Comparison of Clinical Course and Outcomes between Dilated and Hypokinetic Non-Dilated Cardiomyopathy

Background: By definition, dilated cardiomyopathy (DCM) is characterized by enlargement of the left ventricular (LV) cavity, and systolic dysfunction. However, in 2016 ESC introduced a new clinical entity - hypokinetic non-dilated cardiomyopathy (HNDC). HNDC is defined as LV systolic dysfunction without LV dilatation. However, the diagnosis of HNDC has so far rarely been made by a cardiologist, and it is unknown whether "classic" DCM differs from HNDC in terms of clinical course and outcomes.

Objectives: Comparison of heart failure profiles and outcomes between patients with "classic" dilated (DCM) and HNDCs.

Method: We retrospectively analysed 785 DCM patients, defined as impaired left ventricle (LV) systolic function (ejection fraction [LVEF] <45%) in the absence of coronary artery disease, valve disease, congenital heart disease, and severe arterial hypertension. "Classic" DCM was diagnosed when LV dilatation was present (LV end-diastolic diameter >52 mm/58 mm in women/men); otherwise, HNDC was diagnosed. After 47 ± 31 months, the all-cause mortality and composite endpoint (all-cause mortality, heart transplant - HTX, left ventricle assist device implantation - LVAD) were assessed.

Results: There were 617 (79%) patients with LV dilatation. Patients with "classic" DCM differed from HNDC in terms of clinically relevant parameters [hypertension (47% vs. 64%, p = 0.008), ventricular tachyarrhythmias (29% vs. 15%, p = 0.007), NYHA class (2.5 ± 0.9 vs. 2.2 ± 0.8, p = 0.003)], had lower cholesterol (LDL: 2.9 ± 1.0 vs. 3.2 ± 1.1 mmol/L, p = 0.049), and higher N-terminal pro-brain natriuretic peptide (3,351 ± 5,415 vs. 2,563 ± 8584 pg/mL, p = 0.0001) and required higher diuretics dosages (57.8 ± 89.5 vs. 33.7 ± 48.7 mg/day, p ≤ 0.0001). All of their chambers were larger (LVEDd: 68.3 ± 4.5 vs. 52.7 ± 3.5 mm, p < 0.0001) and they had lower LVEF (25.2 ± 9.4 vs. 36.6 ± 11.7%, p < 0.0001). During the follow-up, there were 145 (18%) composite endpoints ("classic" DCM vs. HNDC: 122 [20%] vs. 26 [18%], p = 0.22): deaths (97 [16%] vs. 24 [14%], p = 0.67), HTX (17 [4%] vs. 4 [4%], p = 0.97) and LVAD (19 [5%] vs. 0 [0%], p = 0.03). Both groups did not differ in terms of all-cause mortality (p = 0.70), cardiovascular (CV) mortality (p = 0.37) and composite endpoint (p = 0.26).

Conclusions: LV dilatation was absent in more than one-fifth of DCM patients. HNDC patients had less severe heart failure symptoms, less advanced cardiac remodelling, and required lower diuretics dosages. On the other hand, "classic" DCM and HNDC patients did not differ in terms of all-cause mortality, CV mortality, and composite endpoint.