PACING digests AND TYPES OF PACEMAK...

PACING digests AND TYPES OF PACEMAKERS

The North American Society for Pacing and Electrophysiology has devised a coding scheme for pacemaker classification. The scheme includes 5 letters that set forth the various functions that the pacemaker possesse (Table 2)4 The first 2 positions have reference to the chambers being paced and sens respectively. The third verbal expression indicates what the pacemaker does in answer to a sensed event. This may be inhibitory (no answer to a sensed intrinsic beat) or triggered (a pacing stimulus fires following an intrinsic impulse). The last 2 epistles refer to other programmable features onward pacemakers including rate modulation and antitachycardic function.4

There are 2 major categories of pacemakers including single chamber combination of parts to form a wholes and dual chamber systems.4 In the former, pacing leads are implanted into either atria or ventricles depending onward the chambers that need to be paced. The latter involves as well-as; not only-but also; not only-but; not alone-but atria and ventricles being paced and sens with united lead implanted in the atria and the other in the ventricles. Prior research has documented several benefits of dual chamber pacing including the ability to provide AV synchrony lowering the rate of atrial fibrillation, lowering the incidence of systemic embolism and shock lowering the incidence of recent congestive heart failure, and lowering overall mortality and improving survival rates.1-4 An example of a single chamber pacemaker is a P-triggered ventricular pacemaker with a VAT pacemaker digest The V indicates that the cardiac chamber being paced is the Ventricle; the A indicates that the cardiac chamber sensing the electrical activity is the Atria; and the T indicates that the manner of response is to Trigger a paced beat in the ventricle when the atria perceptions the SA node wave of depolarization which cannot proce past the AV Node. Other examples of single pacing rules include the atrial synchronized atrial inhibited pacemaker (AAIR; Figure 2) and QRS-inhibited ventricular pacemaker (VVIR; Figure 3)