Permanent Pacemaker and ICD Implantation

28 May 2010
Posted by padma

The natural pace maker or sinoatrial node, a specialized tissue in the heart’s right atrium helps to generate the electrical stimulus that regulates the heart beat frequency as they pass through the conduction pathway. If there is a defect in the sinoatrial node, it results in altered heart beat. If the heart beat is low or high then the condition are termed as bradycardias and tachycardias respectively. When an abnormality is seen in the natural pacemaker, the artifical pacemaker fulfills the missed out function and helps to regulate the electrical impulse that aids in the heart pumping efficiency.

pacemaker

The permanent pacemaker is a small electronic device that helps to analyze the electrical impulse of the heart and regulate them, which in turn regulates the frequency of the heart beat. They regulate the electrical impulse by coordinating the auricles and ventricles of the heart. Cardiac resynchronization therapy is a treatment method where a specialized pacemaker to coordinate the two ventricles to generate the electric signals, and this therapy is used in heart failures. 

The permanent pacemakers are made of a pulse generator and the leads. The pulse generator consists of a battery made of lithium and an electronic circuitry package which has a computer attached to it to monitor the heart beat. The shelf life of the battery can be more than 10 years. The leads are flexible, insulated wires that help to transmit the information from the pulse generator to the heart and vice versa. These permanent pacemakers  normally cannot slow down heart rhytm.
Besides, regulating the heart rhythm and coordinating the electrical impulse, these pacemakers also help to monitor the levels of blood temperature and breathing rates.
The permanent pacemakers are usually implanted under the collarbone near the neck by giving local anesthesia. Once it is implanted, the pacemakers are programmed in such a way to meet he requirements of the patient. Pacemaker checks need to be done routinely and if the battery becomes low, it should be replaced by the same implantation procedures.

 

The patient who is implanted with the permanent pacemaker should avoid the interference of electronic devices so as to avoid the generation of a strong magnetic field which may collapse the pacemaker programming and cause unusual sensation like dizziness, head ache, etc. 

cardiac pacemaker


Implantable cadioverter defibrillator (ICD) is a small device, similar to a pacemaker which helps to regulate heart beat using electrical impulse. It is used in critical conditions like sudden cardiac arrest. ICD monitors the heart to see if any abnormalities are seen in the heart beat. It functions by low energy electrical pulses to rectify the defect. When this fails, it switches to high energy electrical pulses for defibrillation. ICD’s are used only in an emergency condition and is more advanced than the pacemakers.
 

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Medical help

My father in law age 66 years had CABG in the year of 1996,and implanted with ICD in the year of 2008,and now he is suffering from severe LV dysfunction,EF 28%,now our doctor is advising us to replace ICD with CRT-d,please advise in this regard.


Re: Medical help

Your father is eligible for cardiac synchronisation if he has

  • severe or moderately severe heart failure symptoms  ( which he has)
  • is taking medications to treat heart failure
  • has delayed electrical activation of the heart (such as intraventricular conduction delay or bundle branch block)
I assume that he does have left bundle branch block (LSB) , QRS duration should be longer than 120 ms. Also is there evidence of asynchrony in echocardiogram? Since the left ventricular lead is placed at the lateral wall , the myocardium should have vitality in this region. Please discuss this with your cardiologist. The procedure as such does not require general anesthesia and will not take long if performed by  experienced cardiologist.
 
Medical Team, Heart Consult

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