Q wave is typically a late finding on ECG during STEMI and consequently, when Q wave is found on the first ECG, many patients do not receive reperfusion therapy. In reality, the Q wave can also appear early in the course of the infarct and may represent a large reversible myocardial damage. The aim of our study was to evaluate the association between ischemic time and the appearance of the Q wave in STEMI acute phase and to assess whether the presence of an early Q wave can affect the management of STEMI patients. Materials and Methods: From January 1st 2009 to December 31st 2014, 248 consecutive patients with STEMI were transported from Emergency System to our CCU. Patients were divided into two groups based on the presence of Q wave in infarction leads at first ECG: group Q-wave (QWG) with 44 patients and group No Q-wave (NQWG) composed of 204 patients. For each patient following intervals were calculated: - the time between pain onset and first ECG (pain to ECG time ); - the time between the first ECG and the first intervention that restored the necrosis vessel patency (first medical contact-to-balloon time, FMC);- The time from the arrival of the patient to the hospital, and the reopening of the necrosis vessel (door-to-balloon time, DTB). Results: Pain to ECG time was greater in patients with Q-wave (119 ± 97 vs 113.02 ± 92.6 minutes, p = 0:09). The percentage of patients with early Q-wave increased progressively with increasing pain to ECG time from 2.5% in patients with Pain to ECG less than 30 minutes to 11.6% and 18.2% respectively in patients with Pain-to-ECG more than two hours and four hours (p for trend = 0.011). The DTB time, was quite comparable in both groups, 55 ± 54 vs 24.6 ± 31.2 min, p = 0.9. The FMC did not present statistically significant differences between groups (102.2 ± 35.9 minutes vs 97.8 ± 40.05 minutes, p = 0.48). Conclusions: The appearance of the Q wave is a time dependent phenomenon and is therefore affected by the delay between the onset of ischemia and the performing ECG, with a tendency to be present even in the earliest stages of the infarct itself. Despite the presence of Q waves at the first diagnostic ECG, management standard protocol of STEMI was applied in all patients, ensuring the similar reperfusion times.
Relationship Between The First Diagnostic Ecg And Time To The Start Of Symptoms In Acute Myocardial Infarction
MONTISCI, ROBERTA;FLORIS, ROBERTO;CORDA, GIULIA;CONGIA, MICHELA;CACACE, CRISTINA;MARCHETTI, MARIA FRANCESCA;MELONI, LUIGI
2016-01-01
Abstract
Q wave is typically a late finding on ECG during STEMI and consequently, when Q wave is found on the first ECG, many patients do not receive reperfusion therapy. In reality, the Q wave can also appear early in the course of the infarct and may represent a large reversible myocardial damage. The aim of our study was to evaluate the association between ischemic time and the appearance of the Q wave in STEMI acute phase and to assess whether the presence of an early Q wave can affect the management of STEMI patients. Materials and Methods: From January 1st 2009 to December 31st 2014, 248 consecutive patients with STEMI were transported from Emergency System to our CCU. Patients were divided into two groups based on the presence of Q wave in infarction leads at first ECG: group Q-wave (QWG) with 44 patients and group No Q-wave (NQWG) composed of 204 patients. For each patient following intervals were calculated: - the time between pain onset and first ECG (pain to ECG time ); - the time between the first ECG and the first intervention that restored the necrosis vessel patency (first medical contact-to-balloon time, FMC);- The time from the arrival of the patient to the hospital, and the reopening of the necrosis vessel (door-to-balloon time, DTB). Results: Pain to ECG time was greater in patients with Q-wave (119 ± 97 vs 113.02 ± 92.6 minutes, p = 0:09). The percentage of patients with early Q-wave increased progressively with increasing pain to ECG time from 2.5% in patients with Pain to ECG less than 30 minutes to 11.6% and 18.2% respectively in patients with Pain-to-ECG more than two hours and four hours (p for trend = 0.011). The DTB time, was quite comparable in both groups, 55 ± 54 vs 24.6 ± 31.2 min, p = 0.9. The FMC did not present statistically significant differences between groups (102.2 ± 35.9 minutes vs 97.8 ± 40.05 minutes, p = 0.48). Conclusions: The appearance of the Q wave is a time dependent phenomenon and is therefore affected by the delay between the onset of ischemia and the performing ECG, with a tendency to be present even in the earliest stages of the infarct itself. Despite the presence of Q waves at the first diagnostic ECG, management standard protocol of STEMI was applied in all patients, ensuring the similar reperfusion times.
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