Do statins influence the prognostic impact of non-sustained ventricular tachycardia after ST-elevation myocardial infarction?

AIMS: The study evaluates the effect of statin therapy on the prognostic impact of non-sustained ventricular tachycardia (NSVT) occurring after acute ST-elevation myocardial infarction (STEMI). METHODS AND RESULTS: From the German Acute Coronary Syndrome Registry (ACOS), 3137 patients with STEMI and in-hospital Holter monitoring were analysed. Three hundred and forty-six (11.0%) patients had NSVT. When compared with patients with no documented NSVT, patients with NSVT were older, more often had myocardial infarction in their history, diabetes mellitus, and an ejection fraction <40%. Regarding frequency of drug application, medication at discharge did not (beta-blockers, ACE-inhibitors, amiodarone) or only slightly (acetylsalicylic acid, statins, and sotalol) differ between both groups. Multivariable analysis of 1 year mortality, adjusted for age, gender, diabetes, reperfusion therapy, ejection fraction <40%, and beta-blocker therapy showed the following results: In patients without statin treatment and no NSVT, 1 year mortality after STEMI was 9.2%, but increased to 25.0% [odds ratio (OR) 3.02; 95% confidence interval (CI) 1.47-6.20], if NSVT were present. In patients on statin treatment and no NSVT, 1 year mortality was only 3.2%, and in the presence of NSVT 1 year mortality was not significantly increased anymore (5.3%; OR 1.03; 95% CI 0.55-1.92). CONCLUSION: After STEMI, only in patients not on statin treatment, the occurrence of NSVT is associated with a significant and marked increase in 1 year mortality.

Assessment of coronary flow reserve: comparison between contrast-enhanced magnetic resonance imaging and positron emission tomography.

OBJECTIVES: The study compared flow reserve indices by magnetic resonance imaging (MRI) with quantitative measures of coronary angiography and positron emission tomography (PET). BACKGROUND: The noninvasive evaluation of myocardial flow by MRI has recently been introduced. However, a comparison to quantitative flow measurement as assessed by PET has not been reported in patients with coronary artery disease (CAD). METHODS: Two groups of healthy volunteers and 25 patients with angiographically documented CAD were examined by MRI and PET at rest and during adenosine stress. Dynamic MRI was performed using a multi-slice ultra-fast hybrid sequence and a rapid gadolinium-diethylenetriaminepenta-acetic acid bolus injection (0.05 mmol/l). Upslope and peak-intensity indices were regionally determined from first-pass signal intensity curves and compared to N-13 ammonia PET flow reserve measurements. RESULTS: In healthy volunteers, the upslope analysis showed a stress/rest index of 2.1 plus minus 0.6, which was higher than peak intensity (1.5 plus minus 0.3), but lower than flow reserve by PET (3.9 plus minus 1.1). Localization of coronary artery stenoses (> 75%, MRI < 1.2), based on the upslope index, yielded sensitivity, specificity and diagnostic accuracy of 69%, 89% and 79%, respectively. Upslope index correlated with PET flow reserve (r = 0.70). A reduced coronary flow reserve (PET < 2.0, MRI < 1.3) was detected by the upslope index with sensitivity, specificity and diagnostic accuracy of 86%, 84% and 85%, respectively. CONCLUSIONS: Magnetic resonance imaging first-pass perfusion measurements underestimate flow reserve values, but may represent a promising semi-quantitative technique for detection and severity assessment of regional CAD.

Assessment of myocardial viability with contrast-enhanced magnetic resonance imaging: comparison with positron emission tomography.

BACKGROUND: Recent studies indicate that MRI, after administration of gadolinium-diethylenetriamine pentaacetic acid, can identify nonviable areas in dysfunctional myocardium. We compared MRI hyperenhancement with PET as a gold standard for detection and quantification of myocardial scar tissue. METHODS AND RESULTS: Thirty-one patients with ischemic heart failure (ejection fraction, 28+/-9%) were imaged with PET and MRI. Scar was defined as regionally increased MRI signal intensity 20 minutes after injection of 0.2 mmol/kg gadolinium-diethylenetriamine pentaacetic acid and as concordantly reduced perfusion and glucose metabolism as defined by PET. Sensitivity and specificity of MRI in identifying patients and segments (n=1023) with matched flow/metabolism defects was 0.96 of 1.0 and 0.86 of 0.94, respectively. Eleven percent of segments defined as viable by PET showed some degree of MRI hyperenhancement. Defect severity score based on visual analysis was 44.3+/-9.1 for PET and 47.6+/-11.1 for MRI (r=0.91, P<0.0001). Quantitatively assessed relative MRI infarct mass correlated well with PET infarct size (r=0.81, P<0.0001). Furthermore, MRI hyperenhancement was a better predictor of scar tissue than end-diastolic and end-systolic wall thickness or thickening. CONCLUSIONS: In severe ischemic heart failure, MRI hyperenhancement as a marker of myocardial scar closely agrees with PET data. Although hyperenhancement correlated with areas of decreased flow and metabolism, it seems to identify scar tissue more frequently than PET, reflecting the higher spatial resolution. Additional functional studies after revascularization are required to define the significance of small islands of scar detected by MRI.