Assessment of a new non-invasive index of cardiac performance for detection of dobutamine-induced myocardial ischemia.
BACKGROUND
Electrocardiography has a very low sensitivity in detecting dobutamine-induced myocardial ischemia.


OBJECTIVE
To assess the added diagnostic value of a new cardiac performance index (dP/dtejc) measurement, based on brachial artery flow changes, as compared to standard 12-lead ECG, for detecting dobutamine-induced myocardial ischemia, using Tc99m-Sestamibi single-photon emission computed tomography as the gold standard of comparison to assess the presence or absence of ischemia.


METHODS
The study group comprised 40 patients undergoing Sestamibi-SPECT/dobutamine stress test. Simultaneous measurements of ECG and brachial artery dP/dtejc were performed at each dobutamine level. In 19 of the 40 patients perfusion defects compatible with ischemia were detected on SPECT. The increase in dP/dtejc during infusion of dobutamine in this group was severely impaired as compared to the non-ischemic group. dP/dtejc outcome was combined with the ECG results, giving an ECG-enhanced value, and compared to ECG alone.


RESULTS
The sensitivity improved dramatically from 16% to 79%, positive predictive value increased from 60% to 68% and negative predictive value from 54% to 78%, and specificity decreased from 90% to 67%.


CONCLUSIONS
If ECG alone is used for specificity, the combination with dP/dtejc improved the sensitivity of the test and could be a cost-savings alternative to cardiac imaging or perfusion studies to detect myocardial ischemia, especially in patients unable to exercise.
Gorenberg
Miguel
M
Department of Nuclear Medicine, Sieff Government Hospital, Safed, Israel. miggoren@actcom.co.il
Marmor
Alon
A
D000368:Aged; D001794:Blood Pressure / Q000502:physiology*; D002316:Cardiotonic Agents / Q000008:administration & dosage / Q000009:adverse effects*; D004280:Dobutamine / Q000008:administration & dosage / Q000009:adverse effects*; D004562:Electrocardiography; D005080:Exercise Test / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D009200:Myocardial Contraction / Q000502:physiology*; D017202:Myocardial Ischemia / Q000139:chemically induced / Q000000981:diagnostic imaging* / Q000503:physiopathology; D019275:Radiopharmaceuticals / Q000008:administration & dosage; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017256:Technetium Tc 99m Sestamibi / Q000008:administration & dosage; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
D002316:Cardiotonic Agents; D019275:Radiopharmaceuticals; D004280:Dobutamine; D017256:Technetium Tc 99m Sestamibi