Indonersia - By Will Boggs, MD
The presence of ST-deviation in ECG lead aVR forebodes a worse prognosis in patients with ST-elevation myocardial infarction (STEMI), researchers from Canada report.
"In an increasingly technologically orientated world, simple assessment of aVR on the baseline ECG in patients with STEMI should be part of every clinician and health professional caring for such patients," Dr. Paul W. Armstrong from University of Alberta in Edmonton told Reuters Health by email.
Rarely assessed in STEMI, aVR explores two myocardial regions missed by the other 11 leads: the inferior and lateral apex and the basal interventricular septum. Studies in non-ST elevation acute coronary syndrome have shown an association between aVR ST-elevation and poor outcomes, but there are few such studies in STEMI.
Dr. Armstrong and colleagues used data from 5,683 patients in the APEX-AMI trial to examine the incidence and prognostic value of aVR ST-deviation in STEMI patients undergoing primary PCI within six hours of onset.
Three hundred fifty-two patients (6%) had aVR ST-elevation and 1,512 (27%) had aVR ST-deviation, and the remaining 3,819 patients (67%) had normal aVR leads, according to the report, online July 3 in the American Heart Journal.
ST-deviation in aVR was significantly associated with death within 90 days, compared with the lack of ST-deviation.
Patients with inferior MI and aVR ST-elevation were nearly six times more likely to die than other patients (with ST-deviation or with normal aVR), and patients with noninferior MI and aVR ST-deviation had a 50% relative increase in the risk of death compared with patients normal aVR.
ST-elevation in lead aVR was associated with increased risk of the composite 90-day endpoint of death, cardiogenic shock, and heart failure, but there was no significant association with ST-deviation in lead aVR.
Left main disease and multivessel disease were more frequent in patients with aVR ST-elevation, whereas aVR ST-deviation was seen more often with left circumflex artery disease.
"Assessing lead aVR will help disclose that one third of STEMI patients have increased risk of 90-day mortality and adverse outcome," Dr. Armstrong said. "In addition, this finding will also provide insight about more advanced coronary disease, namely multivessel disease and left main coronary narrowing that may have management consequences prior to intervention."
Unfortunately, he said, ST changes in aVR are not generally reported by automatic interpretations of ECGs, "nor is it usually examined by those interpreting ECGs in STEMI patients."
"Validation of our findings in a broader non clinical trial population, e.g., a registry, would be helpful," Dr. Armstrong added.
Am Heart J 2013.