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[Effect of low dobutamine doses dobutamine on left ventricular diastolic flow parameters in subjects with a low
Andrzej Wojtarowicz1, Robert Kaliszczak, Edyta Płońska
1Klinika Kardiologii PAM, 70-111 Szczecin, al. Powstańców Wlkp. 72. wojtaro@sci.pam.szczecin.pl
Unlabelled:
A low dobutamine dose (DOB) improves the systolic function of impaired myocardium. There are some data suggesting the improvement of left ventricular (LV) diastolic function as well. The aim of this work was to assess the influence of DOB on some left ventricular diastolic flow parameters: inflow curve profile and early inflow wave propagation velocity (Prop).
Material And Methods:
33 persons (7 women and 26 men) aged 35-74, with a mean age of 53 and with an ejection fraction (EF) < 35% were examined. DOB was administered in doses of 5 and 10 micrograms/kg/min every 3 minutes. At the beginning of the examination (D-0) and at the end (D-1), the LV contractility and the following inflow parameters were assessed: E and A waves velocities, E/A-ratio on mitral orifice level (U) and at the half of LV (1/2 LV) and Prop.
Results:
DOB increased the heart rate from 69.4/min to 74.4/min (p < 0.01) and improved the LV contractility in every case. We observed no significant changes of the E wave velocity influenced by DOB on U (D-O: 0.7 +/- 0.22 m/s; D-1: 0.68 +/- 0.2 m/s) and in 1/2 LV, or no E/A changes (D-O: 1.24 +/- 0.71; D-1 1.21 +/- 1.08 on U and D-O: 1.68 +/- 1.06; D-1: 1.64 +/- 1.16 in 1/2 LV). Statistically significant differences were recorded only between A in D-O and A in D-1 on both levels (p < 0.05): D-O was 0.66 +/- 0.21 m/s and D-1 was 0.71 +/- 0.22 m/s on U and D-O was 0.422 +/- 0.2 m/s and D-1 was 0.47 +/- 0.2 m/s in 1/2 LV. Significant Prop shortening was ascertained: from 39.4 +/- 10.9 cm/s to 45.4 +/- 16.1 cm/s; p < 0.01. The correlation registered at rest between Prop and EF (R = 0.4) and Prop and contractility index (R = -0.52), was recorded at a similar level after DOB as well. No correlation between Prop and heart rate was seen.
Conclusions:
1. Dobutamine in low doses in subjects with impaired LV causes no significant heart rate acceleration and no progression in contractility disorders, improves LV diastolic function, expressed by early diastolic blood flow towards the apex (inflow propagation) acceleration. 2. Dobutamine in low dose increases mitral A wave velocity caused by improvement of LV diastolic function and/or improvement of LA contractility.