Bilateral carotid body resection in man enhances hypoxic tachycardia.

Honda, Yoshiyuki; Hashizume, Ikko; Kimura, Hiroshi; Severinghuas, John W.

doi:10.2170/jjphysiol.38.917

Cited by 18 publications

(11 citation statements)

References 31 publications

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“…This increase in heart rate resembles the chemoreflex increase in heart rate of ϳ8 beats/min (occurring also without a pressure rise) seen when unanesthetized humans breathe hypoxic gas mixtures (of 13% or lower) in hypo-or isocapnia (18,27,44). In humans this chemoreflex is unaffected by carotid body denervation (18,27) and, hence, may involve aortic and or pulmonary chemoreceptors (13). Aortic chemoreceptors are stimulated by decreases in O 2 availability at constant Pa O 2 (25), and their stimulation increases heart rate (21).…”

Section: Discussionmentioning

confidence: 59%

“…Because this increase in heart rate was absent during hypocapnia when subjects breathed O 2 [as we reported previously (9)], it appears to be caused by a reduced availability of O 2 rather than by withdrawal of any CO 2 -dependent tonic drive (50) or by the pH increase directly affecting the sinoatrial or atrioventricular nodes (1,38). This increase in heart rate resembles the chemoreflex increase in heart rate of ϳ8 beats/min (occurring also without a pressure rise) seen when unanesthetized humans breathe hypoxic gas mixtures (of 13% or lower) in hypo-or isocapnia (18,27,44). In humans this chemoreflex is unaffected by carotid body denervation (18,27) and, hence, may involve aortic and or pulmonary chemoreceptors (13).…”

Section: Discussionmentioning

confidence: 99%

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Hypocapnia reduces the T wave of the electrocardiogram in normal human subjects

Rutherford¹,

Clutton-Brock²,

Parkes³

2005

American Journal of Physiology-Regulatory, Integrative and Comp

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During voluntary hyperventilation in unanesthetized humans, hypocapnia causes coronary vasoconstriction and decreased oxygen (O 2) supply and availability to the heart. This can induce local epicardial coronary artery spasm in susceptible patients. Its diagnostic potential for detection of early heart disease is unclear. This is because such hypocapnia produces an inconsistent and irreproducible effect on electrocardiogram (ECG) in healthy subjects. To resolve this inconsistency, we have applied two new experimental techniques in normal, healthy subjects to measure the effects of hypocapnia on their ECG: mechanical hyperventilation and averaging of multiple ECG cycles. In 15 normal subjects, we show that hypocapnia (20 Ϯ 1 mmHg) significantly reduced mean T wave amplitude by 0.1 Ϯ 0.0 mV. Hypocapnia also increased mean heart rate by 4 beats/min without significantly altering blood pressure, ionized calcium or potassium levels, or the R wave or other features of the ECG. We therefore provide the first unequivocal demonstration that hypocapnia does consistently reduce T wave amplitude in normal, healthy subjects. coronary circulation; carbon dioxide; angina DURING VOLUNTARY HYPERVENTILATION in unanesthetized humans, hypocapnia causes coronary vasoconstriction and decreased oxygen (O 2 ) supply and availability to the heart. Thus cardiac catheterization studies show that voluntary hyperventilation [to partial pressure levels of carbon dioxide in arterial blood (Pa CO 2 ) of 20 mmHg] increases coronary vascular resistance by 17% (47), decreases coronary blood flow by 30% (47), and increases the affinity of hemoglobin for O 2 by 25% (35). During voluntary hyperventilation, hypocapnia can induce local epicardial coronary artery spasm in single or multiple vessels with associated ST displacement, both in susceptible patients with voluntary hyperventilation syndrome (but without symptoms of heart disease) (15, 24) and in the rare group of patients with Prinzmetal's variant angina (29,59).It is unclear whether this effect has any diagnostic potential for early coronary heart disease. This is because numerous studies in healthy subjects report that hypocapnia produces only inconsistent decreases in the amplitude of the ECG T wave that are not reproducible in every subject (5,6,8,16,20,22,30,49,54,58).Such inconsistency is not surprising because of the methodological difficulties inherent with voluntary hyperventilation in the variability of inflation volumes achieved and of the duration, level, and stability of hypocapnia. Variability in movement of the body surface (and its attached electrodes) relative to the heart with each inflation introduces a crucial artifact that alone might explain this inconsistency. These difficulties are compounded by the lack of a standardized procedure for ECG analysis during hyperventilation. It is unclear precisely how many ECG complexes were measured, how they were selected, and what was their precise relationship to the inflation cycle (6,16,58,60).We have therefore applied two novel ap...

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Section: Discussionmentioning

confidence: 59%

Section: Discussionmentioning

confidence: 99%

Hypocapnia reduces the T wave of the electrocardiogram in normal human subjects

Rutherford¹,

Clutton-Brock²,

Parkes³

2005

American Journal of Physiology-Regulatory, Integrative and Comp

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“…And although neither the adults nor the children studied were trained athletes, different levels or types of habitual activity could exist in these two populations. In addition, peripheral chemoreceptor contribution to ventilation during exercise is somewhat different in children compared with adults (26), and the carotid bodies are known to have cardiac as well as respiratory effects (27,28). The peripheral chemoreceptors are stimulated by COz, and differences in body composition, circulation time, and C 0 2 caniage in the blood could affect the transport of CO2 produced in the cells during exercise to the carotid bodies.…”

Section: Discussionmentioning

confidence: 99%

Heart Rate Recovery from 1 Minute of Exercise in Children and Adults

1991

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ABSTRACT. Previous studies demonstrated that the time required for oxygen uptake, COz production, and minute ventilation to return to baseline levels after I-min bursts of exercise is different in children compared with adults. To test the hypothesis that the heart rate (HR) recovery time after exercise is also different in children compared with adults, we examined H R in 10 children (range 7-11 y old) and 12 adults (26-42 y old) for 10 min after I min of cycle ergometer exercise. Each subject exercised a t work rates corresponding to 80% of the lactate or anaerobic threshold (AT), 50% of the difference between AT and maximal O 2 uptake (A), 100% of maximal uptake, and 125% of maximal uptake. Gas exchange was measured breath by breath. In adults, the H R recovery time increased significantly with work intensity a s judged by the time constant of a single exponential curve fit to postburstexercise H R 123 f 8 (SD) s a t 80% AT, 55 f 16 at 50%A, 7 4 f 13 a t 100% of maximal uptake, and 83 k 20 a t 125% of maximal uptake]. H R recovery time tended to increase with work intensity in children (16 f 7, 20 f 4, 23 f 7, and 27 f 9; for 80%AT, 50%A, 100% of maximal uptake, and 125% of maximal uptake respectively), but to a much smaller extent, and the H R recovery time was significantly smaller in children in the high-intensity (above AT) range of exercise (p < 0.001). Despite the markedly faster recoveries in children, the time course of the O 2 pulse (Voz/ HR) was indistinguishable between children and adults. These data suggest that the regulation of H R after highintensity exercise is different in children compared with adults, and that the pulsatile delivery of O z to the tissues is controlled during the growth period. (Pediatr Res 29: 575-579,1991) Abbreviations AT, anaerobic threshold HR, heart rate ~0 2 , 0 2 uptake vcoz, C 0 2 production v*:, minute ventilation vozmax, maximal O 2 uptake %max, % of Vo-m a x A, difference between vo2max and AT THR, H R recovery timeThe adaptive response to sudden changes in metabolic rate can be characterized by physiologic responses at the beginning of exercise as well as by those occurring in the recovery phase. Sudden changes in metabolic rate are common occurrences in children who, in general, tend toward frequent short intervals of physical activity. In previous studies of gas exchange responses to exercise, we observed that growth-related changes of V O~ kinetics (i.e. the time course of VO? adjustments at the onset of exercise) were the same in adults and children, but dynamic ventilatory (VI-) and Vco7 responses were faster in children ( I , 2). Similarly, in recent preliminary studies (3, 4), the recovery period (i.e. the time required to return to baseline values after 1 min of exercise) for Vo2 was surprisingly similar in adults and children over a,wide range of exercise intensities, whereas recovery for V E and VcoZ was substantially faster in children compared with adults for exercise performed in the high-intensity range.The goal of our study was to determine w...

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“…They found that exercise hyperpnea decreased in patients after the procedure (Honda et al, 1979a). In another study they found the procedure enhanced hypoxic tachycardia (Honda et al, 1988) in eight subjects 25 years post-surgery. In 11 asthmatic patients with the bilateral CB resection they reported some residual chemosensitivity some 23 years post-surgery (Honda et al, 1979b).…”

Section: Treatment Of the Target To Reduce Its Impactmentioning

confidence: 92%

Carotid body: a new target for rescuing neural control of cardiorespiratory balance in disease

Fitzgerald

2014

Front. Physiol.

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Significant insight into the mechanisms involved in chronic heart failure (CHF) have been provided by Schultz and his associates at the University of Nebraska Medical Center with the use of pacing-induced heart failure rabbits. Critical among the CHF mechanisms was the role of the carotid body (CB). The stimulated CB produces a wide array of systemic reflex responses; certainly those in the cardiopulmonary (CP) system are the most important in CHF. This generates a question as to whether the CB could serve as a target for some kind of treatment to reestablish control of cardiorespiratory balance in CHF. Any treatment would have to be based on a solid understanding of the mechanisms of chemosensing by the CB as well as the transducing of that sensing into neural activity sent to the medullary centers and regions of autonomic outflow to the periphery. Two avenues of treatment could be to (1) silence or attenuate the CB's neural output pharmacologically and (2) excise the CBS. There is a long history of CB removal mostly as a remedy for chronic obstructive lung disease. Results have been inconclusive as to the effectiveness of this procedure. But if carefully planned, the procedure might be a helpful treatment.

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Bilateral carotid body resection in man enhances hypoxic tachycardia.

Cited by 18 publications

References 31 publications

Hypocapnia reduces the T wave of the electrocardiogram in normal human subjects

Hypocapnia reduces the T wave of the electrocardiogram in normal human subjects

Heart Rate Recovery from 1 Minute of Exercise in Children and Adults

Carotid body: a new target for rescuing neural control of cardiorespiratory balance in disease

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