Exercise CMR at NHCS: A Comprehensive Physiologic Stress Imaging Solution

The MRI-compatible in-scanner exercise ergometer enables patients to perform graded cycling during ExCMR, allowing real-time assessment of cardiac function and perfusion under physiologic stress.

Symptoms such as exertional chest pain, dyspnoea and reduced exercise tolerance are commonly seen in primary care and cardiology practice. Yet, for many patients, resting imaging or conventional stress test may yield normal or inconclusive findings.

In such cases, a more comprehensive evaluation – such as Stress Cardiovascular Magnetic Resonance (CMR) – is often required to identify subtle structural, functional or perfusion abnormalities. Unlike other stress modalities, CMR provides a single-session, multiparametric assessment that integrates biventricular function, myocardial tissue characterisation (including fibrosis, inflammation and infiltration) and stress perfusion imaging.

These components would otherwise require multiple separate tests across different imaging platforms, increasing cost, radiation exposure and diagnostic
uncertainty. CMR consolidates these elements into one comprehensive examination, enabling clinicians to gain a more complete understanding of underlying pathology.

NEW EXERCISE CMR

The National Heart Centre Singapore (NHCS) has now introduced Exercise Cardiovascular Resonance Imaging (ExCMR), a novel stress magnetic resonance imaging (MRI) test that allows clinicians to accurately distinguish between normal changes in the heart from exercise and potentially life-threatening or serious heart conditions in just one session, transforming how heart conditions are diagnosed in active individuals.

Unlike pharmacologic stress testing, Exercise Cardiovascular Magnetic Resonance (ExCMR) evaluates the heart under true dynamic exercise offering a physiologic stress option that closely mirrors a patient’s real-world symptoms.

HOW ExCMR WORKS

Using an MRI-compatible supine ergometer, patients perform graded cycling while cine and perfusion imaging are acquired at, or immediately after, peak workload.

This allows direct assessment of exercise-induced wall motion abnormalities, myocardial perfusion defects, contractile reserve and haemodynamic response, features that may be absent under adenosine based stress.

THE VALUE OF EXERCISE STRESS CMR

ExCMR has demonstrated particular value in detecting early cardiomyopathy, and exertional ischaemia in patients whose symptoms are exercise dependent.

The protocol is generally well tolerated, avoids the side effects associated with vasodilator stress agents and provides a detailed pathophysiologic profile in a single test.

By combining the strengths of multiparametric CMR with true physiologic stress, ExCMR provides clinicians with a high-resolution, integrative assessment that significantly enhances diagnostic confidence in cases where routine stress tests are inconclusive.

SUITABLE REFERRALS

Patients can be referred for ExCMR if they meet any of the following criteria:

• Athletes or active individuals with suspected cardiomyopathy but inconclusive findings on resting imaging tests.
• Patients with exertional symptoms, dyspnoea or reduced exercise tolerance that are not explained by resting imaging or treadmill ECG.

Routine screening of asymptomatic individuals is not recommended.

HOW TO REFER

Building on nearly a decade of research and protocol development at the National Heart Centre Singapore, including early feasibility work, protocol optimisation, validation studies,and cost-effectiveness analyses, ExCMR has now been incorporated into clinical practice.

GPs may refer patients to NHCS Specialist Outpatient Clinic via the usual referral pathway:

• A cardiologist will review the case and determine suitability for the ExCMR.
• If indicated, the cardiologist will order theinvestigation through the NHCS CardiacImaging pathway.
• The Cardiac Magnetic Resonance Imaging team will conduct pre-scan assessment, schedule the appointment and provide detailed patient instructions for the exercise protocol.

CALL FOR RESEARCH PARTICIPATION

NHCS is actively conducting research programmes involving patients with exertional symptoms, dyspnoea or suspected microvascular disease.

Patients interested in participating may contact the Clinical Trials & Research Office (CTRO) at mribike@nhcs.com.sg to obtain more information. Participation is voluntary and does not affect standard clinical care.