From the Guidelines
The workup for inpatient sinus tachycardia should begin with identifying and treating the underlying cause, as sinus tachycardia is typically a physiologic response rather than a primary arrhythmia. According to the 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care 1, sinus tachycardia is common and usually results from a physiologic stimulus, such as fever, anemia, or hypotension/shock.
Initial Evaluation
The initial evaluation should include:
- Obtaining vital signs, including temperature, blood pressure, and oxygen saturation to assess for fever, hypotension, or hypoxemia
- Ordering basic laboratory tests, including complete blood count to evaluate for anemia or infection, basic metabolic panel to check for electrolyte abnormalities, and thyroid function tests to rule out hyperthyroidism
- Performing an ECG to confirm sinus tachycardia and exclude other arrhythmias
Common Causes to Investigate
Common causes to investigate include:
- Pain
- Anxiety
- Dehydration
- Infection
- Pulmonary embolism
- Myocardial ischemia
- Heart failure
- Medication effects, particularly beta-agonists, anticholinergics, or withdrawal from beta-blockers
- Substance use or withdrawal
Treatment
If the patient is hemodynamically stable, treatment should focus on addressing the underlying cause rather than simply reducing the heart rate. For symptomatic patients without a clear reversible cause, cautious use of beta-blockers like metoprolol 5mg IV or 25-50mg orally twice daily may be considered if there are no contraindications such as decompensated heart failure, bronchospasm, or hypotension 1. Ivabradine 2.5-7.5mg twice daily is an alternative for patients who cannot tolerate beta-blockers. Continuous cardiac monitoring should be maintained until the tachycardia resolves or stabilizes. The 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care also emphasize the importance of searching for and treating reversible causes in patients with sinus tachycardia 1.
From the Research
Diagnostic Approach
The workup for inpatient sinus tachycardia should start by ruling out identifiable causes of sinus tachycardia, such as medications, substances, or medical conditions 2, 3. A basic cardiovascular and autonomic workup is suggested to exclude structural heart disease and guide therapy 2.
Diagnostic Tests
Diagnostic tests may include:
- EKG to differentiate other causes of tachycardia 3
- 24-hour Holter monitor if indicated 3
- Serum thyroid levels 3
- Hemoglobin levels 3
- Toxicology screen 3
- Electrophysiological studies may be considered in certain patients in whom concurrent supraventricular tachycardia is suspected 3
Treatment Options
Treatment options for inpatient sinus tachycardia may include: