Assessment of a widely applicable torso ECG in acute coronary syndrome

Abstract

IntroductionThe time from symptom onset to arrival at healthcare facility, and door to reperfusion time in treatment of acute coronary syndrome (ACS) can be improved significantly if the patient or the relatives can record a 12-lead ECG at home and transmit it to the physician for prompt interpretation. To make this widely applicable, the 12-lead ECG recording device has to be simple and user friendly. In this regard, torso ECG (T-ECG) electrode positions that are less cumbersome than the conventional ECG (C-ECG) electrode positions are an alternative worthy of consideration. Objectiveand setting: To study the utility of T-ECG versus C-ECG in ACS patients. Designand intervention: We proposed torso electrode positions in which upper limb electrodes were placed in the respective deltopectoral grooves below the lateral end of the clavicle; the right lower limb electrode was placed 2 finger breadths above the umbilicus and the left lower limb electrode, 2 finger breadths to the left of the umbilicus. We then studied the ECGs recorded, to ascertain whether T-ECGs miss or over-diagnose ACS changes. Twelve lead ECGs were recorded by both techniques (C-ECG & T-ECG) in 1361 patientsfrom the coronary care unit & out-patient department of a tertiary care hospital. A total of 1526 sets of ECGs (each set consisting of one C-ECG and one T -ECG) were read by two trained cardiologists independently and in a blinded fashion. There were 457 ECG sets from 342 patients with ACS. Of these, 116 ECG sets from 112 patients of anterior infarction who had changes restricted to precordial leads were excluded. Finally, 341 ECG sets from 230 patients with ACS and 324 sets of patients diagnosed to be normal on C-ECG were considered for the purpose of this study. Main resultsAll 341 ECG sets from the 230 patients of ACS diagnosed by C-ECG were correctly diagnosed by T-ECG (100% sensitivity) and all 324 normal ECGs on C-ECG were also identified as normal on T-ECG (100% specificity). Of the ACS ECGs, ST elevation was seen in 234 ECGs and ST depressions 154 ECGs. The localizations of ST elevation and ST depression were also accurately diagnosed by the T-ECG. ConclusionThe ECG recorded by our novel proposed torso electrode positions is comparable to a conventional ECG for the diagnosis of ACS.