Alterations of autonomic nervous activity preceding nocturnal variant angina: sympathetic augmentation with parasympathetic impairment

Role of polyunsaturated fatty acids in Japanese patients with coronary spastic angina

BACKGROUND

n-3 polyunsaturated fatty acids (PUFAs) reduce the risk of ischemic heart disease. However, there are few reports of a relationship between n-3 PUFAs and coronary spastic angina (CSA). This study aimed to assess the age-dependent role of serum levels of fatty acid in patients with CSA.

METHODS AND RESULTS

We enrolled 406 patients who underwent ergonovine tolerance test (ETT) during coronary angiography for evaluation of CSA. All ETT-positive subjects were diagnosed as having CSA. We categorized the patients by age and results of ETT as follows: (1) young (age ≤ 65 years) CSA-positive (n = 32), (2) young CSA-negative (n = 134), (3) elderly (age > 66 years) CSA-positive (n = 36), and (4) elderly CSA-negative (n = 204) groups. We evaluated the serum levels of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), arachidonic acid, and dihomo-gamma-linolenic acid. In the young groups, the serum levels of EPA (64.3 ± 37.7 μg/mL vs. 49.4 ± 28.8 μg/mL, p = 0.015) and DHA (135.7 ± 47.6 μg/mL vs. 117.4 ± 37.6 μg/mL, p = 0.020) were significantly higher in the CSA-positive group than in the CSA-negative group, respectively. However, this was not the case with elderly groups. In the multivariate analysis in young groups, the serum levels of EPA (p = 0.028) and DHA (p = 0.049) were independently associated with the presence of CSA, respectively.

CONCLUSION

Our results suggested that the higher serum levels of EPA and/or DHA might be involved in the pathophysiology of CSA in the young population but not in the elderly population.

Vasospastic Angina in a Young Woman: A Case Report

Vasospastic angina (VSA) is a disease that causes myocardial ischemia due to transient vasoconstriction of the epicardial coronary arteries. This disease generally occurs in middle-aged and older adults, but there are also reports of it occurring in young people. We report a case of VSA in a woman in her 20's. Six months ago, a female patient in her 20s became aware of a strangling sensation in the chest that lasted for approximately 1-20 minutes at rest or during stress. She consulted her family doctor who prescribed nitroglycerin sublingual tablets, which were effective. She was a current smoker and had a history of bronchial asthma, with no family history of coronary artery disease. Resting electrocardiogram and echocardiography revealed no clear abnormalities. The patient was referred to our hospital for coronary angiography (CAG) and spasm provocation test (SPT), primarily to thoroughly examine her chest pain at rest. CAG revealed no significant stenosis. A subsequent SPT using acetylcholine demonstrated diffuse coronary spasm in the left anterior descending coronary artery (LAD). The coronary spasm resolved spontaneously, but the catheter was difficult to maneuver owing to the radial artery spasm at the puncture site; thus, nitroglycerin was administered, which alleviated the radial artery spasm. Another SPT was performed on the right coronary artery (RCA) and revealed no coronary spasm. Coronary microcirculatory function using a pressure wire in response to the peripheral infusion of adenosine triphosphate was assessed in the RCA and LAD, both of which were normal. The patient was discharged from the hospital on an oral calcium channel blocker (CCB). She continued to experience chest pain, but her chest symptoms improved with CCB medication and a change in her workplace. It must be kept in mind that coronary spasms can occur even in young women and should be one of the differentials of chest pain in such patients.

Vasospastic angina: Past, present, and future

Vasospastic angina (VSA) is characterized by episodes of rest angina that are responsive to short-acting nitrates and are attributable to coronary artery vasospasm. The condition is underdiagnosed as the provocation test is rarely performed. VSA, the most important component of non-obstructive coronary artery disease, can present with angina, be asymptomatic, or can even present with fatal arrhythmias and cardiac arrest. Although most patients with VSA respond well to vasodilating medications, prognosis does not improve as expected in most patients, suggesting the existence elusive prognostic factors and pathogenesis that warrant further exploration. Moreover, patients with either severe or refractory VSA barely respond to conventional treatment and may develop life-threatening arrhythmias or suffer sudden cardiac death during ischemic attacks, which are associated with immune-inflammatory responses and have been shown to achieve remission following glucocorticoid and immunoglobulin treatments. Our recent work revealed that inflammation plays a key role in the initiation and development of coronary spasms, and that inflammatory cytokines have predictive value for diagnosis. In contrast to the existing literature, this review both summarizes the theoretical and clinical aspects of VSA, and also discusses the relationship between inflammation, especially myocarditis and VSA, in order to provide novel insights into the etiology, diagnosis, and treatment of VSA.

Coronary Vascular (DYS) Function and Invasive Physiology Assessment: Insights into Bolus and Continuous Thermodilution Methods

A considerable number of patients with angina or myocardial ischemia have no significant coronary artery disease on invasive angiography. In recent years, several steps towards a better comprehension of the pathophysiology of these conditions, angina or ischemia with non-obstructive coronary arteries (ANOCA/INOCA), have been made. Nevertheless, several gaps in knowledge still remain. This review is intended to provide a comprehensive overview of ANOCA and INOCA, with a particular focus on pathophysiology, recent diagnostic innovations, gaps in knowledge and treatment modalities.

Management of vasospastic angina

Vasospastic angina is a well-established cause of chest pain that is caused by coronary artery spasm. It can be clinically diagnosed during a spontaneous episode by documenting nitrate-responsive rest angina with associated transient ischaemic ECG changes but more often requires provocative coronary spasm testing with acetylcholine during coronary angiography. Vasospastic angina may result in recurrent episodes of angina (including nocturnal angina), which can progress on to major adverse cardiac events. Calcium channel blockers are first-line therapy for this condition, given their anti-anginal and cardioprotective benefits. Despite an established diagnostic and therapeutic management pathway for vasospastic angina, this diagnosis is often overlooked in patients presenting with chest pain. Thus, there is need for increased clinical awareness of vasospastic angina to improve outcomes in affected patients.

Coronary Spasm During Postoperative Sedation With Dexmedetomidine

This is a case report of an 81-year-old woman who underwent tracheostomy, bilateral cervical dissection, partial tongue resection, radial forearm free flap reconstruction, and split-thickness skin grafting under general anesthesia. After successful surgery, she was moderately sedated postoperatively with intravenous dexmedetomidine (DEX) and fentanyl. The fentanyl was discontinued 5 hours postoperatively. Eight hours after the operation, an atrioventricular junctional rhythm, a 2-mm elevation of the ST segment, and biphasic T waves were detected in lead II that lasted approximately 3 minutes. Hypotension and bradycardia were observed simultaneously with the abnormal electrocardiogram. The next day, a cardiologist examined the patient and suggested that coronary spasm had occurred based on those findings. The transient coronary spasm was likely caused by a combination of various factors including surgical stress and altered autonomic function. However, it is possible that stimulation of α-2 adrenergic receptors induced by DEX may also be linked to the coronary vasospasm that occurred.

Decreased Double Product at Rest in Patients With Severe Vasospasm

BACKGROUND

Autonomic nerve system and endothelial function play important roles in vasospastic angina. Elevated heart rate (HR), blood pressure (BP), and double product (DP) can increase endothelial-dependent coronary artery dilation and blood flow. However, the impact of HR, BP, and DP on occurrence and severity of VSA in the clinical setting is unclear.

METHOD

A total of 170 patients undergoing intracoronary acetylcholine (ACh) provocation test during hospitalisation was included. Resting HR, BP, and DP were measured at least four times, and their variabilities were evaluated by standard deviations (SD) and coefficient of variations (CVs). Angiographic coronary artery vasospasm was defined as total or subtotal occlusion induced by ACh provocation.

RESULTS

Mean±SD HR (65.7±9.1 vs 69.6±7.9 beats per minute; p=0.003), systolic BP (122.3±13.4 vs 127.7±14.6 mmHg; p=0.01), and DP (8,001±1,229 vs 8,903±1,495; p<0.001) were significantly lower in patients with a positive ACh test than the counterpart, whereas SD and CV of both HR and systolic BP were not significantly different between the two groups. Mean HR, BP, and DP progressively decreased with increase in the number of vessels with angiographic vasospasm. Multivariate analysis showed current smoking and lower DP as independent predictors of the greater number of vessels with provoked angiographic vasospasm.

CONCLUSIONS

Resting HR, BP, and DP were lower in patients with vasospastic angina, especially in those with severe vasospasm.

Autonomic dysregulation and phenobarbital in patients with masked primary hypertension

Introduction

Primary hypertension can be masked and be responsible of a severe impact on the target bodies. The purpose of this study was to see if Phenobarbital at low dose is able to decrease the sympathetic hyperactivity assessed by cardiovascular autonomic reflexes in patients with masked hypertension.

Materials and methods

This prospective study was conducted on a total of 91 patients with masked hypertension (average age 52.1 ± 10.3 years old). The cardiovascular autonomic tests performed in this group, before and after 3 months of daily oral administration of Phenobarbital, included deep breathing, hand-grip, mental stress and orthostatic tests. Statistical analysis was done using the Student's t-test, Univariate and Multivariate logistic regression analysis; p is significant if < 0.05.

Results

Cardiovascular autonomic reflexes responses before and after 3 months of Phenobarbital oral administration were as follows: Vagal response (XDB) obtained on deep breathing test was of 32.6 ± 5.4% VS 30.4 ± 6.1%, (p = 0.08), alpha peripheral sympathetic response (alpha SP) obtained on hand grip test was of 35.6 ± 8.7% VS 12.0 ± 2.5%, (p < 0.001), alpha central sympathetic response (alpha SC), beta central sympathetic response (beta SC) obtained during mental stress were of respectively 29.3 ± 9.2% VS 11.8 ± 2.4%, (p < 0.001) and 11.0 ± 5.3% VS 10.4 ± 6.1%, (p = 0.2), alpha peripheral adrenergic sympathetic (alpha PAS) obtained during orthostatic test was of 25.3 ± 6.0% VS 13.0 ± 3.4%, (p < 0.001).

Conclusion

These results demonstrated that Phenobarbital at low dose may have an anti-sympathetic effect in patients with masked hypertension.

Vasospastic angina: A literature review of current evidence

Vasospastic angina (VSA) is a variant form of angina pectoris, in which angina occurs at rest, with transient electrocardiogram modifications and preserved exercise capacity. VSA can be involved in many clinical scenarios, such as stable angina, sudden cardiac death, acute coronary syndrome, arrhythmia or syncope. Coronary vasospasm is a heterogeneous phenomenon that can occur in patients with or without coronary atherosclerosis, can be focal or diffuse, and can affect epicardial or microvasculature coronary arteries. This disease remains underdiagnosed, and provocative tests are rarely performed. VSA diagnosis involves three considerations: classical clinical manifestations of VSA; documentation of myocardial ischaemia during spontaneous episodes; and demonstration of coronary artery spasm. The gold standard diagnostic approach uses invasive coronary angiography to directly image coronary spasm using acetylcholine, ergonovine or methylergonovine as the provocative stimulus. Lifestyle changes, avoidance of vasospastic agents and pharmacotherapy, such as calcium channel blockers, nitrates, statins, aspirin, alpha1-adrenergic receptor antagonists, rho-kinase inhibitors or nicorandil, could be proposed to patients with VSA. This review discusses the pathophysiology, clinical spectrum and management of VSA for clinicians, as well as diagnostic criteria and the provocative tests available for use by interventional cardiologists.

Provocation of Coronary Vasospastic Angina Using an Isoproterenol Head-up Tilt Test

The goals of this study were to determine the value of the isoproterenol (ISO) head-up tilt (HUT) test in detecting coronary vasospastic angina and to investigate the possible mechanism responsible for coronary artery spasm. The ISO + HUT test was performed in 16 patients with coronary artery spasm documented by the intracoronary ergonovine provocation test. Patients’ blood pressure and heart rate were measured at baseline, during the ISO + HUT (phase I), and during HUT after discontinuation of ISO (phase II). Patients were categorized as test-positive if they developed angina with ST-segment elevation during testing. Eight patients (50%) were test-positive (5 in phase I and 3 in phase II). Between the test-positive and test-negative groups, no significant differences were noted in the changes in blood pressure throughout the test. However, there were significant differences in the changes in heart rate from supine to 2 minutes after HUT under ISO infusion (-17 ±22 vs 11 ±25 beats/minute; p=0.035). In those patients with a positive result in the phase I stage, the heart rate decreased initially after tilt-up, and then significantly increased later (from 85 ±16 to 110 ±27 beats/minute; p=0.043), when coronary vasospasm occurred. In those patients with a positive result in the phase II stage, coronary vasospasm occurred immediately after HUT, when there was an insignificant transient increase in heart rate from the supine to the HUT position (from 85 ±12 to 92 ±11 beats/minute; p=0.109). The ISO + HUT test can provoke coronary vasospasm with ST-segment elevation in 50% of the patients with coronary artery spasm, when combined with an extensional protocol of HUT after discontinuation of ISO. This study suggests that the induction of coronary artery spasm during HUT testing is associated with a rapid elevation of sympathetic activity during augmented parasympathetic activity.

Paradoxical nocturnal elevation of sympathetic tone and spontaneous ventricular fibrillation in Brugada syndrome

BACKGROUND

Nocturnal dominance of the incidence of spontaneous ventricular tachyarrhythmias has been reported in patients with Brugada syndrome (BrS). The purpose of the present study is to analyze the QT dynamics and autonomic balance as well as their diurnal variations in BrS patients.

METHODS

Of the 33 consecutive patients with BrS included in the study, 14 had a history of cardiopulmonary arrest due to spontaneous ventricular fibrillation (VF) episodes (VF-BrS) and 19 had asymptomatic BrS (A-BrS). QT dynamics and heart rate variability were analyzed using 24-h Holter electrocardiogram recordings.

RESULTS

Of the total 14 first cardiopulmonary arrest episodes due to spontaneous VF, 11 (79%) occurred in VF-BrS patients during the nighttime or at rest. The QT/RR slope during daytime was significantly steeper than that during nighttime in the A-BrS patients (p=0.031), but not in the VF-BrS patients (p=1.0). There were significant diurnal differences pertaining to the high-frequency (HF) and low-frequency (LF)/HF ratios in the A-BrS patients (p=0.019 and p=0.019, respectively), but not in the VF-BrS patients (p=1.0 and p=1.0, respectively). The VF-BrS patients were characterized by relatively high LF/HF ratios, whereas the A-BrS patients were characterized by relatively low LF/HF ratios throughout the daytime and nighttime. Furthermore, the LF/HF ratios during the nighttime in the VF-BrS patients were significantly higher than those in the A-BrS patients (p=0.021).

CONCLUSIONS

Most first episodes of spontaneous VF in the VF-BrS patients occurred during the nighttime or at rest. The autonomic imbalance of paradoxical nocturnal elevation of the sympathetic tone along with an underlying persistent sympathetic tone throughout the day may play a key role for spontaneous VF initiation in BrS patients.

Coronary spasm during cardiac electrophysiological study following isoproterenol infusion

Sudden cardiac death (SCD) remains the leading cause of death in industrialized world. The majority of SCD is caused by ventricular fibrillation associated with structural and/or ischemic heart disease. Ventricular fibrillation represents the final common pathway for SCD and, thus, is an attractive target for ablation. According to class I recommendation level of evidence A, an implantable cardioverter defibrillator (ICD) should be implanted for such patients [1]. Other than programmed electrical extrastimulus technique, isoproterenol infusion is commonly used in invasive cardiac electrophysiology labs for arrhythmia induction. We hereby report a rare case of transient coronary spasm during isoproterenol infusion for ventricular tachycardia induction testing.

Cardiovascular autonomic response to amlodipine in primary hypertension

Sympathetic hyperactivity may be involved in primary hypertension. The purpose of this study was to evaluate both sympathetic and vagal activity responses in patients receiving amlodipine as antihypertensive agent. Patients and Methods. This prospective study included a group of primary hypertensive patients (N = 32, mean age 54.6 ± 7.6 years). The cardiovascular autonomic tests performed in this group, before and after 3 months of daily oral administration of amlodipine, included deep breathing, hand-grip, and mental stress tests. Statistical analysis was done using the Student's t-test. Results. Cardiovascular autonomic reflexes responses before and after 3 months of amlodipine oral administration were as follows: the mental stress test stimulation method produced a central alpha adrenergic response of 23.9 ± 8.7% versus 11.2 ± 2.0% (P < 0.05), a central beta sympathetic response of 16.7 ± 9.2% versus 10.4 ± 1.3% (P < 0.05), a blood pressure increase in response to hand grip test of 20.5 ± 7.3% versus 10.7 ± 2.4% (P < 0.05), vagal response to deep breathing test was 21.2 ± 6.5% versus 30.8 ± 2.9%, (P < 0.05). Conclusion. The results attest that amlodipine may have an anti-sympathetic effect.

Variant angina and coronary artery spasm: the clinical spectrum, pathophysiology, and management

Variant angina is a form of angina pectoris that shows transient ST-segment elevation on electrocardiogram during an attack of chest pain. Ischemic episodes of variant angina show circadian variation and often occur at rest from midnight to early morning. Ischemic episodes also occur during mild exercise in the early morning. However, they are not usually induced by strenuous exercise in the afternoon. Other important clinical features of variant angina include the high frequency of asymptomatic ischemic episodes and the syncope that sometimes occur during the ischemic episodes. Syncope is due to severe arrhythmias, including ventricular tachycardia, ventricular fibrillation, and high-degree atrioventricular block. Coronary artery spasm is the mechanism of ischemic episodes in variant angina. The incidence of coronary artery spasm shows a racial difference and is higher in Japanese than in Caucasians. Coronary arteriograms are normal or near-normal in most Japanese patients with variant angina. Deficient basal release of nitric oxide (NO) due to endothelial dysfunction, and enhanced vascular smooth muscle contractility with the involvement of the Rho/Rho-kinase pathway are reported to play important roles in the pathogenesis of coronary artery spasm. Other precipitating factors of coronary artery spasm include imbalance in autonomic nervous activity, increased oxidative stress, chronic low-grade inflammation, magnesium deficiency, and genetic susceptibility. The genetic risk factors associated with coronary artery spasm include gene polymorphisms of endothelial NO synthase (NOS), paraoxonase, and other genes. Calcium channel blockers are extremely effective in preventing coronary spasm. The long-acting nitrate, nicorandil, and Rho-kinase inhibitor are also useful for inhibiting coronary artery spasm. Because variant angina can lead to acute myocardial infarction, fatal arrhythmias, and sudden death, early treatment is important. The prognosis of patients with variant angina is favorable, if early complications can be overcome. However, because coronary artery spasm cannot be suppressed in some patients, even with multiple medications, medications to suppress intractable coronary artery spasm must be developed.

Disruption of coronary vasomotor function: the coronary spasm syndrome

Abnormal coronary vasoconstriction, or coronary spasm, can be the result of several factors, including local and neuroendocrine aberrations. It can manifest clinically as a coronary syndrome and plays an important role in the genesis of myocardial ischemia. Over the past half century, coronary angiography allowed the in vivo demonstration of spasm in patients who fit the initial clinical description of the condition as reported by Prinzmetal et al. Several clinical, basic, and more recently, genetic studies have provided insight into the pathogenesis, manifestations, and therapy of this condition. It is not uncommonly encountered in patients with coronary syndromes and absence of clearly pathologic lesions on angiography. Provocation tests utilizing pharmacologic and nonpharmacologic stimuli combined with imaging (echocardiography or coronary angiography) can help make the correct diagnosis. The use of calcium channel blockers and long-acting nitrates is currently considered standard of care and the overall prognosis appears to be good. The recent discovery of genetic abnormalities predisposing to abnormal spasm of the coronaries has stimulated interest in the development of targeted therapies for the management of this condition.

[Sympathetic response in primary hypertension]

High blood pressure (BP) is a major cause of cardiovascular disease and primary hypertension is a frequent pathological condition. Sympathetic hyperactivity may be involved in primary hypertension. The purpose of this study was mainly to evaluate sympathetic activity when performing cardiovascular autonomic profile examination in patients with primary hypertension in comparison with normotensive subjects.

PATIENTS AND METHODS

This prospective study included one group of hypertensive patients (n=120, mean age 54 years) compared with a control group (n=120, mean age 52 years) of normotensive subjects. Autonomic tests included deep-breathing (DB), hand-grip (HG) and echostress test (ES). Comparison tests between the two groups, similar in age, were expressed as mean+/-SE and made using the t Student test, p<0.05 was considered significant.

RESULTS

Alpha-adrenergic sympathetic response using ES method produced a BP response of 20,0%+/-9,8 in hypertensive patients group and 15,2%+/-8,6 in the control group (p<0.001). Alpha-adrenergic sympathetic response using three minutes HG test was of 16,7%+/-7,5 in hypertensive patients group and 13,3%+/-6,5 in the control group (p<0.001). Vagal stimulation in hypertensive group after DB showed that electrocardiographic: ECG (EKG) waves R (RR) interval variation was of 30,2%+/-8,1 meanwhile in the control group this RR variation was of 46,1%+/-21,1 p<0.001, and the one of HG of 15 seconds was 17,6%+/-10,2 versus 32,5%+/-12,7 p<0.001.

CONCLUSION

Hypertensive patients had a significantly higher sympathetic response to central and peripheral stimulations and a significantly lower parasympathetic response when compared to normotensive controls.

Resting Chest Pain, Negative Treadmill Exercise Electrocardiogram, and Reverse Redistribution in Dipyridamole Myocardial Perfusion Scintigraphy Might be the Features of Coronary Artery Spasm

BACKGROUND

Coronary artery spasm usually attacks while at rest and the diagnosis depends on provoking tests which mostly are invasive, expensive and not practical. Previous investigations demonstrated that in most patients with coronary artery spasm, treadmill exercise electrocardiography (TEEC) did not induce any ischemic changes, and myocardial perfusion scintigraphy (MPS) showed reverse redistribution (RR).

HYPOTHESIS

Combination of resting chest pain, negative TEEC and RR might be a rational noninvasive set to predict coronary artery spasm.

METHODS

Patients with chest pain at rest, no significant coronary artery stenosis, and willing to undergo acetylcholine test were included. TEEC, dipyridamole and rest thallium-201 MPS were performed before or after coronary angiography. The patients were divided into spasm and nonspasm groups by acetylcholine test. The clinical features and results of TEEC and MPS were compared between the spasm and nonspasm groups.

RESULTS

Acetylcholine test was performed in 92 patients and coronary artery spasm was successfully provoked in 68 patients. Positive TEEC was induced in only 4 patients in the spasm group. RR was present in totally 77 patients and 68 of them were from the spasm group. By a combination of resting chest pain, negative TEEC and RR to diagnose coronary artery spasm, the sensitivity and specificity were 94% and 96% respectively.

CONCLUSION

Combination of resting chest pain, negative TEE and RR appears to be a rational noninvasive set to predict coronary artery spasm.

Vagus–brain communication in atherosclerosis-related inflammation: A neuroimmunomodulation perspective of CAD

The current understanding of the pathophysiology of atherosclerosis leading to coronary artery disease (CAD) emphasizes the role of inflammatory mediators. Given the bidirectional communication between the immune and central nervous systems, an important question is whether the brain can be "informed" about and modulate CAD-related inflammation. A candidate communicator and modulator is the vagus nerve. Until now, the vagus nerve has received attention in cardiology mainly due to its role in the parasympathetic cardiovascular response. However, the vagus nerve can also "inform" the brain about peripheral inflammation since its paraganglia have receptors for interleukin-1. Furthermore, its efferent branch has a local anti-inflammatory effect. These effects have not been considered in research on the vagus nerve in CAD or in vagus nerve stimulation trials in CAD. In addition, various behavioural interventions, including relaxation, may influence CAD prognosis by affecting vagal activity. Based on this converging evidence, we propose a neuroimmunomodulation approach to atherogenesis. In this model, the vagus nerve "informs" the brain about CAD-related cytokines; in turn, activation of the vagus (via vagus nerve stimulation, vagomimetic drugs or relaxation) induces an anti-inflammatory response that can slow down the chronic process of atherogenesis.

Vagal nerve-mediated vasospasm-induced lethal ventricular fibrillation

We report a case of variant angina complicated by lethal ventricular fibrillation. Serial ambulatory electrocardiogram monitoring revealed high-frequency spectra reflecting augmented vagal nerve activity preceding the vasospastic episodes. Our case suggests that heart rate variability analysis can help identify potential unexpected sudden cardiac death in patients with variant angina.

An increased monocyte count predicts coronary artery spasm in patients with resting chest pain and insignificant coronary artery stenosis

BACKGROUND

Coronary atherosclerosis with inflammation gives rise to coronary vasospasm in the patients with coronary vasospastic angina. We have postulated that the peripheral leukocyte count and the differential count are associated with vasospastic angina.

METHODS

144 patients who underwent intracoronary ergonovine provocation testing between January 2002 and December 2004 were divided into two groups: Group I (72 patients with provoked spasm, mean age: 54.8 +/- 10.7 years, males: 75%) and Group II (72 without spasm, mean age: 55.3 +/- 10.2 years, males: 35%). Blood sampling was done to measure the lipid profiles and inflammatory markers, including the high sensitive C-reactive protein (hsCRP) levels and the monocyte counts. We compared the angiographic findings and laboratory data between the two groups.

RESULTS

There were no significant differences in the levels of serum lipid and hsCRP between the two groups. The white blood cell count and the monocyte count were higher in Group I than with Group II (7496.4 +/- 2622.28 vs. 6703.2 +/- 1768.37/mm3, respectively, p = 0.035; 627.5 +/- 270.70 vs. 426.9 +/- 205.76/mm3, respectively, p < 0.001). Gensini's score was higher in Group I than in Group II (2.2 +/- 2.88 vs. 0.5 +/- 1.03, respectively, p < 0.001). Multivariate analysis showed that the monocyte count and Gensini's score were independent factors affecting coronary spasm (p = 0.047 and p = 0.018, respectively). According to a receiver operating characteristics curve analysis, the area under the curve of the monocyte count was 0.738, that of the neutrophil count was 0.577 and that of the WBC count was 0.572. The cut-off value of the monocyte count was 530/mm3; the sensitivity and specificity of this cut-off value were 64% and 76%, respectively.

CONCLUSIONS

The peripheral monocyte count is an independent marker for predicting vasospastic angina in the patients with resting chest pain and insignificant coronary artery stenosis.

Common adrenergic receptor polymorphisms as novel risk factors for vasospastic angina

BACKGROUND

Sympathetic activity mediated by adrenergic receptors (ARs) appears to play an important role in controlling the vasomotor tone and, thus, may be associated with vasospastic angina (VA). We investigated the association of the common functional polymorphisms of the AR gene and VA. The candidates were alpha2CDel322-325, beta1Gly389Arg, beta2Arg16Gly, and beta2Gln27Glu polymorphisms.

METHODS

Eighty-two patients with VA, confirmed by coronary angiography with or without ergonovine provocation test, and 114 apparently healthy control subjects were investigated for genotype of 4 AR polymorphisms and established risk factors of ischemic heart disease.

RESULTS

The minor alleles were alpha2CDel322-325, beta1Gly389, beta2Gly16, and beta2Glu27 and their frequencies were 7%, 18%, 42%, and 29%, respectively, in the control subjects of this Korean population, which were different from those of other ethnic groups. On univariate analysis, age, smoking, male sex, alpha2CDel322-325 allele carrier state, and beta2Gln27 homozygote state were significant risk factors for VA. After multivariate analysis using multiple logistic regression model, age (odds ratio [OR] 1.809, CI 1.046-1.135, P < .0001), smoking (OR 4.902, CI 2.105-11.416, P = .0002), alpha2CDel322-325 allele carrier state (OR 5.132, CI 2.094-12.578, P = .0003), and beta2Gln27 allele homozygosity (OR 3.152, CI 1.364-7.285, P = .0072) remained as independent risk factors. In the combined genotype analysis, the effect of beta2Gln27 allele was evident only when the alpha2CDel322-325 allele was absent.

CONCLUSIONS

The alpha2CDel322-325 allele carrier state and beta2Gln27 allele homozygote state were identified as novel risk factors of VA in this Korean population. This result suggests the importance of the adrenergic stimuli and the genetic background in the pathogenesis of the VA.

Differences in heart rate variability in non-hypertensive diabetic patients correlate with the presence of underlying cerebrovascular disease

We previously showed that diabetes contributes to the development of sclerotic lesions in cerebral arteries. In this study, we attempted to clarify whether differences in heart rate variability in non-hypertensive diabetic patients were dependent on the presence or absence of underlying cerebrovascular disease. Thirty diabetic subjects between 40 and 59 years of age and who had no prior history of hypertension were used in this study. Lacunar lesions (LA) were detected with magnetic resonance imaging and atherosclerotic lesions (AS) were detected using intra- and extracranial magnetic resonance angiography, and by ultrasonographic scanning of the carotid artery. Patients underwent a full clinical laboratory screening and a power spectrum analysis of their heart rate variability. Subjects were divided into two groups: those with and without LA. The low frequency/high frequency ratio (LF/HF ratio) was found to be significantly increased (P<0.01) in subjects with LA (2.2 +/- 0.3) compared to those without LA (1.3 +/- 0.1). When subjects were divided into groups based on their presence or absence of AS, high-frequency power was found to be significantly reduced (P<0.05) in the subjects with AS (12.8 +/- 3.4 ms) compared to those without AS (19.4 +/- 1.7 ms). The LF/HF ratio was found to be significantly increased (P<0.05) in the subjects with AS (2.2 +/- 0.3) compared to those without AS (1.4 +/- 0.1). Our data suggested that atherosclerotic lesions in cerebrovascular diseased linked to decrease of vagal nerve activity in non-hypertensive diabetic patients.

Two cases of Brugada syndrome associated with spontaneous clinical episodes of coronary vasospasm

Two patients with life-threatening episodes of ventricular fibrillation (VF) showed typical ST elevation in V1-V3 leads. Both had spontaneous clinical episodes of resting angina. Intracoronary injection of acetylcholine provoked coronary vasospasm and ST elevation was the same as Brugada-type ST elevation in 1 case but not in the other. Calcium channel antagonist was prescribed to prevent coronary vasospasm but Brugada-type ST elevation and the occurrence of VF could not be prevented. The symptoms accompanied both cases. Considering these cases, the pathogenesis of Brugada syndrome should differ from that of coronary vasospasm because it could not be prevented by calcium channel antagonist.

Circadian periodicity of heart rate variability in hospitalized angor patients

The relationship between unstable angor (angina) and circadian periodicity of heart rate variability (HRV) was explored in a group of patients hospitalized in a coronary care unit (CCU). Patients were classified as normal (whose symptoms had non-cardiovascular origin, n=8), moderate angor (n=13) and severe angor (n=11). A fourth group of ambulatory healthy volunteers (n=12) was included. Individual 24 h Holter records were analyzed, mean RR and standard deviation of RR (SDNN) being obtained from 1 h-length windows. For frequency domain analysis, 5 min-length windows were employed. The spectral components analyzed were total power (spectral power between 0.01 and 0.5 Hz), low frequency power (LF: power between 0.04 and 0.15 Hz), and high frequency power (HF: power between 0.15 and 0.4 Hz). In addition, LF to HF areas ratio (L/H) was computed. Mesor, amplitude and acrophase for every 24 h rhythm were calculated by cosinor analysis. As compared to ambulatory controls, admission to the CCU diminished amplitude and phase-delayed the circadian oscillation of most HRV parameters, except for SDNN. Moderate angor patients showed decreased amplitude of RR and L/H and augmented amplitude of SDNN when compared to normal hospitalized subjects. A phase delay of about 1.5 h for RR intervals and a phase advance of 3.5-6 h for LFA and SDNN were found in the moderate angor group when compared to normal. Amplitude of 24 h variation of total power decreased in severely angor patients and the circadian oscillation of HF (an indicator of vagal control on the heart) became free running. A phase delay of 2.5 h in SDNN acrophase was found in severely affected patients when compared to moderate. The results indicate that severity of unstable angor correlates with desynchronization of parasympathetic control of heart rate.

On the genesis of myocardial ischemia

About three quarters of myocardial ischemic events are triggered by the autonomic nervous system. The pathognomonic constellation is a combination of an almost complete withdrawal of tonic vagal activity with increased sympathetic activity. The reduction of tonic vagal activity, which is characteristic for ischemic heart disease, and the acute withdrawal of vagal drive preceding the onset of ischemia are not dependent on coronary artery disease. In this paper, the pathophysiological steps that lead from sympathetic-parasympathetic imbalance to myocardial ischemia shall be discussed. A considerable increase of aerobic glycolysis within the myocardium as a result of the autonomic imbalance is of special importance in this process.

Autonomic antecedents to variant angina exacerbation after β-blockade withdrawal

We describe a patient with nonsignificant coronary artery disease who experienced variant angina after beta -blockade withdrawal. Standard therapy with nifedipine and nitrates aimed at suppressing symptoms and typical transient ST-segment elevations was superseded by the reinstitution of metoprolol. The autonomic alternations before and after readministration of metoprolol were analyzed by time and spectral indices of heart rate variability (HRV). Metoprolol reduced the HRV and reversed the low-frequency/high-frequency power ratio toward a more physiological autonomic balance. We conclude that the reinstitution of beta -blocker acted protectively by preventing surges of sympathetic activity on an underlying basis of parasympathetic predominance.

Prevention of Ventricular Fibrillation, Acute Myocardial Infarction (Myocardial Necrosis), Heart Failure, and Mortality by Bretylium

It is widely, but mistakenly, believed that ischemic heart disease (IsHD) and its complications are the sole and direct result of reduced coronary blood flow by obstructive coronary artery disease (CAD). However, cardiac angina, acute myocardial infarction (AMI), and sudden cardiac death (SCD) occur in 15%-20% of patients with anatomically unobstructed and grossly normal coronaries. Moreover, severe obstructive coronary disease often occurs without associated pathologic myocardiopathy or prior symptoms, ie, unexpected sudden death, silent myocardial infarction, or the insidious appearance of congestive heart failure (CHF). The fact that catecholamines explosively augment oxidative metabolism much more than cardiac work is generally underappreciated. Thus, adrenergic actions alone are likely to be more prone to cause cardiac ischemia than reduced coronary blood flow per se. The autonomic etiology of IsHD raises contradictions to the traditional concept of anatomically obstructive CAD as the lone cause of cardiac ischemia and AMI. Actually, all the signs and symptoms of IsHD reflect autonomic nervous system imbalance, particularly adrenergic hyperactivity, which may by itself cause ischemia as in rest angina. Adrenergic activity causing ischemia signals cardiac pain to pain centers via sympathetic efferent pathways and tend to induce arrhythmogenic and necrotizing ischemic actions on the cardiovascular system. This may result in ischemia induced metabolic myocardiopathy not unlike that caused by anatomic or spasmogenic coronary obstruction. The clinical study and review presented herein suggest that adrenergic hyperactivity alone without CAD can be a primary cause of IsHD. Thus, adrenergic heart disease (AdHD), or actually adrenergic cardiovascular heart disease (ACVHD), appears to be a distinct entity, most commonly but not necessarily occurring in parallel with CAD. CAD certainly contributes to vulnerability as well as the progression of IsHD. This vicious cycle, which explains the frequent parallel occurrence of arteriosclerosis and IHD, an association that appears to be linked by the same cause, comprises a common vulnerability to deleterious adrenergic actions on the myocardium, lipid metabolism, and vascular system alike, rather than viewing CAD and IsHD as having a putative cause and effect relationship as commonly thought. Adrenergic actions can also cause the abnormal lipid metabolism that is associated with CAD and IsHD by catecholamine-induced metabolic actions on lipid mobilization by activation of phospholipases. This may also be part of toxic catecholamine hypermetabolic actions by enhancing deleterious cholesterol and lipid actions in damaging coronary vessels by plaque formation as well as inducing obstructive coronary spasm and platelet aggregation. This may also cause direct toxic necrosis on the myocardium as well as atherosclerosis in blood vessels. In fact, drugs that inhibit adrenergic actions like propranolol, reserpine, and guanethidine all inhibit arteriosclerosis induced by hypercholesterolemia in experimental animals and prevent carotid vascular disease (associated with stroke) in humans. The concomitant development of myocardiopathy and coronary vascular lesions or coronary and carotid artery intimal medial thickening by catecholamine toxicity is reflected by the frequent primary presentation of patients with catecholamine-secreting pheochromocytoma with cardiovascular disease, ie, hypertension arrhythmias, AMI, SCD, CHF, and vascular disease, which represents a clear example of the primary deleterious impact of catecholamines on the entire cardiovascular system causing adrenergic cardiovascular disease. Thus, like myocardiopathy, CAD and atherosclerosis in general may be the consequences of or a complication of catecholamine actions rather than its putative cause. This report shows how prophylactic bretylium not only prevents arrhythmias but prevents myocardial necrosis, shock, CHF, maintains or restores normal contractility, and lowers mortality in AMI patients by inducing adrenergic blockade.

Circadian distribution of acute myocardial infarction by anatomic location and coronary artery involvement

PURPOSE

Acute myocardial infarction follows a circadian pattern, with a morning peak ascribed to sympathetic activation. However, about 20% of myocardial infarctions occur between midnight and 6 AM; these events may have different characteristics.

METHODS

We studied 1571 patients with acute myocardial infarction (866 anterior and 705 inferior myocardial infarctions) who were admitted to our coronary care units from January 1997 to February 2001. We noted the time of the infarction, its anatomic location, and the involved coronary arteries.

RESULTS

Inferior myocardial infarctions were more frequent during the night (midnight to 6 AM) than during other periods of the day (n = 238, 34% of all inferior infarctions, P <0.01). When coronary angiography was performed (795 patients), 92% (127/138) of inferior infarctions were due to right coronary artery occlusion, whereas only 54% (130/242) of the remaining inferior infarctions involved that artery.

CONCLUSION

Inferior myocardial infarctions occur disproportionately at night, usually due to right coronary artery occlusion. This suggests that a protective role for sleep may be limited to left coronary artery-related events.

Wavelet transform analysis of heart rate variability to assess the autonomic changes associated with spontaneous coronary spasm of variant angina

We used Wavelet transform (WT) to investigate whether variation in autonomic tone was associated with spontaneous coronary spasm in patients with variant angina by analysis of heart rate variability (HRV). Twenty-one episodes preceding ST-segment elevation were selected under Holter monitoring in 12 men and 3 women with variant angina. HRV indices were calculated at 10 second intervals with the continuous WT, and analyzed within 30 minutes preceding ST-segment elevation. High frequency (HF; 0.15 approximately 2.00 Hz) increased significantly during the 4 minutes prior to ST-segment elevation, low frequency (LF; 0.04 approximately 0.15 Hz) decreased significantly during the period from 10 to 5 minutes and increased significantly during the 2 minutes prior to ST-segment elevation, the LF/HF ratio decreased significantly during the period from 10 to 3 minutes and increased significantly during the 2 minutes prior to ST-segment elevation. The RR interval decreased significantly during the 2 minutes prior to ST-segment elevation. These results suggest that the acute variation in autonomic tone was associated with spontaneous coronary spasm in patients with variant angina. A reduction in sympathetic activity, then enhancement of vagal activity may play a key role in triggering the spontaneous coronary spasm, and the secondary activation of sympathetic activity may worsen the coronary spasm resulting in the attack.

Coronary vasospasm as a possible cause of elevated cardiac troponin I in patients with acute coronary syndrome and insignificant coronary artery disease

BACKGROUND

Abnormal levels of serum cardiac troponin I (cTnI) are occasionally found in patients presenting with acute coronary syndromes but having insignificant coronary artery disease. Before one concludes that an abnormal cTnI level is a false-positive result, the possibility of coronary vasospasm should be considered. This study investigated whether coronary vasospasm could be a reason for elevated cTnI in this patient population.

METHODS AND RESULTS

This investigation enrolled 93 patients who presented to the emergency department with suspected coronary ischemia and had insignificant coronary artery disease. cTnI was elevated in 23 patients (25%) and was normal in 70 patients (75%). Coronary vasospasm, documented by an ergonovine provocation test, was found in 38 patients (41%). Patients with elevated cTnI levels, compared with those with normal cTnI, were older (63 +/- 13 y vs 56 +/- 14 y, P =.032), had a higher incidence of males (78% vs 52%, P =.049) and positive ergonovine provocation tests (74% vs 30%, P <.0001), and tended to have a lower incidence of hypercholesterolemia (26% vs 48%, P =.088) and normal electrocardiograms (48% vs 70%, P =.078). Multivariate analysis showed that the variables independently associated with an elevated cTnI level included coronary vasospasm (odds ratio 2.41, 95% CI 1.48-3.18, P <.0001) and hypercholesterolemia (odds ratio 0.64, 95% CI 0.47-0.99, P =.049). Coronary vasospasm (positive ergonovine provocation test) could explain 74% of elevated cTnI levels in patients with insignificant coronary stenosis.

CONCLUSIONS

In patients with acute coronary syndrome with elevated cTnI and insignificant coronary artery disease, the possibility of coronary vasospasm as a cause of elevated cTnI should be considered.

The impact of ocular blood flow in glaucoma

Two principal theories for the pathogenesis of glaucomatous optic neuropathy (GON) have been described--a mechanical and a vascular theory. Both have been defended by various research groups over the past 150 years. According to the mechanical theory, increased intraocular pressure (IOP) causes stretching of the laminar beams and damage to retinal ganglion cell axons. The vascular theory of glaucoma considers GON as a consequence of insufficient blood supply due to either increased IOP or other risk factors reducing ocular blood flow (OBF). A number of conditions such as congenital glaucoma, angle-closure glaucoma or secondary glaucomas clearly show that increased IOP is sufficient to lead to GON. However, a number of observations such as the existence of normal-tension glaucoma cannot be satisfactorily explained by a pressure theory alone. Indeed, the vast majority of published studies dealing with blood flow report a reduced ocular perfusion in glaucoma patients compared with normal subjects. The fact that the reduction of OBF often precedes the damage and blood flow can also be reduced in other parts of the body of glaucoma patients, indicate that the hemodynamic alterations may at least partially be primary. The major cause of this reduction is not atherosclerosis, but rather a vascular dysregulation, leading to both low perfusion pressure and insufficient autoregulation. This in turn may lead to unstable ocular perfusion and thereby to ischemia and reperfusion damage. This review discusses the potential role of OBF in glaucoma and how a disturbance of OBF could increase the optic nerve's sensitivity to IOP.

Circadian variation of autonomic nervous activity in patients with multivessel coronary spasm

The present study investigated whether the circadian rhythm of sympathovagal activity is related to the severity of coronary spasm or multivessel coronary spasm. Heart rate variability was examined in 22 consecutive patients with vasospastic angina provoked by intracoronary injection of acetylcholine, who had either multivessel spasm (Group M, n=11 ) or single vessel spasm (Group S, n= 11), in 20 subjects without coronary artery disease (Group C) and 20 patients with effort angina who had organic coronary artery stenosis (Group E). The frequency domain indices were analyzed, including low frequency (LF: 0.04-0.15 Hz) and high frequency (HF: 0.15-0.4Hz), the latter being an index of efferent parasympathetic activity, and the ratio (L/H) as an index of sympathovagal balance. The circadian variation of the parameters was analyzed by its pattern and was quantified by the difference of the mean values between daytime and nighttime. Although the HF power increased during nighttime in Groups C and S, this increase was attenuated in Groups E and M. The circadian variation of the L/H ratio (ie, a drop during nighttime) was smaller in the S and M groups than in Groups C and E. Accordingly, in Group M, the circadian variation of both sympathetic and parasympathetic nervous activity was attenuated, but in Group S, the variation of sympathetic nervous activity, but not parasympathetic nervous activity, was decreased. These data suggest that relatively enhanced sympathetic nervous activity at night may be involved in the mechanism underlying multivessel coronary spasm.

Vagal neurostimulation in patients with coronary artery disease

We tested the hypotheses that (1) progression of coronary artery disease (CAD) increases sympathetic inflow to the heart, thus impairing cardiac blood supply, and (2) reduced sympathetic tone improves cardiac microcirculation and ameliorates severity of anginal symptoms. Electrical irritation of the nerve auricularis--a sensitive ramus of the vagus nerve--provides a central sympatholytic action. Using this technique, we studied the effects of vagal neurostimulation (VNS) on hemodynamics, the content of atrial noradrenergic nerves and the microcirculatory bed of CAD patients. VNS was performed in the preoperative period of CAD patients with severe angina pectoris. The comparison groups consisted of untreated patients with CAD or Wolff-Parkinson-White syndrome. Atrial tissue of patients with this syndrome (n = 6); with effort angina (n = 14); with angina at rest (n = 10); and with severe angina treated with VNS (n = 8) contained the following volume percentages of noradrenergic nerves: 1.7+/-0.1%, 1.3+/-0.3%, 0.5+/-0.1% (p < 0.05 vs. the other groups) and 1.3+/-0.2%, respectively. In these groups, cardiac microcirculatory vessels (diameter, 10-20 microm) had the following densities: 2.7+/-0.2%, 3.4+/-0.2%, 2.0+/-0.4% (p < 0.05 vs. the other groups) and 3.3+/-0.3%, respectively. VNS treatment abolished angina at rest, decreased heart rate and blood pressure. It improved left ventricular ejection fraction from 50+/-1.5% to 58+/-1.0% (p < 0.05), also changing left ventricular diastolic filling. The ratio of time velocity integrals of the early (Ei) to late (Ai) waves increased from 1.07+/-0.12 to 1.65+/-0.17 after VNS (p < 0.05). In electrocardiograms of VNS-treated patients, QRS- and QT-duration were shortened. the PQ-interval did not change, but T-wave configuration improved. In the postoperative period, heart failure occurred in 90% of the control group. vs. 12% in patients treated with VNS (p < 0.05). We conclude that CAD is characterized by overactivity of sympathetic cardiac tone. Vagal stimulation reduced sympathetic inflow to the heart, seemingly via an inhibition of norepinephrine release from sympathetic nerves. VNS' sympatholytic/vagotonic action dilated cardiac microcirculatory vessels and improved left ventricular contractility in patients with severe CAD.

Altered baroreflex responses in alpha7 deficient mice

The autonomic nervous system controls and coordinates several cardiovascular functions, including heart rate, arterial pressure, blood flow and vasomotor tone. Neuronal nicotinic acetylcholine receptors (nAChRs) are the interface between the nervous system and the cardiovascular system, but it is not known which nAChR subtypes regulate autonomic function in vivo. Nicotinic AChRs containing the alpha7 subunit are a candidate subtype in autonomic ganglia. Stimulation of these nAChRs can increase neurotransmitter release via presynaptic mechanisms, as well as mediate fast synaptic transmission via postsynaptic mechanisms. To investigate the role of the alpha7 nAChR subunit in cardiac autonomic function, we measured baroreflex-mediated responses in alpha7 null mice. Here we show that the alpha7 null mice have impaired sympathetic responses to vasodilatation, as sodium nitroprusside infusion triggered a 48% heart rate increase in wild type mice but only a 21% increase in the alpha7 nulls (P < 0.001). The mutant mice developed supersensitivity to adrenergic agonists, although norepinephrine release from sympathetic nerve terminals could be elicited through mechanisms alternative to nAChR stimulation. Baroreflex-mediated parasympathetic responses were normal in alpha7 null mice. The decreased baroreflex-mediated tachycardia in alpha7 mutant mice indicates that alpha7-containing nAChRs participate in the autonomic reflex that maintains blood pressure homeostasis. The alpha7 mutant mice may serve as a model of baroreflex impairment arising from autonomic dysfunction.

Changes in autonomic nervous activity prior to spontaneous coronary spasm in patients with variant angina

Although the autonomic nervous system has been implicated in the genesis of coronary spasm, the precise mechanism by which it serves as the trigger of coronary spasm remains unclear. The aim of this study was to investigate changes in autonomic nervous activity associated with ischemic episodes in patients with variant angina (VA). Heart rate variability (HRV) on Holter monitoring was analyzed during 17 ischemic episodes in 11 patients with VA. The parameters of HRV were measured during a 2-min period at various time intervals prior to the onset of ST-segment elevation. The low frequency (LF) and high frequency (HF) components of the HRV, LF/HF ratio, mean RR interval, and the coefficient of the RR interval variation (CV) were calculated for each time interval. Both the HF and the CV increased significantly in the 2 min prior to the onset of ST-segment elevation, suggesting heightened vagal activity. The LF/HF ratio, a measure of cardiac sympatho-vagal balance, did not change. The LF, a measure of sympathetic activity with vagal modulation, also did not change. The RR interval decreased significantly in the 2 min prior to the onset of ST-segment elevation. These results suggest that enhancement of both the vagal and the sympathetic nervous activity plays an important role in the initiation of coronary spasm.