Asymptomatic or “Silent” Atrial Fibrillation

Abstract

for the Azimilide Supraventricular Arrhythmia Program (ASAP) Investigators Background-Asymptomatic, or "silent" atrial fibrillation could increase the risk of stroke. Little is known about the frequency of asymptomatic atrial fibrillation in patients who also have symptomatic atrial fibrillation; similarly, little is known about the effect of antiarrhythmic drug therapy on asymptomatic atrial fibrillation. Methods and Results-Patients in sinus rhythm with a history of symptomatic atrial fibrillation or atrial flutter received placebo or azimilide (35 to 125 mg) once daily for 6 or 9 months in 4 similar double-blind trials. The end point was the first recurrence of a symptomatic ECG-documented supraventricular arrhythmia. Routine transtelephonic electrocardiograms, in the absence of symptoms, were recorded for 30 seconds every 2 weeks until patients completed follow-up or documented a symptomatic supraventricular arrhythmia. Of the 1380 patients, 489 received placebo. Among these patients receiving placebo, 303 transmitted at least one routine ECG while asymptomatic. Asymptomatic atrial fibrillation was recorded in 50 (17%) within 6 months and before recurrence of symptomatic supraventricular arrhythmia. In the 3 trials evaluating azimilide in therapeutic doses (100 and 125 mg), asymptomatic atrial fibrillation occurred in 49 of 382 (13%) receiving azimilide and 43 of 233 (18%) receiving placebo. Although drug effect on time to first asymptomatic event was not statistically significant (hazard ratio, 0.70; Pϭ0.09), there was a 40% reduction in asymptomatic atrial fibrillation on azimilide compared with placebo (Pϭ0.03) when repeated observations were considered. Conclusions-Asymptomatic atrial fibrillation is common in untreated patients with a history of symptomatic atrial fibrillation (and is likely underestimated by this analysis). Azimilide may reduce the occurrence of this silent arrhythmia.

ACC/AHA/ESC 2006 Guidelines for the Management of Patients With Atrial Fibrillation

“…Ambulatory ECG recordings and devicebased monitoring have revealed that an individual may experience periods of both symptomatic and asymptomatic AF. [287][288][289][290] Patients in whom the arrhythmia has become permanent often notice that palpitation decreases with time and may become asymptomatic. This is particularly common among the elderly.…”

Progressive Nature of Paroxysmal Atrial Fibrillation-Observations From a 14-Year Follow-up Study-

“…[13][14][15][16][17][18] In the short-term, PAF could be suppressed by antiarrhythmic drugs, but might not be prevented completely 12 and this incompleteness of the conventional antiarrhythmic therapy might promote remodeling and make the AF more refractory. These possibilities are supported, in part, by the existence of asymptomatic PAF, 19,20 which is more common than expected, 19 although it partially alleviated by the use of antiarrhythmic drugs. 12,19 Previous investigators have shown ischemic heart disease and valvular disease as independent risk factors for AF, [21][22][23] and aging and increased left atrial size have been also identified as important risk factors.…”

“…These possibilities are supported, in part, by the existence of asymptomatic PAF, 19,20 which is more common than expected, 19 although it partially alleviated by the use of antiarrhythmic drugs. 12,19 Previous investigators have shown ischemic heart disease and valvular disease as independent risk factors for AF, [21][22][23] and aging and increased left atrial size have been also identified as important risk factors. 21 In accordance with those previous reports, our study, using multivariate analysis, revealed that these 4 factors were significant predictors of early chronic AF development.…”

Relationship between silent atrial fibrillation and the maximum heart rate in the 24-hour Holter: cross-sectional study

“…Early diagnosis is important in preventing morbidity and mortality, which are largely due to stroke. 4,5 Several tools for assessment of AF have been developed, such as transtelephonic monitoring, 24-hour Holter and implantable loop monitoring of electrocardiographic changes. 6 All these techniques have been evaluated in order to better define the presence of paroxysmal arrhythmias such as paroxysmal atrial fibrillation (PAF).…”