The AHA Guidelines and Scientific Statements Handbook

Chapter 3 ST-Elevation Myocardial Infarction

Fascicular block

• RBBB

ObserveA TCTV

III III I IIb

ObserveA TCTV

III III I IIa

ObserveA TCTV

III III I IIa

ObserveA*TCTV

III III I IIa

ObserveA TCTV

III III I IIa

ObserveA TCTV

III III IIbI

ObserveA TCTV

III III IIbI

Alternating left and right bundle branch block

ObserveA TCTV

III III IIbI

ObserveA TCTV

III III IIbI

ObserveA TCTV

III III IIbI

ObserveA*TCTV

III III IIbI

ObserveA TCTV

III III IIbI

ObserveA TCTV

III III IIbI

ObserveA TCTV

III III IIbI

Explanation of table:This table is designed to summarize the atrio-ventricular (column headings) and intra-ventricular (row headings) conduction dis

turbances that may occur during acute anterior or non-anterior STEMI, the possible treatment options, and

the indications for each possible therapeutic option.ActionThere are 4 possible actions, or therapeutic options, listed and classifi ed for each bradyarrhythmia or conduction problem:1. Observe: continued electrocardiographic monitoring, no further action planned.2. A, and A*: atropine administered at 0.6 to 1.0 mg intravenously every 5 minutes to up to 0.04 mg/kg. In general, because the

increase in sinus rate with atropine is unpredictable, this is to be avoided unless there is

symptomatic

bradycardia

that will likely respond to a vagolytic agent – such as sinus bradycardia or Mobitz I, as denoted by the asterisk, above.

3. TC: application of transcutaneous pads and standby transcutaneous pacing with no further progression to transvenous pacing i

mminently planned.

4. TV: temporary transvenous pacing. It is assumed, but not specifi ed in the table, at the discretion of the clinician, trancut

aneous pads will be applied and standby transcutaneous pacing will be in effect as the patient is transferred to

the fl uoroscopy unit for temporary transvenous pacing.ClassEach possible therapeutic option is further classifi ed according to ACC/AHA criteria as I, IIa, IIb, and III. There are no rand

omized trials available that address or compare specifi c treatment options. Moreover, the data for this table and

recommendations are largely derived from observational data of pre-fi brinolytic era databases. Thus, the recommendations above

must be taken as recommendations and tempered by the clinical circumstances.

Level of evidenceThis table was developed from: (1) published observational case reports and case series; (2) published summaries, not meta-anal

yses, of these data; and (3) expert opinion, largely from the pre-reperfusion era. There are no published

randomized trials comparing different strategies of managing conduction disturbances post-STEMI. Thus, the level of evidence fo

r the recommendations in the table is C.

How to use the tableExample: 54-year-old man is admitted with an anterior STEMI and a narrow QRS on admission. On day 1 he develops a right bundle

branch block (RBBB), with a PR interval of 0.28 seconds.

1. RBBB is an intra-ventricular conduction disturbance, so look at row “New BBB”.2. Find the column for “First Degree AV Block”.3. Find the “Action” and “Class” cells at the convergence.4. Note that Observe and Atropine are Class III, not indicated; transcutaneous pacing (TC) is Class I. Temporary transvenous pa

cing (TV) is Class IIb.