The potential impact of the tension of the pelvic muscles on set-up errors in radiotherapy for pelvic malignancies

The purpose of the study reported here was to evaluate the potential impact of the tension of pelvic muscles on set-up errors. Twenty-nine consecutive patients with rectal cancer were included. The treatment simulation of the lateral beam in prone position was performed twice-with relaxed and next with maximally tense pelvic muscles. During the second simulation, the couch was moved so as to align the centre of the beam with the actual position of the skin mark tattooed during the first simulation. The bony landmarks on both images of corresponding lateral fields were matched. The beam's centre displacement and the rotation were measured using the beam image taken in relaxed position as a reference. The absolute values were used in calculation of the mean. For the anterior-posterior direction, the mean value of displacements was 15.3 mm, standard deviation (SD) 6.9 mm and the maximal value 37 mm. For the cranial-caudal direction, the mean value was 4.4 mm, SD 4 mm and the maximal value 17 mm. The mean rotation of the pelvis was 5.3 degrees, SD 2.4 degrees and maximal rotation 11 degrees. The majority of displacements were in the posterior (86%) and caudal (55%) directions. The majority of rotations were clockwise (76%). It was shown that pelvic muscle tension was the reason for anal verge displacements and mispositionings of the shielding block. This results in set-up inaccuracy, especially in the anterior-posterior direction, shielding block mispositioning and anal verge displacement.     

Mesenteric vascular dysfunction after cardiopulmonary bypass with cardiac arrest is aggravated by coexistent heart failure

Although patients suffering from heart failure (HF) have an increased incidence of nonocclusive mesenteric ischemia after opened heart surgery, the impact of cardiopulmonary bypass with cardiac arrest (CPB) on mesenteric vascular circulation in such situation remains unexplored. Therefore, the present study investigates the effects of CPB on mesenteric vascular reactivity, regional metabolism, and oxidative stress in an experimental model of HF. Volume-overload HF was induced in six dogs by bilateral femoral arteriovenous fistula. Six sham-operated dogs were used as controls. Eight weeks later, the short-term effects of 90 min of CPB were assessed in vivo during acute experiments. The significant increase in left ventricular end-diastolic volume in HF animals did not influence the vasodilator response of the superior mesenteric artery to acetylcholine (ACH) and nitroprusside (SNP) under baseline conditions. However, reduced mesenteric oxygen delivery, increased oxygen extraction, and lactate release were found during CPB in the HF group. In addition, an increased free radical production was assessed in the HF group during (89 +/- 23 x 10 relative light units [RLU]) and after CPB (93 +/- 15 x 10 RLU) compared with controls (45 +/- 15 and 49 +/- 7 x 10 RLU, respectively). Finally, 90 min of CPB led to a more pronounced decrease of ACH- (-22% +/- 5% vs. -42% +/- 9%, P < 0.05) and SNP- (-14% +/- 4% vs. -50% +/- 7%, P < 0.002) induced mesenteric vasodilations in the HF group compared with controls. We conclude that coexistent HF significantly enhances the pathological effects of CPB on the mesenteric vascular circulation by additionally altering endothelial and smooth muscle vascular function consequent to augmented oxidative stress.     

Pharmacological and ablative hybrid therapy of atrial fibrillation Long-term effect on quality of life and arrhythmia-related symptoms

The pharmacological and ablative hybrid therapy of atrial fibrillation (AF) consists of radiofrequency catheter ablation of antiarrhythmic drug-induced typical atrial flutter (AFl) and continuation of drug therapy. The purpose of this study was to determine the effect of this therapy on AF symptoms and quality of life (QoL). Forty-six patients were monitored after isthmus-ablation of drug-induced typical AFl and continuation of their antiarrhythmic drug treatment over a mean follow-up of 22.4±11.6 months. AF characteristics, symptoms and QoL before and after ablation were evaluated by the SF-36 question- naire, the Symptoms Checklist-Frequency and Severity Scale and the analysis of ECG recordings. 63% of patients demonstrated recurrences of AF. However, the frequency and duration of symptomatic episodes significantly decreased in 82.6 and 76% of patients. All categories of the SF-36 improved significantly and the AF symptomatology showed a relevant attenuation in 65.8% of the study population.

Conclusion  

The pharmacological and ablative hybrid therapy significantly reduced the mean number and the duration of symptomatic AF episodes as well as AF-correlated symptoms and was associated with significant QoL improvement.