Atrial fibrillation and its management

Atrial fibrillation (AF) is uncoordinated atrial electrical activation with loss of effective atrial mechanical function — the commonest sustained arrhythmia in older people.

Prevalence rises from <0.5% at age 40–50 to 5–15% at age 80. Men are affected earlier, but in old age there are more women with AF than men. Lifetime risk at age 55 is about 35%.

Stroke risk rises steeply with age — from about 1.5% per year at 50–59 years to 23.5% at 80–89 years. Up to 30% of all ischaemic strokes are attributable to AF, and AF-related strokes are larger and more disabling.

AF also causes heart failure (in 20–30%), a 60% relative increase in risk of significant cognitive decline, impaired quality of life in over 60%, and up to a 3.5-fold increase in all-cause mortality.

Ageing changes: atrial amyloid deposition, loss of sinoatrial pacemaker myocytes, and collagen/fibrous replacement of conducting tissue and myocardium.

Risk factors: hypertension (each 10 mmHg rise in systolic BP raises AF risk by 11–16%), heart failure, valvular disease (especially mitral), ischaemic heart disease, diabetes, obesity, obstructive sleep apnoea, alcohol, hyperthyroidism, chronic kidney disease and systemic inflammation.

First detected → paroxysmal (self-terminating, usually within 48 hours) → persistent (>7 days or requiring intervention) → long-standing persistent (≥1 year with a rhythm-control strategy still intended) → permanent (a statement of intent — no further attempt at sinus rhythm). Permanent AF is re-designated long-standing persistent if the plan changes.

May be asymptomatic (found on routine examination or device interrogation) or present with palpitations, dyspnoea, fatigue, angina, syncope, falls, heart failure, stroke or delirium.

ECG shows absent P waves with an irregularly irregular ventricular response. A regular rhythm with a fibrillatory baseline in a patient with AF implies complete AV block with an escape rhythm — a classic examination point. Slow ventricular rates are common in the elderly because of AV nodal disease.

Ambulatory monitoring is matched to symptom frequency: 24-hour Holter for daily symptoms; 48–72 hours or patch for several times weekly; 7-day for weekly; event recorder for monthly; implantable loop recorder for less frequent symptoms. Pacemaker-detected atrial high-rate episodes >200 bpm should prompt further investigation.

Score every patient with CHA₂DS₂-VASc: Congestive heart failure 1, Hypertension 1, Age ≥75 2, Diabetes 1, Stroke/TIA/thromboembolism 2, Vascular disease 1, Age 65–74 1, Sex category (female) 1 — maximum 9.

Anticoagulate all men with score ≥2 and women with score ≥3 (Class I); consider at 1 (men) and 2 (women). Every patient over 75 with AF therefore qualifies unless there is a major contraindication.

DOACs are preferred over warfarin in non-valvular AF (Class I). Warfarin (INR 2–3) remains mandatory for moderate-to-severe mitral stenosis and mechanical prosthetic valves, as no DOAC trial included these patients.

Warfarin reduces stroke by about 64%; aspirin reduces it by only about 22% with substantial bleeding risk, so antiplatelet therapy is no longer recommended for stroke prevention in AF. BAFTA showed warfarin superior to aspirin in community elderly.

Use HAS-BLED to identify and correct modifiable bleeding risks and to flag patients needing closer review — not to withhold anticoagulation. Essentials lists among its "Don'ts": do not withhold anticoagulation for atrial fibrillation because of fall risk.

For patients with a genuine contraindication (recurrent intracranial haemorrhage, recurrent embolic stroke despite adequate anticoagulation), consider percutaneous left atrial appendage occlusion (WATCHMAN) — procedural complication risk about 4%; surgical LAA exclusion may be added during cardiac surgery.

Beta blockers are the most effective agents for controlling rate on exertion and are first-line with hypertension, ischaemic heart disease or stable LV dysfunction. Non-dihydropyridine calcium channel blockers (verapamil, diltiazem) are alternatives when airways disease is present but must be avoided in reduced LV systolic function and pulmonary oedema. Digoxin — use 0.125 mg/day in the elderly, monitor levels and renal function; it controls rate at rest but not on exertion. Amiodarone can be used for rapid control but long-term use is limited by thyroid, pulmonary, hepatic, ocular and skin toxicity. Lenient rate control (resting rate <110 bpm) was non-inferior to strict control in RACE II.

Classical trials (AFFIRM, RACE, STAF, HOT CAFE, PIAF) showed no survival advantage for rhythm over rate control, so rhythm control was traditionally reserved for symptom relief. Options are cardioversion (electrical or pharmacological), antiarrhythmic drugs (amiodarone, sotalol, flecainide only if no structural disease) and catheter ablation. Ablation is effective in symptomatic paroxysmal AF and is not less successful in older patients, though success is higher with shorter AF duration; risks and benefits must be weighed individually.

The ABC pathway (Avoid stroke — Better symptom control — Cardiovascular and comorbidity optimisation) improves outcomes in anticoagulated AF patients. Additional geriatric considerations: cognitive impairment reduces adherence (missed DOAC doses cause periods of under-anticoagulation because of the short half-life); dementia is not in itself a contraindication, especially in multi-infarct dementia where anticoagulation may halt stepwise decline; and warfarin interacts with many drugs and with vitamin K-rich foods.