# Myocardial Infarction in Conduction System Pacing: Trust the ECG or Rely on Algorithms?

## TL;DR

A patient with a pacemaker had a heart attack, and the ECG was still useful for diagnosis despite the pacemaker.

## Contribution

Demonstrates that ECG can accurately detect heart attacks in patients with conduction system pacing.

## Key findings

- STEMI was diagnosed using ECG in a patient with a CSP pacemaker.
- Physiological activation preserved by CSP allows accurate ischemia localization.
- Coronary angiography confirmed ECG findings of a large diagonal branch occlusion.

## Abstract

A 66‐year‐old male patient with a conduction system pacing (CSP) pacemaker, implanted after a pace‐and‐ablate strategy for persistent, poorly rate‐controlled atrial fibrillation, presented to the outpatient clinic with worsening dyspnea. Laboratory findings and ECG were indicative of an anterolateral ST‐segment elevation myocardial infarction (STEMI), confirmed by coronary angiography showing occlusion of a large diagonal branch. STEMI diagnosis in paced patients is often challenging due to altered ventricular activation. However, this case demonstrates that surface ECG remains interpretable with CSP, which preserves physiological activation, allowing accurate localization of ischemia even in the presence of a pacemaker.