Coronary artery spasm is defined as intense vasoconstriction of the coronary arteries that causes total or subtotal vessel occlusion. It plays an important role in myocardial ischemic syndromes, including stable and unstable angina, acute myocardial infarction, and sudden cardiac death . The characteristics of coronary artery spasm are that it occurs at rest and is not provoked by exertion, is associated with ST segment elevation on the ECG, and is often more prolonged than ischemic angina pectoris . The mechanisms underlying coronary artery spasm remain unexplained; however, autonomic nervous system imbalance and endothelial dysfunction are known to be significant factors.
Coronary artery spasm is recognized as one of the causes of sudden death in adults; however, it is rarely observed in pediatric and adolescent patients in the absence of confounding risk factors . Few cases of coronary artery spasm have been reported in pediatric patients. Subramanian et al. reported that a 15-month-old girl without coronary aneurysm developed acute myocardial infarction 3 months after treatment for Kawasaki disease . Jasmin et al. reported that a 13-year-old girl with systemic lupus erythematosus experienced left-sided chest pain, ECG changes, and troponin elevation, which were suggestive of acute myocardial infarction, possibly due to coronary artery spasm. In these cases, the patients had comorbidities and risk factors related to endothelial dysfunction or small vessel disease, which may have led to coronary artery spasm. In our case, a complete AV block occurred in the absence of other risk factors after a direct laryngoscopy was performed by the surgeon. Simultaneously, ST elevation in lead II of the ECG was observed. These clinical findings suggest that vagal stimulation due to direct laryngoscopy resulted in right coronary artery spasm, which decreased the blood flow to the AV node and caused a complete AV block. The branches of the vagus nerve are distributed in the pharyngeal and laryngeal mucosa. Mechanical stimulation by the laryngoscope or tracheal tube stimulates the vagal cardiac branch through the medullary vagal nucleus, which induces bradycardia .
Moreover, propofol and remifentanil induce bradycardia, which has an inhibitory effect on the sympathetic nervous system . In the present case, vagal stimulation by direct laryngoscopy and the use of propofol and remifentanil led to an imbalance between the parasympathetic and sympathetic nervous systems, which may have caused severe right coronary artery spasm and the complete AV block. We believe that the infusion rates of remifentanil and propofol were sufficient for direct laryngoscopy; however, pediatric patients might need more profound anesthesia than adults, and we should have been more careful while performing direct laryngoscopy.
Pediatric life support algorithm suggests the consideration of atropine administration for bradycardia caused by an increased vagal tone . However, we should have considered epinephrine administration or the use of an external pacemaker because atropine, which acts at the AV node, is rarely effective in patients with a complete AV block. Continuous infusion of trinitroglycerin might have worked prophylactically against coronary artery spasm during the second laryngoscopy.
We searched the PubMed database on 27 March 2021 using the following keywords: <coronary artery spasm or coronary vasospasm> AND <child> or <coronary artery spasm or coronary vasospasm> AND <complete atrioventricular block>. A total of 109 papers and 38 papers were found respectively, but reports describing coronary artery spasms secondary to direct laryngoscopy in healthy pediatric patients were not found. We additionally checked the references cited in these papers and found no reports on pediatric patients suffering from a coronary artery spasm following a direct laryngoscopy. Therefore, to the best of our knowledge, this is the first report of a severe coronary artery spasm in a healthy pediatric patient at the time of direct laryngoscopy.