Reduced regional myocardial perfusion reserve is associated with impaired contractile performance in idiopathic dilated cardiomyopathy

Area of Science:

• Cardiology
• Nuclear Cardiology
• Cardiovascular Imaging

Background:

• Idiopathic dilated cardiomyopathy (IDC) may involve an imbalance between myocardial oxygen supply and demand.
• Subclinical myocardial ischemia might accelerate left ventricular dysfunction in IDC.
• Investigating the link between regional myocardial perfusion reserve (MPR) and contractile function is crucial.

Purpose of the Study:

• To explore the relationship between regional myocardial perfusion reserve (MPR) and cardiac contractile performance in newly diagnosed IDC patients.
• To determine if impaired myocardial perfusion is associated with contractile dysfunction in IDC.

Main Methods:

• Positron emission tomography (PET) with (13)N-ammonia for perfusion (baseline and dipyridamole stress) and (18)F-FDG for viability.
• Dobutamine stress cardiac magnetic resonance imaging (MRI) to assess wall motion score (WMS).
• Analysis of MPR and WMS in a 17-segment model for 22 newly diagnosed IDC patients.

Main Results:

• Wall motion abnormalities were observed at rest and during dobutamine stress in a significant portion of analyzed segments.
• Myocardial perfusion reserve (MPR) was significantly higher in segments that improved contractility during stress compared to those that did not.
• Regional ischemia was evident, with impaired contractility during stress in ischemic regions.

Conclusions:

• Regional ischemia is clearly present in patients with idiopathic dilated cardiomyopathy (IDC).
• Ischemic myocardial regions exhibit impaired contractility during stress, supporting the role of impaired oxygen supply in cardiac dysfunction.
• These findings highlight the contribution of reduced myocardial perfusion to the progression of left ventricular dysfunction in IDC.