Index Provides New Insights into Lupus Cardiac Risks

The heart rate recovery (HRR) index is deteriorated in persons who have systemic lupus erythematosus (SLE). This index is a simple measure that may be clinically useful for identifying patients with SLE who are at high risk for cardiac disease.

In this study-perhaps the only one to examine the HRR index in persons with SLE-Dogdu and coworkers tested cardiac function (electrocardiography, echocardiography, treadmill exercise) in 48 patients and 44 controls. They defined the HRR index as the reduction in heart rate from peak exercise to the first, second, third, and fifth minutes (HRR1, HRR2, HRR3, HRR5) of exercise recovery.

The SLE and control groups did not differ in baseline echocardiographic values: left ventricular (LV) diameter, ejection fraction, LV mass, right ventricular diastolic diameter, and pulmonary artery systolic pressure. However, differences emerged during stress testing. HRR1 and HRR2 indices were significantly lower in persons with SLE than in controls. The same was true for HRR3 and HRR5 during exercise recovery. Metabolic equivalents during exercise testing were significantly lower in persons with SLE.

The authors noted that when the prognostic significance of the HRR index is considered, these results may explain the increased occurrence of cardiac death in patients with SLE.