Chaos attractors of ventricular elastance to evaluate cardiac performance

Quantitative evaluation of cardiac function is very important in the clinical application of a ventricular assist device. This article reports a new evaluating method of E max, which is the most reliable parameter to evaluate cardiac function. Fluctuation in the E max time series data was evaluated by the nonlinear mathematical analyzing method including chaos and fractal theory. Experimental goats were anesthetized with halothane inhalation, and left ventricular volume and pressure were measured with other hemodynamic parameters to evaluate E max during various drug administrations. E max was evaluated by two methods. One was the conventional pressure volume loop evaluation and the other was the parameter optimization method without left ventricular volume data. As a result, E max evaluated by the parameter optimization method correlated well with the E max with conventional PV curve. Furthermore, interesting results were obtained. There were rhythmical fluctuations in the E max time series data. By the methodology of Takens, E max time series data was embedded into the phase space and a strange attractor was observed. These results may be important when considering E max evaluation during left ventricular assistance.     

William Harvey (2 April 1578)--400 years of physiology]

William Harvey, born on 2 April 1578, was the founder of modern scientific physiology. The importance of his work was that he was the first prominent exponent of the tremendous value of experimental physiology. By postulating the machine model of the circulatory system he also reinforced the idea of Descartes that man is a machine. During the past 400 years this model led to sensational discoveries on the one hand, as well as scientific limitations and cultural and spiritual crises on the other. Serious rethinking about prescientific and prephilosophic premises is urgently needed for the future.     

Correlation between myocardial fibrosis and restrictive cardiac physiology in patients undergoing retransplantation

After cardiac transplant, there is often development of restrictive cardiac physiology. Little is known about the factors that contribute to this physiology and its correlation with pathology. Heart retransplantation provides a valuable opportunity to further understand this relationship. In this study, we investigated the correlation of myocardial fibrosis and restrictive physiology, and possible risk factors utilizing data from all retransplants at our center. A retrospective review of the 30 patients who underwent retransplantation at our institution between 1994 and 2004 was performed. Hemodynamic and imaging data were reviewed for the presence of restrictive physiology. Pathology reports were reviewed for the presence of myocardial fibrosis in the explanted hearts. The cohort with restrictive physiology preceding redo heart transplant had significantly more patients exhibiting myocardial fibrosis compared with the non‐restrictive physiology group (94.1% vs. 15.4%, p < 0.001). We found no difference in the immunosuppressive regimen, history of rejection, and reason for transplant. In our study, we observed that myocardial fibrosis is an important contributor to the development of restrictive physiology. Further work needs to be done for risk stratification and the mechanism of fibrosis development.     

Primary cardiac osteosarcoma with imaging that revealed no calcification

Osteosarcoma is a rare primary cardiac malignancy. Calcification on imaging is crucial to differentiating osteosarcoma, but we encountered a case that was difficult to diagnose because imaging revealed no calcification. A 67-year-old man was admitted for heart failure. Echocardiography demonstrated mitral regurgitation and a mass in the left atrium. A cardiac malignancy was suspected. Computed tomography revealed no calcification. Operation was performed, and histopathological examination identified the tumor as an osteosarcoma.     

Anorectal physiology measurements are of no value in clinical practice. True or false?

This article examines whether there is any clinical value in anorectal physiology measurements. The function of the human rectum is poorly understood and the factors which affect function of the anal sphincters are complex. Several laboratories have reported results of anorectal physiology measurements, but there is extensive variation between normal values in different laboratories. It is argued that anorectal physiology measurements fail to meet the criteria of a useful clinical test: 1. It is not widely available to clinicians; 2. It is not possible to establish a reproducible normal range; 3. Abnormal measurements do not correlate with disease entities or explain symptoms; 4. The results are often unhelpful in diagnosis and management; 5. Clinical outcome after intervention does not correlate with alteration in the measurements obtained. On the other hand it can be argued that anorectal physiology measurements do provide information that assists in the management of conditions such as constipation, anismus, Hirschsprung''s disease, faecal incontinence and tenesmus. Management based on biofeedback modification of physiological responses requires these techniques as part of the biofeedback system. There is evidence that this may be appropriate in anismus and solitary rectal ulcer syndrome. However, the assessment of these difficult conditions and the interpretation of the results are probably at present best confined to specialist units.     

Risk factors for de novo acute cardiac events in patients initiating hemodialysis with no previous cardiac symptom

An initial major adverse cardiac event (MACE) is an important predictor of future cardiovascular events in patients with chronic kidney disease (CKD). We sought to identify factors influencing occurrence of initial MACE in new maintenance hemodialysis patients without previous cardiac symptoms during the predialysis phase of CKD. Among 112 participating patients with no predialysis cardiac history, 57 underwent coronary angiography, whereas the other 55 underwent stress thallium-201 single-photon emission computed tomography within 1 month of beginning hemodialysis to detect asymptomatic coronary artery disease (CAD). In subsequent follow-up for a median of 24 months, subjects experiencing an initial MACE were compared with those who did not have such an event based on several clinical parameters at the end of predialysis phase. Asymptomatic CAD was present in 47 patients (42%), who had a higher cumulative MACE rate, than subjects without CAD (49 vs 3%, P<0.001). Multivariate Cox's regression analysis showed that three variables independently predicted initial MACE: asymptomatic CAD (hazard ratio or HR, 611.31; 95% confidence interval or CI, 14.07-26549.23; P<0.001), diabetes (HR, 20.41; 95% CI, 2.07-200.00; P=0.010), and each 1 mg/l increment in C-reactive protein (CRP) (HR, 1.94; 95% CI, 1.27-2.94; P=0.002). In conclusion, detection of asymptomatic CAD, presence of diabetes, or elevated CRP at the end of the predialysis phase were significantly associated with occurrence of an initial MACE in CKD patients starting hemodialysis who had no CAD symptoms.     

Surgical treatment of a primary cardiac lymphoma presenting with tamponade physiology

Primary cardiac lymphomas (PCL) are rare cardiac neoplasms that carry an ominous prognosis. They occur more frequently in immunocompromised patients. We report on an immunocompetent 67-year-old who presented with dyspnea and dysphagia. Echocardiographic evidence of impending cardiac tamponade and obstruction of the inferior vena cava (IVC) with the tumor was seen. The deteriorating hemodynamics of our patient prompted an urgent surgical intervention. Pathohistological diagnosis showed diffuse large B-cell lymphoma of centroblastic subtype. Chemotherapy remains the standard treatment of PCL, with surgery reserved for relieving life-threatening complications of the neoplasm.     

Emergency medicine -- new concepts and therapies improve outcome from cardiac arrest

According to scientific articles focusing on emergency medicine published in international journals in the past few months, early defibrillation by lay persons, thrombolysis during cardiopulmonary resuscitation (CPR) and treatment with mild therapeutic hypothermia have been identified as relevant, new and clinically important treatment options to improve outcome following cardiac arrest. Early defibrillation using automated external defibrillators by lay persons reduces the time interval between collapse and first attempts at defibrillation and thus improves outcome after prehospital cardiac arrest. Thrombolysis during CPR -- for which the results regarding safety and efficacy are available from nonrandomized trials -- can also be safely performed in case of pulseless electrical activity. Thrombolysis during cardiopulmonary resuscitation has, however, no significant effect in this subgroup of patients with pulseless electrical activity in whom outcome is poor if the drug is administered at the end of conventional CPR procedures. Mild therapeutic hypothermia, i. e., cooling of cardiac arrest victims to 32-34 degrees C central body temperature for 12-24 h following out-of-hospital cardiac arrest, markedly improves survival rate and neurological outcome. Since this has now been clearly documented in two randomized clinical trials, it can be assumed that this kind of intervention will be recommended and translated into clinical practice soon. In conclusion, new and clinically relevant methods to improve outcome following cardiac arrest are available and can now be widely used clinically.     

Autotransfusion decreases blood usage following cardiac surgery -- a prospective randomized trial

INTRODUCTION: 10% of blood issued by the National Blood Service (220,000) is utilised in cardiac procedures. Transfusion reactions, infection risk and cost should stimulate us to decrease this transfusion rate. We tested the efficacy of autotransfusion of washed postoperative mediastinal fluid in a prospective randomized trial. PATIENTS AND METHODS: 166 patients undergoing coronary artery bypass grafting (CABG), valve or CABG + valve procedures were randomized into three groups. The indication for transfusion was a postoperative haemoglobin (Hb) < 10 g/l or a packed cell volume (PCV) < 30. When applicable, group A patients received washed post-operative drainage fluid. Group B all received blood processed from the cardiopulmonary bypass (CPB) circuit following separation from CPB and if appropriate washed post-operative drainage fluid. Group C were controls. Groups were compared using analysis of variance. RESULTS: There was no significant difference in age, sex, type of operation, CPB time and preoperative Hb and PCV between the groups. Blood requirements were as shown. [table - see text] Twelve patients in group A and 10 in group B did not require a homologous transfusion following processing of the mediastinal drainage fluid. CONCLUSION: Autotransfusion of washed postoperative mediastinal fluid can decrease the amount of homologous blood transfused following cardiac surgery. There was no demonstrable benefit in processing blood from the CPB circuit as well as mediastinal drainage fluid.     

Recombinant activated factor VII in cardiac surgery – first, do no harm

We present a case of an asymptomatic right atrial mass detected on a screening ECHO. Pre-operative imaging and intraoperative frozen section suggested an atrial myxoma, but the extracardiac nature of the mass and its adherence to the right superior pulmonary vein and interatrial septum were inconsistent with this. Detailed histological assessment confirmed the diagnosis of atrial schwannoma. Limited case reports have shown complete resection is curative.     

"Highlights" in emergency medicine -- severe head trauma, polytrauma and cardiac arrest

According to scientific publications focusing on emergency medicine and published in international journals in the past few months, new and clinically important results can be identified. In patients with severe head trauma (SHT), application of hypertonic solutions is possible; long term outcome, however, is not improved by this measure. Prehospital capnometry is important, because otherwise up to 40 % of all mechanically ventilated patients are hypoventilated. In a study in 200 patients with prehospital cardiac arrest and ventricular fibrillation as initial cardiac rhythm, subgroup analysis (alarm-response time > 5 min) showed an increase in survival rate (14 % vs. 2 %), if defibrillation was proceeded by 3 min of conventional cardiopulmonary resuscitation (CPR) for reperfusion. If ACD ("active compression decompression")-CPR is combined with a specific ventilatory valve ("inspiratory impedance threshold device", ITD) which does not allow passive inspiration, survival rate after cardiac arrest is increased for up to 24 h. Such a device facilitates an increase in venous return to the heart during decompression of the thorax. High-dose adrenalin for intrahospital CPR in children is not associated with better survival but with worse outcome. Comparison of an emergency medical service (EMS) system from U.K. with paramedics and a physician-staffed German EMS system demonstrated that survival rate following prehospital cardiac arrest is markedly increased with doctors on board. The European multicentre trial comparing vasopressin vs. adrenalin as first vasopressor during CPR in 1219 patients did not reveal any differences between both groups. In subgroup analyses of patients with asystoly and prolonged CPR, vasopressin was superior without being associated with a benefit on neurological outcome. Further subgroup analyses revealed beneficial effects of amiodarone and thrombolysis during CPR. Thrombolysis during CPR apears to be associated with an increased rate of haemodynamic stabilisation without increased risk of bleeding complications. In a very clear advisory statement, the "International Liaison Committee on Resuscitation" (ILCOR) has recommended mild therapeutic hypothermia (i. e., cooling of cardiac arrest victims to 32 - 34 degrees C central body temperature for 12 - 24 h following cardiac arrest of cardiac etiology) not only for unconciuous patients with ventricular fibrillation as initial prehospital rhythm, but also for all other adult patients (other rhythms, intrahospital CPR) following cardiac arrest. In randomised controlled clinical trials, this therapy has markedly improved survival rate and neurological outcome. Such therapeutic cooling can be initiated nearly everywhere and with simple methods - like the infusion of ice-cold cristalloid solutions.