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Differences in cerebrogenic cardiac disturbance in men and women
Correspondence
Differences in cerebrogenic cardiac disturbance in men and women
Lisbeth Hjort/Science Photo Library
In The Lancet Neurology Peter Sörös and Vladamir Hachinski1 reviewed findings on sudden death and nonfatal cardiac events after stroke. The authors reported that sudden cardiac death occurs about four times more often in men than in women; however, sex was not discussed as a factor in cerebrogenic cardiac disturbance. Many retrospective studies have shown sex-related differences in cardiac sympatovagal regulation, prevalence of arrhythmias, and hemispheric influences on autonomic cardiovascular control. Women are less lateralised than men for various cerebral functions.2 According to neuroradiological studies, women tend to show more diffuse patterns of physiological activation in both hemispheres, whereas men typically show more physiological asymmetry between left and right cortices when completing cognitive or perceptual tasks. In a study investigating heart rate in patients with epilepsy,3 a greater increase in heart rate early in the course of the seizure was shown only in male patients with righttemporal-lobe seizures. Neither
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male patients with left-temporalepileptic focus nor female patients showed significant changes in heart rate, suggesting that hemispheric influence on autonomic cardiac regulation is lateralised in men.3 According to PET data,4 women display more left-hemisphere than right-hemisphere intrahemispheric correlations, whereas men display more right-hemisphere than left hemisphere intrahemispheric correlations. Reports on sexspecific differences in hemispheric recruitment suggest that men are right-hemisphere dominant, whereas women are left-hemisphere dominant. Nevertheless, a large body of evidence suggests that changing levels of sex hormones in women during the menstrual cycle affect functional cerebral asymmetries, as a result of oestrogen-related and/ or progesterone-related modulation of interhemispheric inhibition. Low hormonal levels (menstrual phase) seem to enhance lateralisation patterns, whereas high levels (follicular and luteal phases) result in more bilateral lateralisation.5 A study in rats showed that males were more susceptible than females to epinephrine-induced arrhythmias.6 This female advantage was diminished by the loss of endogenous hormones through ovariectomy, which increased the frequency of arrhythmias, indicating that the hormones were protective. In human beings, a left-hemisphere stroke might lead to atrioventricular and ventricular electrophysiological abnormalities.7 If men are righthemisphere dominant, and the right hemisphere has a sympathetic predominance, this might explain a substantial increase in heart rate only in male patients with righttemporal-lobe seizures, and the higher incidence of ventricular arrhythmias and sudden cardiac deaths in men.8 In human beings, a right-hemisphere stroke might primarily lead
to supraventricular tachycardia.7 Female left-hemisphere dominance is associated with parasympathetic predominance. This could explain why paroxysmal supraventricular tachycardia is more common in women.8 Heart rate variability in women is lower than in men, as a result of reduced sympathetic influence on the heart. An important step to improve clinical outcomes in patients after stroke would be to study sex-related differences in cerebrogenic cardiac dysfunction. I declare that I have no conflicts of interest.
Sanja Drača [email protected] College of Vocational Studies, Cirila i Metodija 22–24, Kruševac 37000, Serbia 1
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Sörös P, Hachinski V. Cardiovascular and neurological causes of sudden death after ischemic stroke. Lancet Neurol 2012; 11: 179–88. Drača S. Gender-specific functional cerebral asymmetries and unilateral cerebral lesion sequelae. Rev Neurosci 2010; 21: 421–25. Kirchner A, Pauli E, Hily MJ, Neundorfer B, Stefan H. Sex difference and lateral asymmetry in heart rate modulation in patients with temporal lobe epilepsy. J Neurol Neurosurg Psychiatry 2002; 73: 73–75. Azari NP, Rappaport SI, Grady CL, DeCarli C. Gender differences in correlations of cerebral glucose metabolic rates in young normal adults. Brain Res 1992; 574: 198–208. Hausmann M, Güntürkün O. Steroid fluctuations modify functional cerebral asymmetries: the hypothesis of progesterone-mediated interhemispheric decoupling. Neuropsychologia 2000; 38: 1362–74. Teplitz L, Igić R, Berbaum MK, Schwertz DW. Sex differences in susceptibility to epinephrine-induced arrhythmias. J Cardiovasc Pharmacol 2005; 46: 548–55. Hachinski VC, Oppenheimer SM, Wilson JX, Guiraudon C, Cechetto DF. Asymmetry of sympathetic consequences of experimental stroke. Arch Neurol 1992; 49: 697–702. Peters RW, Gold MR. The influence of gender on arrhythmias. Cardiol Rev 2004; 12: 97–105.
Authors’ reply We appreciate Sanja Dračas important comments about our Review on sudden death after ischaemic stroke.1 We fully agree that sex-related cerebral asymmetries in autonomic control have not received sufficient attention. To study the lateralisation of sympathetic and www.thelancet.com/neurology Vol 11 October 2012
Differences in cerebrogenic cardiac disturbance in men and women
Lisbeth Hjort/Science Photo Library
In The Lancet Neurology Peter Sörös and Vladamir Hachinski1 reviewed findings on sudden death and nonfatal cardiac events after stroke. The authors reported that sudden cardiac death occurs about four times more often in men than in women; however, sex was not discussed as a factor in cerebrogenic cardiac disturbance. Many retrospective studies have shown sex-related differences in cardiac sympatovagal regulation, prevalence of arrhythmias, and hemispheric influences on autonomic cardiovascular control. Women are less lateralised than men for various cerebral functions.2 According to neuroradiological studies, women tend to show more diffuse patterns of physiological activation in both hemispheres, whereas men typically show more physiological asymmetry between left and right cortices when completing cognitive or perceptual tasks. In a study investigating heart rate in patients with epilepsy,3 a greater increase in heart rate early in the course of the seizure was shown only in male patients with righttemporal-lobe seizures. Neither
842
male patients with left-temporalepileptic focus nor female patients showed significant changes in heart rate, suggesting that hemispheric influence on autonomic cardiac regulation is lateralised in men.3 According to PET data,4 women display more left-hemisphere than right-hemisphere intrahemispheric correlations, whereas men display more right-hemisphere than left hemisphere intrahemispheric correlations. Reports on sexspecific differences in hemispheric recruitment suggest that men are right-hemisphere dominant, whereas women are left-hemisphere dominant. Nevertheless, a large body of evidence suggests that changing levels of sex hormones in women during the menstrual cycle affect functional cerebral asymmetries, as a result of oestrogen-related and/ or progesterone-related modulation of interhemispheric inhibition. Low hormonal levels (menstrual phase) seem to enhance lateralisation patterns, whereas high levels (follicular and luteal phases) result in more bilateral lateralisation.5 A study in rats showed that males were more susceptible than females to epinephrine-induced arrhythmias.6 This female advantage was diminished by the loss of endogenous hormones through ovariectomy, which increased the frequency of arrhythmias, indicating that the hormones were protective. In human beings, a left-hemisphere stroke might lead to atrioventricular and ventricular electrophysiological abnormalities.7 If men are righthemisphere dominant, and the right hemisphere has a sympathetic predominance, this might explain a substantial increase in heart rate only in male patients with righttemporal-lobe seizures, and the higher incidence of ventricular arrhythmias and sudden cardiac deaths in men.8 In human beings, a right-hemisphere stroke might primarily lead
to supraventricular tachycardia.7 Female left-hemisphere dominance is associated with parasympathetic predominance. This could explain why paroxysmal supraventricular tachycardia is more common in women.8 Heart rate variability in women is lower than in men, as a result of reduced sympathetic influence on the heart. An important step to improve clinical outcomes in patients after stroke would be to study sex-related differences in cerebrogenic cardiac dysfunction. I declare that I have no conflicts of interest.
Sanja Drača [email protected] College of Vocational Studies, Cirila i Metodija 22–24, Kruševac 37000, Serbia 1
2
3
4
5
6
7
8
Sörös P, Hachinski V. Cardiovascular and neurological causes of sudden death after ischemic stroke. Lancet Neurol 2012; 11: 179–88. Drača S. Gender-specific functional cerebral asymmetries and unilateral cerebral lesion sequelae. Rev Neurosci 2010; 21: 421–25. Kirchner A, Pauli E, Hily MJ, Neundorfer B, Stefan H. Sex difference and lateral asymmetry in heart rate modulation in patients with temporal lobe epilepsy. J Neurol Neurosurg Psychiatry 2002; 73: 73–75. Azari NP, Rappaport SI, Grady CL, DeCarli C. Gender differences in correlations of cerebral glucose metabolic rates in young normal adults. Brain Res 1992; 574: 198–208. Hausmann M, Güntürkün O. Steroid fluctuations modify functional cerebral asymmetries: the hypothesis of progesterone-mediated interhemispheric decoupling. Neuropsychologia 2000; 38: 1362–74. Teplitz L, Igić R, Berbaum MK, Schwertz DW. Sex differences in susceptibility to epinephrine-induced arrhythmias. J Cardiovasc Pharmacol 2005; 46: 548–55. Hachinski VC, Oppenheimer SM, Wilson JX, Guiraudon C, Cechetto DF. Asymmetry of sympathetic consequences of experimental stroke. Arch Neurol 1992; 49: 697–702. Peters RW, Gold MR. The influence of gender on arrhythmias. Cardiol Rev 2004; 12: 97–105.
Authors’ reply We appreciate Sanja Dračas important comments about our Review on sudden death after ischaemic stroke.1 We fully agree that sex-related cerebral asymmetries in autonomic control have not received sufficient attention. To study the lateralisation of sympathetic and www.thelancet.com/neurology Vol 11 October 2012