Atrioventricular nodal reentrant tachycardia potentially triggered by hyoscine butylbromide in a young woman undergoing laparoscopic myomectomy: a case report.

INTRODUCTION

Hyoscine butylbromide is commonly administered to relieve smooth muscle spasms. Although usually well tolerated, its anticholinergic activity may influence atrioventricular (AV) nodal conduction and, in rare cases, trigger tachyarrhythmias.

CASE PRESENTATION: A healthy 30-year-old woman underwent elective laparoscopic myomectomy. Near the end of the procedure, after returning from the Trendelenburg position, she received intravenous hyoscine butylbromide (20 mg), paracetamol, and diclofenac. Within minutes, she developed sudden narrow-complex supraventricular tachycardia at 140-150 bpm, as shown in Fig. 1, accompanied by severe hypotension unresponsive to ephedrine or phenylephrine. Anaphylaxis was suspected, and small boluses of adrenaline along with fluid resuscitation were administered without significant improvement. Hemoglobin remained stable, serum tryptase was normal, and no surgical bleeding was identified. She spontaneously reverted to sinus rhythm during central venous catheter placement. After extubation in the intensive care unit, tachycardia recurred and was terminated with adenosine. Cardiology confirmed AV nodal reentrant tachycardia (AVNRT). The patient recovered uneventfully. Figure 1.Perioperative electrocardiograms.

DISCUSSION: The close temporal association between Buscopan administration and the onset of tachyarrhythmia strongly suggests a causal relationship. The drug's vagolytic effect may facilitate AV nodal conduction and promote reentry circuits. This case also highlights the diagnostic challenge posed by perioperative tachycardia, which can closely mimic anaphylaxis.

CONCLUSION

Even a single intravenous dose of hyoscine butylbromide may induce AVNRT in susceptible individuals. Perioperative teams should remain alert to this rare but clinically significant complication.