Areas of Focus
Atrial Fibrillation with Rapid Ventricular Rate (AFib-RVR)
Atrial fibrillation (AFib) is the most common arrhythmia, presenting with an irregular and often rapid heart rate that may increase the risk of stroke, heart failure, and other heart-related complications.
During AFib, the heart’s two upper chambers, or atria, beat chaotically, irregularly, and out of coordination with the two lower chambers, or ventricles. Depending on many factors, the lower chambers, which are the ones that determine your heart rate, may beat at a rapid rate. When there is a rapid heart rate during AFib, it is referred to as “atrial fibrillation with rapid ventricular rate (RVR)”. Symptoms of AFib with RVR often include palpitations, shortness of breath, and weakness.
Frequency and Severity
Episodes of AFib may come and go (paroxysmal AFib), or patients may have AFib that never goes away (permanent or “fixed” AFib), but both almost always require treatment.
Although AFib itself is rarely life-threatening, it is a serious medical condition. It may require emergency medical treatment and if untreated is associated with a significant increase in the risk of stroke and sudden cardiac death.
Prevalence estimates in the U.S. from 2016 indicate that approximately five million patients were suffering from AFib, with that number projected to reach 7-12 million by 2030. Approximately 25% of these patients have paroxysmal AFib, which resolves spontaneously within seven days of symptom onset. Another 25% have persistent AFib, which fails to terminate within seven days of symptom onset and requires treatment to convert back to sinus rhythm; and 50% have permanent AFib, in which the AFib never comes back to normal despite treatment, or a joint decision is reached to leave the patient in AFib and focus on rate control and symptom management. Approximately 40% of all patients with AFib experience at least one episode per year with RVR requiring treatment.
Current AFib management consumes significant healthcare resources in the U.S. In a retrospective claims analysis from commercial and Medicare databases, patients with AFib were more likely to be hospitalized and die during admission compared to their non-AFib counterparts. Additionally, the total incremental cost of AFib in the inpatient setting, outpatient primary care setting, and outpatient pharmacy was over $8,705 per patient. The American Heart Association recently published a report summarizing the current and projected cost burden of cardiovascular diseases in the U.S. This report suggests AFib resulted in $24 billion in direct medical costs in 2015 (~8% of all cardiovascular diseases) and another $7 billion in indirect costs (i.e., $31 billion in total costs). Additionally, the forecasted growth in AFib prevalence is anticipated to result in total healthcare expenditures (direct and indirect) of $66 billion in the U.S. by 2035.
Standard of Care
There are two pharmacological approaches to managing AFib: allow the AFib to continue but control the rapid heart rate; and rhythm control to stop the AFib and restore and maintain a regular rhythm. Rate control typically consists of medications such as beta blockers or calcium channel blockers, while rhythm control entails anti-arrhythmic drug therapy with medications such as flecainide or amiodarone. Unfortunately, “breakthrough” episodes—where the goal is not achieved—are common regardless of which approach is used. When rate or rhythm control drugs are used to manage episodes after they have started, they do not provide immediate ventricular rate control due to their delayed 30- to 90-minute onset of action. Patients living with breakthrough episodes often require visits to the emergency department for urgent administration of IV calcium channel blockers or beta blockers to acutely slow their heart rate.