The Canadian journal of cardiology
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Ambulatory blood pressure monitoring is rapidly becoming an integral part of the diagnosis and management of hypertensive patients, particularly in major urban Canadian centres. To date, there have been several attempts to define the indications for ambulatory blood pressure monitoring, the most recent coming from an ad hoc panel of the American Society of Hypertension. This panel developed an algorithm for diagnosing persistent hypertension using office, home and ambulatory blood pressure readings. ⋯ Concerns about the term 'white coat' hypertension are discussed and the concept of a white coat effect for both untreated and treated patients is presented. There is preliminary evidence that patients who have a white coat component to their office readings experience fewer cardiovascular outcomes than do those with more persistent ambulatory hypertension. Recommendations from the ad hoc committee of the American Society of Hypertension provide a practical basis for using ambulatory blood pressure monitoring in clinical practice in Canada.
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Historical and state-of-the-art review of clinical mechanical circulatory assist and replacement devices. Recent clinical experience at the University of Ottawa Heart Institute with various mechanical circulatory assist devices as a bridge to transplant, and experimental results with the development and testing of a new electrohydraulic ventricular assist device, are described in detail. ⋯ The use of these devices has become an accepted treatment for end-stage heart disease. Additional development and testing is required to address persistent complications in most models if they are to become alternatives to cardiac transplantation. The basis of the future successes is dependent on both technological refinements in the developments of new devices and on continued research into the physiological effects of mechanical circulatory support. However, these devices are used both as a bridge to recovery and a bridge to cardiac transplant and it is expected that they will be used increasingly to provide permanent circulatory assistance or replacement.
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In vitro experiments have shown that an electric field changes coronary vascular resistance (CVR) tone and damages the vascular endothelium. The effect of transthoracic electric current in dogs on the vasodilatory responses mediated through the endothelium and reactive hyperemia were studied. The manner of delivery of the electric current was similar to that used clinically during cardiac resuscitation. ⋯ These results show that transthoracic electrical shocks as used clinically induce coronary vasodilation but simultaneously produce endothelial dysfunction.
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Case Reports
Retrieval of Silastic catheter fragment from heart in septic thromboembolism complicating aplastic anemia.
A 42-year-old man with aplastic anemia presented to hospital toxic and septic secondary to central Silastic catheter sepsis. The chronic indwelling catheter fractured during an attempt at removal and the distal remnant embolized to the right ventricular outflow tract and main pulmonary artery precipitating near cardiopulmonary collapse. The thrombosed catheter was successfully retrieved under fluoroscopy by an endovascular snare technique thus avoiding operative intervention in this immunosuppressed, thrombocytopenic and septic individual. The patient had an uneventful recovery.
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Comparative Study
Direct comparison of monophasic, biphasic and sequential pulse defibrillation over a single current pathway.
Defibrillation waveform and its spatial and temporal distribution are important determinants of its efficacy. Previous comparisons of monophasic, biphasic and sequential waveforms have used one current pathway for monophasic and biphasic defibrillation and two pathways for sequential defibrillation thus confounding a direct comparison of the waveforms. ⋯ Biphasic pulses are superior to monophasic or sequential pulses delivered over a single current pathway.