Surreal illustration of a heart with clockwork, representing synchronicity and heart health assessment.

Decoding Heart Health: Can New Scans Predict Cardiac Risks in Dilated Cardiomyopathy Patients?

Avery Sinclair monogram
Avery Sinclair in Health & Wellness October 2026 • 4 min read.

"Innovative research reveals how analyzing heart function through SPECT MPI scans could revolutionize the prediction and management of heart failure."


Dilated cardiomyopathy (DCM), a condition where the heart's ability to pump blood effectively is compromised, poses significant challenges in healthcare. Predicting which patients are most at risk and tailoring treatments accordingly is critical. Traditionally, factors like age, overall physical condition, and the heart's ejection fraction have been considered. However, recent studies suggest that assessing the heart's synchronicity—how well its different parts contract and relax together—may offer deeper insights.

Heart specialists are focusing on cardiac dyssynchrony, where the heart's chambers do not beat in a coordinated manner. Both systolic dyssynchrony (when the heart contracts) and diastolic dyssynchrony (when it relaxes) can impact cardiac performance. While systolic dyssynchrony is a known risk factor, the role of diastolic dyssynchrony is less understood. New research aims to clarify how both types of dyssynchrony affect patient outcomes in DCM.

By using advanced imaging techniques like gated SPECT MPI (Single Photon Emission Computed Tomography Myocardial Perfusion Imaging), doctors can now measure the heart's mechanical function with greater precision. This non-invasive approach allows for detailed analysis of both systolic and diastolic phases, potentially unlocking new ways to predict and manage heart failure.

AI Search Multiple angles on this topic

Heart Failure’s Growing Burden

The HF Stats 2025 report estimates that approximately 6.7 million Americans over age 20 have heart failure. It projects that prevalence will rise to 8.7 million by 2030. Heart failure contributed to 425,147 deaths and accounted for 45% of cardiovascular deaths in the United States in 2022.

Guideline-Based Care

The 2022 ACC/AHA/HFSA heart failure guideline presents an evidence-based approach to treatment intended to improve quality of care and align management with patients’ interests. The guideline updates earlier recommendations when supported by new evidence and adds recommendations where published data justify them. Its framework reflects contemporary evidence rather than a single diagnostic test or treatment pathway.

How Do SPECT MPI Scans Measure Heart Function?

Surreal illustration of a heart with clockwork, representing synchronicity and heart health assessment.

The study involved 52 patients diagnosed with DCM, who were followed over several years to track cardiac-related deaths. Using SPECT MPI, doctors analyzed the heart's function during both contraction (systole) and relaxation (diastole). The scans provided key measurements of dyssynchrony, including:

These metrics help paint a detailed picture of how efficiently the heart is working and whether there are any timing issues in its contractions and relaxations. The research team then correlated these measurements with patient outcomes to determine which factors were most predictive of cardiac events.

  • Phase Standard Deviation (PSD): Measures the degree of variation in the timing of heart muscle contractions.
  • Phase Histogram Bandwidth (PBW): Indicates the range of time over which the heart muscle contracts.
  • Phase Entropy (PE): Quantifies the overall disorder in the timing of the heart's activity.
AI Search Multiple angles on this topic

SPECT and Resynchronization

The VISION-CRT study evaluated intraventricular dyssynchrony using gated-SPECT myocardial perfusion imaging in heart failure patients undergoing cardiac resynchronization therapy. Baseline dyssynchrony was not associated with the study’s primary outcome. However, a change in left-ventricular phase standard deviation from baseline was associated with that outcome, with an odds ratio of 1.04, a 95% confidence interval of 1.01 to 1.07, and P = .007.

Evidence and Sample-Size Limits

Evidence for using phase analysis of gated myocardial perfusion SPECT to assess left-ventricular diastolic dyssynchrony remains limited by study size. One study reported that its findings were based on a relatively small subset of patients. The authors noted that a larger heart-failure cohort would have been preferable for evaluating feasibility.

Beyond Ejection Fraction

Traditional primary-prevention selection for implantable cardioverter-defibrillators in dilated cardiomyopathy has relied on a left-ventricular ejection fraction of 35% or less. This threshold is presented as the conventional basis for identifying candidates for sudden cardiac death prevention. MRI-based risk-stratification approaches are being reviewed in the context of that established framework.

The results showed that patients who experienced cardiac death had more severe systolic and diastolic dyssynchrony compared to those who survived. Specifically, higher PSD, PBW, and PE values were associated with poorer outcomes. Further analysis revealed that phase entropy during both systole and diastole were independent predictors of cardiac death, highlighting their importance in assessing risk.

What's Next for Heart Health?

This research underscores the potential of SPECT MPI scans to provide critical insights into heart function and predict adverse events in DCM patients. By identifying diastolic phase entropy as a key predictor, the study opens new avenues for early intervention and personalized treatment strategies. As technology advances, these sophisticated imaging techniques promise to play an increasingly vital role in the fight against heart failure, offering hope for improved outcomes and enhanced quality of life.

AI Search Multiple angles on this topic

Real-World Evidence in Care

Real-world evidence from de-identified electronic health-record data can help inform and advance appropriate care for patients with systolic, or reduced-ejection-fraction, heart failure receiving guideline-directed medical therapy. A 2024 Truveta case study reported that real-world findings may prompt changes in heart-failure treatment decisions and clinical guidelines. Together, these sources illustrate how routine clinical data can connect evidence generation with practical management.

How DCM prognosis compares across imaging findings

  • 26.8% vs 10.6% death probabilityA cohort of 427 patients with DCM found that midwall late gadolinium enhancement was associated with a higher probability of death: 26.8% of patients with the finding compared with 10.6% without it.[1]
  • 29.6% vs 7% arrhythmic eventsThe same comparison found arrhythmic events in 29.6% of patients with midwall late gadolinium enhancement and 7% of those without it.[1]

Where SPECT phase analysis fits among cardiac imaging measures

In a separate comparison of gated SPECT and echocardiography in DCM, agreement for regional wall motion was 56%, or 298 of 528 segments.[2]

  • Because DCM can involve both chronic heart-failure decompensation and sudden cardiac death, a single imaging marker may not capture every relevant pathway to an adverse outcome.[1] [3]

Terms that clarify DCM risk assessment

Dilated cardiomyopathy
A form of non-ischemic cardiomyopathy marked by dilation and systolic dysfunction of the left ventricle.[3]

Sources

  1. Current Insights and Novel Cardiovascular Magnetic Resonance-Based Techniques in the Prognosis of Non-Ischemic Dilated Cardiomyopathy (pmc.ncbi.nlm.nih.gov)
  2. Evaluation of left ventricular function and volume in patients with dilated cardiomyopathy: gated myocardial single-photon emission tomography (SPECT) versus echocardiography (pmc.ncbi.nlm.nih.gov, 2005)
  3. MRI-based Approach to Sudden Cardiac Death Risk Stratification in Dilated Cardiomyopathy: A State of the Art Review | SN Comprehensive Clinical Medicine | Springer Nature Link (link.springer.com)

About this Article -

Written with AI assistance from published research, and reviewed by the Mystum team. See our About page for more information.

Everything You Need To Know

1

What exactly is dilated cardiomyopathy (DCM)?

Dilated cardiomyopathy, or DCM, is a condition where the heart's ability to effectively pump blood is compromised. This means the heart muscle becomes enlarged and weakened, affecting its ability to circulate blood properly throughout the body. It's significant because it can lead to heart failure if not properly managed, impacting a person's overall health and longevity. Understanding DCM is the first step in predicting and preventing further heart complications.

2

How do SPECT MPI scans work to assess heart function?

SPECT MPI, or Single Photon Emission Computed Tomography Myocardial Perfusion Imaging, is an advanced imaging technique used to measure the heart's mechanical function with greater precision. During a SPECT MPI scan, doctors can analyze how the heart functions during both contraction (systole) and relaxation (diastole). This non-invasive approach provides detailed measurements of dyssynchrony, identifying how efficiently the heart is working and any timing issues in its contractions and relaxations.

3

What does cardiac dyssynchrony mean, and why is it important?

Cardiac dyssynchrony refers to the condition where the different chambers of the heart do not beat in a coordinated manner. This lack of coordination can occur during systole (contraction) or diastole (relaxation) of the heart. Systolic dyssynchrony is a known risk factor, but diastolic dyssynchrony's role is less understood. Identifying and understanding both types of dyssynchrony is important because they impact cardiac performance and can lead to adverse patient outcomes in those with DCM.

4

What is phase entropy, and why is it significant in predicting heart issues?

Phase entropy quantifies the overall disorder in the timing of the heart's activity. It measures the complexity and irregularity of the heart's contractions and relaxations. Higher phase entropy values during both systole and diastole indicate greater dyssynchrony, which is associated with poorer outcomes and increased risk of cardiac events, particularly in patients with DCM. Therefore, it acts as a predictor of cardiac death.

5

What are Phase Standard Deviation, Phase Histogram Bandwidth, and Phase Entropy, and how are they measured?

Phase Standard Deviation (PSD) measures the degree of variation in the timing of heart muscle contractions. Phase Histogram Bandwidth (PBW) indicates the range of time over which the heart muscle contracts. Phase Entropy (PE) quantifies the overall disorder in the timing of the heart’s activity. All of these measurements are captured using SPECT MPI scans. Higher values in PSD, PBW, and PE are associated with more severe systolic and diastolic dyssynchrony, and, consequently, poorer patient outcomes. These metrics help create a detailed picture of how efficiently the heart is working, and highlight the importance of timing in contractions and relaxations.

Newsletter Subscribe

Subscribe to get the latest articles and insights directly in your inbox.