Management of Rapid Ventricular Response (RVR) in Atrial Arrhythmias
Getting out of RVR is not considered a conversion to sinus rhythm; it is only rate control, while conversion refers specifically to restoration of normal sinus rhythm.
Understanding RVR vs. Conversion
Rate control and rhythm control are two distinct management strategies for atrial arrhythmias:
- Rate Control: Achieving a ventricular rate <100-110 bpm while the underlying atrial arrhythmia persists
- Rhythm Control/Conversion: Restoration of normal sinus rhythm from an arrhythmia
Key Distinctions
- When a patient with atrial fibrillation (AF) or atrial flutter has their heart rate reduced from >120 bpm to <100 bpm but remains in the arrhythmia, this is considered successful rate control, not conversion 1
- True conversion requires the termination of the arrhythmia and restoration of normal sinus rhythm 1
- The American Heart Association guidelines clearly distinguish between rate control medications (beta blockers, calcium channel blockers) and rhythm control interventions (cardioversion, antiarrhythmic drugs) 2
Clinical Management Approaches
Rate Control (Managing RVR)
Rate control is achieved through:
AV nodal blocking agents:
- IV beta blockers (metoprolol)
- IV calcium channel blockers (diltiazem, verapamil)
- IV digoxin (slower onset, less effective)
Goals of rate control:
- Heart rate <100-110 bpm at rest
- Relief of symptoms related to rapid rate
- Prevention of tachycardia-induced cardiomyopathy
Rhythm Control (Conversion)
Conversion to sinus rhythm is achieved through:
Electrical cardioversion: Synchronized DC shock
- Immediate direct-current cardioversion is recommended for patients with AF with ongoing myocardial ischemia, symptomatic hypotension, angina, or heart failure 1
Pharmacologic cardioversion:
- Class III antiarrhythmics (amiodarone, ibutilide)
- Class Ic antiarrhythmics (flecainide, propafenone)
- Note: Digoxin and sotalol may be harmful when used for pharmacological cardioversion and are not recommended 1
Clinical Implications
Importance of Distinguishing Between Rate and Rhythm Control
- Treatment selection depends on whether the goal is rate control or conversion
- Different medications are used for each approach
- Documentation should clearly specify whether rate control or conversion was achieved
Outcomes and Prognosis
- Rate control alone may be sufficient for many patients, especially those with permanent AF 3
- Prehospital ALS interventions for AF-RVR are associated with more frequent rate control, more frequent discharge to home from the ED, and lower mortality 4
- Patients with RVR who are not treated may have longer ICU stays and worse outcomes 5
Special Considerations
- In patients with heart failure, beta blockers may be preferred over calcium channel blockers for rate control, as diltiazem has been associated with worsening heart failure symptoms 6
- Serum calcium levels may affect the success of diltiazem treatment, with normal ionized calcium levels associated with better response rates 7
- Patients with AF-RVR and acute stroke may develop a bimodal pattern of RVR, with peaks within 12 hours and 24-48 hours after stroke onset 5
Remember that while rate control is an important initial step in managing symptomatic atrial arrhythmias with RVR, it does not constitute conversion to sinus rhythm, which requires restoration of normal atrial and ventricular activation patterns.