[Holter ECG in evaluating myocardial ischemia. Validation using the exercise test].

OBJECTIVES

Validation of ST-T ischemic changes in the Holter system by those recorded in the 12-lead ECG during the exercise test.

DESIGN

The changes induced by the exercise test in the ST segment of the two Holter leads--aVF e V5 like--were compared with the changes simultaneously registered in the 12-lead ECG.

SETTING

Exercise Test Laboratory and Holter Laboratory of the UTIC-Arsénio Cordeiro. Hospital de Santa Maria de Lisboa.

PATIENTS

31 patients, 23 male and 8 female, with a mean age of 55 +/- 7 years, 84% with ischemic heart disease.

METHODS

The patients underwent a treadmill exercise test. 28 with the Bruce protocol and 3 with the Naugton protocol, during which the electrocardiogram was registered simultaneously with a 2-channel Holter recorder and by a conventional 12-lead system. The changes induced in the ST segment in the two systems were compared.

RESULTS

The results of the two tests were concordant in 94% of the patients. In 4 patients (13%) there was not a good correlation between the inferior and anterior leads of the two methods, which diverged mainly between the Holter lead aVF and the inferior leads of the conventional ECG. The morphology of the ST depression was similar in both methods, and the severity of ST depression as judged by its amplitude showed an excellent positive linear correlation (r = 0.8542, p less than 0.001).

CONCLUSIONS

The sensitivity and the specificity of the Holter system is similar to the conventional 12-lead ECG in detecting ischemic changes during exercise whenever they have electrocardiographic evidence.