Do you continue an exercise stress test in a patient with bigeminy (premature ventricular contractions occurring in an alternating pattern with normal heartbeats)?

Exercise Stress Testing in Patients with Ventricular Bigeminy

Exercise stress testing should be discontinued in patients with ventricular bigeminy only if the bigeminy progresses to complex ectopy, causes hemodynamic compromise, or becomes symptomatic for the patient. 1

Assessment of Ventricular Bigeminy During Exercise Testing

Ventricular bigeminy (premature ventricular contractions occurring in an alternating pattern with normal heartbeats) may be encountered during exercise stress testing. The decision to continue or terminate the test should be based on several key factors:

When to Continue the Test

• Isolated ventricular bigeminy without progression to more complex arrhythmias
• Hemodynamically stable patient (normal blood pressure response)
• Asymptomatic patient (no chest pain, severe dyspnea, dizziness, or near-syncope)
• No evidence of ischemic ECG changes

When to Terminate the Test

According to the ATS/ACCP guidelines, exercise testing should be terminated when any of the following occur 1:

• Complex ectopy (progression from bigeminy to couplets or runs of VT)
• Symptoms develop (chest pain, severe dyspnea, dizziness, near-syncope)
• Hemodynamic compromise (fall in systolic pressure ≥20 mmHg from highest value)
• Ischemic ECG changes
• Patient request to stop

Evidence-Based Rationale

The ATS/ACCP statement on cardiopulmonary exercise testing specifically lists "complex ectopy" as an indication for exercise termination 1. Ventricular bigeminy alone is not specifically listed as an absolute indication to stop testing, but should be monitored closely for progression.

The guidelines distinguish between "uncontrolled arrhythmias causing symptoms or hemodynamic compromise" (absolute contraindication) versus "tachyarrhythmias or bradyarrhythmias" (relative contraindication) 1. This suggests that asymptomatic, hemodynamically stable ventricular bigeminy may not necessitate immediate test termination.

Special Considerations

Pediatric Patients

In pediatric patients, exercise stress testing should be terminated if ventricular bigeminy progresses to more complex forms or becomes symptomatic. The American Heart Association notes that "in all cases, a decision to terminate a stress test should be based on the totality of the available data rather than rigid guidelines" 1.

Patients with Hypertrophic Cardiomyopathy

For patients with hypertrophic cardiomyopathy, exercise stress testing is recommended to determine functional capacity and provide prognostic information 1. However, the test should be terminated if ventricular bigeminy progresses to complex ectopy.

Patients with Channelopathies

In patients with catecholaminergic polymorphic ventricular tachycardia (CPVT), exercise-induced ventricular bigeminy may be an early manifestation of the disease and can progress to bidirectional or polymorphic VT 1, 2. In these patients, the development of ventricular bigeminy during exercise testing should prompt closer monitoring and consideration of test termination if it progresses.

Clinical Approach

1. Monitor closely: Observe for progression to more complex forms of ectopy
2. Assess hemodynamics: Ensure blood pressure and heart rate are responding appropriately
3. Evaluate symptoms: Ask the patient about symptoms such as chest pain, dizziness, or dyspnea
4. Review ECG: Look for signs of ischemia or other concerning changes

Pitfalls to Avoid

• Premature termination: Stopping the test too early for isolated, hemodynamically stable ventricular bigeminy may result in incomplete diagnostic information
• Delayed termination: Continuing the test despite progression to complex ectopy or development of symptoms increases risk
• Failure to monitor: Not closely observing for progression of arrhythmia during the test
• Inadequate preparation: Exercise laboratories should always have resuscitation equipment immediately available 1

Remember that exercise stress testing should always be performed under the supervision of qualified personnel, preferably with a physician certified in advanced cardiovascular life support present or immediately available 1.