Linear and nonlinear parameters of heart rate variability in ischemic stroke patients.

INTRODUCTION: Cardiovascular system presents cortical modulation. Post-stroke outcome can be highly influenced by autonomic nervous system disruption. Heart rate variability (HRV) analysis is a simple non-invasive method to assess sympatho-vagal balance. OBJECTIVES: The purpose of this study was to investigate cardiac autonomic activity in ischemic stroke patients and to asses HRV nonlinear parameters beside linear ones. METHODS: We analyzed HRV parameters in 15 right and 15 left middle cerebral artery ischemic stroke patients, in rest condition and during challenge (standing and deep breathing). Data were compared with 15 age- and sex-matched healthy controls. RESULTS: There was an asymmetric response after autonomic stimulation tests depending on the cortical lateralization in ischemic stroke patients. In resting state, left hemisphere stroke patients presented enhanced parasympathetic control of the heart rate (higher values for RMSSD, pNN50 and HF in normalized units). Right hemisphere ischemic stroke patients displayed a reduced cardiac parasympathetic modulation during deep breathing test. Beside time and frequency domain, using short-term ECG monitoring, cardiac parasympathetic modulation can also be assessed by nonlinear parameter SD1, that presented strong positive correlation with time and frequency domain parameters RMSSD, pNN50, HFnu, while DFA α1 index presented negative correlation with the same indices and positive correlation with the LFnu and LF/HF ratio, indicating a positive association with the sympatho-vagal balance. CONCLUSIONS: Cardiac monitoring in clinical routine using HRV analysis in order to identify autonomic imbalance may highlight cardiac dysfunctions, thus helping preventing potential cardiovascular complications, especially in right hemisphere ischemic stroke patients with sympathetic hyperactivation.

[The association of VAC® therapy, titanium plates osteosynthesis and bilateral pectoral muscle flaps in the management of postoperative mediastinitis in an obese and diabetic patient]. / Intérêt de l'association VAC®-thérapie, ostéosynthèse sternale et lambeaux pectoraux d'avancement dans la prise en charge d'une médiastinite postopératoire après chirurgie cardiaque chez une obèse diabétique.

Postoperative mediastinitis is one of the most worrisome complications after heart surgery. Until now there is no universally accepted strategy in the management of this infectious complication. Recently, various novel techniques like negative pressure therapy and titanium plates sternal reconstruction have allowed a dramatic decrease of mortality and morbidity after mediastinitis. We report the case of a diabetic patient suffering from morbid obesity who developed a severe postoperative mediastinitis after a coronary artery bypass; she was successfully treated by combining negative pressure therapy, titanium plates osteosynthesis and bilateral pectoral muscle flaps.

Dramatic improvement in survival after lung transplantation over time: a single center experience.

Lung transplantation (LT) is a recognized procedure for selected patients with end-stage respiratory failure. We performed 123 LT, including 32 single lung, 84 double lung, and 7 heart-lung transplantations in 48 patients with chronic obstructive pulmonary disease (COPD), 13 patients with pulmonary hypertension (PH), 33 with cystic fibrosis (CF), and 29 with interstitial lung disease (ILD) between July 1990 and January 2008. Survival was compared for periods before and after December 2001. The mean age of patients was 44.4 years (range 16-66.5 years); 84 (69%) were men. Before LT, 1 second forced expiratory volume was 28.7% +/- 18.1% and PaCO(2) = 6.3 kPa. Fifty-five patients were on noninvasive ventilation. Cold ischemia time was 320 +/- 91 minutes. Cardiopulmonary bypass (CPB) was used in 77 patients (64%). There were 18 early surgical reinterventions, 8 extracorporeal membrane oxygenations, and 38 bronchial stent insertions among 206 at-risk bronchial sutures. Crude survivals were 69%, 58%, 41%, and 18% at 1, 2, 5, and 10 years, respectively. Comparing before (n = 70 with 15 CF) vs after December 2001 (n = 53 with 17 CF), survivals were 63% vs 78%, 51% vs 71%, and 33% vs 60% at 1, 2, and 5 years, respectively (P = .01) and for CF patients, 52% vs 100%, 52% vs 94%, and 25% vs 94% at 1, 2, and 5 years, respectively (P = .005). There was significant improvement in survival before and after 2001 in 123 LT and particularly among CF patients. Improvement in survival after LT may be related to the sum of numerous changes in our practice since December 2001, including the use of pulmonary rehabilitation pre-LT, extracellular pneumoplegia, statins, macrolides for chronic rejection, monitoring of Epstein-Barr blood load, changes in maintenance immunosuppressants, as well as position movement up the coordinator nurse and learning curve.

Characteristics and possible mechanisms of low-Na+ induced contractions in rat aorta.

The influence of reducing external Na+ concentration ([Na+]ex) upon vascular smooth muscle contractility was investigated using the rat isolated aorta. NaCl from the physiological saline solution (PSS) was replaced with either choline-Cl, sucrose, or LiCl to give the following [Na+]ex (mM): 115, 85, 55, and 25 (115NaPSS to 25NaPSS). Small reductions in [Na+]ex (115NaPSS) induced a biphasic contraction, comparable in amplitude with the control one induced by phenylephrine 10(-6) M. Elimination of the endogenous catecholamine participation using either phentolamine 10(-5) M or guanethidine 3.10(-6) M similarly reduces these contractions to 25% (sucrose replacement). A similar relaxing effect was obtained with D600 10(-5) M, an antagonist of the voltage operated Ca2+ channels (25-30% residual tension for all the substitutes). Large reductions in [Na+]ex (25NaPSS) induced contractions comparable in amplitude and shape, but less sensitive to phentolamine and guanethidine (residual tension 65-75%, sucrose replacement) and insensitive to D600 (all the substitutes). The Na+/K+ ATPase inhibitor ouabain (10(-4) M) elicited slowly developing contractions, the amplitude being 115% of the phenylephrine 10(-6) M control. Phenylephrine further contracted the 115NaPSS precontracted preparations, but was significantly less effective in 25NaPSS, although the precontraction levels were similar for the same substitute used. The amplitude of the superimposed phenylephrine contractions exhibited [Na+]ex dependence. Phenylephrine 10(-6) M failed to further contract the ouabain 10(-4) M precontracted rings. We conclude that relatively small reductions in [Na+]ex are able to induce contractions of rat aorta primarily through release of endogenous catecholamines, probably through neural Na+/Ca2+ exchange. Larger reductions in [Na+]ex appear to cause contraction through muscular Na+/Ca2+ exchange.