Holter features to detect coronary artery spasm in ANOCA patients: A pilot study

Diantha JM Schipaanboord; Caïa Crooijmans; Nicole S Erler; Peter David Faasse; Tijn PJ Jansen; Timo Nijkamp; Saskia ZH Rittersma; Tim P van de Hoef; Pim van der Harst; Aukelien C Dimitriu-Leen; Peter Damman; Suzette E Elias-Smale; René van Es; N Charlotte Onland-Moret; Hester M den Ruijter. IJC Heart & Vasculature (formerly IJC Heart & Vessels), April 01, 2026, Volume 63, Article 101884, Copyright © 2026 The Author(s)

This pilot study investigated whether 12-lead Holter monitoring with symptom tracking could identify ECG features to diagnose coronary artery spasm (CAS) in ANOCA patients (angina with non-obstructive coronary artery disease).

Key Findings:

• 42 ANOCA patients (88% female) wore a Holter for 2–7 days before coronary function testing (CFT); 33 (79%) were diagnosed with CAS.
• Patients with CAS more frequently showed ≥1 min of ST depression per day (≥0.035 mV: 88% vs 44%), though discriminative ability was limited (AUC = 0.65)
• CAS patients had lower heart rates and longer PQ/QT times, especially at night and early morning.

Conclusion: Holter monitoring shows promising signals in CAS patients, supporting the need for larger AI-based diagnostic studies.