Experimental studies on A-V nodal rhythm following suppression of activity of the sinus node

Scherf, David; Blumenfeld, Serge; Yildiz, Muhtar

doi:10.1016/0002-9149(62)90300-4

Cited by 20 publications

(3 citation statements)

References 10 publications

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“…This difference may be the result of a greater level of resting vagal tone in the dog, or to a species difference in the relative levels of cardiac sympathetic and parasympathetic tone.29 Abnormal vagal control mechanisms have been demonstrated in many patients with symptomatic pacemaker dysfunction during carotid sinus massage. 30 31 In these patients, carotid sinus massage resulted in prolonged asystoles (3)(4)(5)(6) seconds) which were eliminated after administration of atropine.30' 31 The role of both parasympathetic and sympathetic tone in the genesis of the spontaneous episodes of asystole in the patient with symptomatic sinus node dysfunction requires further investigation.…”

Section: Discussionmentioning

confidence: 98%

Cardiac arrhythmias in the conscious dog after excision of the sinoatrial node and crista terminalis.

Euler¹,

Jones²,

Gunnar³

et al. 1979

Circulation

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dia in 4 patients evaluated by programmed electrical stimulation of heart and treated in 2 patients by surgical division of anterior radiation of left bundle branch. Br Heart J 35: 1013, 1973 23. Wellens HJJ, Schuilenberg R, Durrer D: Electrical stimulation of the heart in patients with ventricular tachycardia. Circulation 46: 216, 1972 24. Wellens HJJ, Duiren DR, Lie KI: Observations on mechanisms of ventricular tachycardia in man. Circulation 54: 237, 1976 25. Wellens HJJ: Observations on the pathophysiology of ventricular tachycardia in man. Arch Intern Med 135: 473, 1975 26. Chapman JH, Schrank JP, Cramptom RS: Idiopathic ventricular tachycardia. Am J Med 59: 470, 1975 27. Bodenheimer MM, Banka V, Helfant RH: Relation between the site of origin of ventricular complexes and the presence and severity of coronary artery disease.SUMMARY A stable junctional rhythm was produced in 16 dogs after surgical excision of the sinoatrial node and a large section of the crista terminalis. An unstable ectopic atrial rhythm appeared within the first week after surgery in 94% of the dogs. The pacemaker instability was characterized by spontaneous pacemaker shifts and periodic episodes of asystole which were prominent for several months after surgery in most of the dogs. In contrast to sinus arrhythmia observed before surgery, the ectopic atrial arrhythmias were not related to the respiratory cycle. The prompt disappearance of the asystoles after atropine or during treadmill exercise indicated the essential role of the vagus in producing the unstable rhythms. Atropine increased the average rate of the ectopic rhythms from 63 ± 3 beats/min to 107 ± 9 beats/min (p < 0.001) and shortened the corrected recovery time (CRT) following overdrive pacing from 3.8 ± 0.3 seconds to 1.9 ± 0.6 seconds (p < 0.001). Propranolol, in the absence of atropine, decreased the spontaneous heart rate from 56 ± 5 beats/min to 39 ± 6 beats/min (p < 0.01), and increased the CRT to 6.5 ± 2 seconds (p < 0.001) when administered after atropine. The data suggest that unstable ectopic atrial pacemakers could be responsible for some of the arrhythmias associated with the sick sinus syndrome in man.

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Section: Discussionmentioning

confidence: 98%

Cardiac arrhythmias in the conscious dog after excision of the sinoatrial node and crista terminalis.

Euler¹,

Jones²,

Gunnar³

et al. 1979

Circulation

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“…These procedures often resulted in early appearance of coronary sinus or atrioventricular junctional rhythms that were later replaced by atrial escape rhythms.23 24,26,28,30,31 Jones et a132 performed stepwise excisions of right atrial tissue segments beginning at the sinoatrial node and extending caudally along the sulcus terminalis to the junction of the inferior vena cava and inferior right atrium. In the acute open-chest canine preparation they found atrial, atrioventricular, and ventricular ectopic pacemakers to emerge.…”

Section: Short-term Effects Of Lasingmentioning

confidence: 99%

Modification of sinus node function by epicardial laser irradiation in dogs.

et al. 1990

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This study tested the feasibility of neodymium:YAG laser photocoagulation of selected sinus node areas to depress sinus rate responsiveness. In 14 open-chest dogs, origin of the sinus impulse (0 point) was electrically mapped from the epicardium before and during isoproterenol infusion. Epicardial laser photocoagulation was applied to the 0 point observed during isoproterenol infusion and stepwise to remapped new 0 points until a 30±5% decrease in heart rate occurred. Long-term effects were assessed by Holter monitoring and electropharmacologic testing preoperatively and up to 10 weeks or 6 months. Mean (± SEM) percent decreases were observed at 10 weeks in the following parameters: average 24-hour heart rate, 17.4+±5.0%; maximum heart rate on Holter, 30.5+±3.5%; heart rate during pharmacologic autonomic blockade, 32.7±3.5%; and maximum heart rate on isoproterenol, 23.1±4.6% (all p<0.01). Curves with pacemaker recovery time plotted against control cycle length remained unchanged. Holter monitoring did not show excessive bradycardic episodes even after administration of propranolol. In three control dogs (sham operation), sinus node function remained unchanged. Histologic study of the irradiated area showed replacement by inflammatory cells, fibrosis, and cartilage formation with surrounding normal cells and occasional cells resembling pacemakerlike cells at the caudal end of the sinoatrial node. This study suggests that 1) map-guided graded laser photocoagulation of sinus node regions showing earliest activation during catecholamine stimulation successfully limits maximum heart rates without causing significant bradycardia, 2) the effects are long lasting, and 3) the remaining pacemaker behaves like the sinus node. Laser modification of sinus node function could become a form of nonpharmacologic heart rate control in patients with coronary artery disease undergoing surgery and in the syndrome of inappropriate sinus tachycardia. (Circulation 1990;81:350-359) P harmacologic control of excessive sinus tachycardia in humans is occasionally limited by side effects inherent to the drugs used, patient intolerance, or treatment failure related to the nature of the disease.12 Therapeutic options for severe cases of drugresistant sinus tachycardia today include total surgical exclusion of the sinus node region or cryosurgical ablation.34 Both procedures usually result in atrial or Supported by grants from the Heineman Medical Research Center of Charlotte, NC, Inc, and HL-30558-06 from the National Institutes of Health, National Heart, Lung, and Blood Institute, Bethesda, Maryland.Address for correspondence: Laszlo Littmann, MD, Laser and Applied Technologies Laboratory, Carolinas Heart Institute, PO Box 32861, Charlotte, NC 28232.Received April 11, 1989; revision accepted September 13, 1989. atrioventricular junctional escape rhythms and necessitate implantation of a permanent pacemaker. The functional anatomy of the sinus node region in humans and dogs is unique in that it shows widespread distribution and rate differ...

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“…Since 1912, cardiologists have paid atten tion to the coronary sinus region with respect to the possible development of the coronary sinus rhythm [1][2][3][4][5][6][7], We were unable to find any anatomical study concerning the arterial supply to that region in the available litera ture, although that of the neighbouring areas of human cardiac atria -(including the si nuatrial and atrioventricular nodes) are well known [8][9][10][11][12][13]. Coronary sinus rhythm with characteristically inverted electrocardio graphic P waves occurs during suppression of the sinuatrial node from various causes, digitalis intoxication, myocardial infarction or atrial surgery [14,15].…”

Section: Introductionmentioning

confidence: 99%

Arterial Supply of the Region of the Coronary Sinus in Man

Eliska¹,

Elisková²

1990

Cardiology

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Patterns of arterial supply to the atria were studied with respect to the coronary sinus region in 60 human hearts obtained from patients with a negative cardiac history and in 2 hearts with ECG-demonstrated coronary sinus rhythm. The atria, including the interatrial septum, were supplied by the right (40%) or left (30%) or both (30%) sinuatrial arteries which, however, did not reach as far as the posterior margin of the oval fossa and the coronary sinus. The region of the coronary sinus with the Eustachian ridge received direct branches from the trunk of the right (41 %) or left (11 %) coronary artery or both (48 %) in the adjacent part of the coronary sulcus. Possible development of the ‘coronary sinus rhythm’ on the basis of multifocal damage of the sinuatrial arteries is discussed.

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Experimental studies on A-V nodal rhythm following suppression of activity of the sinus node

Cited by 20 publications

References 10 publications

Cardiac arrhythmias in the conscious dog after excision of the sinoatrial node and crista terminalis.

Cardiac arrhythmias in the conscious dog after excision of the sinoatrial node and crista terminalis.

Modification of sinus node function by epicardial laser irradiation in dogs.

Arterial Supply of the Region of the Coronary Sinus in Man

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