Hemodynamic effects of dobutamine and dopexamine after cardiopulmonary bypass in pediatric cardiac surgery*

Background: After surgical repair of congenital heart disease, inotropic support is sometimes necessary to wean from cardiopulmonary bypass. In pediatric cardiac surgery, dobutamine and dopamine are often used as inotropic support. Dopexamine is a synthetic catecholamine, which has positive inotropic and vasodilating properties. Because the hemodynamic effects of catecholamines are modified after cardiopulmonary bypass, the aim of this study was to investigate the effects of dobutamine and dopexamine on cardiac index and systemic vascular resistance index after cardiopulmonary bypass in pediatric cardiac surgery. Methods: The study was performed in a prospective, randomized, and double‐blinded cross‐over design. The investigation included 11 children for elective, noncomplex congenital heart surgery. After weaning from cardiopulmonary bypass and a 20‐min period of steady state, children received either 2.5 μg·kg^?1·min^?1 dobutamine or 1 μg·kg^?1·min^?1 dopexamine for 20 min. Cardiac index (transpulmonary thermodilution), mean arterial pressure, central venous pressure, stroke volume, systemic vascular resistance, and central venous oxygen saturation were determined. The primary outcome variable was cardiac index. Results: No difference in cardiac index was observed between the two groups (P = 0.594). Both drugs increased cardiac index, dopexamine from 3.9 ± 0.6 to 4.7 ± 0.8 l·min^?1·m^?2 (P = 0.003) and dobutamine from 4.1 ± 0.7 to 4.8 ± 0.7 l·min^?1·m^?2 (P = 0.004). During treatment with dobutamine, children presented with significantly higher mean arterial pressure (P = 0.003) and systemic vascular resistance index (P = 0.026). Conclusions: This trial demonstrates that low‐dose dobutamine and dopexamine both increase cardiac index during pediatric cardiac surgery but with different hemodynamic effects.     

Recurrence of pleomorphic adenoma of the parotid gland—predictive value of cadherin‐11 and fascin

The predictive value of cadherin‐11, tenascin, fascin, and mucin‐1 as markers for the likelihood of recurrence in pleomorphic adenoma of the parotid gland was examined. In this retrospective study we analysed 20 tumours from16 patients by immunohistochemistry. Staining intensities were measured using a semiquantitative scoring approach; localisation (tumour centre vs border) as well as clinical data were analysed and correlated with follow‐up. Cadherin‐11 was increased in recurrent tumours. However, no changes of fascin, tenascin or mucin‐1 were observed. Cadherin‐11 and fascin were increased in primary tumours of patients with later recurrence, with fascin upregulation restricted to the tumour border. In conclusion, cadherin‐11 and fascin should be further analysed for their value as markers for later recurrence in pleomorphic adenoma. Our observations might reflect dysregulation of cellular pathways contributing to cellular dissemination, which might potentially result in later recurrence.     

Exercise Chronotropy in Patients with Normal and Impaired Sinus Node Function After Cardiac Transplantation

The chronotropic response during graded, symptom limited exercise was investigoted in 32 cardiac transplant recipients a mean of 49 ± 18 days after transplantation. All patients had systematic evaluation of postoperative donor sinus node (SN) function and the cardioacceleratory response was compared according to the SN function. Twenty-one patients had normal postoperative SN studies (corrected SN recovery time < 520 msec, group I) while the SN function was impaired postoperatively in the remainder (n = 11, group II; corrected SN recovery time 4,149 ± 6,283 msec in 5 patients, junctionai escape rhythm in 6 patients). All patients had regained sinus rhythm at time of the exercise test Patients in group II had lower basal sinus rates at the beginning of exercise (91.5 ± 11 vs 101.4 ± 7 beats/min, P < 0.02). This lower chronotropy was maintained over every incremental step (F_{rato between groups}= 30, P = 0.0001, F_{rate vs workload}= 15, P = 0.0001 by two-way ANOVAJ and resulted in a significantly lower heart rate at individual peak exercise (108.3 ± 20 vs 124.2 ±13 beats/min, P < 0.02). A total of 14/16 patients in group I but only 2/16 patiejils in group 11 accomplished a peak heart rate ± 120 beats/min (P = 0.009). The workload achieved did not differ between the groups (107 ± 29 vs 102 ± 32 watts, P > 0.5). These data show a lower SN chronotropy during rest and at peak exercise in cardiac transplant recipients with postoperative SN deficiency and apparent normalization of SN fundion.     

The distribution of cartilage thickness within the joints of the lower limb of elderly individuals

The objective of this study was to investigate the normal distribution of cartilage thickness in the major joints of the lower limb in elderly individuals. A 12.5 MHz ultrasound transducer was used to measure the cartilage thickness in the right and left hip, knee and ankle joint of 10 individuals aged between 62 and 99 y. Distribution patterns of cartilage thickness were derived by b-spline interpolation and the average distribution computed in each surface. The maximum cartilage thickness in the hip joint was 2.6 (±0.36) mm and the mean thickness 1.3 (±0.17) mm. The CV% (a measure of thickness inhomogeneity within the joint surface) was 32%. In the knee, the maximal and mean values were 3.8 (±0.46) mm and 1.9 mm (±0.24) mm, respectively (CV%=34%), and in the ankle 1.7 (±0.25) mm and 1.0 (±0.16) mm (CV%=32%). Systematic differences existed between both sides in the knee, the distal femur showing a significantly greater thickness on the right. While the mean and maximal thicknesses were systematically higher in the knee than in the hip, and in the hip higher than in the ankle ( P <0.05), there were no systematic differences in the thickness inhomogeneity of the 3 joints. Only the malleolus showed a somewhat more uniform thickness than the other joint surfaces. The variablity between individuals was similar for all joints for mean thickness, but the interindividual variability of the maximal thickness values was highest in the knee and lowest in the ankle. Whereas the cartilage thickness distributions in the joints of the lower limb have been suggested to reflect the pressure distribution within the articular surface, the absolute thickness is proposed to be a function of dynamic loading (range of motion) during gait, rather than being a reflection of the static articular pressure.     

Myocardial Drainage via Thebesian Veins: Demonstration by Contrast Enhanced Color Doppler

In order to increase the sensitivity of color Doppler imaging, 15 patients with ischemic heart disease were evaluated before and after intravenous injections of 10 mL SH U 508 (200 mg/mL). This new contrast agent contains stabilized microbubbles capable of transpulmonary passage and it is expected to enhance left ventricular flow display. After injection of SH U508, left ventricular filling and outflow were imaged in brighter colors and on wider areas than in the baseline study: the display of filling (percentageof thecross-sectionalarea) increasedfrom 30%± 14% (mean value ± standard deviation) to 54%± 16%, P < 0.01, the display of outflow increased from 27%± 13% to45%± 15%, P < 0.01, respectively. In addition, color Doppler imaging with SH U 508 demonstrated single or multiple mosaic flow patterns, which were different from the flow areas in the inflow and outflow tracts. The additional flow areas were found during systole and diastole and originated from the apical myocardium in most of the patients. Further clinical and angiographic investigation revealed no evidence of coronary artery fistulas to the left ventricle. Color Doppler after intravenous injection of SH U 508 provides improved display of left ventricular filling and outflow. In addition, flow patterns are displayed that probably represent myocardial drainage by Thebesian veins. (ECHOCARDIOGRAPHY, Volume 8, September 1991)     

Echocardiographic and Electrocardiographic Predictors for Atrial Fibrillation Recurrence Following Cardioversion

Introduction: Identification of suitable candidates for cardioversion currently is not based on individual electrical and mechanical atrial remodeling. Therefore, this study analyzed the meaning of atrial fibrillatory rate obtained from the surface ECG (as a measure of electrical remodeling) and left atrial size (as measure of mechanical remodeling) for prediction of early atrial fibrillation (AF) recurrence following cardioversion.
Methods and Results: Forty-four consecutive patients (26 men and 18 women, mean age 62 ± 11 years, no antiarrhythmic medication at baseline) with persistent AF were studied. Fibrillatory rate was obtained from high-gain, high-resolution surface ECG using digital signal processing (filtering, QRST subtraction, Fourier analysis) before electrical cardioversion. Univariate and multivariate regression analysis revealed larger systolic left atrial area (Beta = 0.176, P = 0.031) obtained by precardioversion echocardiogram from the apical four-chamber view and higher atrial fibrillatory rate (Beta = 0.029, P = 0.021) to be independent predictors for AF recurrence (n = 13). Stratification based on the regression equation (electromechanical index [EMI]= 0.176 systolic left atrial area + 0.029 fibrillatory rate − 17.674) allowed identification of groups at low, intermediate, or high risk. No patient with an EMI < −1.85 had early AF recurrence, as opposed to 78% with an EMI > −0.25. Intermediate results (40% recurrence rate) were obtained when the calculated EMI ranged between −1.85 and −0.25 (P < 0.001).
Conclusion: Fibrillatory rate obtained from the surface ECG and systolic left atrial area obtained by echocardiography may predict early AF recurrence in patients with persistent AF. These parameters might be useful in identifying candidates with a high likelihood of remaining in sinus rhythm after cardioversion. (J Cardiovasc Electrophysiol, Vol. 14, pp. S162-S165, October 2003, Suppl.)     

Evolution of Cardiac Autonomic Nervous Activity Indices in Patients Presenting with Transient Left Ventricular Apical Ballooning

Backround: Transient left ventricular (LV) apical ballooning (AB) is characterized by a rapidly reversible, acute LV systolic dysfunction, triggered by physical or emotional stress. Despite observations strongly suggesting catecholamine-mediated myocardial stunning due to enhanced sympathetic activity, the early time course of heart rate variability (HRV) has not been described.
Methods: We prospectively enrolled 39 consecutive patients (median age = 68 years, range 35–85 years, 38 women) with LV AB. Indices of HRV were extracted from 24-hour ambulatory electrocardiograms on the day of hospital admission, on days 2 and 3, and 3 months after the hospitalization.
Results: Within 48 hours after hospital admission, the indices of HRV were markedly depressed (standard deviation of normal-to-normal [NN] intervals [SDNN] 89.6 ± 19.9 ms; mean standard deviation of NN intervals for 5-minute segments [SDNNi] 37.8 ± 6.2 ms; root mean square of consecutive difference of normal-to-normal intervals [rMSSD] 23.0 ± 9 ms; standard deviation of the averages of NN intervals for all 5-minute segments [SDANN] 70.1 ± 18.0 ms; geometric triangular index [TI] 23.7 ± 5.9 ms), recovered in the subacute phase and had normalized at 3 months follow-up (SDNN 124.7 ± 24 ms; SDNNi 47.1 ± 5.7 ms; rMSSD 31.1 ± 10.5 ms; SDANN 118.5 ± 27 ms; TI 31.2 ± 8 ms; all P < 0.05). Mean RR-interval increased from 845 ± 121 ms on day 1, to 929 ± 84 ms at 3 months (P = 0.06).
Conclusions: A marked depression of cardiac parasympathetic activity was observed in the acute phase of LV AB, followed by recovery of autonomic modulation between the subacute and the chronic phases. The rapid return of parasympathetic function may partially explain the favorable outcomes of patients presenting with LV AB.