Prognostic value of normal myocardial perfusion scintigraphy in patients with chest pain and left bundle branch block.

BACKGROUND

The purpose of this study was to assess the prognostic value of normal myocardial perfusion scintigraphy in patients with chest pain and left bundle branch block (LBBB) undergoing myocardial perfusion scintigraphy without ischemia.

METHODS

Retrospectively (between February 1999 and March 2001) we assessed consecutive patients with LBBB and chest pain of suspected ischemic origin who underwent scintigraphy in our institution with tetrofosmin (technetium-99m) and thallium-201 SPECT one-day dipyridamole or adenosine stress-rest protocol and no evidence of ischemia. Of a total of 61 patients with a mean age of 67.6 +/- 9.7 years, 23 (37.7%) were male and 38 (62.3%) female. Hospital admission or death from cardiac cause, suspected ischemic pain and infarction were classified as hard events. Outcome was defined as survival free of events. We used Cox regression to assess the univariate association between outcome and the variables gender, ejection fraction < 45%, diabetes, hypertension, smoking, and LDL-cholesterol > 130 in a period of one month around the date of scintigraphy, and body mass index (BMI) > or = 25; the Kaplan-Meier test to assess the relation of prognosis to hard events; and the chi-square test to assess the distribution between genders.

RESULTS

The mean follow-up was 14.2 +/- 7.0 months. 19.7% were smokers, 70.5% had a history of hypertension, 19.7% were diabetics, 64.8% had a BMI > or = 25, 53.8% had LDL-cholesterol > 130 mg/dl and 36.1% had an ejection fraction < 45%. Nine patients (14.8%) had a hard event (5 hospital admissions and 4 cardiac deaths). We found an association between diabetes and outcome (hard event relative risk 5.7; 95 percent confidence interval 1.53 to 21.37; p = 0.009) but not with other variables.

CONCLUSIONS

Myocardial scintigraphy was shown to be a useful prognostic tool in our patients with LBBB and suspected coronary artery disease, and no evidence of ischemia on scintigraphy. 14.8% patients had a hard event in a mean follow-up of 14.2 +/- 7.0 months. Patients with diabetes had a 5.7 times increased relative risk for a hard event.