Surgical Treatment of Complete Heart Block

ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities

“…[63][64][65][66][67][68] Although there is little evidence to suggest that pacemakers improve survival in patients with isolated first-degree AV block, 69 it is now recognized that marked (PR more than 300 milliseconds) first-degree AV block can lead to symptoms even in the absence of higher degrees of AV block. 70 When marked first-degree AV block for any reason causes atrial systole in close proximity to the preceding ventricular systole and produces hemodynamic consequences usually associated with retrograde (ventriculoatrial) conduction, signs and symptoms similar to the pacemaker syndrome may occur.…”

“…Patients with firstdegree AV block in association with bifascicular block and symptomatic, advanced AV block have a high mortality rate and a substantial incidence of sudden death. 64,101 Although thirddegree AV block is most often preceded by bifascicular block, there is evidence that the rate of progression of bifascicular block to third-degree AV block is slow. 102 Furthermore, no single clinical or laboratory variable, including bifascicular block, identifies patients at high risk of death due to a future bradyarrhythmia caused by bundle-branch block.…”

“…There is convincing evidence that in the presence of permanent or transient third-degree AV block, syncope is associated with an increased incidence of sudden death regardless of the results of the electrophysiological study. 64,114,115 Finally, if the cause of syncope in the presence of bifascicular block cannot be determined with certainty, or if treatments used (such as drugs) may exacerbate AV block, prophylactic permanent pacing is indicated, especially if syncope may have been due to transient thirddegree AV block. [102][103][104][105][106][107][108][109][110][111][112]116 Of the many laboratory variables, the PR and HV intervals have been identified as possible predictors of third-degree AV block and sudden death.…”

2012 ACCF/AHA/HRS Focused Update Incorporated Into the ACCF/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities

“…Nonrandomized studies strongly suggest that permanent pacing does improve survival in patients with third-degree AV block, especially if syncope has occurred. [63][64][65][66][67][68] Although there is little evidence to suggest that pacemakers improve survival in patients with isolated first-degree AV block, 69 it is now recognized that marked (PR more than 300 milliseconds) first-degree AV block can lead to symptoms even in the absence of higher degrees of AV block. 70 When marked first-degree AV block for any reason causes atrial systole in close proximity to the preceding ventricular systole and produces hemodynamic consequences usually associated with retrograde (ventriculoatrial) conduction, signs and symptoms similar to the pacemaker syndrome may occur.…”

“…Patients with first-degree AV block in association with bifascicular block and symptomatic, advanced AV block have a high mortality rate and a substantial incidence of sudden death. 64,101 Although third-degree AV block is most often preceded by bifascicular block, there is evidence that the rate of progression of bifascicular block to third-degree AV block is slow. 102 Furthermore, no single clinical or laboratory variable, including bifascicular block, identifies patients at high risk of death due to a future bradyarrhythmia caused by bundle-branch block.…”