Let me begin with explaining what Atrial Fibrillation (AF) is. In this condition, the upper chamber of the heart experiences irregular impulses, resulting in rapid and chaotic heart beats. The may case shortness of breath and intolerance to exercise. Its serious long-term consequences include; stroke; serious bleeding; cardiac arrest, and even death.
Traditionally treatment used to be started with medications. But, this approach had a limited effect. Since 1990s, hospitals had been performing a procedure, which does not require elaborate surgery or drugs. It focuses on the causes of atrial fibrillation. This procedure is called catheter ablation. In this procedure, a long, thin catheter is inserted in one of the veins of the leg. It is then used to guide the tiny electrodes all the up to the patient’s heart. Once there, these electrodes are used to do the ablation. So, the basic line of treatment has been, first beginning with medications, and if require do the ablation. However, the drug is limited by a long half-life and potentially severe extra-cardiac side effects.
However, the researchers believe that the future lies in other treatment modalities. In one such example, Mayo Clinic is researching a variation of catheter ablation, called the CABANA. Here they will try to determine of doing ablation right away, without having to try medications first, should be the first line of treatment. They believe that this will save lives that are put at risk by trying medications first.
At the same time, researchers at Mayo Clinic are also studying another approach. Here they are targeting the formation of blot clots. These clots are formed due to AF, and they have the potential to precipitate a stroke. And strokes can potentially be fatal. Traditionally, medications have been used to make blood thinners, and therefore used to prevent blood clots. But, this also makes excessive bleeding their major side effect. However, in this approach, a catheter is inserted to the patient’s leg and guided all the way up to the heart. It is then used to give suture into patient’s heart valves. It is at these valves of the left atrium part of the heart, where clots are most likely to be formed. Therefore, by isolating that area, the procedure will prevent clot formations.
Very recently, the FDA has granted approval for marketing of the Thermocool Smarttouch ablation catheter in patients with drug-resistant paroxysmal atrial fibrillation (AF), which is particularly a serious condition. According to the manufacturers, it is first of a kind of catheter in the United States. It allows for the measurement of heart’s contact force during catheter ablation procedure. In simple terms, it means that it will allow the surgeon to apply precise amount of pressure on the heart valve during the ablation procedure
In another similar study, researchers expressed confidence in Focal Impulse and Rotor Modulation (FIRM) guided ablation in patients with AF. It is a real-time diagnostic mapping system, which makes the treatment more patient specifice, rather than depending upon generalized features of the heart. Here it helps identify abnormal electrical impulses in the heart that cause the AF. The approach helps provide stability and focus the treatment where required.
Among the medications that are being used today, those which are used to control the rate of onset of AF, include, Diltiazem, Metoprolol, Digoxin, and Amiodarone. Dronedarone is another drug that has been used in treating AF, and as an amiodarone analogue, the agent is able to keep the pharmacokinetic complexity and toxicity to a minimum. As for anticoagulants, which are blood thinning agents, those who are newly diagnosed should be started on intravenous (IV) heparin or low-molecular-weight heparin (LMWH). In inpatient settings, concomitant use of warfarin is recommended. Also, oral direct thrombin inhibitors can be considered as an alternative to Warfarin in those with higher risk.
Alternate to Warfarin, which have recently been approved by FDA, include; Dabigatran, Rivaroxaban, and Apixaban. Further, the drugs used to control the rate, include; oral β-blockers, Calcium Channel Blockers (CCBs), Digoxin, and Amiodarone. Finally, the drugs used to control the rhythm include, flecainide, propafenone, Dofetilide, Amiodarone, Dronedarone, and Sotalol.
References
Baldwin, K. (2012, 05 10). Focal Impulse and Rotor Modulation (FIRM) mapping effectively targets atrial fibrillation (AF) sources and improves ablation therapy outcomes. Retrieved from Heart Rhythm Society: http://tinyurl.com/lkx2p4k
Dobrev, D., & Nattel, S. (2010). New antiarrhythmic drugs for treatment of atrial fibrillation. Lancet, 1212-1223.
Husten, L. (2014, 02 25). FDA Approves New Catheter For Treatment Of Atrial Fibrillation. Retrieved from Forbes: http://www.forbes.com/sites/larryhusten/2014/02/25/fda-approves-new-catheter-for-treatment-of-atrial-fibrillation/
Kalus, J. (2009). Pharmacologic Management of Atrial Fibrillation: Established and Emerging Options. Journal of Managed Care Pharmacy, 10 - 18.
Mayo Clinic. (2010, Nov). NEW TREATMENT FOR ATRIAL FIBRILLATION. Retrieved from Discovery's Edge: Mayo Clinic's Online Research Magazine: http://www.mayo.edu/research/discoverys-edge/new-treatment-atrial-fibrillation
Rosenthal, L. (2014, 02 27). Atrial Fibrillation. Retrieved from Medscape: http://emedicine.medscape.com/article/151066-overview
