What Is Afib with RVR?
Afib with RVR refers to atrial fibrillation with rapid ventricular rate. Usually the heart is like clockwork, the top (collecting) chambers beat then the bottom (main pumping) chambers sense this and also beat, and so on, in a nice regular fashion just like a clock ticking second after second. Usually the heart beats at about 60-80 beats per minute. In Afib the top chamber basically goes crazy often firing off over 400 beats per minute! Luckily the bottom chamber doesn’t allow all those impulses through but it does let every second or third one through. This can give a heart rate of 100-180 beats per minute at rest, still too many beats, known as Afib with RVR, leading to symptoms and problems with heart function. Afib does not necessarily lead to Afib with RVR however, Afib can be rate controlled, sometimes naturally, sometimes using medications and sometimes requiring procedures as discussed below.
What Are The Symptoms of Afib with RVR?
In most people with AFib although symptoms can sometimes be unpleasant it is generally not harmful. The main concern is stroke, but that can be treated with the use of blood thinning medications in people at risk. In Afib with RVR, basically the heart is beating too fast. Of course palpitations (sometimes described as heart flutter) are the most common symptom. Other symptoms of AFib with RVR may include dizziness, lack of energy, exercise intolerance and shortness of breath. If Afib with RVR goes on for too long then this may result in heart failure and of course worsening of existing heart failure. Control of the heart rate in patients with Afib with RVR often causes these symptoms to improve.
What Are The Treatments?
This is known as cardioversion and is used typically either when an immediate result is required or used when the Afib is of relatively recent onset or only intermittent, and so has more chance of staying in normal rhythm. In cardioversion a small shock is given using defibrillation pads. It is done under light anesthesia therefore it doesn’t hurt. The Afib may return however.
Rate Control Drugs
The biggest problem in Afib with RVR is too fast a heart rate. In a rhythm control strategy we use drugs such as beta-blockers to slow the heart rate down. These drugs typically will leave the patient in AF. For many people with AF it turns out that a rate control strategy is preferred as it is considered less risky than the rhythm control drugs used to get rid of the AF while being just as effective. In Afib with RVR rate control drugs can often slow the heart rate down fairly quickly and improve symptoms.
Rhythm Control Drugs
These medications are generally more powerful than the rate control drugs and attempt to convert the Afib back in to a normal rhythm. They are often given after a shock treatment to try and help the heart stay in normal rhythm. These drugs are also commonly used in hospitalized Afib with RVR patients. The problem with these drugs is that they may have side effects and associated risks. Many patients simply cannot tolerate Afib even if the rate is controlled and therefore require rhythm control drugs. They may be safe and effective however if used in selected patients. In cases of Afib with RVR these medications may need to be used if patients cannot tolerate other rate control medications.
Ablation procedures are minimally invasive procedures typically done through the groin. They are typically used in patients that have tried, or cannot tolerate medicines for control of AFib. Ablation is typically not used as an emergency treatment of Afib with RVR, rather it is used for stable patients in AF, or those with intermittent AFib that wish to remain in normal rhythm. In patients that have had persistent Afib for a long time these procedures are not likely to be successful in the long term.
This is typically the last throw of the dice for AF control. In some patients, drugs can either not control the rate in AFib with RVR, or the drugs can simply not be tolerated. In these patients who have no other choice, and in whom it is determined the Afib is causing harmful effects, a procedure called AV node ablation and pacemaker is done. In a relatively minor procedure, a small burn is made to the connection that connects the top and bottom chambers of the heart. A pacemaker is then inserted. This prevents Afib with RVR as although the top chambers continue to fire at a fast rate, the pacemaker now controls the bottom chamber, in a nice regular way. The downside of course is that now although the patient cannot have Afib with RVR, they have a pacemaker.