Impact of Cardio-Selective Beta-Blockers on Infarct Size After Acute Myocardial Infarction

This measurement represents one of the two co-primary outcomes of the study. Infarct size will be quantified by cardiac magnetic resonance imaging (CMR) and expressed in grams. CMR will be performed at least 3 months after the myocardial infarction to minimize the influence of myocardial edema.

This measurement represents one of the two co-primary outcomes of the study. Left ventricular global longitudinal strain will be assessed by transthoracic echocardiography during hospitalization to evaluate myocardial systolic function.

Arrhythmia burden will be quantified from continuous telemetry monitoring during the first 24 hours after PCI. The arrhythmia burden will be expressed as a composite index integrating the following components obtained from the same monitoring period:

• frequency of non-sustained ventricular tachycardia (NSVT) episodes (≥3 consecutive ventricular beats lasting <30 seconds),
• frequency of ventricular tachycardia (VT) episodes (≥3 consecutive ventricular beats lasting ≥30 seconds),
• cumulative duration (in seconds) of all NSVT/VT episodes, and
• total number of ventricular ectopic beats recorded during NSVT/VT events. All components will be analyzed collectively as quantitative descriptors of the overall arrhythmia burden.

Serial measurements of hs-troponin concentrations will be performed. Hs-troponin will be measured in ng/ml. Reported summary measure will include the peak value from the scheduled samples. Samples are obtained as part of routine clinical care and analyzed by the site laboratory.

Number of participants who develop cardiogenic shock during hospitalization, defined as sustained hypotension accompanied by clinical or laboratory evidence of end-organ hypoperfusion and requiring initiation of inotropic support.

Number of participants with new or worsened symptomatic bradycardia (heart rate <55 bpm with symptoms) or new conduction disturbances (e.g., new second- or third-degree AV block), documented by ECG or telemetry.

Number of participants who develop hypotension defined as systolic blood pressure <90 mmHg or mean arterial pressure <65 mmHg, as recorded in observations.

Number of participants with documented recurrent myocardial infarction or recurrent ischemic chest pain (angina) requiring medical evaluation or intervention.

Number of participants who develop sudden worsening of chronic heart failure (HF) or new-onset HF with congestion requiring therapy or prolongation of hospital stay.

Number of participants with cardiovascular death occurring during the hospitalization, defined as death resulting from acute myocardial infarction, arrhythmia, cardiogenic shock, progressive heart failure, sudden cardiac death, death due to cardiovascular procedures (e.g., PCI complications), or death from other confirmed cardiovascular pathology such as aortic dissection, acute valvular failure, or pulmonary embolism.

Area under the curve for creatinine phosphokinase (CPK) calculated using the trapezoidal rule from serial CPK measurements.

Area under the curve calculated using the trapezoidal rule from serial hs-Troponin I measurements. Samples are obtained as part of routine clinical care and analyzed by the site laboratory.

Serial measurements of creatinine phosphokinase (CPK) concentrations will be performed. CPK will be measured in U/L. Reported summary measure will include the peak value from the scheduled samples. Samples are obtained as part of routine clinical care and analyzed by the site laboratory.