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Sleep and the Cardiovascular System
CHEST VOLUME 73 I NUMBER 2 I FEBRUARY, 1978
Editorials
of editorial review is a profound misconception. Such review is meant to assist and not to obstruct the investigator. The ultimate recommendation to accept or reject a manuscript represents the judgmental role of review, but this is only one aspect of the process. Effective editorial review provides constructive criticism which can make a good paper better and an excellent paper superb. We should view consultants' comments as part of an educational experience, and in optimal circumstances, this entails a dialogue between all parties concerned. An attitude as flexible as this elicits the awareness that serious errors can be prevented only if there is an ongoing exchange of views in the pre-publication phase. The open editorial office is practical and effective. Recently, I rejected a manuscript from an excellent medical center because the reviewer described fundamental defects in the investigational protocol. The specific problems were described in a three-page critique. The authors responded with their own detailed criticism of the referee's comments and I transmitted this commentary to the consultant. In response, the referee outlined in further detail the reasons for his original opinion and his belief that the modified manuscript was still inappropriate for publication. Of particular delight to me was the referee's final comments: "Thank you for sending to me the authors' rebuttal; regardless of what you as an editor choose to do, I feel that this is appropriate both to the author of the manuscript, and to this reviewer. Through such a mechanism, I think that scientific questions can, in many cases, be sorted out and should always be available as a recourse to the author of a manuscript which has been refused publication." Alfred Soffer, M.D., F.C.C.P. Park Ridge, Illinois
The Open Editorial Office a recent medical convention, I spoke on the A t subject, "Medical Editor-Friend or Foe?" The title appropriately described the mood of some authors in the audience who claimed that editorial boards frequently are arbitrary and capricious in judgment. Some recounted instances when reviewers had totally misunderstood major elements of their reports and that, as a result, unwarranted rejection of their manuscripts had occurred. These critics were startled when I in tum asked why they had not written or called the editors of the journals in question to request the opportunity for continued dialogue on the merits of their manuscripts. "I assumed," said one interrogator, "that when a rejection letter is received that ends the matter." I explained that it has always been my philosophy that an author should have recourse to further consideration if he believes that his paper has been misjudged. I conduct what I term an open editorial office, that is, one in which the editor is responsive to letters or phone calls regarding the editorial review process. Indeed, I specifically encourage continued open lines of communication among authors, referees, and the editorial board. Peer review of scientific data is, I believe, the most impartial and effective method to ensure validity and significance of original research. Nevertheless, the fallibilities of this system of review must not be overlooked. Editors quickly learn the overt prejudices of some investigators and discount their condemnations. I refer, however, not to such unusual circumstances, but rather to the unconscious biases of even the most conscientious referee. I have no doubt that some exceedingly important work may have been denied publication or the appearance of this information may have been delayed because of erroneous judgments by editorial boards. Many of these episodes could have been prevented if the investigators had insisted upon and been permitted to have additional editorial consideration by further review. Why are so many investigators unaware of the desire of editors to hear from disappointed authors? Part of the problem may be that the traditional view
Reprint requests: Dr. SoDer, 911 Busse Highway, Park Ridge, Illinois 60068
Sleep and the Cardiovascular System the state of sl.eep demands A lthough ly one-third of our hves, much about Its nature app~oximate
and effects have still eluded investigation. However,
125
in recent years it has become important to learn the full 24-hour behavior of patients with certain illnesses, especially cardiovascular and pulmonary, in order to uncover heretofore unknown danger zones requiring therapeutic interventions. Sleep in mammals is a special example of a more generalized phenomenon, namely a periodicity or cyclic variation timed by internal clocks of uncertain nature; sleep, however, is basically a neural phenomenon. 1 Circadian rhythms (when the periods of oscillation approximate the period of the earth's rotation ) are quite precise in many organisms and are relatively independent of variables except for sensitivity to light.1 It is likely that the internal clock depends upon the hypothalamus for its viability. 1 The newborn infant shows cycles of rest and activity of about 90 minutes' duration, and during the first year or two of life, these cycles gradually shift to the ordinary daily rhythm of adult life, although 90 minute undulations can still be noted during sleep.2 In the adult, modem studies of psychophysiology have indicated not only that sleep can be divided into five stages, but also that there are recurring sleep cycles and that during sleep the brain and the peripheral nervous system under its control, undergo continuous oscillations and activity with a periodicity approximating 90 minutes. 3 Deep sleep is often normally associated with sinus bradycardia in the range of 45-50 beats per minute. u The change in heart rate during onset of sleep is interesting in that the cardiac rate decreases progressively throughout the night reaching its nadir at about the sixth hour. 3 In addition to slowing of sinus rate during sleep, there is also a fall in cardiac output, respiratory rate and arterial blood pressure.u In normal young adults, the fall in blood pressure reaches its nadir within one and a half to two and a baH hours after the onset of sleep. The heart rate and cardiac alterations are mediated by changes in sympathetic and parasympathetic neural outflow and are abolished after cardiac denervation. 3 Thus, the partial sympathetic withdrawal that occurs during sleep may be the basis, because of lessened sympathetic discharge, of the normal sinus bradycardia which is seen. There is movement of extravascular water in the blood on assumption of the recumbent position and water excretion by the kidney is lowered during the night. 1 There is alteration in breathing patterns during sleep, with Cheyne-Stokes oscillations seen not infrequently, and a reduction in alveolar ventilation occurs with its consequent slight rise in C02 in arterial blood. These facts emphasize that nocturnal problems in cardiopulmonary diseases have bases in normal fluctuations. In critical states, major organ systems126 EDITORIALS
brain, coronary, renal, may move into hypoperfused status during sleep. The subject with respiratory insufficiency may accumulate carbon dioxide to a critical level which makes for a somnolent day and further hypoventilation unless assisted breathing is used. Left ventricular failure, as is well known, may reach dangerous levels in bed at night and diuresis becomes imperative to prevent this. 5 Most recently, attention to malfunction of the sinoatrial node during sleep has become an important diagnostic move.6 Little information exists concerning the performance of the damaged sinoatrial node during sleep, but since there exists the normal tendency to lower SAN activity during sleep, it would not be surprising to find accentuations of the normal behavior at this time, producing abnormalities which could have been cryptic because of the whipping up of the performance of endogenous catecholamines while the subject was awake. Indeed, the diagnosis of a failing SA node may only be suspected when a subject has peculiar central nervous system symptoms and these are evaluated by 24-hour ECG monitoring. Monitoring for shorter periods would be insufficient to uncover the dangerous bradycardia manifest only in sleep. Thus, it is now important to include a survey of sleep performance, when feasible, in subjects with cardiopulmonary diseases, since this restful period may in fact contain some real danger zones. M. Irene Ferrer, M.D.0 New York City •From the Department of Medicine, Columbia University College of Physicians and Surgeons, and the Presbyterian Hospital of Columbia-Presbyterian Medical Center.
REFERENCES 1 Mountcastle VB: Medical Physiology. St. Louis, C.V. Mosby, 1974, p 260 2 Kleitman N: Sleep and Wakefulness (ed 2) Chicago, University of Chicago Press, 1963 3 Lown B, Tykocinski M, Garfein A, et al: Sleep and ventricular premature beats. Circulation 48:691, 1973 4 Biological Handbooks. Respiration and Circulation. (Altman PL, Dittmer DS, editors). Bethesda, Federation of American Societies for Experimental Biology, 1971, p333 5 Gensini GG: Coronary artery spasm and angina pectoris. Chest 68:709, 1975 6 Ferrer Ml : The Sick Sinus Syndrome. Mt. Kisco, New York, Futura Publishing, 1974 p 21-22
When to Hospitalize the COPD Patient Empirical: founded on practical experience but not proved scientifically (Stedman's Medical Dictionary, 22nd Ed. )
proof of the methods used in managing Scientific clinical problems often lags behind both recognition of need and availability of potential modalities of treatment; this is clearly shown in the
CHEST, 73: 2, FEBRUARY, 1978
Editorials
of editorial review is a profound misconception. Such review is meant to assist and not to obstruct the investigator. The ultimate recommendation to accept or reject a manuscript represents the judgmental role of review, but this is only one aspect of the process. Effective editorial review provides constructive criticism which can make a good paper better and an excellent paper superb. We should view consultants' comments as part of an educational experience, and in optimal circumstances, this entails a dialogue between all parties concerned. An attitude as flexible as this elicits the awareness that serious errors can be prevented only if there is an ongoing exchange of views in the pre-publication phase. The open editorial office is practical and effective. Recently, I rejected a manuscript from an excellent medical center because the reviewer described fundamental defects in the investigational protocol. The specific problems were described in a three-page critique. The authors responded with their own detailed criticism of the referee's comments and I transmitted this commentary to the consultant. In response, the referee outlined in further detail the reasons for his original opinion and his belief that the modified manuscript was still inappropriate for publication. Of particular delight to me was the referee's final comments: "Thank you for sending to me the authors' rebuttal; regardless of what you as an editor choose to do, I feel that this is appropriate both to the author of the manuscript, and to this reviewer. Through such a mechanism, I think that scientific questions can, in many cases, be sorted out and should always be available as a recourse to the author of a manuscript which has been refused publication." Alfred Soffer, M.D., F.C.C.P. Park Ridge, Illinois
The Open Editorial Office a recent medical convention, I spoke on the A t subject, "Medical Editor-Friend or Foe?" The title appropriately described the mood of some authors in the audience who claimed that editorial boards frequently are arbitrary and capricious in judgment. Some recounted instances when reviewers had totally misunderstood major elements of their reports and that, as a result, unwarranted rejection of their manuscripts had occurred. These critics were startled when I in tum asked why they had not written or called the editors of the journals in question to request the opportunity for continued dialogue on the merits of their manuscripts. "I assumed," said one interrogator, "that when a rejection letter is received that ends the matter." I explained that it has always been my philosophy that an author should have recourse to further consideration if he believes that his paper has been misjudged. I conduct what I term an open editorial office, that is, one in which the editor is responsive to letters or phone calls regarding the editorial review process. Indeed, I specifically encourage continued open lines of communication among authors, referees, and the editorial board. Peer review of scientific data is, I believe, the most impartial and effective method to ensure validity and significance of original research. Nevertheless, the fallibilities of this system of review must not be overlooked. Editors quickly learn the overt prejudices of some investigators and discount their condemnations. I refer, however, not to such unusual circumstances, but rather to the unconscious biases of even the most conscientious referee. I have no doubt that some exceedingly important work may have been denied publication or the appearance of this information may have been delayed because of erroneous judgments by editorial boards. Many of these episodes could have been prevented if the investigators had insisted upon and been permitted to have additional editorial consideration by further review. Why are so many investigators unaware of the desire of editors to hear from disappointed authors? Part of the problem may be that the traditional view
Reprint requests: Dr. SoDer, 911 Busse Highway, Park Ridge, Illinois 60068
Sleep and the Cardiovascular System the state of sl.eep demands A lthough ly one-third of our hves, much about Its nature app~oximate
and effects have still eluded investigation. However,
125
in recent years it has become important to learn the full 24-hour behavior of patients with certain illnesses, especially cardiovascular and pulmonary, in order to uncover heretofore unknown danger zones requiring therapeutic interventions. Sleep in mammals is a special example of a more generalized phenomenon, namely a periodicity or cyclic variation timed by internal clocks of uncertain nature; sleep, however, is basically a neural phenomenon. 1 Circadian rhythms (when the periods of oscillation approximate the period of the earth's rotation ) are quite precise in many organisms and are relatively independent of variables except for sensitivity to light.1 It is likely that the internal clock depends upon the hypothalamus for its viability. 1 The newborn infant shows cycles of rest and activity of about 90 minutes' duration, and during the first year or two of life, these cycles gradually shift to the ordinary daily rhythm of adult life, although 90 minute undulations can still be noted during sleep.2 In the adult, modem studies of psychophysiology have indicated not only that sleep can be divided into five stages, but also that there are recurring sleep cycles and that during sleep the brain and the peripheral nervous system under its control, undergo continuous oscillations and activity with a periodicity approximating 90 minutes. 3 Deep sleep is often normally associated with sinus bradycardia in the range of 45-50 beats per minute. u The change in heart rate during onset of sleep is interesting in that the cardiac rate decreases progressively throughout the night reaching its nadir at about the sixth hour. 3 In addition to slowing of sinus rate during sleep, there is also a fall in cardiac output, respiratory rate and arterial blood pressure.u In normal young adults, the fall in blood pressure reaches its nadir within one and a half to two and a baH hours after the onset of sleep. The heart rate and cardiac alterations are mediated by changes in sympathetic and parasympathetic neural outflow and are abolished after cardiac denervation. 3 Thus, the partial sympathetic withdrawal that occurs during sleep may be the basis, because of lessened sympathetic discharge, of the normal sinus bradycardia which is seen. There is movement of extravascular water in the blood on assumption of the recumbent position and water excretion by the kidney is lowered during the night. 1 There is alteration in breathing patterns during sleep, with Cheyne-Stokes oscillations seen not infrequently, and a reduction in alveolar ventilation occurs with its consequent slight rise in C02 in arterial blood. These facts emphasize that nocturnal problems in cardiopulmonary diseases have bases in normal fluctuations. In critical states, major organ systems126 EDITORIALS
brain, coronary, renal, may move into hypoperfused status during sleep. The subject with respiratory insufficiency may accumulate carbon dioxide to a critical level which makes for a somnolent day and further hypoventilation unless assisted breathing is used. Left ventricular failure, as is well known, may reach dangerous levels in bed at night and diuresis becomes imperative to prevent this. 5 Most recently, attention to malfunction of the sinoatrial node during sleep has become an important diagnostic move.6 Little information exists concerning the performance of the damaged sinoatrial node during sleep, but since there exists the normal tendency to lower SAN activity during sleep, it would not be surprising to find accentuations of the normal behavior at this time, producing abnormalities which could have been cryptic because of the whipping up of the performance of endogenous catecholamines while the subject was awake. Indeed, the diagnosis of a failing SA node may only be suspected when a subject has peculiar central nervous system symptoms and these are evaluated by 24-hour ECG monitoring. Monitoring for shorter periods would be insufficient to uncover the dangerous bradycardia manifest only in sleep. Thus, it is now important to include a survey of sleep performance, when feasible, in subjects with cardiopulmonary diseases, since this restful period may in fact contain some real danger zones. M. Irene Ferrer, M.D.0 New York City •From the Department of Medicine, Columbia University College of Physicians and Surgeons, and the Presbyterian Hospital of Columbia-Presbyterian Medical Center.
REFERENCES 1 Mountcastle VB: Medical Physiology. St. Louis, C.V. Mosby, 1974, p 260 2 Kleitman N: Sleep and Wakefulness (ed 2) Chicago, University of Chicago Press, 1963 3 Lown B, Tykocinski M, Garfein A, et al: Sleep and ventricular premature beats. Circulation 48:691, 1973 4 Biological Handbooks. Respiration and Circulation. (Altman PL, Dittmer DS, editors). Bethesda, Federation of American Societies for Experimental Biology, 1971, p333 5 Gensini GG: Coronary artery spasm and angina pectoris. Chest 68:709, 1975 6 Ferrer Ml : The Sick Sinus Syndrome. Mt. Kisco, New York, Futura Publishing, 1974 p 21-22
When to Hospitalize the COPD Patient Empirical: founded on practical experience but not proved scientifically (Stedman's Medical Dictionary, 22nd Ed. )
proof of the methods used in managing Scientific clinical problems often lags behind both recognition of need and availability of potential modalities of treatment; this is clearly shown in the
CHEST, 73: 2, FEBRUARY, 1978