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Isolated ventricular noncompaction is associated with coronary microcirculatory dysfunction
Rolf Jenni1, Christophe A Wyss, Erwin N Oechslin
1Department of Echocardiography, Cardiovascular Center, University Hospital, Zurich, Switzerland.
Insights
Coronary microcirculatory dysfunction is linked to isolated ventricular noncompaction (IVNC). This dysfunction affects most segments with wall motion abnormalities, not just noncompacted areas, in IVNC patients.
Area of Science:
- Cardiology
- Cardiovascular Research
- Medical Imaging
Background:
- Isolated ventricular noncompaction (IVNC) is an unclassified cardiomyopathy associated with heart failure and sudden cardiac death.
- The underlying pathophysiologic mechanisms of IVNC remain largely unknown.
- Understanding IVNC pathophysiology is crucial for improving patient outcomes.
Purpose of the Study:
- To investigate the association between microcirculatory dysfunction and isolated ventricular noncompaction (IVNC).
- To quantitatively assess myocardial perfusion and coronary flow reserve in IVNC patients.
- To determine if microcirculatory dysfunction is localized to noncompacted segments or more widespread.
Main Methods:
- Positron emission tomography with (13)N-ammonia was used to measure myocardial blood flow (MBF) and coronary flow reserve (CFR).
- 12 patients with IVNC and 14 control subjects were included in the study.
- Left ventricular myocardium was segmented, and CFR was compared with echocardiographic findings of noncompaction and wall motion abnormalities.
Main Results:
- Patients with IVNC exhibited significantly reduced CFR (2.1+/-0.8) compared to controls (4.2+/-0.9).
- Perfusion defects were more common in noncompacted segments (14/24) than normal segments (84/76).
- Decreased CFR was observed in most segments with wall motion abnormalities (45/57), indicating widespread microcirculatory dysfunction.
Conclusions:
- Coronary microcirculatory dysfunction is a significant finding in patients with isolated ventricular noncompaction (IVNC).
- The observed dysfunction extends beyond noncompacted segments, affecting areas with wall motion abnormalities.
- These findings highlight the importance of assessing microvascular function in IVNC management.
Objectives:
We sought to analyze whether a microcirculatory dysfunction might be associated with isolated ventricular noncompaction (IVNC).
Background:
In IVNC, which is a cardiomyopathy thus far "unclassified" by the World Health Organization, heart failure and sudden cardiac death are common findings, but the pathophysiologic mechanisms are unknown.
Methods:
In 12 patients with IVNC and 14 control subjects, quantitative evaluation of regional myocardial perfusion (myocardial blood flow [MBF]) and coronary flow reserve (CFR, hyperemic/baseline MBF) was performed using positron emission tomography and (13)N-ammonia. The left ventricular myocardium was divided into nine segments, and the two-dimensional echocardiogram in each patient with IVNC was compared with CFR in each segment. Noncompaction was defined as a two-layered structure with excessive trabeculation.
Results:
The CFR in control subjects averaged 4.2+/-0.9, providing a cut-off value > or =2.5, but it was 2.1+/-0.8 in patients with IVNC. A perfusion scan defect was found in 14 of 24 segments with noncompaction, although no defect was found in 76 of 84 normal segments (overall agreement 83%, p < 0.0001 by the chi-square test). In 16 of 21 segments with noncompaction, a decreased CFR was found; but a decreased CFR was also found in 36 of 60 segments without noncompaction (p = NS). In 45 of the 57 segments with wall motion abnormalities, CFR was decreased, but it was preserved in 17 of the 24 segments with normal wall motion (agreement 77%, p < 0.0001).
Conclusions:
In patients with IVNC, a decreased CFR is not confined to noncompacted segments, but extends to most segments with wall motion abnormalities. Thus, coronary microcirculatory dysfunction is associated with IVNC.