ABSTRACT
BACKGROUND: Wide variations in the sensitivity and specificity of the exercise ECG for the diagnosis of coronary artery disease (CAD) have been reported. The aim of this study was to reexamine the sensitivity and specificity of the stress ECG and stress myocardial perfusion imaging (MPI) relative to cardiac catheterization in an era of aggressive screening. METHODS AND RESULTS: We evaluated 218 patients [mean age: 62+/-13 (SD) years; 69% males] with symptoms of chest pain or dyspnea, normal resting ECGs, and no earlier myocardial infarction. All patients exercised to age-corrected and sex-corrected Bruce protocol times and achieved >or=85% of predicted maximum heart rate. Coronary angiography was performed within 3 months of stress testing. Sixty-six percent of patients had significant CAD by angiography. The overall sensitivity of the exercise ECG (36%) was significantly lower than that of exercise MPI (81%) (P<0.001). In addition, the specificity of the exercise ECG was higher in men than in women (94% men, 74% women; P<0.01), whereas there were no significant differences in sensitivity or specificity (79%) of MPI between men and women. In patients with multivessel CAD or proximal left anterior descending stenosis >or=70%, the sensitivity of the exercise ECG was higher (58%), but still less than MPI (88%) (P<0.01). CONCLUSION: MPI is vastly superior to the stress ECG for the diagnosis of CAD, especially in patients with single-vessel CAD. Older literature reporting higher sensitivity for the stress ECG was likely biased by patients with more severe CAD and must be reexamined in the era of earlier diagnosis and intervention.
Subject(s)
Coronary Disease/diagnosis , Electrocardiography , Exercise Test/methods , Tomography, Emission-Computed, Single-Photon/methods , Adult , Aged , Cardiac Catheterization , Coronary Angiography , Coronary Disease/physiopathology , Diagnosis, Differential , Female , Humans , Male , Middle Aged , Prognosis , Severity of Illness IndexABSTRACT
OBJECTIVE: Erectile dysfunction and coronary artery disease share similar risk factors. Although phosphodiesterase-5 inhibitors used to treat erectile dysfunction do not adversely affect hemodynamic parameters in patients with coronary artery disease, their effects on myocardial blood flow are unknown. METHODS: In a randomized, double-blind, crossover study we examined the effects of tadalafil, 20 mg, compared with placebo on myocardial blood flow in patients with stable coronary artery disease (n=7, 52-73 years old). After tadalafil or placebo, myocardial blood flow was measured with positron emission tomography (nine-segment model) at rest, during maximal coronary hyperemia with adenosine, and during increased myocardial work with dobutamine. Abnormal flow was defined as myocardial blood flow <75% of maximum perfusion during adenosine plus placebo (46 normal/17 abnormal segments dentified). RESULTS: Compared with placebo, tadalafil had no significant effect on global myocardial blood flow at rest, during adenosine infusion, or during dobutamine infusion. Similarly, in normal and abnormal segments, tadalafil versus placebo had no significant effect on resting myocardial blood flow or on adenosine-induced increases in myocardial blood flow. In normal segments, myocardial blood flow with dobutamine plus tadalafil was greater than that with dobutamine plus placebo (1.79+/-0.56 versus 1.56+/-0.37 ml/g per min, P<0.01), and in abnormal segments, there was a trend for tadalafil compared with placebo to increase myocardial blood flow during dobutamine infusion (1.46+/-0.44 versus 1.36+/-0.36 ml/g per min, P=0.7). CONCLUSIONS: Tadalafil had no significant effect on global myocardial blood flow at rest, during adenosine infusion, or during dobutamine infusion. Compared with placebo, tadalafil significantly augmented myocardial blood flow during increased workload in normal regions, with a trend toward improving myocardial blood flow in poorly perfused regions.
