Quick method for mean frontal QRS axis determination.

Background: ECGs are the recording of the electrical activity of the heart. The direction of it's current in the frontal plane can be determined by analyzing the QRS direction and magnitude in limb leads. Several methods for determination of the QRS frontal axis have been proposed, however most of them require memorization of the exact location of the leads in the frontal plane with pen and paper calculations.

Novel predictor of prognosis from exercise stress testing: heart rate variability response to the exercise treadmill test.

Background: Although the prognostic power of heart rate variability (HRV) at rest has been demonstrated, the prognostic potential of exercise-induced HRV has not been investigated. We aimed to evaluate the prognostic power of exercise-induced HRV during and after standard exercise testing.

Methods: Time- and frequency-domain HRV analysis was performed on R-R interval data taken from 1335 subjects (95% male, mean age 58 years) during the first and last 2 minutes of exercise treadmill testing and the first 2 minutes of recovery.