What is the next step for a patient with shortness of breath (SOB) who is scheduled for a stress test but presents with tachycardia?

Postpone the Stress Test and Investigate the Tachycardia

Do not proceed with the stress test when the patient presents with a heart rate of 130 bpm—this represents an absolute contraindication to stress testing due to uncontrolled tachycardia. 1, 2

Immediate Management Steps

1. Assess for Contraindications to Stress Testing

The patient's elevated heart rate of 130 bpm falls under the category of uncontrolled arrhythmias, which is an absolute contraindication to cardiac stress testing. 1, 2 The American College of Cardiology explicitly states that uncontrolled arrhythmias preclude stress testing due to safety concerns. 1

2. Determine the Etiology of Tachycardia

Before any stress testing can proceed, you must identify and address the cause of the elevated heart rate:

• Check vital signs comprehensively: Assess blood pressure, temperature, respiratory rate, and oxygen saturation to identify systemic causes 1
• Obtain a 12-lead ECG immediately: Determine if this is sinus tachycardia versus a primary arrhythmia (such as atrial fibrillation, atrial flutter, or supraventricular tachycardia) 1
• Evaluate for reversible causes: Consider fever, infection, dehydration, anemia, hyperthyroidism, anxiety, pain, medication effects (stimulants, bronchodilators), or caffeine intake 1
• Assess for acute coronary syndrome: Given the patient's presenting complaint of shortness of breath, evaluate for ongoing ischemia with ECG changes, cardiac biomarkers (troponin), and clinical symptoms 3

3. Risk Stratification Based on Clinical Presentation

If the patient has high-risk features (ongoing chest pain, hemodynamic instability, ECG changes suggesting ischemia), hospitalization is required rather than outpatient stress testing. 1 This patient requires immediate evaluation for acute coronary syndrome. 3

If the patient appears stable with sinus tachycardia from a reversible cause (anxiety, dehydration), address the underlying issue first. 1

When to Reschedule the Stress Test

Criteria for Safe Stress Testing

The stress test can only proceed when:

• Heart rate is controlled: The patient should have a resting heart rate in a normal range (typically <100 bpm for most protocols) 1
• No contraindications exist: Absence of acute coronary syndrome, decompensated heart failure, severe aortic stenosis, uncontrolled arrhythmias, or severe hypertension 1, 2
• Patient is clinically stable: No ongoing symptoms suggesting cardiac instability 3

Appropriate Timing

For low-risk patients with suspected coronary artery disease who have normal initial cardiac biomarkers and ECG, stress testing should be performed within 72 hours of presentation if they remain pain-free with normal ECGs and cardiac biomarkers. 1 However, this timeline only applies once the patient meets safety criteria.

Common Pitfalls to Avoid

• Never proceed with stress testing in the presence of uncontrolled tachycardia—this significantly increases the risk of adverse events including arrhythmias, myocardial ischemia, or hemodynamic compromise 1, 2
• Do not assume sinus tachycardia without ECG confirmation—primary arrhythmias require different management 1
• Avoid dismissing tachycardia as "just anxiety" without ruling out serious underlying causes, particularly in a patient with shortness of breath 1

Alternative Testing Considerations

If the patient cannot achieve adequate heart rate control or has persistent contraindications to exercise testing, consider pharmacological stress testing once the acute tachycardia is resolved and the patient is stable. 1, 2 Pharmacological stress testing is preferred for patients who cannot exercise adequately. 1, 2