![]() Myocardial conduction cells initiate and propagate the action potential (the electrical impulse) that travels throughout the heart and triggers the contractions that propel the blood. Their function is similar in many respects to neurons, although they are specialized muscle cells. Except for Purkinje cells, they are generally much smaller than the contractile cells and have few of the myofibrils or filaments needed for contraction. ![]() The myocardial conducting cells (1 percent of the cells) form the conduction system of the heart. Contractile cells conduct impulses and are responsible for contractions that pump blood through the body. The myocardial contractile cells constitute the bulk (99 percent) of the cells in the atria and ventricles. There are two major types of cardiac muscle cells: myocardial contractile cells and myocardial conducting cells. Even though cardiac muscle has autorhythmicity, heart rate is modulated by the endocrine and nervous systems. Neither smooth nor skeletal muscle can do this. This property is known as autorhythmicity. Not the least of these exceptional properties is its ability to initiate an electrical potential at a fixed rate that spreads rapidly from cell to cell to trigger the contractile mechanism. Recall that cardiac muscle shares a few characteristics with both skeletal muscle and smooth muscle, but it has some unique properties of its own. Identify blocks that can interrupt the cardiac cycle.Relate characteristics of an electrocardiogram to events in the cardiac cycle.Compare the effect of ion movement on membrane potential of cardiac conductive and contractile cells.Identify and describe the components of the conducting system that distributes electrical impulses through the heart.Describe the structure of cardiac muscle.All rights reserved.By the end of this section, you will be able to: No unique patterns were associated with the underlying causes or survival.Īetiology Cardiac arrest Causes Defibrillator Pulseless electrical activity Resuscitation.Ĭopyright © 2016 The Author(s). None of the patients with 'normal' PEA survived.Ībnormal ECG patterns were frequent at the early stage of in-hospital PEA. Abnormal ECG patterns were seen in all survivors. Further 7 episodes with a corresponding defibrillator file, but without a reliable cause, were included in analysis of survival. No unique cause-specific ECG pattern could be identified. Ninety percent (46/51) had widened QRS complexes, 63% (32/51) were defined as 'wide-slow' due to QRS-widened bradycardia, and only 6% (3/51) episodes were categorized as normal. The defibrillator was attached after a median of one minute (75th percentile 3min) after the onset of arrest. QRS width and HR were considered to be normal below 120ms and within 60-100 cardiac cycles per minute, respectively.įifty-one episodes fulfilled the inclusion criteria. QRS width, QT interval, Bazett's corrected QT interval, presence of P waves and heart rate (HR) was determined. Prospectively observed episodes of IHCA presenting as PEA between January 2009 and august 2013, with a reliable cause of arrest and corresponding defibrillator ECG recordings, were analysed. The aim of this study was to investigate possible associations between early ECG patterns in PEA and the underlying causes and survival of in-hospital cardiac arrest (IHCA). ![]() Pulseless electrical activity (PEA) is an increasingly common presentation in cardiac arrest. Olav University Hospital, Trondheim, Norway. 5 Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway Department of Anaesthesia and Intensive Care Medicine, St.4 Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway Department of Cardiology, St.3 Department of Anaesthesia and Intensive Care Medicine, St.Electronic address: 2 Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway. Olav University Hospital, Trondheim, Norway Norwegian Air Ambulance Foundation, Norway. 1 Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway Department of Anaesthesia and Intensive Care Medicine, St.
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