Pacemaker vs Defibrillator
Pacemaker is an electronic device used to regularize the heart beat by generating electrical impulses that transmit along the cardiac conducting pathways causing rhythmic contraction of the heart chambers. Defibrillator is a medical device used in the emergency room, to give a high voltage electrical jolt to jump-start the physiological cardiac pacemaker; the SA node.
There are many methods of pacing. Percussive pacing is an old method where striking the left sternal edge from a distance of one feet to induce a ventricular contraction. This is a life-saving maneuver that is also known as precordial thump. Transcutaneous pacing is a method where two pacer pads are kept on the chest and giving electrical impulses at a predetermined rate till capture is achieved. This is also a stop-gap measure used until proper pacing methods are available. Temporary epicardial pacing is a life-saving method used if a cardiac procedure creates an atrio-ventricular conduction block. Transvenous pacing is a temporary method where a pacemaker wire is introduced into a vein and passed into the right atrium or the right ventricle. The pacemaker tip is then placed in contact with the atrial or ventricular wall. This method may be used until a permanent pacemaker is placed or until there is no further need of a pacemaker. Subclavicular pacing is the permanent method where an electronic pacemaker generator is inserted under the skin under the clavicle. A pacemaker wire is introduced into a vein and passed into the right atrium or ventricle until it gets lodged in the wall of the chamber. Then the other end is connected to the implanted pacemaker generator.
There are three main types of pacemakers. Single chamber pacing is a method where one lead is inserted into the atrium or the ventricle. Dual chamber pacing is a method where two pacing leads go into the heart. One goes into the right atrium while the other goes into the right Ventricle. This is very similar to the natural electrical signal generation. Rate responsive pacing changes the pacemaker discharge rate according to body requirement. Intracardiac pacemakers are inserted into the heart with guide wires. They are under clinical trials and are expected to last for 10 to 15 years once inserted.
Once a cardiac pacemaker is inserted routine regular checkups are essential. Lead integrity, impulse threshold and intrinsic cardiac activity should be tested during these checkups. After pacemaker insertion, no major lifestyle alterations are needed. Avoiding contact sports, avoiding magnetic fields and powerful electrical impulses are some essential cautions.
Defibrillation is a life-saving emergency treatment method for ventricular tachycardia and ventricular fibrillation. During a cardiorespiratory arrest, CPR and DC shock are the two methods available to restart the heart. There are five types of defibrillators. Manual external defibrillator is almost exclusively found in hospitals or ambulances where a trained healthcare provider is available. It usually has a cardiac monitor to record cardiac electrical rhythm, as well. Manual internal defibrillators are used in operating theaters, to restart the heart during an open thorax operation, and the leads are placed in direct contact with the heart. Automatic external defibrillators need little training because it assesses the cardiac rhythm on its own and suggest the use of DC shock. It is mainly for use by untrained lay person. Implantable cardioverter defibrillators (ICD) recognize the need for shock and administer them as needed. Wearable cardiac defibrillator is a vest that can be worn to monitor the patient 24/7 and administers shock when needed.
What is the difference between Pacemaker and Defibrillator?
• Pacemakers are medical devices used to manage non-emergency cardiac dysrhythmias.
• Defibrillators are used in an emergency, to correct ventricular tachycardia and ventricular fibrillation.