Coronary Flow During Rapid Heart Rates

Recruiting

• Conditions: Coronary Artery Disease; Ventricular Tachycardia; Coronary Microvascular Dysfunction; Heart Failure; Coronary Microvascular Disease
• Interventions: Diagnostic Test: Pressure and flow measurement during simulated VT

• Registration Number: NCT05841199
• Lead Sponsor: Imperial College London

Brief Summary

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.

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 Timeline

• Study First Submitted: 2023-03-23
• Study First Submitted QC: 2023-04-21
• Study First Posted: 2023-05-03
• Study Start: 2023-08-01
• Status Verified: 2023-11
• Last Update Submitted: 2023-11-07
• Last Update Posted: 2023-11-08
• Primary Completion: 2026-02-02
• Study Completion: 2026-02-02

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 70

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 & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
Controls	Pressure and flow measurement during simulated VT	10 patients with unobstructed coronary arteries, normal microvascular function and normal LV function.
Coronary artery disease	Pressure and flow measurement during simulated VT	25 patients with severe, single-vessel coronary artery disease of the proximal LAD or proximal other dominant vessel awaiting PCI.
Microvascular dysfunction	Pressure and flow measurement during simulated VT	15 patients with without severe disease in any coronary artery, impaired microvascular function and normal LV function.
Heart failure	Pressure and flow measurement during simulated VT	20 patients with LV systolic dysfunction (LVEF\<40%).

Primary Outcome Measures

Name	Time	Method
Change in blood pressure in participants before and after PCI	At baseline and during simulated VT, immediately before PCI and after PCI
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

Secondary Outcome Measures

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

Trial Locations

Locations (1)

Imperial College NHS Foundation Trust; 🇬🇧 London, United Kingdom