Usefulness of endocoronary electrocardiogram in the detection of myocardial viability and comparison with single-photon emission computed tomography Tl-201

Intracoronary ECG ST-segment recovery during primary percutaneous intervention for ST-segment myocardial infarction: insights from a cardiac MRI study

BACKGROUND

ST-segment-resolution (STR) on surface electrocardiogram (ECG) is a good surrogate for myocardial reperfusion in patients with acute ST-segment-elevation-myocardial-infarction (STEMI). We sort to determine the optimal criteria of measuring STR on intracoronary-ECG (IC-ECG) for prediction of myocardial injury evaluated by cardiac MRI (CMR).

METHODS

Measurements of IC-ECG ST-segments were performed at baseline, immediately after (early) and 15 min (late) after achieving TIMI-3 flow during primary-PCI. The degree of ST-segment-shift from baseline noted upon the IC-ECG was divided into four groups: (group 1) ST-segment-resolution >1 mm, (group 2) <30% resolution, (group 3) >50% resolution, (group 4) >70% resolution at both early and late time points. Patients had CMR at days 3 and 90 postprimary-PCI.

RESULTS

Fifty two patients (aged 60 ± 11 years; 43 males) were evaluated. Early intracoronary-ECG ST-segment resolution (early IC-STR >1 mm) correlated with smaller scar mass (P = 0.003), nonviable myocardial mass (P < 0.001), and microvascular obstruction (MVO) (P = 0.004) on CMR at day 3. Ejection fraction (EF) was also better at day 3 (P = 0.026) and 90 (P = 0.039). Patients with poor early IC-STR (IC-STR <30%) conversely is associated with larger scar mass (P = 0.017), nonviable myocardial mass (P = 0.01), and MVO (P = 0.021) at day 3. This was also associated with worse EF at day 90 (P = 0.044). Neither group 3 or 4, or the late measurements of late IC-STR correlated with CMR markers of myocardial injury.

CONCLUSION

The degree of early IC-STR (defined by IC-STR > 1 mm or <30%) successfully predicts myocardial damage following primary-PCI for an acute STEMI. Further studies are required to investigate its potential utility.

Intracoronary electrocardiogram and angina pectoris during percutaneous coronary interventions as an assessment of myocardial viability: Comparison with low-dose dobutamine echocardiography

The aims of this study were to evaluate the diagnostic value of intracoronary electrocardiogram (ECG) and presence of angina pectoris during percutaneous coronary interventions in the prediction of myocardial viability assessed by low-dose dobutamine echocardiography (LDDE). Seventy-one patients (60 men; mean age, 54 +/- 11 years) with recent Q-wave MI and angiographically documented regional wall motion abnormality in the presence of a significant (>/= 70%) nonocclusive stenosis of the infarct-related vessel who were referred for angioplasty were prospectively included in the study. The intracoronary ECG was recorded using coronary angioplasty guidewire. Significant ST segment elevation was defined as a new or worsening ST segment elevation of >/= 0.1 mV at 80 msec after the J-point. Angina pectoris was noted as present or absent during balloon inflation. All patients underwent LDDE for viability assessment. Significant ST segment elevation in the intracoronary ECG and chest pain were observed in 56 (78.9%) and 49 (69%) of the 71 patients. Viability was present on LDDE in 52 (92.9%) of 56 patients with and 3 (20%) of 15 without ST segment elevation. Viability was detected in 45 (91.8%) of 49 patients with and 10 (45.4%) of 22 without angina pectoris during balloon occlusion. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of ST segment elevation for viability were 94.5%, 75%, 92.9%, 80%, and 90.1%, respectively. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of angina pectoris for viability were 81.8%, 75%, 91.8%, 54.5%, and 80.3%, respectively. The present study demonstrated that a simple assessment of ST segment elevation in the intracoronary ECG or angina pectoris during coronary angioplasty can be used to assess myocardial viability identified by LDDE in patients with previous MI.

Design and synthesis of novel pyridoxine 5'-phosphonates as potential antiischemic agents

On the basis of previous reports that the natural cofactor pyridoxal 5'-phosphate 1 appears to display cardioprotective properties, a series of novel mimetics of this cofactor were envisioned. As pyridoxal 5'-phosphate is a natural compound and is subject to biological degradation and elimination pathways, the objective was to generate active phosphonates that are potentially less light sensitive and more stable in vivo than the parent vitamer. Several phosphonates were designed and synthesized, and in particular, compounds 10 and 14 displayed similar biological traits to natural phosphate 1 in the rat model of regional myocardial ischemia and reperfusion. A reduction in infarct size was observed in animals treated with these compounds. In an effort to identify other relevant cardioprotective models in order to potentially define structure-activity relationships, these three compounds were tested in the rat working heart model. Compounds 1, 10, and 14 were compared to dichloroacetic acid (DCA) as positive control in this model. As with DCA, compounds 1, 10, and 14 were found to induce a shift from fatty acid oxidation toward glucose oxidation.