Pacemakers are electrical devices that stimulate the heart and are expected to maintain cardiac rhythm as near normal as possible.

They may be internal or external. An external pacemaker is also called a "Zolle" in the US. Internal pacing can be done using leads that traverse the veins to reach the heart. The leads are expected to be in the right ventricle. Although newer types of pacemakers that are both left and right sided are now in use for conditions such as HOCM.

Pacemakers also can be in combination with a defibrillator in which case they are called PCDs (Pacemaker Cardiovertor Defibrillator).

The commonest scenario where a pacemaker will be useful is bradycardia. Any symptomatic bradycardia where the etiology suggests irreversibility is a good scenario for pacing.

Pacemakers are also used for treating tachy-brady syndrome where the tachy is treated with drugs and the brady that these drugs could cause is prevented by the pacer. For instance - such a patient could be started on either a beta blocker or a calcium channel blocker and concomitantly have a pacer to prevent the possible bradycardia.

Pacers are also used in someone who has a left bundle branch block when the patient has right heart catheterization with a swan or central line. These are temporary pacers. This sis done because the right sided manipulation can block the RBB and thus lead to a complete heart block (3rd degree AV block).

Pacers have certain properties. These are described using designated letters.

VVI is the basic pacemaker mode. The first V tells us that the pacer has a single lead that paces the ventricle. The second V tells us the chamber sensed which in this case is the ventricle and the third letter designates what happens it senses a ventricular beat which in this case is inhibition if it senses the ventricle beat by itself.

More to be added.

CARDIOLOGY

Recognize and manage patients with acute inferior myocardial infarction and second-degree atrioventricular block.

Explanation:

Pacing is on the minds of people when they see blocks on the EKG associated with MIs. Not all blocks are to be paced. Those that need pacing are Symptomatic blocks, Third degree and Mobitz type 2 blocks associated with ANTERIOR MI. Those associated with Inferior MIs can be observed unless symptomatic. The last part is important because most of us see them paced during our training in the USA.