Guidelines
Guidelines Summary
The following are recommendations from the 2012 American College of Cardiology Foundation/American Heart Association/Heart Rhythm Society (ACCF/AHA/HRS) focused update of their 2008 guidelines for device-based therapy of cardiac rhythm abnormalities. [2]
Class I indications for implantation of a permanent pacemaker in atrioventricular (AV) block
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Advanced second-degree AV block (two or more consecutive P waves are blocked)
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Symptomatic Mobitz I second-degree block
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Symptomatic Mobitz II second-degree block
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Mobitz II second-degree block with wide QRS or chronic bifascicular block, with or without symptoms
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Exercise-induced second- or third-degree AV block in the absence of ischemia
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Second- or third-degree AV block in asymptomatic awake patients in sinus rhythm, resulting in periods of asystole longer than 3.0 sec or ventricular rates less than 40 beats per minute
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Second -or third-degree AV block in asymptomatic awake patients in atrial fibrillation, resulting in pauses of at least 5 seconds
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AV node ablation
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Advanced second- or third-degree AV block with or without symptoms associated with neuromuscular diseases (eg, myotonic dystrophy, Kearns-Sayer syndrome, Erb dystrophy [limb-girdle muscular dystrophy]), and peroneal muscular atrophy
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Recurrent syncope due to carotid massage, causing ventricular pauses of longer than 3 seconds
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AV block caused by a medication that is an essential drug therapy for another medical condition
In addition, permanent pacemaker implantation is recommended after acute myocardial infarction for the following:
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Symptomatic and persistent second- and third-degree AV block
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Persistent second-degree AV block in the His-Purkinje system
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Alternating bundle branch block
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Third-degree AV block at or below the His bundle
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Transient infranodal AV block with bundle branch block
Class II indications for implantation of a permanent pacemaker in AV block
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Alternating bundle branch block
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Bifascicular or trifascicular block with syncope
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First-degree AV block in associated neuromuscular diseases
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First-degree AV block causing bradycardia and hypotension due to very long PR intervals resulting in AV dissociation
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Asymptomatic Mobitz II AV second-degree AV block with a narrow QRS complex
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Second-degree AV block found during electrophysiology study to be infra-AV nodal
Class III (pacing not indicated) conditions in patients with AV block
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Asymptomatic Mobitz I second-degree AV block
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Reversible AV block (due to electrolyte abnormalities, Lyme disease, sleep apnea, enhanced vagal tone, following surgery, medications)
Media Gallery
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Atrioventricular Block. This rhythm strip shows first-degree atrioventricular block with a PR interval of 0.360 sec. Note the fixed prolonged PR interval.
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Atrioventricular Block. First-degree atrioventricular block. PR interval is constant and is 0.280 sec.
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Atrioventricular Block. Second-degree Mobitz type I atrioventricular block. Note the prolongation of the PR interval preceding the dropped beat and the shortened PR interval following the dropped beat.
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Atrioventricular Block. Second-degree atrioventricular block, Mobitz type I (Wenckebach). Note the prolongation of the PR interval preceding the dropped beat and the shortened PR interval following the dropped beat.
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Atrioventricular Block. Second-degree Mobitz II atrioventricular block. Note the fixed PR interval, but after the third beat, an atrial impulse fails to conduct to the ventricle. Courtesy of Wikimedia Commons (https://commons.wikimedia.org/wiki/File:Second_degree_heart_block.png).
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Atrioventricular Block. Second-degree atrioventricular block, Mobitz type II. A constant PR interval in conducted beats is present. Intraventricular conduction delay is also present.
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Atrioventricular Block. A constant PP interval and normal PR interval in conducted beats is present. This progresses to 2:1 atrioventricular (AV) block. A 2:1 AV block can be present with conduction delay in the AV node or His-Purkinje system, but it is more likely to be in the AV node for all patients (with a greater chance of AV block in the His-Purkinje system if there is a bundle branch block). Review extended monitoring strips because Mobitz I or Mobitz II may be present at other times, and this might help to determine the level of the block.
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Atrioventricular Block. High-degree atrioventricular block is demonstrated with a 4:1 atrial-to-ventricular conduction ratio. Note the P wave prior to the QRS conducts whereas the others do not. Courtesy of Life in the Fast Lane (https://lifeinthefastlane.com/ecg-library/basics/high-grade-block/), Edward J Burns, MD, Sydney, Australia.
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Atrioventricular Block. This rhythm strip shows third-degree atrioventricular block (complete heart block). The atrial rate is faster than the ventricular rate, and no association exists between the atrial and ventricular activity. Courtesy of Life in the Fast Lane (https://lifeinthefastlane.com/ecg-library/basics/complete-heart-block/), Edward J Burns, MD, Sydney, Australia.
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Atrioventricular Block. Third-degree atrioventricular block (complete heart block). The atrial rate is faster than the ventricular rate, and no association exists between the atrial and ventricular activity.
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