TY - JOUR
T1 - Tachycardia- and bradycardia-dependent atrioventricular block
T2 - Observations regarding the mechanism of block
AU - Denes, P.
AU - Murabit, I.
AU - Ezri, M.
AU - Eybel, C.
PY - 1987
Y1 - 1987
N2 - A case of paroxysmal bradycardia- and tachycardia-dependent atrioventricular (AV) block is described in a patient with right bundle branch block. The His bundle recordings demonstrated the site of the AV block to be distal to the His bundle recording site (probably in the left bundle branch). Whereas AV block distal to the His bundle occurred at an atrial paced cycle length of 700 ms, intact ventriculoatrial (VA) conduction was present up to a ventricular paced cycle length of 400 ms. Resumption of AV conduction was dependent on a critical HH or RH (in case of escapes) interval. These findings suggest that the bradycardia-dependent block is related to a time-dependent decrease in the amplitude of the current intensity of the proximal segment during late diastole. Spontaneous diastolic depolarization during late diastole resulted in impaired anterograde (AV) conduction but facilitated retrograde (VA) conduction. These findings are consistent with experimental “in vitro” observation in the sucrose gap model of AV block.
AB - A case of paroxysmal bradycardia- and tachycardia-dependent atrioventricular (AV) block is described in a patient with right bundle branch block. The His bundle recordings demonstrated the site of the AV block to be distal to the His bundle recording site (probably in the left bundle branch). Whereas AV block distal to the His bundle occurred at an atrial paced cycle length of 700 ms, intact ventriculoatrial (VA) conduction was present up to a ventricular paced cycle length of 400 ms. Resumption of AV conduction was dependent on a critical HH or RH (in case of escapes) interval. These findings suggest that the bradycardia-dependent block is related to a time-dependent decrease in the amplitude of the current intensity of the proximal segment during late diastole. Spontaneous diastolic depolarization during late diastole resulted in impaired anterograde (AV) conduction but facilitated retrograde (VA) conduction. These findings are consistent with experimental “in vitro” observation in the sucrose gap model of AV block.
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U2 - 10.1016/S0735-1097(87)80402-3
DO - 10.1016/S0735-1097(87)80402-3
M3 - Article
C2 - 2433320
AN - SCOPUS:0023097098
SN - 0735-1097
VL - 9
SP - 446
EP - 449
JO - Journal of the American College of Cardiology
JF - Journal of the American College of Cardiology
IS - 2
ER -