Third degree AV block surgery

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Cafer Zorkun, M.D., Ph.D. [2]; Raviteja Guddeti, M.B.B.S. [3] Soroush Seifirad, M.D.[4]

Surgery

Implantation of permanent pacemakers in both asymptomatic and symptomatic patients is usually done. Asymptomatic Mobitz II are prone to be converted to symptomatic or third degree heart AV block. Thus, they should be considered for a pacemaker even if asymptomatic.

Pacemaker Indications

The American College of Cardiology, the American Heart Association, and the Heart Rhythm Society (ACC/AHA/HRS) have published guidelines for implantation of cardiac pacemakers. Some of these indications are certain, while others require considerable expertise and judgment.

The ACC/AHA/HRS guidelines divided these guidelines for pacemaker implantation into three specific categories.

●Class I – Conditions in which permanent pacing is definitely recommended, beneficial, and useful.

●Class II – Conditions in which permanent pacing may be reasonable, but there is conflicting evidence and/or divergence opinion.

●Class III – Conditions in which permanent pacing is not beneficial/useful and, in some cases, maybe harmful.

Class-I

• Patients with symptomatic atrioventricular block as a consequence of guideline-directed management for which there is no alternative treatment and continued treatment is clinically necessary; a permanent pacemaker is recommended to improve symptoms.
• Symptomatic sinus bradycardia (usually with a heart rate below 40 beats per minute)
• Symptomatic chronotropic incompetence
• Patients with symptomatic atrioventricular block as a consequence of guideline-directed management for which there is no alternative treatment and continued treatment is clinically necessary; a permanent pacemaker is recommended to improve symptoms.
• Complete heart block with or without sysmptoms
• Symptomatic second degree AV block, Mobitz type II
• Symptomatic second degree AV block, Mobitz type I
• Exercise induced second or third degree AV block in absence of myocardial ischemia
• Advanced second degree AV block (block of two or more consecutive P waves)

Class-II

• Patients with permanent atrial fibrillation and symptomatic bradycardia.
• Patients with acquired second-degree Mobitz type II heart block, third-degree atrioventricular block not attributable to reversible causes, require a permanent pacemaker regardless of symptoms.
• Patients with the following neuromuscular diseases with evidence of second-degree and third-degree atrioventricular block require permanent pacemaker regardless of the symptoms.
  • Myotonic dystrophy type 1
  • Kearns-Sayre Syndrome
• .
• Patients with infiltrative cardiomyopathies, such as cardiac sarcoidosis or amyloidosis, and second-degree Mobitz type II atrioventricular block, high-grade atrioventricular block, or third-degree atrioventricular block with a life expectancy of greater than one years; permanent pacemaker is reasonable.
• Patients with marked first-degree or second-degree Mobitz type 1 AV block with symptoms that are attributable to the atrioventricular block, permanent pacing is reasonable.
• Patients with alternating bundle branch block.
• Patients with Anderson-Fabry disease and QRS prolongation more significant than 110 ms with a meaning life expectancy greater than one year, a permanent pacemaker can be considered.
• Patients with postoperative sinus node dysfunction or atrioventricular block associated with persistent symptoms that do not resolve after isolated coronary artery bypass surgery, permanent pacing is recommended.
• Patients with postoperative sinus node dysfunction or atrioventricular block associated with persistent symptoms that do not resolve after mitral valve repair or replacement surgery, permanent pacing is recommended before discharge.
• Patients who have new postoperative sinus node dysfunction or atrioventricular block associated with persistent symptoms that do not resolve after aortic valve replacement, permanent pacing is recommended before discharge.
• Patients who have a new atrioventricular block after transcatheter aortic valve replacement associated with symptoms that do not resolve, permanent pacing is recommended.

Pacing Mode

VVI pacing mode was widely used in the past. But this mode has been shown to be associated with AV dyssynchrony leading to pacemaker syndrome. A dual chamber DDD pacemaker is preferred over a single chambered VVI pacemakers as it maintains physiologic AV synchrony. A dual-chamber artificial pacemaker is a type of device that typically listens for a pulse from the SA node and sends a pulse to the AV node at an appropriate interval, essentially completing the connection between the two nodes. Pacemakers in this role are usually programmed to enforce a minimum heart rate and to record instances of atrial flutter and atrial fibrillation , two common secondary conditions that can accompany third degree AV block.