Comparison of continuous versus intermittent monitoring of atrial arrhythmias

The ability of intermittent or symptom-based monitoring to accurately identify patients with atrial tachycardia/atrial fibrillation (AT/AF) and to quantify AT/AF burden is not well established.

The purpose of this study was to compare intermittent and symptom-based monitoring to continuous monitoring for (1) identification of patients with any AT/AF, (2) identification of patients with long-duration AT/AF, and (3) assessment of AT/AF burden.

Data from 574 pacemaker (AT500, Medtronic) patients were analyzed retrospectively over 1 year. The device recorded the amount of AT/AF detected each day. Intermittent monitoring (annual, quarterly, and monthly 24-hour Holter; 7-day and 30-day annual long-term recordings) was simulated by analyzing data from randomly selected days within a prescribed monitoring window. Symptom-based monitoring was approximated by analyzing days when patients indicated symptoms with an external activator.

All intermittent and symptom-based monitoring resulted in significantly lower sensitivity (range 31%-71%) and negative predictive value (range 21%-39%) for identification of patients with any AT/AF (P <.001) and underestimated AT/AF burden (P <.001) compared with continuous monitoring. Sensitivity for identifying patients with long-duration episodes ranged from 23% to 58% (P <.001 vs continuous monitoring). Identification of patients with AT/AF and assessment of AT/AF burden with intermittent monitoring depended on the patient's actual AT/AF burden and improved with increasing frequency or duration of intermittent monitoring.

Intermittent and symptom-based monitoring is highly inaccurate for identifying patients with any or long-duration AT/AF and for assessing AT/AF burden. Further investigation is required to determine if full AT/AF disclosure with implantable devices is effective in reducing stroke risk and facilitating maintenance of sinus rhythm.