Correspondence

Use of Right Precordial Leads during Exercise Testing

N Engl J Med 2000; 343:968-969September 28, 2000

Article

To the Editor:

Michaelides et al. (Feb. 4, 1999, issue)1 reported that the use of right precordial leads has the same diagnostic accuracy as thallium-201 scintigraphy during exercise testing for the detection of coronary artery disease. We evaluated 900 consecutive patients (514 men and 386 women) with a mean age of 64 years (range, 39 to 84) who were referred to a tertiary care, hospital-based laboratory for the evaluation of chest pain or dyspnea. Of these 900 patients, 740 underwent treadmill exercise testing and 160 underwent pharmacologic stress testing. We excluded patients whose electrocardiograms at rest had abnormalities known to alter the specificity of the stress electrocardiogram.

During stress testing, electrocardiographic recordings were made with three right precordial leads (V₃R, V₄R, and V₅R) in addition to the standard 12 leads. The electrocardiogram was considered positive when the ST segment was either elevated or depressed by at least 0.1 mV when measured 60 msec after the J point. The results were compared with those of myocardial perfusion imaging performed by gated single-photon-emission computed tomography.

Of the 900 patients, 158 had positive ST-segment changes in the standard 12-lead electrocardiogram. Only four patients had positive changes in the right precordial leads (P<0.001 by Fisher's exact test), and in these four, the recordings from the left-sided leads were also positive. Of the patients who had positive electrocardiographic changes, 60 percent had abnormal perfusion scans. In contrast, 373 of the 900 patients (41 percent) had abnormal scans but no electrocardiographic evidence of ischemia.

Thus, our observations are different from those of Michaelides et al. Several additional differences should be noted. The patients in the study by Michaelides et al. were younger than those in our series, and all their medications were discontinued before exercise testing. In addition, only 11 percent of the patients in their study were women, whereas 43 percent of our patients were women. Michaelides et al. used coronary angiography as their gold standard; according to this method, 86 percent of their patients had clinically significant coronary artery disease. We used radionuclide perfusion scanning, and 52 percent of our patients had abnormal scans.

As compared with coronary arteriography, myocardial perfusion imaging has a sensitivity of approximately 90 percent and a specificity of approximately 70 percent. The use of gated perfusion images further enhances both the sensitivity and specificity of this technique.2,3 However, the use of arteriography would not have had an effect on our results. In contrast to Michaelides et al., we found in our prospective evaluation that the addition of right precordial leads did not improve the diagnostic accuracy of exercise stress testing; thus, it cannot be recommended for routine use.

Sabahat Bokhari, M.D.
David K. Blood, M.D.
Steven R. Bergmann, M.D., Ph.D.
College of Physicians and Surgeons of Columbia University, New York, NY 10032-3784

3 References

1. 1

   Michaelides AP, Psomadaki ZD, Dilaveris PE, et al. Improved detection of coronary artery disease by exercise electrocardiography with the use of right precordial leads. N Engl J Med 1999;340:340-345
   Full Text | Web of Science | Medline

2. 2

   Germano G, Kiat H, Kavanagh PB, et al. Automatic quantification of ejection fraction from gated myocardial perfusion SPECT. J Nucl Med 1995;36:2138-2147
   Web of Science | Medline

3. 3

   DePasquale EE, Nody AC, DePuey EG, et al. Quantitative rotational thallium-201 tomography for identifying and localizing coronary artery disease. Circulation 1988;77:316-327
   CrossRef | Web of Science | Medline

Author/Editor Response

The authors reply:

To the Editor: Bokhari et al. studied a large number of consecutive patients who underwent exercise testing and, contrary to our findings, concluded that the use of right precordial leads does not significantly increase the diagnostic performance of exercise testing. However, methodologic differences and the lower probability of disease in their patients than in ours may affect the interpretation of their results. Some of the features of the study by Bokhari et al. that represent key methodologic differences between the two studies are the different electrocardiographic criteria for the detection of exercise-induced ST-segment elevation, the performance of exercise testing without the discontinuation of medication, the use of pharmacologic testing in 18 percent of the patients, the use of different exclusion criteria, and the use of a study population of whom 43 percent were women.

Furthermore, 86 percent of our patients and 68 percent of the patients in the study by Braat et al.1 had angiographic evidence of clinically significant coronary artery disease, whereas only 18 percent of the patients studied by Bokhari et al. had positive exercise-induced electrocardiographic changes; moreover, only 60 percent of these patients also had abnormal perfusion scans. Unfortunately, angiographic evidence of coronary artery disease was not available in their study. Surprisingly, positive ST-segment changes in the right precordial leads were found only in 0.4 percent of the patients in the study by Bokhari et al., whereas such changes were found in 19.6 percent and in 19.2 percent of the patients in the study by Braat et al. and in our study, respectively.

Andreas P. Michaelides, M.D.
George K. Andrikopoulos, M.D.
Pavlos K. Toutouzas, M.D.
University of Athens, Athens, Greece

1 References

1. 1

   Braat SH, Kingma JH, Brugada P, Wellens HJ. Value of lead V₄R in exercise testing to predict proximal stenosis of the right coronary artery. J Am Coll Cardiol 1985;5:1308-1311
   CrossRef | Web of Science | Medline

Citing Articles (1)

Citing Articles

1. 1

   Kenji Ueshima, Noboru Kobayashi, Junya Kamata, Masahiko Saitoh, Takuya Yamazaki, Ikuo Chiba, Katsuhiko Hiramori. (2004) Do the right precordial leads during exercise testing contribute to detection of coronary artery disease?. Clinical Cardiology 27:2, 101-105
   CrossRef