A chronic total occlusion (CTO) is common in patients with coronary artery disease. CTO recanalization has been shown to improve survival in comparison to failed CTO recanalization. Whether this is related to ventricular arrhythmias (VA) is unknown. The purpose of this pilot study is to evaluate the incidence of VA after successful CTO recanalization and in those with failed CTO recanalization or untreated CTO. Patients will be monitored using an insertable cardiac monitor.

Rationale: Successful chronic total occlusion (CTO) recanalization has been associated with improved long-term survival. Furthermore, CTO is an independent predictor for the occurrence of ventricular arrhythmias (VA) in patients with ischemic cardiomyopathy and implantable cardioverter defibrillators (ICDs). One may speculate that a successful CTO recanalization may provide electrical stability. However, no data are available on the incidence of sustained VA in this patient population.

Objective: The objective of the present pilot study is to assess the incidence of sustained VA in 2 CTO groups: patients with successful percutaneous CTO recanalization (group A), patients with failed percutaneous CTO recanalization or untreated CTO (group B).

Study design: Pilot study of patients with CTO.

Study population: A total of 90 patients will be enrolled with a maximum of 45 patients in each arm.

Intervention: A Medtronic Reveal LINQ™ Insertable cardiac monitor (ICM) will be implanted in every patient to continuously monitor heart rhythm during the follow-up period.

Main study parameters/endpoints: To assess the incidence of VA defined as sustained ventricular tachycardia >30 s or ventricular fibrillation.

Inclusion criteria:

1. Presence of CTO defined as complete obstruction of the vessel with Thrombolysis In Myocardial Infarction (TIMI) flow grade 0 and an estimated duration of ≥3 months, and one of the following:

   1. A successful percutaneous CTO recanalization for stable angina within the previous 6 months. A successful CTO recanalization is defined as a final TIMI flow grade ≥2 and a residual stenosis ≤30% after stent implantation.
   2. A failed percutaneous CTO recanalization for stable angina within the previous 6 months. A failed CTO recanalization is defined as not fulfilling the criteria for successful CTO recanalization.
   3. Untreated CTO diagnosed in the previous 6 months.

2. Age ≥18 years.

3. Written informed consent.

4. Patient agrees to the follow-up including the implantation of the ICM.

Exclusion Criteria:

1. Patients who are potential candidates for an ICD according to the 2015 ESC guidelines.
2. Patients who have a cardiac implantable electrical device (CIED) (e.g., pacemaker, ICD).
3. Patient has reduced immune function or is otherwise at high risk for infection.
4. Patient has had a recent (within 30 days) or otherwise unresolved infection.
5. Known pregnancy at time of inclusion.
6. Patient has severe co-morbidity that may cause the patient to be non-compliant with the protocol, confound the data interpretation or is associated with limited life expectancy (i.e., less than one year).