Temporal dynamics and clinical correlates of ischemic J waves in the early phase of acute myocardial infarction

OBJECTIVES: This study aims to explore the temporal relationship between ischemic J waves and the progression of chest discomfort in patients experiencing acute myocardial infarction (AMI) during its earliest phase. METHODS: A retrospective analysis was conducted on 466 AMI cases, each reporting chest discomfort lasting no longer than 4 h. The cohort was divided into four subgroups based on the duration of pain, and electrocardiographic (ECG) alterations were compared across these groups. Patients were categorized based on the presence or absence of J waves on their initial ECG, and a comprehensive analysis was performed comparing patient demographics, ECG characteristics, echocardiographic data, and coronary angiography results. RESULTS: J waves were most prominent within the first hour of chest pain onset (p < 0.05). Patients with J waves had higher rates of ST-segment elevation myocardial infarction (STEMI) (91.4% vs. 50.4%, p < 0.001), lower heart rates (74.22 ± 9.49 vs. 80.43 ± 13.80 bpm, p < 0.001), elevated fasting glucose (8.50 ± 3.12 vs. 6.99 ± 2.20 mmol/L, p = 0.011), increased QT dispersion (90.48 ± 9.12 ms vs. 66.29 ± 11.84 ms, p < 0.001), and prolonged TpTe interval (the time interval from the peak of the T wave to its end point) (131.88 ± 19.81 ms vs. 96.99 ± 11.29 ms, p < 0.001). Multivariate analysis identified five independent factors linked to J wave presence: ST-segment elevation myocardial infarction (STEMI), reduced heart rate, elevated glucose, increased QT dispersion, and prolonged TpTe. J waves were also more frequent in patients with multi-vessel disease and right coronary artery involvement. CONCLUSION: Ischemic J waves are most detectable within the first hour of chest discomfort in AMI patients and are independently associated with STEMI, bradycardia, hyperglycemia, and specific ECG changes.