SMS: Substrate Modification Study in Patients Getting an Implantable Cardioverter Defibrillator (ICD) (SMS)

Substrate Modification Study in Patients Getting an ICD

The present standard of care for the management of unstable ventricular tachycardia (VT) in the setting of chronic coronary artery disease is the placement of an implantable cardioverter defibrillator (ICD) after the initial episode, and radiofrequency ablation and/or antiarrhythmic medication in the event of recurrences causing frequent ICD interventions.

The primary purpose of this randomized study is the assessment of recurrences of unstable VT in patients who undergo ICD implantation plus substrate ablation after the initial episode compared to patients who only undergo ICD implantation. Thus the primary purpose is an improvement in the quality of life. A decrease in mortality is not a primary purpose of this study.

Study Overview

• Status: Completed
• Conditions: Tachycardia, Ventricular
• Intervention / Treatment: Procedure: ICD Ablation plus VT-ablation; Device: ICD Therapy

• Study Type: Interventional
• Enrollment (Actual): 116
• Phase: Phase 4

Contacts and Locations

Study Locations

• Denmark
  • Aarhus, Denmark, 8200
    • Skejby Skygehus
• Germany
  • Bad Neustadt / Saale, Germany, 97616
    • Herz- und Gefäßklinik GmbH
  • Bochum, Germany, 44789
    • Berufsgenossenschaftliche Kliniken Bergmannsheil
  • Frankfurt, Germany, 60590
    • Klinikum der J.W. Goethe Universität
  • Hamburg, Germany, 20251
    • Universitätsklinikum Hamburg-Eppendorf
  • Hamburg, Germany, 20099
    • Allgemeines Krankenhaus St. Georg
  • Ludwigshafen, Germany, 67063
    • Klinikum der Stadt Ludwigshafen am Rhein

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 80 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Coronary artery disease documented by coronary angiography. For the purpose of this study, coronary artery disease will be defined as the presence of a 50% or more diameter stenosis of the left main or of a 75% or more diameter stenosis of the left anterior descending, circumflex or right coronary arteries, or the history of a surgical or percutaneous revascularization procedure.
• Left ventricular ejection fraction < 40% as estimated by echocardiography or contrast ventriculography within the previous 30 days.

• Clinical unstable VT without reversible factors (acute ischemia or antiarrhythmic medications as defined below). Unstable VT can have one of the following clinical presentations:

  • Hypotensive VT without major neurologic dysfunction;
  • Syncope; or
  • Cardiac arrest.

Exclusion Criteria:

• Age < 18 years or > 80 years
• Protruding left ventricular (LV) thrombus on pre-ablation echocardiogram
• Acute myocardial infarction within the preceding 2 months
• Class IV New York Heart Association (NYHA) heart failure
• Valvular heart disease or mechanical heart valve precluding access to the left ventricle
• Unstable angina
• Cardiac surgery within the past 2 months
• Serum creatinine > 220 mmol/L (2.5 mg/dL)
• Thrombocytopenia or coagulopathy
• Contraindication to heparin
• Pregnancy
• Acute illness or active systemic infection
• Other disease process likely to limit survival to less than 12 months
• Significant medical problem that, in the opinion of the principal investigator, would preclude enrollment into the study
• Participation in another investigational study
• Unwillingness to participate or lack of availability for follow-up

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: 1; ICD Therapy plus VT-Ablation	Procedure: ICD Ablation plus VT-ablation; ICD-Therapy for the treatment of unstable VT´s plus catheter ablation for substrate modification
Active Comparator: 2; ICD Therapy only	Device: ICD Therapy; ICD Therapy for the Treatment of unstable VT´s

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Time to the first documented recurrence of any sustained VT/ventricular fibrillation (VF) during the follow-up period	12 Months

Secondary Outcome Measures

Outcome Measure	Time Frame
All appropriate ICD therapies (number of shocks, number of antitachycardia pacing therapies)	12 Months
Quality of life	12 Months
Number of hospital readmissions due to a cardiac indication	12 Months
Severe clinical events	12 Months

Collaborators and Investigators

• Sponsor: Medtronic Cardiac Rhythm and Heart Failure
• Collaborators: Medtronic
• Investigators: Principal Investigator: Karl-Heinz Kuck, MD, Allgemeines Krankenhaus St. Georg

Publications and helpful links

General Publications

• Kuck KH, Tilz RR, Deneke T, Hoffmann BA, Ventura R, Hansen PS, Zarse M, Hohnloser SH, Kautzner J, Willems S; SMS Investigators. Impact of Substrate Modification by Catheter Ablation on Implantable Cardioverter-Defibrillator Interventions in Patients With Unstable Ventricular Arrhythmias and Coronary Artery Disease: Results From the Multicenter Randomized Controlled SMS (Substrate Modification Study). Circ Arrhythm Electrophysiol. 2017 Mar;10(3):e004422. doi: 10.1161/CIRCEP.116.004422.

Study record dates

Study Major Dates

• Study Start: May 1, 2002
• Primary Completion (Actual): April 1, 2010
• Study Completion (Actual): August 1, 2011

Study Registration Dates

• First Submitted: September 9, 2005
• First Submitted That Met QC Criteria: September 9, 2005
• First Posted (Estimated): September 15, 2005

Study Record Updates

• Last Update Posted (Actual): July 3, 2025
• Last Update Submitted That Met QC Criteria: June 30, 2025
• Last Verified: September 1, 2017

More Information

Terms related to this study

• Keywords: Unstable Ventricular Tachycardia
• Additional Relevant MeSH Terms: Cardiac Conduction System Disease; Cardiovascular Diseases; Pathologic Processes; Heart Diseases; Arrhythmias, Cardiac; Tachycardia; Tachycardia, Ventricular
• Other Study ID Numbers: CEN_G_CA_3

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO