P4681Early findings in patients with noncompaction cardiomyopathy and normal ejection fraction: a cardiopulmonary exercise test, echocardiographic and biomarkers study

Background

Noncompaction cardiomyopathy (NCC) is a cardiomyopathy with controversial diagnostic criteria. Furthermore, it has been discussed whether asymptomatic individuals with normal left ventricular (LV) ejection fraction (EF) and diagnostic criteria for this disease could be classified as NCC. Therefore, the objective of this study was to evaluate the functional capacity of patients with NCC and the relation with echocardiographic and biomarkers indices.

Methods

Fifty-nine patients with NCC were prospectively divided into three groups: ejection fraction (EF)>50% (G1), EF between 40 - 50% (G2) and EF <40% (G3). In addition, 11 normal healthy volunteers were selected for control group (CG). All subjects underwent 2D echocardiography with tissue Doppler and myocardial deformation indices, cardiopulmonary exercise test (CPET), troponin I and BNP measurements.

Results

There was a decrease in VO2 peak (ml/km/min) in all NCC groups compared to CG (GC= 34.5±5.3, G1= 25.56±5.6, G2= 25.12±7.7 and G3= 21.86±6.3 ml/kg/min, p<0.001), but no difference was shown among NCC patients (p=0.37). In addition, the VO2 at anaerobic threshold (AT) was lower in all NCC groups compared to CG (GC= 22.88±3.3, G1= 17.30±4.7, G2= 18.58±5.2, e G3= 15.65±3.7 ml/kg/min, p<0.001). There was an increase in indexed ventricular mass in all NCC groups when compared to CG (p<0.001), but it was similar among NCC groups (p=0.72). Regarding to diastolic function, G2 and G3 presented a reduction in the peak velocity of the septal E' when compared to the control group (GC= 14.0±2.4, G2= 8.92±3.0 e G3= 6.86±3.9 cm/s, p<0,001), while E/E' was increased in G3 compared to all groups (p<0.001). G2 and G3 presented a decrease in global longitudinal strain (GLS) when compared to CG and G1 (p<0.001). The BNP levels were higher in G3 compared to the other groups (p<0.05), but no difference was found in troponin I levels. There was a positive correlation between VO2 peak and E' (r=0.56, p<0.001) and a negative correlation between VO2 peak and E/E' (r=−0.53, p<0.001). In addition, there was an inverse correlation between VO2 peak and BNP (r=−0.50, p<0.001).

Conclusion

Our results show that NCC patients present alterations in functional capacity, echocardiographic indices and biomarkers values according to LV dysfunction. Moreover, patients with preserved LV function already present predominant alterations in CPET suggesting subclinical myocardial dysfunction. For this reason, clinical treatment could be considered in this initial stage of this disease.