Diagnostic and prognostic applications for vasodilator stress myocardial perfusion imaging and the importance of radiopharmaceutical selection

Do electrocardiographic changes with adenosine myocardial perfusion imaging predict ischaemia in patients with left ventricular hypertrophy?

BACKGROUND

Electrocardiographic (ECG) changes during adenosine myocardial perfusion imaging (MPI) correlate with severe coronary artery disease and the presence of collaterals. However, the significance of these changes during adenosine MPI in patients with left ventricular hypertrophy (LVH) on baseline electrocardiogram is less well understood.

OBJECTIVE

To evaluate whether ECG changes on adenosine MPI predict ischaemia in patients with LVH.

METHODS

We reviewed retrospectively 454 consecutive patients who had undergone adenosine MPI at our institution. The baseline electrocardiogram was reviewed to determine whether or not LVH was present. All patients were administered adenosine at 140 microg x kg x min for a total of 6 min and Tc-sestamibi was injected at 3 min into the protocol. None of the patients underwent any form of exercise during the stress test.

RESULTS

Of the 146 patients with LVH, 10 had stress ECG changes suggestive of ischaemia and 40 had evidence of ischaemia on MPI. Similarly, of the 308 patients without LVH, 43 had stress ECG changes suggestive of ischaemia and 68 had ischaemia on MPI. The sensitivity and specificity of stress ECG changes in predicting ischaemia on perfusion in patients with LVH were 12.5% and 95.3%, respectively, with a positive predictive value of 50% and a negative predictive value of 74.3%.

CONCLUSION

ECG changes suggestive of ischaemia in patients with LVH are very specific for ischaemia on MPI, and their significance is similar to that in patients without LVH.

First annual Mario S. Verani, MD, Memorial lecture: clinical value of myocardial perfusion imaging in coronary artery disease

I am honored to give this lecture in memory of Dr Mario S. Verani, a friend and a respected colleague in the field of nuclear cardiology. Dr Verani made many immense contributions to the field of nuclear cardiology during his lifetime. He was a pioneer in the field of pharmacologic stress imaging and played a leading role in validating the utility of intravenous adenosine infusion for stress imaging in detecting significant coronary stenoses and assessing prognosis. He and his colleagues at Baylor reported that pharmacologic stress imaging could separate high- and low-risk patient subsets after acute myocardial infarction, particularly among patients who underwent thrombolytic therapy. He informed us that certain drugs that patients took could influence perfusion defect severity. This work led to a clinical study showing that ischemic defect size could be substantially reduced with medical therapy in patients who had recently had an acute infarction. An outcome of this observation was the launching of the INSPIRE (adenosINe technetium-99m Sestamibi single-photon emission computed tomography Post-InfaRction Evaluation) trial in which postinfarction patients are randomized to medical therapy or revascularization. Dr Verani was an able debater when assigned the position for advocating for stress radionuclide perfusion imaging against stress echocardiography. He engaged in these debates with substantial knowledge but always with a touch of humor. Dr Verani's courage was an inspiration to all of us during his illness. His legacy as a pioneer will endure as the field of nuclear cardiology continues to mature and expand.