Atrial Fibrillation in Older Adults: What Marion County Patients Need to Know

Atrial fibrillation (AFib) is the most common sustained heart arrhythmia in the world, and it is disproportionately concentrated in communities like ours. In Marion County, where nearly 30% of residents are 65 or older, the prevalence of AFib is estimated at 9% of the senior population approximately 11,000 people in our county living with a condition that has been directly linked to a 5-fold increased risk of stroke and a 2-fold increased risk of heart failure.

The problem is not just prevalence. It is underdiagnosis and undertreated stroke risk. Studies consistently show that a significant fraction of AFib patients, particularly elderly patients and those in lower-income communities are never prescribed anticoagulation therapy despite clear guideline recommendations. In a county with a 14.3% poverty rate and 14.2% of residents under 65 uninsured, that gap has direct life-or-death consequences.

This article explains what AFib is, how it is diagnosed, why it must be actively managed, and what the current treatment landscape looks like for patients in Ocala and the surrounding area.

WHAT IS ATRIAL FIBRILLATION?

The heart has four chambers. The two upper chambers, the atria, are responsible for pumping blood into the lower chambers (ventricles), which then push blood to the lungs and body. In a normal heart, a single electrical signal originates from the sinus node in the right atrium and coordinates contraction in an orderly sequence.

In AFib, the atria receive chaotic, disorganized electrical signals from multiple sites simultaneously. Instead of contracting in a coordinated beat, the atria quiver fibrillates at rates of 300-600 electrical impulses per minute. The AV node, which gates conduction to the ventricles, filters most of these, but allows through enough signals to cause an irregularly irregular ventricular rate, typically between 100 and 160 beats per minute if untreated.

The consequence of this quivering atrium is twofold: the atrium does not fully empty, allowing blood to pool and clot, particularly in a small pouch of the left atrium called the left atrial appendage (LAA). When those clots embolize, they go to the brain, causing stroke. Second, the persistently rapid and irregular ventricular rate weakens the heart muscle over time, causing a reversible form of heart failure called tachycardia-mediated cardiomyopathy.

TYPES OF AFIB

• Paroxysmal AFib — Episodes that start and stop spontaneously, lasting minutes to less than 7 days. Self-terminating. Stroke risk is the same as persistent AFib.
• Persistent AFib — Episodes lasting more than 7 days, or terminated only by cardioversion. Requires anticoagulation.
• Long-Standing Persistent AFib — Continuous AFib for more than 12 months.·        
• Permanent AFib — Patient and physician have agreed not to pursue rhythm control; rate control is the management strategy.

SYMPTOMS — AND WHY MANY PATIENTS HAVE NONE

AFib symptoms vary widely. Some patients experience dramatic palpitations, shortness of breath, and fatigue. Others feel nothing at all and their AFib is found incidentally on an EKG, a Holter monitor, or a smartwatch rhythm strip.

The clinical implication of silent AFib is critical: stroke risk does not require symptom awareness. A patient who never feels their AFib can still have a clot embolize and cause a devastating stroke. Stroke prevention decisions are made based on risk score, not on symptom burden.

STROKE RISK: THE CHA2DS2-VASC SCORE

The strongest evidence-based tool for quantifying stroke risk in AFib patients is the CHA2DS2-VASc score, which assigns points for: Congestive heart failure (1), Hypertension (1), Age 75+ (2), Diabetes (1), prior Stroke or TIA (2), Vascular disease history (1), Age 65-74 (1), Sex, female (1).

Current ACC/AHA guidelines recommend oral anticoagulation for men with a score of 2 or higher, and women with a score of 3 or higher. In a Marion County patient population with high rates of hypertension, diabetes, and age over 75, the majority of AFib patients qualify for anticoagulation. The first-line agents are direct oral anticoagulants (DOACs), apixaban (Eliquis), rivaroxaban (Xarelto), dabigatran (Pradaxa), or edoxaban (Savaysa) which do not require INR monitoring and have demonstrated superior efficacy and safety profiles compared to warfarin in major clinical trials.

TREATMENT: RATE CONTROL VS. RHYTHM CONTROL

AFib management has two parallel tracks: controlling the ventricular rate (rate control) and attempting to restore and maintain normal sinus rhythm (rhythm control). The 2023 ACC/AHA AFib guidelines represent a significant shift toward earlier rhythm control, particularly for newly diagnosed AFib, younger patients, and those with significant symptoms or heart failure.

Rate control uses medications, beta-blockers, non-dihydropyridine calcium channel blockers, or digoxin to keep the ventricular rate below 80-100 bpm at rest. It is appropriate for older, less symptomatic patients with long-standing AFib and no reversible causes.

Rhythm control uses antiarrhythmic medications (flecainide, amiodarone, sotalol, propafenone, dofetilide) or catheter ablation to restore and maintain sinus rhythm. Catheter ablation, an interventional electrophysiology procedure has demonstrated superiority over antiarrhythmic drugs in multiple clinical trials for maintaining sinus rhythm and improving quality of life, and is increasingly the preferred strategy for symptomatic patients who fail or are intolerant of antiarrhythmic therapy.

WHAT TO DO IF YOU THINK YOU HAVE AFIB

If you experience palpitations, irregular heartbeat, unexplained fatigue, or if a smartwatch or fitness device has flagged an irregular rhythm, do not ignore it. An in-office EKG takes minutes and can confirm or exclude AFib in real time. If your AFib is paroxysmal and an EKG does not capture it, a 24-48 hour Holter monitor or a prolonged event monitor can be used.

Do not attempt to self-manage a suspected arrhythmia. Do not stop anticoagulation without cardiologist guidance. Do not assume that because an episode resolved it no longer matters.

If you are in Ocala or Marion County and suspect AFib or if you have been told you have it but are not under the care of a cardiologist, call Florida Heart & Vascular Institute at (352) 572-7730. We prioritize new AFib referrals.

BOTTOM LINE

• AFib affects ~11,000 Marion County residents over 65.
• Most AFib patients qualify for stroke prevention with anticoagulation and many are not on it.
• Early rhythm control is increasingly the preferred strategy for newly diagnosed AFib.
• Catheter ablation is a viable option for appropriate candidates who fail antiarrhythmic therapy.
• troke risk is independent of whether you feel your AFib episodes.

If you have AFib, palpitations, or an irregular heartbeat, do not wait. Book an Appointment or Call (352) 572-7730.