Infarto agudo de miocardio en el paciente con marcapasos

Abstract

The electrocardiographic diagnosis of acute myocardial infarction (AMI) in patients with pacemakers has always been a problem in clinical practice, causing delays in management and worse clinical outcomes. Although complete left bundle branch block (LBBB) and right ventricular pacing can produce electrocardiogram (ECG) abnormalities, specific morphological changes often allow the diagnosis of AMI or an old infarction. Case report A 76-year-old patient with history of permanent pacemaker implantation due to a 3rd-degree atrioventricular block was admitted for chest pain. Upon admission, he was hemodynamically stable but with ECG showing pacemaker rhythm with LBBB fulfilling 2 points of Sgarbossa criteria (discordant elevation of the ST segment > 5 mm in leads V2 to V3) and ST/S ratio < - 0.25 in leads V3-V4. Laboratories showed elevated troponins, integrating diagnosis of AMI, and moving on to urgent coronary angiography. A lesion on the anterior descending coronary artery was documented, and a drug-eluting stent was successfully implanted. The patient was discharged stable, asymptomatic, and with pharmacological management for secondary prevention. ECG identification of an AMI in patients with pacemakers is essential to initiate reperfusion therapy. Guideline recommendations are constantly changing, but an algorithm that uses hemodynamic instability and the modified Sgarbossa criteria (MSC) to decide these patients; management could be a high-sensitivity tool and allow physicians to make the best decisions without waiting for laboratory results. MSC, which are more sensitive than the original criteria, continue to be helpful in the diagnosis of AMI. Clinicians should carefully choose the appropriate MSC cut-off (ST/T Ratio -0.20 and -0.25) on a case-by-case basis. Keywords: Acute myocardial infarction, Electrocardiogram, Pacemaker, Left bundle branch block, Acute coronary syndrome