From the Guidelines
Reflex tachycardia is not explicitly defined in the provided guideline evidence, but based on the context of orthostatic tachycardia, it can be inferred as a sustained increase in heart rate in response to a physiological stimulus, such as a drop in blood pressure.
Definition and Mechanism
Reflex tachycardia is a compensatory increase in heart rate that occurs when the body attempts to maintain adequate blood pressure and cardiac output. This physiological response typically happens when blood pressure drops, such as after taking certain blood pressure medications or during significant blood loss. The body detects the decrease in blood pressure through baroreceptors in the carotid sinus and aortic arch, triggering the sympathetic nervous system to increase heart rate as a compensatory mechanism 1.
Clinical Context
In the context of the provided guideline evidence, orthostatic tachycardia is defined as a sustained increase in heart rate of ≥30 bpm within 10 min of moving from a recumbent to a quiet standing position (or ≥40 bpm in individuals 12–19 y of age) 1. While reflex tachycardia is not explicitly defined, it can be inferred as a similar physiological response to a drop in blood pressure.
Key Points
- Reflex tachycardia is a compensatory increase in heart rate in response to a drop in blood pressure.
- The underlying mechanism involves activation of the sympathetic nervous system and release of catecholamines.
- Reflex tachycardia can be problematic in patients with heart conditions, as the increased heart rate may worsen cardiac symptoms or increase myocardial oxygen demand.
- The provided guideline evidence does not explicitly define reflex tachycardia, but it provides context on orthostatic tachycardia and other related conditions 1.
From the Research
Definition of Reflex Tachycardia
- Reflex tachycardia refers to a rapid heart rate that occurs in response to a specific stimulus, such as hypovolemia or other physiological changes 2, 3.
- It is characterized by an increase in heart rate, often accompanied by other symptoms such as hypotension, dizziness, or anxiety 2, 4, 3.
Causes of Reflex Tachycardia
- Hypovolemia, or decreased blood volume, can trigger reflex tachycardia as the body attempts to compensate for the loss of fluid 2, 3.
- Other potential causes include orthostatic intolerance, anxiety, and flushing 3.
- Reflex tachycardia can also occur in response to certain medications or medical conditions, such as anemia or cardiac arrhythmias 4, 5.
Diagnosis and Treatment
- Diagnosis of reflex tachycardia typically involves a physical examination, medical history, and analysis of electrocardiogram (ECG) results 4.
- Treatment may involve addressing the underlying cause of the tachycardia, such as correcting hypovolemia or treating an underlying medical condition 2, 4, 5.
- In some cases, medications such as atropine, beta-blockers, or calcium channel blockers may be used to slow the heart rate or regulate cardiac function 4, 5.