From the Guidelines
The next step should be to evaluate for underlying causes of physiological sinus tachycardia, as outlined in the 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia 1. Given the patient's normal laboratory results, including normal TSH, lactic acid, WBC count, CXR, and procalcitonin levels, it is essential to consider other potential causes of persistent tachycardia. Some possible causes to investigate include:
- Anemia, which can be checked with a complete blood count (CBC)
- Dehydration and electrolyte imbalances
- Anxiety or panic disorder
- Medication side effects, particularly from stimulants or beta-agonists, such as albuterol, salmeterol, amphetamines, or cocaine, as mentioned in the 2015 ACC/AHA/HRS guideline 1
- Other substances, including caffeine, that may be contributing to the tachycardia If these tests are inconclusive, further cardiac evaluation may be necessary, including:
- Echocardiogram to assess heart structure and function
- 24-hour Holter monitor to detect any underlying arrhythmias It is crucial to note that the patient's presentation, including age and sex, may be consistent with inappropriate sinus tachycardia, as described in the 2003 ACC/AHA/ESC guidelines for the management of patients with supraventricular arrhythmias 1. However, the most recent and highest quality study, the 2015 ACC/AHA/HRS guideline 1, should take precedence in guiding the next steps in management.
From the Research
Patient Presentation
The patient is a 40-year-old female presenting with persistent tachycardia, but has a normal Electrocardiogram (EKG) showing sinus tachycardia. Her laboratory results show normal lactic acid levels, normal Thyroid-Stimulating Hormone (TSH) levels, normal White Blood Cell (WBC) count, normal Chest X-Ray (CXR), and normal procalcitonin levels.
Potential Next Steps
- Consider the use of beta blockers to control heart rate, as they have been shown to be effective in reducing morbidity and mortality in patients with heart failure 2, 3, 4, 5.
- Initiate beta blocker therapy at a low dose and slowly titrate upward as tolerated, with a goal of achieving the target dose used in clinical trials 2, 5.
- Monitor the patient's heart rate and adjust the beta blocker dose accordingly, aiming for a heart rate of less than 100 beats per minute 3, 6.
- Consider the patient's overall clinical stability and adjust the treatment plan accordingly, taking into account any potential contraindications or adverse events 5, 6.
Key Considerations
- The patient's normal laboratory results and EKG suggest that there may not be an underlying cardiac condition that needs to be addressed, but the persistent tachycardia still needs to be managed.
- The use of beta blockers has been shown to be effective in reducing heart rate and improving outcomes in patients with heart failure, but may also be beneficial in patients with persistent tachycardia without heart failure 4, 6.
- The patient's response to beta blocker therapy should be closely monitored, and the dose adjusted as needed to achieve optimal heart rate control while minimizing adverse events 5, 6.