Introduction: The study of importance of left ventricular contractile reserve presence and changes plasma brain natriuretic peptide levels (BNP) during exercise in patinets with idiopathic dilated cardiomyopathy is very popular today, but these two parametres have rarely been interconnected. The study of response BNP during echocardiography stress tests in patients with idiopathic dilated cardiomyopathy with or without preserved left ventricular contractile reserve. We studied 55 consecutive patients with idiopathic dilated cardiomyopathy (mean age 54.98 ± 9.84, 49 (89.1%) male) treated in the outpatient clinic for heart failure at the Institute of Cardiovascular Diseases "Dedinje". All the patients underwent the echocardiography stress test. Contractile reserve was assessed by measuring of the changes of the left ventricle ejection fraction basally and in the first minute after the strongest stress. Level of BPN was measured at rest, in the first minute and after 20 minutes of maximal exercise stress. Following the kinetics of BNP level during stress testing, we find that in patients with preserved left ventricular contractile reserve BNP level is rising at maximum load achieved (Mediana (IQR) - 59 (22-113) vs. 91 (37-135) vs. 78 (30-159) ng/L, p<0.001), whereas in patients without preserved left ventricular contractile reserve BNP level does not change significantly (Mediana (IQR) – 89 (50-322) vs. 119.5 (61.3-321.8) vs. 136 (72- 281), p=0.102). The increase in BNP in the peak load compared to its value at rest was positively correlated with preserved contractile reserve (r=0.38, p=0.009), better WMSI at rest (r=-0.28, p=0.04), greater difference in the double product (r=0.40, p=0.002), as well as the work accomplished on the test (r = 0.47, p <0.001), and longer duration of the test (r = 0.43, p = 0.001). The increase in BNP during physical exercise in patients with idiopathic dilated cardiomyopathy suggests a preserved contractile reserve of the left ventricle.

Očuvana kontraktilna rezerva leve komore podrazumeva sposobnost hipokinetičnih segmenata miokarda da pod dejstvom različitih inotropnih stimulusa poprave svoju kontraktilnost. Utvrditi razlike u kliničkim karakteristikama kod pacijenata sa dilatacionom kardiomiopatijom u zavisnosti od očuvane kontraktilne rezerve leve komore. U studiju je uključeno uzastopnih 55 bolesnika sa idiopatskom dilatativnom kardiomiopatijom. Svim bolesnicima uključenim u studiju urađen je stres ehokardiografski test fizičkim opterećenjem po standardnom protokolu. Postojanje očuvane kontraktilne rezerve je određivano uz pomoć promene ejekcione frakcije leve komore. Prosečna starost ispitivanih bolesnika je bila 54,98 ± 9,84 godina, 49 (89,1%) je bilo muškog pola. Na osnovu promene ejekcione frakcije leve komore kao kriterijuma kontraktilne rezerve leve komore, očuvanu kontraktilnu rezervu je imalo 25 bolesnika (45,5%). Bolesnici bez očuvane kontraktilne rezerve leve komore znatno češće u anamnezi imaju zastupljenu arterijsku hipertenziju (46,7 vs. 20,0%, p=0,038). Nema značajne razlike u zastupljenosti ostalih faktora rizika. Pacijenti sa očuvanom kontraktilnom rezervom leve komore imaju manju dimenziju leve komore na kraju sistole (49,64 ± 7,26 vs. 55,27 ± 8,36 mm, p=0.011), manji indeks volumena leve komore na kraju dijastole (77,35 ± 26,41 vs. 94,59 ± 34,97 ml/m2, p=0,005) i na kraju sistole (59,31 ± 26,05 vs. 78,62 ± 34,42 ml/m2, p=0,002), veću ejekcionu frakciju leve komore (25,48 ± 8,32 vs. 18,33 ± 6,49%, p=0,002) i niži indeks pokreta zidova leve komore (2,23 ± 0,27 vs. 2,48 ± 0,27, p=0,002). Kod bolesnika sa očuvanom kontraktilnom rezervom leve komore nalazimo manju zastupljenost arterijske hipertenzije i morfološki i funkcionalno manje oštećenu levu komoru.