الفهرس 
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Abstract
In 1889, John Alexander MacWilliam reported in the British Medical Journal (BMJ) of his experiments in which application of an electrical impulse to the human heart in asystole caused a ventricular contraction and that a heart rhythm of 60–70 beats per minute could be evoked by impulses applied at spacings equal to 60–70/minute.
In 1958, Arne Larsson (1915–2001) became the first to receive an implantable pacemaker. He had a total of 26 devices during his life and campaigned for other patients needing pacemakers. Since that time and intra cardiac devices in progress from single to dual champer pacemaker until reaching CRT-D
General types of intracardiac devices include PMs, CRTs, ICDs and circulatory support devices which are collectively called cardiac implantable electrical device or (CIED).
Permanent pacemakers are implantable devices that sense intrinsic cardiac electric potentials and, if these are too infrequent or absent, transmit electrical impulses to the heart to stimulate myocardial contraction. Pacing systems consist of a pulse generator and pacing leads. The pulse generator contains a battery, as well as sensing, timing, and output circuits. The battery (most commonly lithium-iodide) typically has a lifespan of 5-10 years.
An implantable cardioverter-defibrillator (ICD) is a specialized device designed to directly treat a cardiac tachyarrhythmia, while a permanent pacemaker is an implanted device that provides electrical stimuli, thereby causing cardiac contraction when intrinsic myocardial electrical activity is inappropriately slow or absent.
Cardiac resynchronization therapy (CRT), also known as biventricular pacing or multisite ventricular pacing, involves simultaneous pacing of the right ventricle and the left ventricle. To this end, a coronary sinus lead is placed for LV pacing in addition a conventional RV endocardial lead (with or without a right atrial lead) and The basic goal of CRT is to restore LV synchrony in patients with dilated cardiomyopathy and a widened QRS, which is predominantly a result of left bundle branch block, in order to improve the mechanical functioning of the LV.
Mechanical support devices either Counterpulsation/ intraaortic ballon pump (IABP), Extra corporeal membrane oxygenator orVentricular assist devices (VADS), they make as artificial blood pumps which are capable of providing supplementary mechanical circulatory support or complete cardiac support. Ventricular assist devices can be placed to support one or both ventricles. The last decade has seen a variety of devices being developed, seeking a more practical form of support with features that will reduce the potential for infection, fit a variety of body sizes, be easy to implant and/or replace, and have fewer moving parts thereby reducing the risk of mechanical failure.
The first clinical applications of ventricular assist devices merely aimed to support a ventricle failing after an open-heart procedure (postcardiotomy failure). The goal was to support circulation for a few days or weeks, in an expectation of some recovery in myocardial contractility. The physiological repair of reversibly damaged contractile elements (e.g. recovery of the normal response to calcium ions) and restoration of the consumed ATP reserves usually require days. The recovery of other systems (such as kidneys) that may be damaged during the low output state also necessitates a sustained, adequate circulation supplying nutritients, oxygen, and precursors for repair. Although rare in today’s clinical practice, there are still patients who cannot be weaned off from cardiopulmonary bypass at the end of an open-heart procedure. Complication of insertion of that devices should be put in mind because it is not uncommon and if occur, it is annoysing, life threatening and difficult to treat.