The Utility of Holter Monitoring Compared to Loop Recorders in the Evaluation of Syncope and Presyncope

Background: Holter monitoring is frequently used to assess patients with syncope, but rarely provides a diagnosis. Newer loop recorders provide the opportunity for prolonged electrocardiographic monitoring to enhance diagnostic yield. Methods: The results of 232 Holter monitors and 81 loop recordings performed for the investigation of syncope or presyncope were reviewed for indication, patient demographics, and presence and type of symptoms and/or arrhythmias. The results were classified as (1) symptom‐arrhythmia correlation, (2) clinically useful information (group 1 plus those excluding arrhythmic syncope, and those demonstrating asymptomatic serious arrhythmias) and (3) unhelpful (asymptomatic and no serious arrhythmias). Results: Loop recorders provided a symptom‐arrhythmia correlation in 11.1% of patients compared to only 0.4% in the Holter group (P < 0.0001). Clinically useful information was obtained in 54.3% of loop patients compared to 27.6% in the Holter group (P < 0.0001). Technical problems occurred in 0.4% of the Holter patients and in 3.7% of loop patients (P = 0.05). Classification was difficult in seven patients in the Holter group; two experienced symptoms during sinus rhythm but also had a serious asymptomatic arrhythmia, and five patients had 6–10 beats of asymptomatic ventricular tachycardia at a rate < 160 beats/min. Conclusion: Loop recording was well tolerated and superior to Holter monitoring in providing a symptom‐arrhythmia correlation or clinically useful information in patients with syncope and presyncope. An initial approach with a loop‐recording device should be employed in these patients.