Non-dilated left ventricular cardiomyopathy vs. dilated cardiomyopathy: clinical background and outcomes

Area of Science:

• Cardiology
• Cardiovascular Medicine
• Heart Failure Research

Background:

• Non-dilated left ventricular cardiomyopathy (NDLVC) is a proposed cardiomyopathy category characterized by preserved left ventricular (LV) dimensions despite wall motion abnormalities or scar.
• The clinical profile and prognostic implications of NDLVC, particularly with reduced LV ejection fraction (NDLVC-REF), remained unclear compared to traditional dilated cardiomyopathy (DCM).

Purpose of the Study:

• To investigate the clinical characteristics and cardiac event rates of patients diagnosed with NDLVC and reduced LV ejection fraction (NDLVC-REF).
• To compare NDLVC-REF patients with those diagnosed with dilated cardiomyopathy (DCM).

Main Methods:

• Retrospective analysis of 363 patients with newly diagnosed non-ischemic cardiomyopathy and reduced LV ejection fraction (<50%) from December 2004 to January 2018.
• Patients were categorized as NDLVC-REF (n=80) if LV dimension index was ≤31 mm/m² (men) or ≤34 mm/m² (women), and as DCM otherwise.
• Cardiac events included sudden cardiac death and heart failure rehospitalization; follow-up median was 68.8 months.

Main Results:

• NDLVC-REF patients exhibited a higher prevalence of atrial fibrillation and higher baseline LV ejection fraction compared to DCM patients.
• LV ejection fraction remained higher and LV end-diastolic diameter smaller in NDLVC-REF versus DCM throughout follow-up.
• No significant difference in cardiac event rates was observed between NDLVC-REF and DCM groups (P=0.349).
• A subset of NDLVC-REF patients (14%) who developed LV dilatation post-diagnosis showed a significantly higher risk of cardiac events (P=0.049).

Conclusions:

• NDLVC-REF and DCM share similar overall cardiac event rates, suggesting comparable long-term prognoses for these conditions.
• A significant proportion (18%) of NDLVC-REF patients experiencing LV dilatation after diagnosis had poor outcomes.
• Both NDLVC-REF and DCM patients warrant equivalent clinical attention, regular follow-up, and consistent assessment of LV function.