Maximal increase in sensitivity with minimal loss of specificity for diagnosis of acute coronary occlusion achieved by sequentially adding leads from the 24-lead electrocardiogram to the orderly sequenced 12-lead electrocardiogram.

OBJECTIVES: This study investigates whether sequential addition of inverted (negative) leads from the 24-lead electrocardiogram (ECG) to the orderly sequenced 12-lead ECG would identify a number of leads with which the sensitivity for diagnosis of acute transmural ischemia is significantly increased with minimal loss of specificity. BACKGROUND: Acute transmural ischemia due to thrombotic coronary occlusion typically progresses to infarction. Its recognition is based on currently accepted ST-elevation myocardial infarction (STEMI) criteria with suboptimal sensitivity, which could be potentially increased by consideration of the principle that each of the 12 ECG leads can be inverted to provide an additional lead with the opposite (180 degrees ) orientation, generating a 24-lead ECG. METHODS: The study population included 162 patients who underwent prolonged coronary occlusion during elective percutaneous transluminal coronary angioplasty. Balloon occlusion was performed in the left anterior descending coronary artery (51 patients), in the right coronary artery (67 patients), or in the left circumflex coronary artery (44 patients). To be classified as indicative of the epicardial injury current of acute ischemia, the ECGs had to fulfill either the criteria of a consensus document from the American College of Cardiology or the European Society of Cardiology or thresholds for the inverted leads based on a population study from Scotland. RESULTS: The addition of -V1, -V2, -V3, -aVL, -I, aVR, and -III increased sensitivity from 61% to 78% (P

Infarct transmurality and adjacent segmental function as determinants of wall thickening in revascularized chronic ischemic heart disease.

BACKGROUND: There are many factors which influence regional left ventricular wall thickening (WT) in ischemic heart disease (IHD). We used magnetic resonance imaging (MRI) to explore, in patients with chronic ischemic heart disease (CIHD), how regional WT is affected by both infarct transmurality (IT) and the function of adjacent segments. We also compared these findings with a group of healthy volunteers (controls). METHODS: Twenty patients (20 men, mean age 63, range 45-80 years) were imaged with cine MRI for function and delayed enhancement MRI for infarction 6 months after revascularization. Twenty age and sex matched controls underwent cine MRI. Short-axis images were analysed using a 12-segment per slice model in four midventricular slices per subject. RESULTS: WT and IT were inversely related (r(2) = 0.11, P<0.001). WT of non-infarcted segments in patients was lower than corresponding segments in controls (5.1 versus 4.6 mm, P<0.001). WT in patients decreased with an increasing number of dysfunctional adjacent segments (P<0.001) and increasing IT (P<0.001). WT was more strongly influenced by the number of dysfunctional adjacent segments (t = -22.93, P<0.001) than by IT (t = -4.50, P<0.001). CONCLUSIONS: The number of dysfunctional adjacent segments is a greater determinant than infarct transmurality on regional wall thickening.