Complete Heart Block Complicating the Head Impulse Test

Background: Symptoms of acute vestibular syndrome include dizziness, nausea, vomiting, and postural instability. The cause may be a peripheral or central lesion. Distinguishing between these two causes is critical because the treatments differ completely. One bedside test to help make this distinction clinically is the head impulse test (HIT), sometimes called the head thrust test. Objective: To describe a case of complete heart block associated with performance of the HIT. Design: Case report. Setting: Academic medical center. Patient: A 52-year-old woman presented to the emergency department with sudden onset of dizziness. Intervention: The HIT. Main Outcome Measure: Use of the HIT to help distinguish between a peripheral or central lesion in a patient with dizziness. Results: Complete heart block occurred immediately after performance of the HIT. Conclusions: Physicians may perform this test in an office, emergency department, or inpatient setting and should be aware that occasionally patients may have a severe vagal reaction including complete heart block.