and search for an associated cardiomyopathy.

We report the case of a 6-month-old infant, born to a first-degree consanguineous marriage, weighing 6 kg and scheduled for congenital cataract surgery. Due to the delay in the management, surgery became urgent, and preanaesthetic consultation was carried out on the ophthalmology ward, 1 day before surgery. There were no particular functional signs, and clinical examination was essentially normal; in particular, there was no heart murmur or signs of heart failure. The child had a mild rhinopharyngitis without fever or rales. The anaesthetist judged the patient fit for anaesthesia without further investigations.

In the operating theatre, after induction of anaesthesia with sevoflurane, the infant received intravenous 2 μg/kg of fentanyl and 3 mg/kg of propofol. At the moment of intubation, incomplete laryngospasm occurred, so anaesthesia was deepened by administrating 30 mg of Propofol, which permitted an easy intubation. However, bradycardia (heart rate 55 bpm) occurred and persisted despite administration of atropine. This bradycardia was not preceded by significant desaturation, and EtCO2 was at 8 mmHg. External cardiac massage was initiated and 100 μg of epinephrine IV administered, which resulted in restoration of an efficient circulation.

Surgical procedure was completed on the right eye within 15 min, and the patient was transferred to the Intensive Care Unit. Transthoracic echocardiogram (TTE) showed a hypertrophied left ventricle (LV) for the age, with abnormal trabeculations [Figure 1], and apical hypokinesis of the LV. There was no obstruction to systolic ejection or associated congenital heart disease. The chest X-ray showed cardiomegaly [Figure 2].

Figure 1

Apical four chamber ultrasound view showing an hypertrophied left ventricle for the age, with abnormal trabeculations

Figure 2

Chest X-ray showing cardiomegaly

The patient was administered low dose dobutamine and norepinephrine, which improved contractility without causing dynamic LV outflow tract obstruction. Extubation was carried out 2 h postoperatively, and noninvasive ventilation was applied. The patient improved, but a moderate lactic acidosis persisted. The association of bilateral congenital cataracts, hypertrophic cardiomyopathy and lactic acidosis characterises Sengers syndrome.

Pre-anaesthetic assessment of children is based generally on anamnestic data and clinical examination, usually without the need for further investigations.[2] During the neonatal period, even careful clinical examination detects only 45% of HCM.[3] It may remain silent and cause cardiac arrest in the operating room. The existence of a bilateral congenital cataracts, even in asymptomatic infants, should trigger the anaesthetist to order a TTE before anaesthesia.

Haemodynamic effects of propofol are exacerbated in the case of HCM. In fact, an impaired LV relaxation and compliance worsens the decrease of the stroke volume due to the drop of venous return. Myocardial hypertrophy increases the oxygen demand leading to myocardial ischaemia, in this context of decreased coronary perfusion. However, rather than the choice of the hypnotic agent, it is how to use it which is decisive for haemodynamic stability.[4] Balanced anaesthesia is the reference in the management of patients with cardiomyopathy. In the case of a situation which requires deepening of anaesthesia such as laryngospasm, it makes more sense to use succinylcholine to allow intubation, instead of using propofol. Sevoflurane can be used cautiously and seems to be fairly well tolerated.[5] The use of sympathomimetic agents may intensify relaxation disorders and promote myocardial ischemia and dynamic obstruction.[3] In our patient, the use of low doses of dobutamine was supported by the presence of LV hypokinesis probably secondary to a myocardial stunning following the circulatory arrest.

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Conflicts of interest

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