# Incidentally Discovered Lown-Ganong-Levine Syndrome in a Patient Presenting With Acute Hypercapnic Respiratory Failure and Type II Myocardial Infarction: A Case Report

## TL;DR

A rare heart condition called Lown-Ganong-Levine syndrome was discovered in a patient with severe respiratory and kidney issues, highlighting the challenges of diagnosing it during critical illness.

## Contribution

This case report presents a rare incidental discovery of LGL syndrome in a patient with acute respiratory and cardiac complications.

## Key findings

- LGL syndrome was identified via ECG in a patient with no prior arrhythmia history.
- The patient's NSTEMI was likely due to increased myocardial demand from critical illness.
- No obstructive coronary artery disease was found, supporting a non-ischemic cause for the myocardial infarction.

## Abstract

Lown-Ganong-Levine (LGL) syndrome is a rare pre-excitation disorder associated with paroxysmal tachyarrhythmias. We present a case of a 53-year-old male with no significant medical history who was found unconscious in his car with dry ice exposure. He was tachypneic, hypotensive, and encephalopathic, requiring intubation for acute hypercapnic respiratory failure. Investigations revealed non-ST elevation myocardial infarction (NSTEMI) that was thought to be secondary to increased myocardial demand in the setting of respiratory failure, acute kidney injury (AKI), and nephrotic-range proteinuria. Electrocardiography (ECG) showed short PR intervals consistent with LGL syndrome. He was not known to have any prior history of arrhythmias. Coronary angiography did not show any obstructive coronary artery disease (CAD). The patient improved, was started on a beta-blocker as a preventative measure to reduce the risk of development of tachyarrhythmias, and discharged with cardiology follow-up on an outpatient basis to complete outpatient cardiac monitoring and assess the need for a cardiac electrophysiology study. This case highlights the diagnostic challenges of LGL syndrome coexisting with critical illness.