Permanent Pacing After the Acute Phase of Acute Myocardial Infarction

Bradyarrhythmias and conduction defects are relatively common after acute myocardial infarction. In patients who have these problems, a decision about permanent pacing must be made prior to the patient's discharge from the hospital. It is important to realize that the indications for temporary pacing in the setting of acute myocardial infarction are different from those for permanent pacing following infarction. Unfortunately, there is some uncertainty regarding permanent pacing for these patients because large prospective controlled trials have not been performed. In addition, the criteria for permanent pacing in patients after a myocardial infarction do not necessarily require the presence of symptoms and the need for temporary pacing in the acute stages of infarction is not by itself an indication for permanent pacing.

The prognosis for these patients is strongly influenced by the amount of underlying myocardial damage.37 In general, sinus node dysfunction tends to be benign and reversible; and permanent pacemakers are rarely required. Similarly, second-degree and even third-degree AV block after inferior wall myocardial infarction is usually reversible and rarely requires permanent pacing. In contrast, conduction defects after an anterior wall myocardial infarction usually warrant permanent pacemaker insertion, although mortality remains extremely high because of pump failure (Fig. 1.18).

The indications for permanent pacing following acute myocardial infarction are:

Class I

1. Persistent second-degree AV block in the His-Purkinje system with bundle branch block or third-degree AV block within or below the His-Purkinje system after acute myocardial infarction. (Level of evidence: B.)

2. Transient advanced (second- or third-degree) infranodal AV block and associated bundle-branch block. If the site of block is uncertain, an electrophys-iology study may be necessary. (Level of evidence: B.)

3. Persistent and symptomatic second- or third-degree AV block. (Level of evidence: C.)

Class IIb

1. Persistent second- or third-degree AV block at the AV node level. (Level of evidence: B)

Figure 1.18. A standard 12-lead ECG from an individual with a large anteroseptal myocardial infarction complicated by congestive heart failure and right bundle branch block with right axis deviation, presumably due to left posterior fascicular block. The patient developed transient high-degree AV block 72 hours after admission (a class I indication) and subsequently underwent permanent pacemaker implantation.

Figure 1.18. A standard 12-lead ECG from an individual with a large anteroseptal myocardial infarction complicated by congestive heart failure and right bundle branch block with right axis deviation, presumably due to left posterior fascicular block. The patient developed transient high-degree AV block 72 hours after admission (a class I indication) and subsequently underwent permanent pacemaker implantation.

Class III

1. Transient AV block in the absence of intraventricular conduction defects. (Level of evidence: B.)

2. Transient AV block in the presence of isolated left anterior fascicular block. (Level of evidence: B.)

3. Acquired left anterior fascicular block in the absence of AV block. (Level of evidence: B.)

4. Persistent first-degree AV block in the presence of bundle-branch block that is old or age indeterminate. (Level of evidence: B.)

Your Heart and Nutrition

Your Heart and Nutrition

Prevention is better than a cure. Learn how to cherish your heart by taking the necessary means to keep it pumping healthily and steadily through your life.

Get My Free Ebook


Post a comment