Determinants of the Duration of the Refractory Period of the Atrioventricular Nodal System in Man*

Linhart, Joseph W.; Braunwald, Eugene; Ross, John

doi:10.1172/jci105204

Cited by 39 publications

(8 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Matsuda et al (22) have demonstrated that epinephrine exerts such actions on A-V nodal fibers. These findings are in agreement with reports that intravenous catecholamines and stellate ganglion stimulation enhance A-V conduction (1-6) and shorten the functional refractory period in experimental ani-mals (1)(2)(3)(4)(5) and in human subjects (6). Furthermore, Wallace and associates (2,3,8) have shown that cardiac adrenergic stimulation shortens the A-V conduction time by as much as 50%, without a concomitant alteration of either the velocity of the spread of excitation through the peripheral Purkinje system or the sequence of epicardial activation of the ventricles.…”

Section: Discussionsupporting

confidence: 93%

Effects of Beta-Receptor Blockade and Glucagon on the Atrioventricular Transmission System in the Dog

Whitsitt

Lucchesi

Laidlaw

1968

Circulation Research

View full text Add to dashboard Cite

The effects of dZ-propranolol, d-propranolol, and ICI 46037, a quaternary analog of propranolol, on the functional refractory period and conduction time of the atrioventricular transmission system were studied in anesthetized dogs. eM-Propranolol, 0.5 mg/kg, prolonged the functional refractory period, increased the conduction time, and reduced the maximum frequency of A-V transmission. Larger doses (5 mg/kg) produced only a small additional depression of A-V transmission. In contrast, neither d-propranolol nor ICI 46037, 0.5 mg/kg, depressed A-V transmission. Larger doses of both drugs prolonged both the functional refractory period and the conduction time, the magnitude of the response being quantitatively similar to that produced by increasing the dose of cM-propranolol from 0.5 mg/kg to 5 mg/kg.The intravenous administration of glucagon, 2 fig/kg, promptly restored normal A-V conduction in animals that had received dl-or d-propranolol, but was ineffective in those which had received ICI 46037. It was concluded that propranolol depresses A-V transmission by both specific (beta-receptor blockade) and nonspecific mechanisms, the former being the more important. In addition, it appears that glucagon is capable of reversing the cardiodepressant action of propranolol on A-V transmission, a finding which may have considerable clinical importance. ADDITIONAL KEY WORDS propranololA-V node d-propranolol conduction time ICI 46037 functional refractory period • Adrenergic stimulation of the heart decreases the functional refractory period of the atrioventricular transmission system both in laboratory animals (1-5) and in human subjects (6). These reports are consistent withFrom the the observation that the effective refractory period of the A-V conducting system in conscious human subjects is controlled to a large extent by the activity of the sympathetic nervous system (6). As anticipated, sympathetic denervation (4, 7, 8), norepinephrine depletion by reserpine (4), and beta-receptor blockade by pronethalol and propranolol (3,5,8,9) have been shown to prolong the refractory period of the A-V transmission system. The clinical effectiveness of propranolol in slowing the ventricular rate in atrial fibrilla-

show abstract

Section: Discussionsupporting

confidence: 93%

Effects of Beta-Receptor Blockade and Glucagon on the Atrioventricular Transmission System in the Dog

Whitsitt

Lucchesi

Laidlaw

1968

Circulation Research

View full text Add to dashboard Cite

show abstract

“…conducted beats had a constant conduction time through the HPS (H-V time). It has been previously'3 14, [28][29][30][31][32][33][34] documented that as the P-P interval is shortened, the P-R interval prolongs due to the increased refractoriness of the A-V node, whereas the conduction time through the HPS usually remains constant at all heart rates. The fewer the impulses transmitted through the A-V node, the shorter the P-R interval.…”

mentioning

confidence: 99%

Wenckebach and Mobitz Type II A-V Block Due to Block Within the His Bundle and Bundle Branches

1970

View full text Add to dashboard Cite

SUMMARYFourteen patients with conduction defects were analyzed by using bundle of His (BH) recordings. The Bilateral bundle-branch block TWO TYPES of second degree atrioventricular (A-V) block were originally described by Hay' and by Wenckebach.2'3 Type I block was characterized by the gradual prolongation of the a-c interval of the jugular pulse with eventual loss of the arterial pulse. In type II second degree heart block, ventricular beats were dropped without any preceding prolongation of the a-c interval. The introduction of the electrocardiogram enabled Mobitz to define the ECG criteria for

show abstract

“…The increase in the degree of block that occurred in the patients with atrial tachycardia, and the slowing of the ventricular rate in atrial fibrillation, both suggest an additional action on the atrioventricular node. These are both sites of action of sympathetic stimulation and of exogenous isoprenaline (Linhart et al, 1965). Patients with congestive cardiac failure have increased basal sympathetic tone (Gaffney and Braunwald, 1963), and it may be that this was a factor in the initiation or maintenance of the arrhythmias in the present series of patients.…”

Section: Discussionmentioning

confidence: 77%

Clinical Use of I.C.I. 50172 as an Antidysrhythmic Agent in Heart Failure

Gibson¹,

Balcon²,

Sowton³

1968

BMJ

View full text Add to dashboard Cite

Determinants of the Duration of the Refractory Period of the Atrioventricular Nodal System in Man*

Cited by 39 publications

References 8 publications

Effects of Beta-Receptor Blockade and Glucagon on the Atrioventricular Transmission System in the Dog

Effects of Beta-Receptor Blockade and Glucagon on the Atrioventricular Transmission System in the Dog

Wenckebach and Mobitz Type II A-V Block Due to Block Within the His Bundle and Bundle Branches

Clinical Use of I.C.I. 50172 as an Antidysrhythmic Agent in Heart Failure

Contact Info

Product

Resources

About