Introduction:
Implantable cardioverter defibrillators due to the possibility of continuous recording of intracardiac electrograms can detect episodes of atrial fibrillation. In practice, this allows better identification of patients with asymptomatic AF episodes, thus increasing the proportion of patients who may benefit from pharmacological prophylaxis of thromboembolic events, particularly stroke.
Hypothesis:
If intracardiac electrogram analysis should be part of each visit carried out in patients with implantable cardioverter defibrillator, how much of detected episodes of atrial fibrillation is asymptomatic.
Methods:
The study included 174 consecutive outpatient cases with heart failure, sinus rhythm and implanted Cardioverter Defibrillator and Cardiac Resynchronisation Therapy with Defibrillator. Control visits with analysis intracardiac electrograms records occurred every three months. Each AF episode stored in the device’s memory lasting at least 30 seconds was considered an episode of atrial fibrillation. A symptomatic episode was considered when arrhythmia led to ICD shock, heart deterioration, collapse or fainting, palpitations, weakness, chest pain or shortness of breath accompanied by a feeling of irregular heartbeat. During mean follow-up of 20 months, 901 visits were carried out. 147 patients had at least one year of follow-up.
Results:
Atrial fibrillation (AF) episodes in the study occurred in 54 (31.0%) patients. Of the 241 atrial fibrillation episodes recorded in the device’s memory, 71.4% were asymptomatic. There was no statistically significant difference in the incidence of new episodes of atrial fibrillation (P = 0.384) in the study group with a history of stroke or transient ischemic episodes during follow-up. However, asymptomatic AF episodes were more common in stroke patients (P = 0.0074). In the time of observation in the whole group of patients there were no new strokes and transient ischemic attack.
Conclusion:
In conclusion, detection of asymptomatic atrial fibrillation episodes based on intracardiac electrocardiogram records is effective method. In the study group, such episodes were up 71.4% of all newly detected AF episodes.
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