Coronary Flow During Rapid Heart Rates (VT flow)

Coronary Epicardial and Microcirculatory Determinants of Ventricular Tachycardia Tolerability

The goal of this observational study is to learn about the factors which determine how well ventricular tachycardia (VT) is tolerated. The main questions it aims to answer are:

1. What impact does coronary artery disease have on the ability for a patient to tolerate VT?
2. Does treatment of coronary artery disease with stents improve the tolerability of VT?

Participants who are undergoing a clinically indicated coronary angiogram or coronary angioplasty procedure will have measurements of blood pressure, coronary pressure and coronary flow made during pacing at a range of heart rates.

Study Overview

• Status: Recruiting
• Conditions: Coronary Artery Disease; Heart Failure; Ventricular Tachycardia; Coronary Microvascular Disease; Coronary Microvascular Dysfunction
• Intervention / Treatment: Diagnostic test: Pressure and flow measurement during simulated VT

Detailed Description

Ventricular tachycardia (VT) is a common and life-threatening arrhythmia that occurs in people with heart problems. Some patients who develop this arrhythmia remain very stable with very little symptoms while others become unstable with low blood pressure or even sudden death. It is not known why some people tolerate the arrhythmia well and others do not.

If VT is not tolerated then current practice is to offer an implantable cardioverter defibrillator (ICD) which can deliver a shock to the heart if dangerous heart rhythms are detected. While shocks can be life-saving, they are also harmful, including causing psychological distress. ICDs also frequently deliver shocks when they are not needed.

If research could identify which factors predispose a person to be stable or unstable in VT, this would allow doctors to help them in a range of ways. One way would be to treat patients to improve the tolerance of VT, so avoiding the need for an ICD. Another would be to assess the the risk of instability and so allow a patient-centred decision on whether an ICD is needed.

In this study the investigators plan to recruit patients who are referred for a coronary angiogram. During the angiogram, the investigators will stimulate the heart at a range of fast heart rates and measure their blood pressure and flow in their coronary arteries. In patients who undergo stenting for a coronary stenosis, the investigators will also make these measurements after stenting so they can see if there is any difference. By recruiting a range of different cardiology patients, the investigators will be able to assess which factors contribute to stability during VT.

• Study Type: Observational
• Enrollment (Estimated): 70

Contacts and Locations

• Study Contact: Name: Rahul Bahl; Phone Number: +44 20 7594 1093; Email: r.bahl@imperial.ac.uk
• Study Contact Backup: Name: Ricardo Petraco; Phone Number: +44 20 7594 1093; Email: r.petraco@imperial.ac.uk

Study Locations

• United Kingdom
  • London, United Kingdom, W12 0HS
    • Recruiting
    • Imperial College NHS Foundation Trust
    • Principal Investigator: Ricardo Petraco, PhD
    • Contact: Rahul Bahl; Phone Number: 020 7594 5735; Email: r.bahl@imperial.ac.uk
    • Contact: Ricardo Petraco; Phone Number: 020 7594 5735; Email: r.petraco@imperial.ac.uk

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Adults referred for coronary angiography or coronary angioplasty.

Description

Inclusion Criteria:

• Able to give valid consent
• Referred for coronary angiography or coronary angioplasty
• Suitable for percutaneous physiological interrogation and PCI when clinically indicated

Exclusion Criteria:

• Unable to give valid consent
• Pregnant or breastfeeding women
• Unstable coronary artery disease (acute coronary syndrome)
• Severe multivessel coronary artery disease suitable for coronary artery bypass grafting
• Severe heart valve disease
• Severe (NYHA IV) heart failure

Study Plan

How is the study designed?

Number of groups / cohorts

4

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Controls; 10 patients with unobstructed coronary arteries, normal microvascular function and normal LV function.	Diagnostic test: Pressure and flow measurement during simulated VT; Participants undergoing coronary angiography will have measurements of blood pressure, coronary pressure and coronary flow during simulated VT. VT will be simulated using pacing at a range of heart rates.
Coronary artery disease; 25 patients with severe, single-vessel coronary artery disease of the proximal LAD or proximal other dominant vessel awaiting PCI.	Diagnostic test: Pressure and flow measurement during simulated VT; Participants undergoing coronary angiography will have measurements of blood pressure, coronary pressure and coronary flow during simulated VT. VT will be simulated using pacing at a range of heart rates.
Microvascular dysfunction; 15 patients with without severe disease in any coronary artery, impaired microvascular function and normal LV function.	Diagnostic test: Pressure and flow measurement during simulated VT; Participants undergoing coronary angiography will have measurements of blood pressure, coronary pressure and coronary flow during simulated VT. VT will be simulated using pacing at a range of heart rates.
Heart failure; 20 patients with LV systolic dysfunction (LVEF<40%).	Diagnostic test: Pressure and flow measurement during simulated VT; Participants undergoing coronary angiography will have measurements of blood pressure, coronary pressure and coronary flow during simulated VT. VT will be simulated using pacing at a range of heart rates.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Change in coronary flow in participants with different levels of coronary microvascular function.	At baseline and during simulated VT
Change in coronary flow in participants immediately before and after PCI	At baseline and during simulated VT, immediately before PCI and after PCI
Change in blood pressure in participants with different levels of coronary microvascular function.	At baseline and during simulated VT
Change in blood pressure in participants before and after PCI	At baseline and during simulated VT, immediately before PCI and after PCI

Secondary Outcome Measures

Outcome Measure	Time Frame
Change in coronary flow in participants with different levels of left ventricular function	At baseline and during simulated VT
Change in blood pressure in participants with different levels of left ventricular function	At baseline and during simulated VT

Collaborators and Investigators

• Sponsor: Imperial College London
• Investigators: Principal Investigator: Ricardo Petraco, Senior Clinical Research Fellow

Study record dates

Study Major Dates

• Study Start (Actual): August 1, 2023
• Primary Completion (Estimated): June 2, 2026
• Study Completion (Estimated): June 2, 2026

Study Registration Dates

• First Submitted: March 23, 2023
• First Submitted That Met QC Criteria: April 21, 2023
• First Posted (Actual): May 3, 2023

Study Record Updates

• Last Update Posted (Actual): March 27, 2026
• Last Update Submitted That Met QC Criteria: March 24, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Heart Failure; Coronary Artery Disease; Percutaneous Coronary Intervention; Coronary Microvascular Dysfunction; Coronary Microvascular Disease; Ventricular Tachycardia; Implantable Cardioverter Defibrillator
• Additional Relevant MeSH Terms: Cardiac Conduction System Disease; Vascular Diseases; Cardiovascular Diseases; Pathologic Processes; Heart Diseases; Arrhythmias, Cardiac; Arteriosclerosis; Arterial Occlusive Diseases; Coronary Disease; Myocardial Ischemia; Angina Pectoris; Tachycardia; Pathological Conditions, Signs and Symptoms; Heart Failure; Coronary Artery Disease; Tachycardia, Ventricular; Microvascular Angina; Mechanical Phenomena; Physical Phenomena; Pressure
• Other Study ID Numbers: 22HH7955

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No