Definition of High Pulse Rate (Tachycardia)
A high pulse rate (tachycardia) is defined as a heart rate greater than 100 beats per minute in adults. 1
Clinical Thresholds
Basic Definition
- Tachycardia begins at >100 beats per minute for all adults, regardless of the underlying rhythm (sinus tachycardia, supraventricular tachycardia, or ventricular tachycardia). 1, 2
Critical Action Threshold
- Heart rates ≥150 beats per minute typically indicate a true tachyarrhythmia requiring immediate evaluation and workup, as this threshold suggests a primary arrhythmia rather than a physiologic response. 1, 3
- Below 150 bpm, tachycardia is more likely secondary to an underlying physiologic stress such as fever, dehydration, pain, or anxiety—unless ventricular dysfunction is present. 1, 3
Age-Related Considerations
Upper Limits of Sinus Tachycardia
- The maximum expected sinus tachycardia is age-related and calculated as approximately 220 beats per minute minus the patient's age in years. 1
- This formula helps determine whether an apparent sinus tachycardia falls within the expected physiologic range for a patient's age. 1
Pediatric and Infant Norms
- Normal resting pulse rates are significantly higher in children: mean of 129 bpm in infants under 1 year, decreasing to 96 bpm by age 5, and further declining to 78 bpm in early adolescence. 4
- Adult resting pulse plateaus at approximately 72 bpm. 4
When to Worry: Immediate Evaluation Triggers
Regardless of Rate
Immediate workup is required when tachycardia is accompanied by any of the following signs of hemodynamic instability: 3
- Acute altered mental status
- Ischemic chest discomfort or pain
- Acute heart failure
- Hypotension or signs of shock
Special Populations
- Patients with known ventricular dysfunction require workup at heart rates <150 bpm, as they are more likely to develop rate-related instability. 3
Important Clinical Pitfalls
Do Not Treat Compensatory Tachycardia
- When tachycardia accompanies hypotension, the elevated heart rate is typically compensatory to maintain cardiac output—treating the tachycardia directly with rate-controlling medications can precipitate cardiovascular collapse. 5
- In compensatory tachycardias where cardiac function is poor and stroke volume is limited, "normalizing" the heart rate can be detrimental. 1
Context Matters
- Sinus tachycardia >100 bpm usually results from a physiologic stimulus (fever, anemia, hypotension/shock) and requires no specific drug treatment—therapy should target the underlying cause. 1
- The key clinical question is whether the tachycardia is the primary cause of symptoms or secondary to an underlying condition causing both the symptoms and the elevated heart rate. 1