Cardiac arrest caused by undersensing of a temporary epicardial pacemaker

Area of Science:

• Cardiology
• Electrophysiology
• Medical Devices

Background:

• The R-on-T phenomenon is a recognized trigger for life-threatening ventricular arrhythmias like tachycardia and fibrillation.
• This electrophysiological event involves a premature ventricular complex landing on the vulnerable T wave of the preceding cardiac cycle.

Observation:

• A patient with temporary epicardial pacing wires post-cardiac surgery experienced recurrent polymorphic ventricular tachycardia.
• These episodes were directly linked to the R-on-T phenomenon.

Findings:

• The R-on-T phenomenon can precipitate dangerous arrhythmias in patients with both asynchronous and synchronous pacemakers.
• Loss of sensing in synchronous pacemakers can also lead to this critical timing, inducing arrhythmias.

Implications:

• Understanding the R-on-T phenomenon is crucial for managing patients with cardiac rhythm devices, especially post-operatively.
• This case underscores the importance of vigilant monitoring for arrhythmias in patients with temporary pacing systems.