A 70-year-old woman diagnosed with atrial fibrillation in 2016, has just undergone cardioversion at the LUMC, a medical procedure by which a cardiac arrhythmia is converted to a sinus rhythm. The patient’s medical history consists of a caesarean section at the age of 32 and angina pectoris due to coronary artery disease, which was diagnosed at the age of 67. Prior to the cardioversion, the patient’s blood pressure was measured at 150/90 mmHg and the ECG showed multiple P-tops, indicating atrial fibrillation. After the cardioversion, the ECG showed a normal sinus rhythm and the blood pressure lowered to 125/80. To prevent another episode of atrial fibrillation, the question arises which type of therapy the patient should receive; rate- or rhythm control. This patient case is exemplary for an ongoing discussion among specialists which is whether rate control or rhythm control is better in the treatment of atrial fibrillation.
Atrial fibrillation is the most common sustained cardiac arrhythmia, with a prevalence of 1% in the general population. The prevalence increases to 7-10% among men and women above the age of 80.[1] Patients with atrial fibrillation not only have twice the risk of death compared to patients without AF, they are also are at risk for serious consequences. Among which thromboembolism, stroke and myocardial ischemia and infarction.[1] This makes an early diagnoses even more important. Symptoms may include palpitations, dyspnoea, angina pectoris, light-headedness, impaired exercise tolerance and chronic fatigue. [1] The typical patient with atrial fibrillation is older than 65 and has mild symptoms. [3]
Atrial fibrillation is, as mentioned before, a cardiac arrhythmia. This means that the normal sequence of electrical impulses has changed, being either too fast, too slow, or irregular. In a good functioning heart the so-called sinus node gives the electric activity needed for the activation of the atria. In patients with atrial fibrillation the activation of the heart occurs at multiple locations. This results in an irregular and often rapid heart rate. [4,5]
There are two main strategies for the management of atrial fibrillation: rate- and rhythm control. Rate control focusses on the heart rate being lower than 80 beats per minute in rest. The therapy primarily consists of rate-controlling drugs.[3] Rhythm control focuses on restoring and maintaining a normal sinus rhythm. This can be accomplished through medication, cardioversion, ablation and pacemaker implantation. [3,6] Until this day, the choice between these therapies remains an ongoing discussion among specialists. We argue that in the treatment of atrial fibrillation, rate control should be preferred over rhythm control for the elderly, which we define as patients above the age of 65.
The main argument in favour of rate control is the difference in effectivity and survival between rate- and rhythm control among patients who are at least 65 years of age or have other risk factors for stroke or death. Whilst several studies hypothesize that rhythm control has a higher effectiveness than rate control,[3,6,7] the results consistently show that there is no significant difference between both therapies. Furthermore, rate control has a slight survival advantage over rhythm control, looking at an overall survival rate of 79% in the rate control group in comparison with 76% in the rhythm control group during a five-year follow-up period. [3,6]
In addition to the hypothesis that rhythm control has a higher effectiveness than rate control, opponents argue that when efficacious rhythm control shows greater effects, such as fewer symptoms, a lower risk of stroke, better exercise tolerance, eventual discontinuation of anticoagulation, better quality of life and better survival, if sinus rhythm can be sustained. Moreover, rhythm control tends to be more effective among younger patients. [3]
What these opponents of rate control do not mention is that rhythm control often is not effective. One of the largest studies on the topic of rate al rhythm control, AFFIRM[3], has shown a significantly higher crossover rate from rhythm to rate control compared with rate to rhythm control. The researchers believe that this crossover is caused by the inability of rhythm control to maintain sinus rhythm and due to its adverse events. Furthermore, the statements made by the opponents related to the greater effects of rhythm control have not been proved so far.[1,3]
For completeness, it should be mentioned that a sub-analysis of the AFFIRM-study showed that rate control is significantly better for patients above the age of 65 and that there is a trend of rhythm control being better for patients below the age of 65. [3]
Another reason why rate control seems beneficial over rhythm control regards adverse events and complications of both therapies. Multiple studies have shown an increased risk of adverse events amid rhythm control medication due to drug toxicity. The most common adverse events are pulmonary and gastro-intestinal events and bradycardia. [1,2,6,8] Moreover, a systematic review concluded that rhythm control results in significantly more cardiovascular hospitalizations. They found no differences between both therapies regarding the occurrence of stroke and bleeding events.[2] However, another meta-analysis found that rate control reduces the risk of stroke significantly.[6]
Opponents of rate control noticed the higher prevalence of adverse events and complications among rhythm control medication. They conducted studies looking at the effect of long- versus short-term rhythm control. They hypothesized that the short-term therapy gives the same effect as long-term therapy, with fewer side effects.[7] So far, the effect of short-term rhythm control remains unclear, thus further research is recommended.
Another important argument in support of our thesis is related to the economic burden of both therapies. This burden can be measured by computing the costs related to medication and medical procedures (e.g. cardioversions and ablation), hospitalizations, complications and costs related to quality of life-issues and the functional status of patients. [1] A meta-analyses that looked at these factors shows that rate control costs $5.077 dollars less per person per year than rhythm control. The authors of the article argue that this is due to rate control medication being less expensive than rhythm control medication and because there were fewer hospitalizations, cardioversions and emergency department visits in the rate control group. [8]
Over the stretch of this essay, we argued that rate control should be preferred over rhythm control for the elderly. Multiple studies have shown that there is no significant advantage for either rate- or rhythm control. Nevertheless, there often is a trend indicating better survival in the rate control group. In addition, rhythm control might improve the prognosis if it succeeds in pursuing sinus rhythm. However, as mentioned before, this goal is often not reached and must be weighed against potential adverse events and a higher economic burden.
In making the decision between rate- and rhythm control, it is important to keep your patient in mind. It has been shown that rate control is more effective in patients above the age of 65 with coronary artery disease and mild symptoms.[3] Rhythm control tends to be more effective among patients below the age of 65 and patients with more severe symptoms. [3,5] Since the patient from our patient case is older than 65 and has coronary artery disease, we believe that in her case rate control will have the highest chance of preventing death and recurrence of atrial fibrillation. We recommend that she will receive 100 mg metoprolol a day, which is a beta-blocker, as prophylaxis for recurrent atrial fibrillation.
To conclude, we would like to propose a recommendation for further research. A limitation of many studies is that they look at the typical patient with atrial fibrillation; someone over the age of 65 with mild symptoms.[4,5] It appears as if the effectiveness of rate- and rhythm control is different per patient group, especially regarding age. Although no study has been executed to discover such a relationship, many articles provide a base for this assumption.[2,3,7,8] It is for this reason that we expect to clarify the ongoing discussion of rate versus rhythm control by dividing the patient population according to age; rate control for the elderly.