April 15, 2011Stroke184 citationsOpen Access

Improving Stroke Risk Stratification Using the CHADS 2 and CHA 2 DS 2 -VASc Risk Scores in Patients With Paroxysmal Atrial Fibrillation by Continuous Arrhythmia Burden Monitoring

GBGiuseppe Boriani GBGiovanni Luca Botto LPLuigi Padeletti

Structured PICO

Does the addition of continuous AF burden monitoring improve stroke risk stratification using CHADS2 and CHA2DS2-VASc scores in patients with paroxysmal atrial fibrillation?

Population

568 patients with a history of atrial fibrillation implanted with a DDDR-P pacemaker (AT-500; Medtronic)

Intervention

Addition of continuous AF burden monitoring (categorized as ≤5 min/day, >5 min to <24 hours/day, and ≥24 hours/day) to clinical risk scores

Comparator

CHADS2 and CHA2DS2-VASc risk scores alone

Outcome

Thromboembolic events and discrimination ability (C-statistic) of risk scoreshard clinical

Combining continuous AF burden monitoring with the CHA2DS2-VASc score significantly improves stroke risk stratification in patients with paroxysmal atrial fibrillation.

Limitations

Retrospective design

Abstract

BACKGROUND AND PURPOSE: In patients with atrial fibrillation (AF), stroke risk stratification schema do not consider AF parameters. The aim of the study is to assess the impact of combining risk factors with continuous AF burden monitoring. METHODS: In this retrospective study 568 patients implanted with a DDDR-P pacemaker (AT-500; Medtronic) and a history of AF were continuously monitored for 1 year. RESULTS: During follow-up, 14 patients (2.5%) had a thromboembolic event. Patients were divided into 3 groups: AF burden ≤5 minutes per day (AF-free; n=223 39%), AF burden >5 minutes but <24 hours per day (AF-5 minutes; n=179 32%), and AF burden ≥24 hours (AF-24 hours; n=166 29%). Patients were also classified according to CHADS2 and CHA2DS2-VASc risk scores. The discrimination ability of each risk score was evaluated performing a logistic regression analysis and calculating the corresponding C-statistic. The addition of AF burden improved C-statistics: for CHADS2 from 0.653 (P=0.051) to 0.713 (P=0.007); for CHA2DS2-VASc, from 0.898 (P<0.0001) to 0.910 (P<0.0001). CONCLUSIONS: The CHA2DS2-VASc score had a high sensitivity to predict thromboembolism. Implementation of device data on AF presence/duration/burden has the potential to contribute to improved clinical risk stratification and should be tested prospectively.

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