Cardiac Autonomic Neuropathy Bedside Test (CAN Testing)
Valsalva maneuver usually causes an increase in HR followed by a decrease after stopping the maneuver. The Valsalva ratio is the maximal HR by Valsalva divided by the lowest after Valsalva. Normal > 1.21, abnormal < 1.2. Deep breathing causes an increase in HR by 15 BPM, borderline 11-14, abnormal < 10 BPM. Standing causes an increase in HR by more than 10% from the 15-30th beat on standing. Less than 10% abnormal. Sustained handgrip raises the BP > 16 mmHg, borderline 11-15, and < 10 mmHg abnormal. Standing up reduces the BP < 10 mmHg, borderline 11-29, and abnormal > 30 mmHg.