Prevalence of classic and non-classic pain sites of coronary artery disease: a cross-sectional study

STUDY OBJECTIVE

This study aims to assess the prevalence of both classic and non-classic pain sites in patients with ischemic heart disease, emphasizing the importance of recognizing and not disregarding non-classic symptoms.

METHODS

This cross-sectional study included 100 patients diagnosed with coronary artery disease (CAD) who were admitted to two major hospitals in Syria. classic pain was identified as pain located in the precordial area, with or without radiation to the neck, jaw, left shoulder or arm. Patients' demographics and previous medical history were documented to investigate any potential associations with non-classic pain.

RESULTS

62% of the patients experienced non-classic pain, while 12% had no precordial pain. For those without precordial pain, the most common pain site was the left chest (66.7%). Non-classic pain was significantly associated with smoking, with 72.2% of smokers experiencing non-classic pain compared to 35.7% non-smokers (p = 0.001). Additionally, patients with previous heart disease were more likely to have non-classic pain (71.7%), compared with patients with no history of heart disease (51.1%) (p = 0.03). Other factors such as age, sex, and diabetes were not statistically significant.

CONCLUSION

Non-classic pain is common, affecting 62% of individuals, primarily in the right shoulder, right arm, and back. This type of pain could be associated with smoking and prior heart disease. Misdiagnosing coronary artery disease can have serious consequences, as patients with non-classic symptoms may miss important pre-hospital procedures like ECG.

Pain from Internal Organs and Headache: The Challenge of Comorbidity

Headache and visceral pain are common clinical painful conditions, which often co-exist in the same patients. Numbers relative to their co-occurrence suggest possible common pathophysiological mechanisms. The aim of the present narrative review is to describe the most frequent headache and visceral pain associations and to discuss the possible underlying mechanisms of the associations and their diagnostic and therapeutic implications based on the most recent evidence from the international literature. The conditions addressed are as follows: visceral pain from the cardiovascular, gastrointestinal, and urogenital areas and primary headache conditions such as migraine and tension-type headache. The most frequent comorbidities involve the following: cardiac ischemic pain and migraine (possible shared mechanism of endothelial dysfunction, oxidative stress, and genetic and hormonal factors), functional gastrointestinal disorders, particularly IBS and both migraine and tension-type headache, primary or secondary dysmenorrhea and migraine, and painful bladder syndrome and headache (possible shared mechanisms of peripheral and central sensitization processes). The data also show that the various visceral pain-headache associations are characterized by more than a simple sum of symptoms from each condition but often involve complex interactions with the frequent enhancement of symptoms from both, which is crucial for diagnostic and treatment purposes.

Daphnoretin inhibited SCI-induced inflammation and activation of NF-κB pathway in spinal dorsal horn

OBJECTIVE

Spinal cord injury (SCI) is a devastating disease for which there is no safe and effective treatment at present. Daphnoretin is a natural discoumarin compound isolated from Wikstroemia indica with various pharmacological activities. Our study aimed to investigate the role of Daphnoretin in NF-κB pathway activation and inflammatory response after SCI.

METHODS

A mouse SCI model was constructed, and the Basso Mouse Scale Score and subscore were used to evaluate the effect of Daphnoretin on the movement capacity of mice. The effect of Daphnoretin on the activation of glial cells in the mouse model and BV2 cells was observed by immunofluorescence. PCR and ELISA were used to detect the expression of inflammatory factors, and Western blot was performed to detect the protein expression associated with NF-κB pathway.

RESULTS

Daphnoretin inhibited the loss of movement ability and the activation of glial cells in mice after SCI, and it also inhibited the activation of NF-κB pathway and the expression of inflammatory factors TNF-α and IL-1β in vivo and in vitro.

CONCLUSIONS

Daphnoretin can inhibit the activation of NF-κB pathway and the inflammatory response induced by SCI. Our study demonstrates the potential of Daphnoretin on clinical application for the treatment of SCI.

Interoceptive signals from the heart and coronary circulation in health and disease

This review considers interoceptive signalling from the heart and coronary circulation. Vagal and cardiac sympathetic afferent sensory nerve endings are distributed throughout the atria, ventricles (mainly left), and coronary artery. A small proportion of cardiac receptors attached to thick myelinated vagal afferents are tonically active during the cardiac cycle. Dependent upon location, these mechanoreceptors detect fluctuations in atrial volume and coronary arterial perfusion. Atrial volume and coronary arterial signals contribute to beat-to-beat feedback control and physiological homeostasis. Most cardiac receptors are attached to thinly myelinated or nonmyelinated C fibres, many of which are unresponsive to the cardiac cycle. Of these, there are many chemically sensitive cardiac receptors which are activated during myocardial stress by locally released endogenous substances. In contrast, some tonically inactive receptors become activated by irregular ventricular wall mechanics or by distortion of the ischaemic myocardium. Furthermore, some are excited both by chemical mediators of ischaemia and wall abnormalities. Reflex responses arising from cardiac receptors attached to thinly myelinated or nonmyelinated are complex. Impulses that project centrally through vagal afferents elicit sympathoinhibition and hypotension, whereas impulses travelling in cardiac sympathetic afferents and spinal pathways elicit sympathoexcitation and hypertension. Two opposing cardiac reflexes may provide a mechanism for fine-tuning a composite haemodynamic response during myocardial stress. Sympathetic afferents provide the primary pathway for transmission of cardiac nociception to the central nervous system. However, activation of sympathetic afferents may increase susceptibility to life-threatening arrhythmias. Notably, the cardiac sympathetic afferent reflex predominates in pathophysiological states including hypertension and heart failure.

Lysophosphatidic acid contributes to myocardial ischemia/reperfusion injury by activating TRPV1 in spinal cord

Lysophosphatidic acid (LPA) is a bioactive phospholipid that plays a crucial role in cardiovascular diseases. Here, we question whether LPA contributes to myocardial ischemia/reperfusion (I/R) injury by acting on transient receptor potential vanilloid 1 (TRPV1) in spinal cord. By ligating the left coronary artery to establish an in vivo I/R mouse model, we observed a 1.57-fold increase in LPA level in the cerebrospinal fluid (CSF). The I/R-elevated CSF LPA levels were reduced by HA130, an LPA synthesis inhibitor, compared to vehicle treatment (4.74 ± 0.34 vs. 6.46 ± 0.94 μg/mL, p = 0.0014). Myocardial infarct size was reduced by HA130 treatment compared to the vehicle group (26 ± 8% vs. 46 ± 8%, p = 0.0001). To block the interaction of LPA with TRPV1 at the K710 site, we generated a K710N knock-in mouse model. The TRPV1K710N mice were resistant to LPA-induced myocardial injury, showing a smaller infarct size relative to TRPV1WT mice (28 ± 4% vs. 60 ± 7%, p < 0.0001). Additionally, a sequence-specific TRPV1 peptide targeting the K710 region produced similar protective effects against LPA-induced myocardial injury. Blocking the K710 region through K710N mutation or TRPV1 peptide resulted in reduced neuropeptides release and decreased activity of cardiac sensory neurons, leading to a decrease in cardiac norepinephrine concentration and the restoration of intramyocardial pro-survival signaling, namely protein kinase B/extracellular regulated kinase/glycogen synthase kinase-3β pathway. These findings suggest that the elevation of CSF LPA is strongly associated with myocardial I/R injury. Moreover, inhibiting the interaction of LPA with TRPV1 by blocking the K710 region uncovers a novel strategy for preventing myocardial ischemic injury.

Silent Myocardial Ischemia: From Pathophysiology to Diagnosis and Treatment

Silent myocardial ischemia (SMI), characterized by a lack of overt symptoms despite an inadequate blood supply to the myocardium, remains a challenging entity in cardiovascular medicine. The pathogenesis involves intricate interactions of vascular, neurohormonal, and metabolic factors, contributing to perfusion deficits without the characteristic chest pain. Understanding these mechanisms is pivotal for recognizing diverse clinical presentations and designing targeted interventions. Diagnostic strategies for SMI have evolved from traditional electrocardiography to advanced imaging modalities, including stress echocardiography, single-photon emission computed tomography (SPECT), positron emission tomography (PET), and cardiac magnetic resonance imaging (MRI). Treating SMI is a matter of ongoing debate, as the available evidence on the role of invasive versus medical management is controversial. This comprehensive review synthesizes current knowledge of silent myocardial ischemia, addressing its pathophysiology, diagnostic modalities, and therapeutic interventions.

Nonpharmacological interventions for 'no-option' refractory angina patients

Refractory angina pectoris (RAP) defined as chronic anginal chest pain because of coronary artery disease (CAD) is a major problem. The increase in the number of patients with RAP in recent years is because of the increasing aging population and improved survival rates among patients with CAD. Management of patients with RAP is often extremely challenging. In this review, we present several interventional approaches for RAP, including device therapies, lifestyle intervention, and cell therapies. Some of these treatments are currently used in the management of RAP, whereas other treatments are under investigation.

Pseudo-vagal Responses Elicited by Cryoballoon Ablation

Pulmonary vein isolation via cryoballoon (CB) ablation is the cornerstone ablation strategy for the treatment of atrial fibrillation (AF). Acute intraprocedural hypotensive and/or bradycardic responses have been reported in patients undergoing CB ablation for AF. However, it remains unclear as to whether these are due to a true vagal response (VR), which can be used to predict long-term outcomes of CB ablation. We analyzed 139 freezes across 17 patients who received CB ablation for paroxysmal AF, measuring vital signs and freeze characteristics. Only one freeze was associated with both hypotension and bradycardia, constituting a true VR. Several freezes were associated with hypotension only that did not respond to atropine administration, suggesting that these responses are not associated with a VR. Hypotensive responses were significantly associated with ice bubble bursts during CB deflation. Unlike the true VR reported in patients undergoing conscious sedation, the presence of acute hypotension shortly after CB deflation cannot be used as a predictor for long-term ablation outcomes.

Thoracic Dorsal Root Ganglion Application of Resiniferatoxin Reduces Myocardial Ischemia-Induced Ventricular Arrhythmias

BACKGROUND

A myocardial ischemia/reperfusion (IR) injury activates the transient receptor potential vanilloid 1 (TRPV1) dorsal root ganglion (DRG) neurons. The activation of TRPV1 DRG neurons triggers the spinal dorsal horn and the sympathetic preganglionic neurons in the spinal intermediolateral column, which results in sympathoexcitation. In this study, we hypothesize that the selective epidural administration of resiniferatoxin (RTX) to DRGs may provide cardioprotection against ventricular arrhythmias by inhibiting afferent neurotransmission during IR injury.

METHODS

Yorkshire pigs (n = 21) were assigned to either the sham, IR, or IR + RTX group. A laminectomy and sternotomy were performed on the anesthetized animals to expose the left T2-T4 spinal dorsal root and the heart for IR intervention, respectively. RTX (50 μg) was administered to the DRGs in the IR + RTX group. The activation recovery interval (ARI) was measured as a surrogate for the action potential duration (APD). Arrhythmia risk was investigated by assessing the dispersion of repolarization (DOR), a marker of arrhythmogenicity, and measuring the arrhythmia score and the number of non-sustained ventricular tachycardias (VTs). TRPV1 and calcitonin gene-related peptide (CGRP) expressions in DRGs and CGRP expression in the spinal cord were assessed using immunohistochemistry.

RESULTS

The RTX mitigated IR-induced ARI shortening (-105 ms ± 13 ms in IR vs. -65 ms ± 11 ms in IR + RTX, p = 0.028) and DOR augmentation (7093 ms2 ± 701 ms2 in IR vs. 3788 ms2 ± 1161 ms2 in IR + RTX, p = 0.020). The arrhythmia score and VT episodes during an IR were decreased by RTX (arrhythmia score: 8.01 ± 1.44 in IR vs. 3.70 ± 0.81 in IR + RTX, p = 0.037. number of VT episodes: 12.00 ± 3.29 in IR vs. 0.57 ± 0.3 in IR + RTX, p = 0.002). The CGRP expression in the DRGs and spinal cord was decreased by RTX (DRGs: 6.8% ± 1.3% in IR vs. 0.6% ± 0.2% in IR + RTX, p < 0.001. Spinal cord: 12.0% ± 2.6% in IR vs. 4.5% ± 0.8% in IR + RTX, p = 0.047).

CONCLUSIONS

The administration of RTX locally to thoracic DRGs reduces ventricular arrhythmia in a porcine model of IR, likely by inhibiting spinal afferent hyperactivity in the cardio-spinal sympathetic pathways.

Cardiovascular Effects of Spinal Cord Stimulation: The Highs, the Lows, and the Don't Knows

BACKGROUND AND OBJECTIVES

There are many potential etiologies of impaired cardiovascular control, from chronic stress to neurodegenerative conditions or central nervous system lesions. Since 1959, spinal cord stimulation (SCS) has been reported to modulate blood pressure (BP), heart rate (HR), and HR variability (HRV), yet the specific stimulation sites and parameters to induce a targeted cardiovascular (CV) change for mitigating abnormal hemodynamics remain unclear. To investigate the ability and parameters of SCS to modulate the CV, we reviewed clinical studies using SCS with reported HR, BP, or HRV findings.

MATERIALS AND METHODS

A keyword-based electronic search was conducted through MEDLINE, Embase, and PubMed data bases, last searched on February 3, 2023. Inclusion criteria were studies with human participants receiving SCS with comparison with SCS turned off, with reporting of either HR, HRV, or BP findings. Non-English studies, conference abstracts, and studies not reporting standalone effects of SCS when comparing SCS with non-SCS interventions were excluded. Results were plotted for visual analysis. When available, participant-specific stimulation parameters and effects were extracted and quantitatively analyzed using ordinary least squares regression.

RESULTS

A total of 59 studies were included in this review; 51 studies delivered SCS invasively through implanted/percutaneous leads. Eight studies used noninvasive, transcutaneous electrodes. We found numerous reports of cervical, high thoracic, and mid-to-low thoracolumbar SCS increasing resting BP, and cervical/mid-to-low thoracolumbar SCS decreasing BP. The effect of SCS location on HR and HRV was equivocal. We were unable to analyze stimulation parameters owing to inadequate parameter reporting in many publications.

CONCLUSIONS

Our findings suggest CV neuromodulation, particularly BP modulation, with SCS to be a promising frontier. Further research with larger randomized controlled trials and detailed reporting of SCS parameters will be necessary for appropriate evaluation of SCS as a CV therapy.

Orofacial Pain with Cardiac Origin of Coronary Artery Disease: A Case Report and Literature Review

When diagnosing orofacial pain, clinicians should also consider non-odontogenic origin and systemic diseases as possible etiological factors, along with odontogenic origin. This case report aimed to provide information for early detection of orofacial pain of cardiac origin by dentists, when pain due to coronary artery disease is the only presenting symptom. A 60-year-old male patient with unexplained isolated bilateral jaw pain that had persisted for the past 5 years was referred to a dentist by an anesthesiologist who suspected temporomandibular joint disorder. In oral examination, no specific pathological changes were observed in the oral cavity, including teeth, surrounding alveolar bone, and buccal mucosa. Magnetic resonance imaging and conventional radiography showed no pathological destruction or abnormalities of bone and soft tissue in the temporomandibular joint region. However, pain was precipitated by ordinary daily activities, and the pain alleviating factor was rest. Eventually, the patient was referred to a cardiologist for further evaluation since his pain was induced by physical activity. Coronary artery disease (CAD) was diagnosed using coronary computed tomography angiography, and the pain was considered to be angina pectoris. Percutaneous coronary intervention was successfully done for the patient, after which his orofacial symptoms disappeared. To conclude, isolated craniofacial pain of cardiac origin may lead to patients seeking dental care or visiting orofacial pain clinics. In these settings, dentists and orofacial pain specialists may contribute to the diagnosis of CAD and refer patients for cardiac evaluation and appropriate management.

Altered functional brain network patterns in patients with migraine without aura after transcutaneous auricular vagus nerve stimulation

Transcutaneous auricular vagus nerve stimulation (taVNS) shows excellent effects on relieving clinical symptoms in migraine patients. Nevertheless, the neurological mechanisms of taVNS for migraineurs remain unclear. In recent years, voxel-wise degree centrality (DC) and functional connectivity (FC) methods were extensively utilized for exploring alterations in patterns of FC in the resting-state brain. In the present study, thirty-five migraine patients without aura and thirty-eight healthy controls (HCs) were recruited for magnetic resonance imaging scans. Firstly, this study used voxel-wise DC analysis to explore brain regions where abnormalities were present in migraine patients. Secondly, for elucidating neurological mechanisms underlying taVNS in migraine, seed-based resting-state functional connectivity analysis was employed to the taVNS treatment group. Finally, correlation analysis was performed to explore the relationship between alterations in neurological mechanisms and clinical symptoms. Our findings indicated that migraineurs have lower DC values in the inferior temporal gyrus (ITG) and paracentral lobule than in healthy controls (HCs). In addition, migraineurs have higher DC values in the cerebellar lobule VIII and the fusiform gyrus than HCs. Moreover, after taVNS treatment (post-taVNS), patients displayed increased FC between the ITG with the inferior parietal lobule (IPL), orbitofrontal gyrus, angular gyrus, and posterior cingulate gyrus than before taVNS treatment (pre-taVNS). Besides, the post-taVNS patients showed decreased FC between the cerebellar lobule VIII with the supplementary motor area and postcentral gyrus compared with the pre-taVNS patients. The changed FC of ITG-IPL was significantly related to changes in headache intensity. Our study suggested that migraine patients without aura have altered brain connectivity patterns in several hub regions involving multisensory integration, pain perception, and cognitive function. More importantly, taVNS modulated the default mode network and the vestibular cortical network related to the dysfunctions in migraineurs. This paper provides a new perspective on the potential neurological mechanisms and therapeutic targets of taVNS for treating migraine.

Acute myopericarditis and left shoulder capsulitis following second dose of mRNA SARS-CoV-2 Moderna vaccination

Vaccination against mRNA SARS-CoV-2 has been administered on a very large scale and various side effects have been described. The increased risk of myopericarditis is known, and only a few cases of shoulder capsulitis have been reported after vaccination. These two pathologies have never been reported in the same patient after vaccination. Our article presents the history of a man in his 40s who presented with myopericarditis a few days after vaccination against SARS-CoV-2 with mRNA(Messenger RNA) Moderna® vaccine and who at the same time developed shoulder capsulitis. His cardiovascular symptoms resolved rapidly, and his shoulder symptoms improved/resolved within 1 year. This case should make physicians aware of the possibility of several concomitant side effects following vaccination against SARS-CoV-2.

Prevalence, clinical characteristics and associated factors of cardiac cephalalgia: A prospective study

BACKGROUND

The prevalence of cardiac cephalalgia is unknown and there is limited information about its clinical features. We aimed to assess the prevalence of cardiac cephalalgia, its clinical characteristics and associated factors.

METHODS

We conducted a prospective study of patients with suspected acute coronary syndrome admitted to the Cardiology Service at Hospital Clínico Universitario Lozano Blesa, Zaragoza, Spain, over a one-year period. We interviewed patients within the first 24 hours of admission using a standardized case-report form to assess the presence of headache in relation to the acute coronary syndrome and its characteristics.

RESULTS

We included 438 patients, 381 with confirmed myocardial ischemia. Prevalence of cardiac cephalalgia was 14.2% (n = 54). The most common features were frontal location, pressing quality and moderate intensity. Pain referred to the jaws (aOR 2.61; 95% CI 1.33-5.12; p = 0.005), palpitations (aOR 3.65; 95% CI 1.57-8.50; p = 0.003) and circumflex coronary artery as the culprit artery for the myocardial ischemia (aOR 3.8; 95% CI 1.07-13.74; p = 0.021) were related to cardiac whereas history of hypertension was inversely associated (aOR 0.37: 95% CI 0.18-0.74; p = 0.005).

CONCLUSION

The prevalence of cardiac cephalalgia was 14.2%. Our study provides valuable information about cardiac cephalalgia characteristics that suggest revision of current diagnostic criteria.

Potential Neuromodulation of the Cardio-Renal Syndrome

The cardio-renal syndrome (CRS) type 2 is defined as a progressive loss of renal function following a primary insult to the myocardium that may be either acute or chronic but is accompanied by a decline in myocardial pump performance. The treatment of patients with CRS is difficult, and the disease often progresses to end-stage renal disease that is refractory to conventional therapy. While a good deal of information is known concerning renal injury in the CRS, less is understood about how reflex control of renal sympathetic nerve activity affects this syndrome. In this review, we provide insight into the role of the renal nerves, both from the afferent or sensory side and from the efferent side, in mediating renal dysfunction in CRS. We discuss how interventions such as renal denervation and abrogation of systemic reflexes may be used to alleviate renal dysfunction in the setting of chronic heart failure. We specifically focus on a novel cardiac sensory reflex that is sensitized in heart failure and activates the sympathetic nervous system, especially outflow to the kidney. This so-called Cardiac Sympathetic Afferent Reflex (CSAR) can be ablated using the potent neurotoxin resinferitoxin due to the high expression of Transient Receptor Potential Vanilloid 1 (TRPV1) receptors. Following ablation of the CSAR, several markers of renal dysfunction are reversed in the post-myocardial infarction heart failure state. This review puts forth the novel idea of neuromodulation at the cardiac level in the treatment of CRS Type 2.

Straight Back Syndrome Presented with Chest and Back Pain: A Case Report

A 17-year-old female adolescent presented with her mother to our clinic with a two-month history of left-sided chest pain and a one-week history of middle back pain. We diagnosed straight back syndrome based on the chest and thoracic radiographic findings and symptoms of chest pain, palpitations, and dyspnea. We reassured the patient that the disease was benign and advised her to start and continue chiropractic therapy. All symptoms, including back pain, disappeared in three weeks. Straight back syndrome is under-diagnosed, and back pain is less recognized as a symptom of the disease.

Cardiac cephalalgia: a narrative review and ICHD-3 criteria evaluation

BACKGROUND

Cardiac cephalalgia is an unusual condition that occurs during an episode of myocardial ischemia. Information about cardiac cephalalgia is scarce and its characteristics and physiopathology remain unclear. Our aim is to provide a narrative review of clinical characteristics and physiopathology of cardiac cephalalgia and to evaluate the current diagnostic criteria.  METHODS: A search through PubMed was undertaken for studies on cardiac cephalalgia published until 20th September 2022. We summarized the literature and provide a comprehensive review of the headache characteristics and possible mechanisms. We also evaluated current International Classification of Headache Disorders third edition diagnostic criteria based on prior reported cases.  RESULTS: In total, 88 cases were found. Headache characteristics were variable. Occipital location and throbbing pain were the most frequently reported. Headache was accompanied in most cases by cardiac symptoms. Criterion B was fulfilled by 98% of cases, criterion C1 by 72%, and criteria C2a and C2b by 37 and 93.2%, respectively. Regarding headache features described in diagnostic criterion C3, 'moderate to severe intensity', 'accompanied by nausea', 'not accompanied by photophobia or phonophobia' and 'aggravated by exertion', were reported in 75, 31, 55 and 55% of cases, respectively.

CONCLUSION

Cardiac cephalalgia characteristics are variable and the headache features described in the diagnostic criterion C3 might not be adequate. Given that cardiac cephalalgia can be the manifestation of a life-threatening condition it is important to increase the knowledge about this entity.

Shared nociceptive dorsal root ganglion neurons participating in acupoint sensitization

When the body is under pathological stress (injury or disease), the status of associated acupoints changes, including decreased pain threshold. Such changes in acupoint from a “silent” to an “active” state are considered “acupoint sensitization,” which has become an important indicator of acupoint selection. However, the mechanism of acupoint sensitization remains unclear. In this study, by retrograde tracing, morphological, chemogenetic, and behavioral methods, we found there are some dorsal root ganglion (DRG) neurons innervating the ST36 acupoint and ipsilateral hind paw (IHP) plantar simultaneously. Inhibition of these shared neurons induced analgesia in the complete Freund’s adjuvant (CFA) pain model and obstruction of nociceptive sensation in normal mice, and elevated the mechanical pain threshold (MPT) of ST36 acupoint in the CFA model. Excitation of shared neurons induced pain and declined the MPT of ST36 acupoint. Furthermore, most of the shared DRG neurons express TRPV1, a marker of nociceptive neurons. These results indicate that the shared nociceptive DRG neurons participate in ST36 acupoint sensitization in CFA-induced chronic pain. This raised a neural mechanism of acupoint sensitization at the level of primary sensory transmission.

Referred Somatic Hyperalgesia Mediates Cardiac Regulation by the Activation of Sympathetic Nerves in a Rat Model of Myocardial Ischemia

Myocardial ischemia (MI) causes somatic referred pain and sympathetic hyperactivity, and the role of sensory inputs from referred areas in cardiac function and sympathetic hyperactivity remain unclear. Here, in a rat model, we showed that MI not only led to referred mechanical hypersensitivity on the forelimbs and upper back, but also elicited sympathetic sprouting in the skin of the referred area and C8-T6 dorsal root ganglia, and increased cardiac sympathetic tone, indicating sympathetic-sensory coupling. Moreover, intensifying referred hyperalgesic inputs with noxious mechanical, thermal, and electro-stimulation (ES) of the forearm augmented sympathetic hyperactivity and regulated cardiac function, whereas deafferentation of the left brachial plexus diminished sympathoexcitation. Intradermal injection of the α₂ adrenoceptor (α₂AR) antagonist yohimbine and agonist dexmedetomidine in the forearm attenuated the cardiac adjustment by ES. Overall, these findings suggest that sensory inputs from the referred pain area contribute to cardiac functional adjustment via peripheral α₂AR-mediated sympathetic-sensory coupling.

Brain-based measures of nociception during general anesthesia with remifentanil: A randomized controlled trial

BACKGROUND

Catheter radiofrequency (RF) ablation for cardiac arrhythmias is a painful procedure. Prior work using functional near-infrared spectroscopy (fNIRS) in patients under general anesthesia has indicated that ablation results in activity in pain-related cortical regions, presumably due to inadequate blockade of afferent nociceptors originating within the cardiac system. Having an objective brain-based measure for nociception and analgesia may in the future allow for enhanced analgesic control during surgical procedures. Hence, the primary aim of this study is to demonstrate that the administration of remifentanil, an opioid widely used during surgery, can attenuate the fNIRS cortical responses to cardiac ablation.

METHODS AND FINDINGS

We investigated the effects of continuous remifentanil on cortical hemodynamics during cardiac ablation under anesthesia. In a randomized, double-blinded, placebo (PL)-controlled trial, we examined 32 pediatric patients (mean age of 15.8 years,16 females) undergoing catheter ablation for cardiac arrhythmias at the Cardiology Department of Boston Children's Hospital from October 2016 to March 2020; 9 received 0.9% NaCl, 12 received low-dose (LD) remifentanil (0.25 mcg/kg/min), and 11 received high-dose (HD) remifentanil (0.5 mcg/kg/min). The hemodynamic changes of primary somatosensory and prefrontal cortices were recorded during surgery using a continuous wave fNIRS system. The primary outcome measures were the changes in oxyhemoglobin concentration (NadirHbO, i.e., lowest oxyhemoglobin concentration and PeakHbO, i.e., peak change and area under the curve) of medial frontopolar cortex (mFPC), lateral prefrontal cortex (lPFC) and primary somatosensory cortex (S1) to ablation in PL versus remifentanil groups. Secondary measures included the fNIRS response to an auditory control condition. The data analysis was performed on an intention-to-treat (ITT) basis. Remifentanil group (dosage subgroups combined) was compared with PL, and a post hoc analysis was performed to identify dose effects. There were no adverse events. The groups were comparable in age, sex, and number of ablations. Results comparing remifentanil versus PL show that PL group exhibit greater NadirHbO in inferior mFPC (mean difference (MD) = 1.229, 95% confidence interval [CI] = 0.334, 2.124, p < 0.001) and superior mFPC (MD = 1.206, 95% CI = 0.303, 2.109, p = 0.001) and greater PeakHbO in inferior mFPC (MD = -1.138, 95% CI = -2.062, -0.214, p = 0.002) and superior mFPC (MD = -0.999, 95% CI = -1.961, -0.036, p = 0.008) in response to ablation. S1 activation from ablation was greatest in PL, then LD, and HD groups, but failed to reach significance, whereas lPFC activation to ablation was similar in all groups. Ablation versus auditory stimuli resulted in higher PeakHbO in inferior mFPC (MD = 0.053, 95% CI = 0.004, 0.101, p = 0.004) and superior mFPC (MD = 0.052, 95% CI = 0.013, 0.091, p < 0.001) and higher NadirHbO in posterior superior S1 (Pos. SS1; MD = -0.342, 95% CI = -0.680, -0.004, p = 0.007) during ablation of all patients. Remifentanil group had smaller NadirHbO in inferior mFPC (MD = 0.098, 95% CI = 0.009, 0.130, p = 0.003) and superior mFPC (MD = 0.096, 95% CI = 0.008, 0.116, p = 0.003) and smaller PeakHbO in superior mFPC (MD = -0.092, 95% CI = -0.680, -0.004, p = 0.007) during both the stimuli. Study limitations were small sample size, motion from surgery, indirect measure of nociception, and shallow penetration depth of fNIRS only allowing access to superficial cortical layers.

CONCLUSIONS

We observed cortical activity related to nociception during cardiac ablation under general anesthesia with remifentanil. It highlights the potential of fNIRS to provide an objective pain measure in unconscious patients, where cortical-based measures may be more accurate than current evaluation methods. Future research may expand on this application to produce a real-time indication of pain that will aid clinicians in providing immediate and adequate pain treatment.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02703090.

Reactive Oxygen Species Cause Exercise-Induced Angina in a Myocardial Ischaemia-Reperfusion Injury Model

Percutaneous coronary intervention (PCI) effectively treats obstructive coronary artery syndrome. However, 30–40% patients continue to have angina after a successful PCI, thereby reducing patient satisfaction. The mechanisms underlying persistent angina after revascularisation therapy are still poorly understood; hence, the treatment or guideline for post-PCI angina remains unestablished. Thus, this study aimed to investigate the mechanisms underlying effort angina in animals following myocardial ischaemia-reperfusion (I/R) injury. Phosphorylated extracellular signal-regulated kinase (p-ERK), a marker for painful stimulation-induced neuronal activation, was used for the investigation. After a forced treadmill exercise (FTE), the number of p-ERK-expressing neurons increased in the superficial dorsal horn of the I/R model animals. Moreover, FTE evoked hydrogen peroxide (H₂O₂) production in the I/R-injured heart, inducing angina through TRPA1 activation on cardiac sensory fibres. Notably, the treatment of a TEMPOL, a reactive oxygen species scavenger, or TRPA1^−/− mice successfully alleviated the FTE-induced p-ERK expression in the dorsal horn. The production of H₂O₂, a reactive oxygen species, through physical exercise contributes to angina development following I/R. Hence, our findings may be useful for understanding and treating angina following revascularisation therapy.

Research Opportunities in Autonomic Neural Mechanisms of Cardiopulmonary Regulation: A Report From the National Heart, Lung, and Blood Institute and the National Institutes of Health Office of the Director Workshop

This virtual workshop was convened by the National Heart, Lung, and Blood Institute, in partnership with the Office of Strategic Coordination of the Office of the National Institutes of Health Director, and held September 2 to 3, 2020. The intent was to assemble a multidisciplinary group of experts in basic, translational, and clinical research in neuroscience and cardiopulmonary disorders to identify knowledge gaps, guide future research efforts, and foster multidisciplinary collaborations pertaining to autonomic neural mechanisms of cardiopulmonary regulation. The group critically evaluated the current state of knowledge of the roles that the autonomic nervous system plays in regulation of cardiopulmonary function in health and in pathophysiology of arrhythmias, heart failure, sleep and circadian dysfunction, and breathing disorders. Opportunities to leverage the Common Fund's SPARC (Stimulating Peripheral Activity to Relieve Conditions) program were characterized as related to nonpharmacologic neuromodulation and device-based therapies. Common themes discussed include knowledge gaps, research priorities, and approaches to develop novel predictive markers of autonomic dysfunction. Approaches to precisely target neural pathophysiological mechanisms to herald new therapies for arrhythmias, heart failure, sleep and circadian rhythm physiology, and breathing disorders were also detailed.

How Does Our Brain Generate Sexual Pleasure?

We present herein an exploratory essay on sexual pleasure, in support of the objective of developing an evidence base of knowledge for the WAS Declaration of Sexual Rights. We have attempted to account for the feeling of erotic sexual pleasure, in terms of what is known about neuronal function. The brain regions that are activated during women's orgasm, and their perceptual and physiological roles, are compared with brain regions related to chemically induced euphoria and craving. The brain regions that are activated at orgasm match those that are activated by both euphoria and craving. Based on these findings, we propose that erotic, sensual feeling is a simultaneous activation of euphoria plus craving. The importance of sensory stimulation, proprioception, sensations, and feelings is emphasized by evidence that their disruption leads to pathologies. The process of buildup of excitation to a peak and then resolution is proposed as a basic "orgasmic" property of the nervous system shared by multiple systems, as in a sneeze, which we consider to be a non-genital orgasm. We postulate a process by which an excitation pattern feels pleasurable and - at higher intensity - euphoric, if it is congruent with an unconscious dynamic "template," but aversive and at higher intensity painful, to the extent that it is incongruent with the template. Under this formulation, peak neuronal excitation that is congruent with the unconscious, simultaneously "getting what is craved," generates orgasmic, erotic, sexual pleasure.

Spinal cord stimulation reduces cardiac pain through microglial deactivation in rats with chronic myocardial ischemia

Angina pectoris is cardiac pain that is a common clinical symptom often resulting from myocardial ischemia. Spinal cord stimulation (SCS) is effective in treating refractory angina pectoris, but its underlying mechanisms have not been fully elucidated. The spinal dorsal horn is the first region of the central nervous system that receives nociceptive information; it is also the target of SCS. In the spinal cord, glial (astrocytes and microglia) activation is involved in the initiation and persistence of chronic pain. Thus, the present study investigated the possible cardiac pain-relieving effects of SCS on spinal dorsal horn glia in chronic myocardial ischemia (CMI). CMI was established by left anterior descending artery ligation surgery, which induced significant spontaneous/ongoing cardiac pain behaviors, as measured using the open field test in rats. SCS effectively improved such behaviors as shown by open field and conditioned place preference tests in CMI model rats. SCS suppressed CMI-induced spinal dorsal horn microglial activation, with downregulation of ionized calcium-binding adaptor protein-1 expression. Moreover, SCS inhibited CMI-induced spinal expression of phosphorylated-p38 MAPK, which was specifically colocalized with the spinal dorsal horn microglia rather than astrocytes and neurons. Furthermore, SCS could depress spinal neuroinflammation by suppressing CMI-induced IL-1β and TNF-α release. Intrathecal administration of minocycline, a microglial inhibitor, alleviated the cardiac pain behaviors in CMI model rats. In addition, the injection of fractalkine (microglia-activating factor) partially reversed the SCS-produced analgesic effects on CMI-induced cardiac pain. These results indicated that the therapeutic mechanism of SCS on CMI may occur partially through the inhibition of spinal microglial p38 MAPK pathway activation. The present study identified a novel mechanism underlying the SCS-produced analgesic effects on chronic cardiac pain.

Relief of Ischemia in Ischemic Cardiomyopathy

PURPOSE OF THE REVIEW

Ischemic heart disease is among the most common causes of morbidity and mortality worldwide. In its stable manifestation, obstructing coronary artery stenoses prevent myocardial blood flow from matching metabolic needs of the heart under exercise conditions, which manifests clinically as dyspnea or chest pain. Prolonged bouts of ischemia may result in permanent myocardial dysfunction, heart failure, and eventually reduced survival. The aim of the present work is to review currently available approaches to provide relief of ischemia in stable coronary artery disease (CAD).

RECENT FINDINGS

Several pharmacological and interventional approaches have proven effectiveness in reducing the burden of ischemia in stable CAD and allow for symptom control and quality of life improvement. However, substantial evidence in favor of improved survival with ischemia relief is lacking, and recently published randomized controlled trial suggests that only selected groups of patients may substantially benefit from this approach. Pharmacological treatments aimed at reducing ischemia were shown to significantly reduce ischemic symptoms but failed to provide prognostic benefit. Myocardial revascularization is able to re-establish adequate coronary artery flow and was shown to improve survival in selected groups of patients, i.e., those with significant left main CAD or severe left ventricular dysfunction in multivessel CAD. Outside the previously mentioned categories, revascularization appears to improve symptoms control over medical therapy, but does not confer prognostic advantage. More studies are needed to elucidate the role of systematic invasive functional testing to identify individuals more likely to benefit from revascularization and to evaluate the prognostic role of chronic total occlusion recanalization.

Management of refractory angina: an update

Despite the use of anti-anginal drugs and/or percutaneous coronary interventions (PCI) or coronary artery bypass grafting, the proportion of patients with coronary artery disease who have daily or weekly angina ranges from 2% to 24%. Refractory angina refers to long-lasting symptoms (for >3 months) due to established reversible ischaemia, which cannot be controlled by escalating medical therapy with the use of 2nd- and 3rd-line pharmacological agents, bypass grafting, or stenting. While there is uncertain prognostic benefit, the treatment of refractory angina is important to improve the quality of life of the patients affected. This review focuses on conventional pharmacological approaches to treating refractory angina, including guideline directed drug combination and dosages. The symptomatic and prognostic impact of advanced and novel revascularization strategies such as chronic total occlusion PCI, transmyocardial laser revascularization, coronary sinus occlusion, radiation therapy for recurrent restenosis, and spinal cord stimulation are also covered and recommendations of the 2019 ESC Guidelines on the Diagnosis and Management of Chronic Coronary Syndromes discussed. Finally, the potential clinical use of current angiogenetic and stem cell therapies in reducing ischaemia and/or pain is evaluated.

Cardiac cephalalgia closely associated with acute myocardial infarction

Cardiac cephalalgia is an uncommon symptom occurring in coronary artery disease. It is difficult to identify cardiac cephalalgia and link it to coronary artery disease because these patients present with only a headache and no typical symptoms of angina, such as chest pain, radiating pain, or chest tightness. Currently, the diagnostic value of cardiac cephalalgia in acute myocardial infarction is still under debate. We here report a case of cardiac cephalalgia. An 83-year-old woman with a severe headache lasting 6 h was diagnosed with acute myocardial infarction. ST elevation and severe stenosis of the right coronary artery were observed. Passage of the guide wire and radiocontrast agent increased the intensity of the headache, which disappeared once the right coronary artery was opened. As of one month into follow-up, the headache had not recurred. These observations strongly indicate a close association between cardiac cephalalgia and acute myocardial infarction, and they could help diagnose acute myocardial infarction related to headaches.

Systemic inflammation in patients with Takotsubo syndrome: a review of mechanistic and clinical implications

Over recent decades, systemic inflammation  as  quantified  with  inflammation  markers  or  indices has been extensively  investigated  in the setting of  various  cardiovascular  conditions  including heart failure (HF),  acute coronary syndromes (ACS). In contrast, systemic inflammation  in patients with  takotsubo syndrome (TTS) has been an underrated  phenomenon in clinical practice. On the other hand, experimental and clinical data  have been  rapidly  accumulating  in the recent years  regarding   pathogenetic, prognostic as well as therapeutic implications of  systemic inflammation in TTS.  Accordingly, the present article  aims to provide a general perspective  on mechanistic and  clinical aspects of  systemic  inflammation in the setting of  TTS.

An unusual presentation of acute myocardial infarction in physiotherapy direct access: findings from a case report

BACKGROUND

Shoulder pain (SP) may originate from both musculoskeletal and visceral conditions. Physiotherapists (PT) may encounter patients with life-threatening pathologies that mimic musculoskeletal pain such as Acute Myocardial Infarction (AMI). A trained PT should be able to distinguish between signs and symptoms of musculoskeletal or visceral origin aimed at performing proper medical referral.

CASE PRESENTATION

A 46-y-old male with acute SP lasting from a week was diagnosed with right painful musculoskeletal shoulder syndrome, in two successive examinations by the emergency department physicians. However, after having experienced a shift of the pain on the left side, the patient presented to a PT. The PT recognized the signs and symptoms of visceral pain and referred him to the general practitioner, which identified a cardiac disease. The final diagnosis was acute myocardial infarction.

CONCLUSION

This case report highlights the importance of a thorough patient screening examination, especially for patients treated in an outpatient setting, which allow distinguishing between signs and symptoms of musculoskeletal from visceral diseases.

Cervical Arthroplasty in the Treatment of Cervical Angina: Case Report and Review of the Literature

Cervical angina is an often-overlooked etiology of noncardiac chest pain that may mimic true angina pectoris but is due to cervical spine disease. Diagnosis can be difficult, and treatment ranges from conservative therapy to surgical management. However, of patient’s refractory to conservative therapy, approximately ninety percent experience postoperative relief of angina symptoms. Here, we present a case report on cervical angina and performed a systematic review of the literature. A 34-year-old male with prior surgery for thoracic outlet syndrome presented with persistent anterior neck and chest pain as well as posterior left scapular and upper lateral arm pain. The pain was refractory to 12 months of conservative therapy. Cardiac workup was negative and cervical spine imaging revealed a C6–7 herniation with neuroforaminal stenosis. A systematic literature search was conducted in PubMed, Web of Science, and Cochrane databases from database inception to April 2020. Studies reporting cervical level, average symptom duration, location of pain, and postoperative pain improvement were included. The patient's atypical symptoms were completely resolved after C6–7 anterior cervical discectomy and arthroplasty. To our knowledge, this is the first study which reports on the use of arthroplasty in the treatment of cervical angina. The systematic review included 11 articles from 1989–2020 consisting of 1,186 total patients and 109 patients (age range, 36–84 years; 60.7% male) meeting inclusion criteria. Symptom duration range was 2 days to 90 months, with the most common location of pain being localized to the anterior chest wall (66.7% of patients). All patients (100%) had postoperative resolution of their pain symptoms. The most common herniation level was C6–7 (87.3% of patients). We conclude that a broad and multidisciplinary approach is necessary for the diagnosis and management of noncardiac chest pain. When cervical disease is identified as the underlying cause for the angina-like pain, conservative therapy should be sought. Refractory cases should be treated surgically depending on the cervical pathology.

Evaluation of the bilateral cardiac afferent distribution at the spinal and vagal ganglia by retrograde labeling

The identity of sensory neurons innervating the heart tissue and the extent of information reported to the brain via these neurons are poorly understood. In order to evaluate the multidimensional distribution and abundance of the cardiac spinal and vagal afferents, we assessed the retrograde labeling efficiency of various tracers, and mapped the cardiac afferents qualitatively and quantitatively at the bilateral nodose ganglia (NGs) and dorsal root ganglia (DRGs). From the five different retrograde tracers evaluated, Di-8-ANEPPQ yielded reproducibly the highest labeling efficiency of cardiac afferents. We demonstrated specific cardiac afferents at NGs and C4 to T11 DRG segments. Next, the 2D reconstruction of the tissue sections and 3D imaging of the whole NGs and DRGs revealed homogeneous and bilateral distribution of cardiac afferents. The quantitative analyses of the labeled cardiac afferents demonstrated approximately 5-6% of the soma in NGs that were equally distributed bilaterally. The neuronal character of Di-8-ANEPPQ labeled cells were validated by coimmunostaning with pan-neuronal marker Tuj-1. In addition, the cell diameters of labeled cardiac sensory neurons were found smaller than 20 μm, implying the nociceptor phenotype confirmed by co-labeling with TRPV1 and Di-8-ANEPPQ. Importantly, co-labeling with two distinct tracers Di-8-ANEPPQ and WGA-647 demonstrated exclusively the same cardiac afferents in DRGs and NGs, validating our findings. Collectively, our findings revealed the cardiac afferents in NGs bilaterally and DRGs with the highest labeling efficiency reported, spatial distribution and quantitation at both 2D and 3D levels, furthering our understanding of this novel neuron population.

Refractory Angina-Unsolved Problem

The article discusses pharmacologic and interventional therapeutic options for patients with refractory angina. Refractory angina refers to long-lasting symptoms (≥3 months) due to established reversible ischemia in the presence of obstructive coronary artery disease, which cannot be controlled by escalating medical therapy with second-line and third-line pharmacologic agents, bypass grafting, or stenting. Due to an aging population, increased number of comorbidities, and advances in coronary artery disease treatment, incidence of refractory angina is growing. Although the number of therapeutic options is increasing, there is a lack of randomized clinical trials that could help create recommendations for this group of patients.

Refractory Angina: From Pathophysiology to New Therapeutic Nonpharmacological Technologies

Despite optimal combination of guideline-directed anti-ischemic therapies and myocardial revascularization, a substantial proportion of patients with stable coronary artery disease continues to experience disabling symptoms and is often referred as "no-option." The appraisal of the pathways linking ischemia to symptom perception indicates a complex model of heart-brain interactions in the generation of the subjective anginal experience and inspired novel approaches that may be clinically effective in alleviating the angina burden of this population. Conversely, the prevailing ischemia-centered view of angina, with the focus on traditional myocardial revascularization as the sole option to address ischemia on top of medical therapy, hinders the experimental characterization and broad-scale clinical implementation of strongly needed therapeutic options. The interventionist, often the first physician to establish the diagnosis of refractory angina pectoris (RAP) following coronary angiography, should be aware of the numerous emerging technologies with the potential to improve quality of life in the growing population of RAP patients. This review describes the current landscape and the future perspectives on nonpharmacological treatment technologies for patients with RAP, with a view on the underlying physiopathological rationale and current clinical evidence.

Neural responses during acute mental stress are associated with angina pectoris

Angina pectoris is associated with increased risk of adverse cardiovascular events in coronary artery disease (CAD) patients, an effect not entirely attributable to the severity of CAD.

OBJECTIVE

Examine brain correlates of mental stress in patients with CAD with and without a history of angina.

METHODS

Participants (n = 170) with stable CAD completed the Seattle Angina Questionnaire along with other psychometric assessments. In this cross-sectional study, participants underwent laboratory-based mental stress testing using mental arithmetic and public speaking tasks along with control conditions in conjunction with positron emission tomography brain imaging using radiolabeled water. Brain activity during mental stress was compared between participants who did or did not report chest pain/angina in the previous month. A factor analysis was coupled with dominance analysis to identify brain regions associated with angina.

RESULTS

Participants reporting angina in the past month experienced greater (p < .005) activations within the left: frontal lobe (z = 4.01), temporal gyrus (z = 3.32), parahippocampal gyrus (z = 3.16), precentral gyrus (z = 3.14), right fusiform gyrus (z = 3.07), and bilateral cerebellum (z = 3.50) and deactivations within the right frontal gyrus (z = 3.67), left precuneus (z = 3.19), and left superior temporal gyrus (z = 3.11) during mental stress. A factor containing the left motor areas, inferior frontal lobe, and operculum (average McFadden's number addition = 0.057) in addition to depression severity (0.10) and adulthood trauma exposure (0.064) correlated with angina history.

CONCLUSIONS

Self-reported angina in patients with stable CAD is associated with increased neural responses to stress in a network including the inferior frontal lobe, motor areas, and operculum, potentially indicating an upregulated pain perception response.

Pseudoanginal chest pain associated with vagal nerve stimulation: a case report

Background

Vagal nerve stimulation (VNS) can be an effective therapy for patients with epilepsy refractory to anti-epileptic drugs or intracranial surgery. While generally well tolerated, it has been associated with laryngospasm, hoarseness, coughing, dyspnea, throat and atypical chest pain, cardiac symptoms such as bradycardia and occasionally asystole. We report on a patient receiving vagal nerve stimulation who experienced severe typical anginal chest pain during VNS firing without any evidence of cardiac ischemia or dysfunction. Thus, the pain appeared to be neuropathic from the stimulation itself rather than nociceptive secondary to an effect on heart function.

Case presentation

A 29-year-old man, with a history of intractable frontal lobe epilepsy refractory to seven anti-epileptic medications and subsequent intracranial surgery, underwent VNS implantation without complications. On beginning stimulation, he began to have intermittent chest pain that corresponded temporally to his intermittent VNS firing. The description of his pain was pathognomonic of ischemic cardiac chest pain. On initial evaluation, he displayed Levine’s sign and reported crushing substernal chest pain radiating to the left arm, as well as shortness of breath walking upstairs that improved with rest. He underwent an extensive cardiac workup, including 12-lead ECG, cardiac stress test, echocardiogram, 12-day ambulatory cardiac monitoring, and continuous ECG monitoring each with and without stimulation of his device. The workup was consistently negative. Inability to resolve the pain necessitated the disabling and eventual removal of the device.

Conclusion

To our knowledge, this is the first report of pseudoanginal chest pain associated with VNS. This occurrence prompted our review of the mechanisms of cardiac chest pain and suggests that vagal afferents may convey anginal pain separately or in parallel with known spinal cord pain mechanisms. These insights into the physiology of chest pain may be of general interest and important to surgeons implanting VNS devices who may potentially encounter such symptoms.

Fast in vivo detection of myocardial norepinephrine levels in the beating porcine heart

The sympathetic nervous system modulates cardiac function by controlling key parameters such as chronotropy and inotropy. Sympathetic control of ventricular function occurs through extrinsic innervation arising from the stellate ganglia and thoracic sympathetic chain. In the healthy heart, sympathetic release of norepinephrine (NE) results in positive modulation of chronotropy, inotropy, and dromotropy, significantly increasing cardiac output. However, in the setting of myocardial infarction or injury, sympathetic activation persists, contributing to heart failure and increasing the risk of arrhythmias, including sudden cardiac death. Methodologies for detection of norepinephrine in cardiac tissue are limited. Present techniques rely on microdialysis for analysis by high-performance liquid chromatography coupled to electrochemical detection (HPLC-ED), radioimmunoassay, or other immunoassays, such as enzyme-linked immunosorbent assay (ELISA). Although significant information about the release and action of norepinephrine has been obtained with these methodologies, they are limited in temporal resolution, require large sample volumes, and provide results with a significant delay after sample collection (hours to weeks). In this study, we report a novel approach for measurement of interstitial cardiac norepinephrine, using minimally invasive, electrode-based, fast-scanning cyclic voltammetry (FSCV) applied in a beating porcine heart. The first multispatial and high temporal resolution, multichannel measurements of NE release in vivo are provided. Our data demonstrate rapid changes in interstitial NE profiles with regional differences in response to coronary ischemia, sympathetic nerve stimulation, and alterations in preload/afterload.

NEW & NOTEWORTHY Pharmacological, electrical, or surgical regulation of sympathetic neuronal control can be used to modulate cardiac function and treat arrhythmias. However, present methods for monitoring sympathetic release of norepinephrine in the heart are limited in spatial and temporal resolution. Here, we provide for the first time a methodology and demonstration of practice and rapid measures of individualized regional autonomic neurotransmitter levels in a beating heart. We show dynamic, spatially resolved release profiles under normal and pathological conditions.

Spinal cord neural network interactions: implications for sympathetic control of the porcine heart

Inherent and acquired factors determine the integrated autonomic response to cardiovascular stressors. Excessive sympathoexcitation to ischemic stress is a major contributor to the potential for sudden cardiac death. To define fundamental aspects of cardiac-related autonomic neural network interactions within the thoracic cord, specifically as related to modulating sympathetic preganglionic (SPN) neural activity. Adult, anesthetized Yorkshire pigs (n = 10) were implanted with penetrating high-density microarrays (64 electrodes) at the T2 level of the thoracic spinal cord to record extracellular potentials concurrently from left-sided dorsal horn (DH) and SPN neurons. Electrical stimulation of the T2 paravertebral chain allowed for antidromic identification of SPNs located in the intermediolateral cell column (57 of total 1,760 recorded neurons). Cardiac stressors included epicardial touch, occlusion of great vessels to transiently alter preload/afterload, and transient occlusion of the left anterior descending coronary artery (LAD). Spatial/temporal assessment of network interactions was characterized by cross-correlation analysis. While some DH neurons responded solely to changes in preload/afterload (8.5 ± 1.9%) or ischemic stress (10.5 ± 3.9%), the majority of cardiovascular-related DH neurons were multimodal (30.2 ± 4.7%) with ischemia sensitivity being one of the modalities (26.1 ± 4.7%). The sympathoexcitation associated with transient LAD occlusion was associated with increased correlations from baseline within DH neurons (2.43 ± 0.61 to 7.30 ± 1.84%, P = 0.04) and between SPN to DH neurons (1.32 ± 0.78 to 7.24 ± 1.84%, P = 0.02). DH to SPN network correlations were reduced during great vessel occlusion. In conclusion, increased intrasegmental network coherence within the thoracic spinal cord contributes to myocardial ischemia-induced sympathoexcitation.NEW & NOTEWORTHY In an in vivo pig model, we demonstrate using novel high-resolution neural electrode arrays that increased intrasegmental network coherence within the thoracic spinal cord contributes to myocardial ischemia-induced sympathoexcitation.

The Analgesic Effect of Oxygen in Suspected Acute Myocardial Infarction: A Substudy of the DETO2X-AMI Trial

OBJECTIVES

In this substudy of the DETO2X-AMI (An Efficacy and Outcome Study of Supplemental Oxygen Treatment in Patients With Suspected Myocardial Infarction) trial, the authors aimed to assess the analgesic effect of moderate-flow oxygen supplementation in patients with suspected acute myocardial infarction (AMI) treated with percutaneous coronary intervention (PCI) and to study the effect of oxygen supplementation on the use of opiates and sedatives during PCI.

BACKGROUND

Routine oxygen in normoxemic patients with AMI does not provide clinical benefit. However, oxygen may relieve ischemic pain.

METHODS

Patients were randomly allocated to oxygen or ambient air according to the main study protocol. After PCI, peak level of pain during PCI was measured by the Visual Analogue Scale. The total amount of opiates and sedatives was reported.

RESULTS

A total of 622 patients were enrolled: 330 in the oxygen group and 292 in the ambient air group. There was no significant difference in peak level of pain (oxygen 4.0 [1.0 to 6.0] vs. air 3.0 [0.6 to 6.0]; p = 0.37), use of opiates (mg) (oxygen 0.0 [0.0 to 3.0] vs. air 0.0 [0.0 to 3.0]; p = 0.31), or use of sedatives between the groups (median [interquartile range]) (oxygen 2.5 [0.0 to 2.5] vs. air 2.5 [0.0 to 2.5]; p = 0.74).

CONCLUSIONS

In the present study, the authors did not find any analgesic effect of routine oxygen as compared with ambient air, and no differences in the use of sedatives and opiates during PCI. Our results indicate that moderate-flow oxygen supplementation does not relieve pain in normoxemic patients with suspected AMI undergoing treatment with PCI and should thus not be used for this purpose.

Thoracic spinal cord neuromodulation obtunds dorsal root ganglion afferent neuronal transduction of the ischemic ventricle

Aberrant afferent signaling drives adverse remodeling of the cardiac nervous system in ischemic heart disease. The study objective was to determine whether thoracic spinal dorsal column stimulation (SCS) modulates cardiac afferent sensory transduction of the ischemic ventricle. In anesthetized canines (n = 16), extracellular activity generated by 62 dorsal root ganglia (DRG) soma (T1-T3), with verified myocardial ischemic (MI) sensitivity, were evaluated with and without 20-min preemptive SCS (T1-T3 spinal level; 50 Hz, 90% motor threshold). Transient MI was induced by 1-min coronary artery occlusion (CAO) of the left anterior descending (LAD) or circumflex (LCX) artery, randomized as to sequence. LAD and LCX CAO activated cardiac-related DRG neurons (LAD: 0.15 ± 0.04-1.05 ± 0.20 Hz, P < 0.00002; LCX: 0.08 ± 0.02-1.90 ± 0.45 Hz, P < 0.0003). SCS decreased basal neuronal activity of neurons that responded to LAD (0.15 ± 0.04 to 0.02 ± 0.01 Hz, P < 0.006) and LCX (0.08 ± 0.02 to 0.02 ± 0.01 Hz, P < 0.003). SCS suppressed responsiveness to transient MI (LAD: 1.05 ± 0.20-0.03 ± 0.01 Hz; P < 0.0001; LCX: 1.90 ± 0.45-0.03 ± 0.01 Hz; P < 0.001). Suprathreshold SCS (1 Hz) did not activate DRG neurons antidromically (n = 10 animals). Ventricular fibrillation (VF) was associated with a rapid increase in DRG activity to a maximum of 4.39 ± 1.07 Hz at 20 s after VF induction and a return to 90% of baseline within 10 s thereafter. SCS obtunds the capacity of DRG ventricular neurites to transduce the ischemic myocardium to second-order spinal neurons, a mechanism that would blunt reflex sympathoexcitation to myocardial ischemic stress, thereby contributing to its capacity to cardioprotect.NEW & NOTEWORTHY Aberrant afferent signaling drives adverse remodeling of the cardiac nervous system in ischemic heart disease. This study determined that thoracic spinal column stimulation (SCS) obtunds the capacity of dorsal root ganglia ventricular afferent neurons to transduce the ischemic myocardium to second-order spinal neurons, a mechanism that would blunt reflex sympathoexcitation to myocardial ischemic stress. This modulation does not reflect antidromic actions of SCS but likely reflects efferent-mediated changes at the myocyte-sensory neurite interface.

Severity of Chest Pain among Acute Myocardial Infarction Patients with Diagonal Branch Vessel Disease: A Pilot Study

INTRODUCTION

 Acute myocardial infarction (AMI) patients present with variable clinical manifestations such as shortness of breath, nausea, etc. among which chest pain is the most common. Previous studies have reported that the clinical presentation of AMI patients with branch vessel disease is indistinguishable from epicardial coronary vessel disease. However, our experience suggests patients with branch vessel disease experience severe chest pain, especially those with a diagonal branch. Therefore, we aim to study the association of chest pain severity with isolated diagonal branch vessel disease as a culprit vessel in AMI patients.

METHODS

 It is a retrospective case-control design, where 10 cases and 40 historic controls were recruited in the study. Cases were patients with isolated diagonal branch disease, whereas controls were patients with epicardial vessel disease in AMI. We reviewed Coronary Angiograms of adult patients who presented with acute myocardial infarction and had undergone coronary angiography at Aga Khan University Hospital, Karachi (AKUH). Information on pain scores was measured using the Numeric Pain Rating Scale (NRS) before administration of analgesics. Other relevant variables were also recorded on a pre-structured questionnaire.

RESULTS

The mean age of all the participants in the study was 60 ± 11.0 years, with 16% of the patients being women. Among all AMI patients, the intensity of chest pain in patients with isolated diagonal branch vessel disease was 2.6 units higher as compared to those with other epicardial coronary vessel diseases (p-value: <0.001; 95% CI: 1.67 - 3.46).

CONCLUSION

 This preliminary study indicates severe chest pain can be a differentiating symptom in AMI patients with diagonal branch disease. It emphasizes clinicians to look for a possibility of a diagonal branch as a culprit vessel in AMI for better judgment, as it is often overlooked. future studies may be conducted at multiple centers for larger sample size and better generalizability.

Identification of lncRNA and mRNA expression profiles in rat spinal cords at various time‑points following cardiac ischemia/reperfusion

The identification of the expression patterns of long non-coding RNAs (lncRNAs) and mRNAs in the spinal cord under normal and cardiac ischemia/reperfusion (I/R) conditions is essential for understanding the genetic mechanisms underlying the pathogenesis of cardiac I/R injury. The present study used high-throughput RNA sequencing to investigate differential gene and lncRNA expression patterns in the spinal cords of rats during I/R-induced cardiac injury. Male Sprague Dawley rats were assigned to the following groups: i) Control; ii) 2 h (2 h post-reperfusion); and iii) 0.5 h (0.5 h post-reperfusion). Further mRNA/lncRNA microarray analysis revealed that the expression profiles of lncRNA and mRNA in the spinal cords differed markedly between the control and 2 h groups, and in total 7,980 differentially expressed (>2-fold) lncRNAs (234 upregulated, 7,746 downregulated) and 3,428 mRNAs (767 upregulated, 2,661 downregulated) were identified. Reverse transcription-quantitative polymerase chain reaction analysis was performed to determine the expression patterns of several lncRNAs. The results indicated that the expression levels of lncRNA NONRATT025386 were significantly upregulated in the 2 and 0.5 h groups when compared with those in the control group, whereas the expression levels of NONRATT016113, NONRATT018298 and NONRATT018300 were elevated in the 2 h group compared with those in the control group; however, there was no statistically significant difference between the 0.5 h and control groups. Furthermore, the expression of lncRNA NONRATT002188 was significantly downregulated in the 0.5 and 2 h groups when compared with the control group. The present study determined the expression pattern of lncRNAs and mRNAs in rat spinal cords during cardiac I/R. It was suggested that lncRNAs and mRNAs from spinal cords may be novel therapeutic targets for the treatment of I/R-induced cardiac injury.

Jaw pain and myocardial ischemia: A review of potential neuroanatomical pathways

Cardiac pain is usually manifested as a crushing, squeezing, or sensation of pressure in the center of the chest. The pain can be referred to the left shoulder, neck, jaw, and epigastric region as well as the temporomandibular region, paranasal sinuses, and head in general. Although not well understood, during myocardial ischemia, the process of cardiac referred pain to craniofacial structures can be explained by the convergence of visceral and somatic relays at the trigeminal nucleus in the brain stem. The goal of this article is to review the possible pathways for referred jaw pain due to myocardial ischemia. Clin. Anat. 32:476-479, 2019. © 2019 Wiley Periodicals, Inc.

Effect of myocardial ischemic preconditioning on ischemia-reperfusion stimulation-induced activation in rat thoracic spinal cord with functional MRI

BACKGROUND

Myocardial ischemia and reperfusion-evoked spinal reflexes involve nociceptive signals that trigger neuronal excitation through cardiac afferents, projecting into the thoracic spinal cord. Ischemic preconditioning (IPC) involves brief episodes of sublethal ischemia and reperfusion enhances the resistance of the myocardium to subsequent ischemic insults. This study investigated the effects of IPC on ischemia-reperfusion (I/R) stimulation-induced activation in the thoracic spinal cord of rats.

METHODS

A new remotely controlled I/R model was established. The infarct size was determined as a percentage of area at risk (IS/AAR) and arrhythmia scores were evaluated. Non-invasive in vivo fMRI was used for signal quantitative analysis of thoracic spinal spatiotemporal. The role of IPC on the excitability of substantia gelatinosa (SG) neurons was assessed by spinal patch clamp recording technique. The altered expressions of c-Fos, SP, and CGRP in T₄ segment were detected by immunohistochemical staining.

RESULTS

The novel I/R model was induced successfully and reliably utilized, and IPC treatment markedly reduced the myocardial infarct size. fMRI analysis revealed that IPC reduced the increased BOLD signals induced by prolonged ischemia-reperfusion. Patch clamp recording showed that IPC treatment reversed the enhanced excitability of SG neurons during I/R treatment. The results of immunofluorescent staining indicated that IPC mitigated the I/R-induced dramatic increase of c-Fos, and reduced the release of SP and CGRP in dorsal horns of spinal cord.

CONCLUSIONS

These results suggested that IPC suppressed neuronal activation induced by I/R stimuli in rat thoracic spinal cord using spinal cord fMRI and patch clamp recording techniques.

Lumbosacral radicular pain during micturition, defecation or orgasm

BACKGROUND

The objective of this study was to describe, in a cohort of patients followed for bladder, bowel or sexual dysfunctions, the occurrence of radicular pain during micturition, defecation and/or orgasm.

METHODS

The study included all patients referred in our neuro-urology department and who suffered from radicular pain before, during or after micturition, defecation and/or orgasm. Data included demographic and medical variables, urodynamic and perineal electromyographic diagnosis.

RESULTS

A total of 30 patients (men: 70%, mean age 45.4 ± 11.8,) complained of radicular pain before, during or after orgasm (51.4%), micturition (34.3%), or defecation (14.3%). In 30% of cases, radiculopathy was found and was predicted by micturition pain. Other pathologies were as follows: vertebral (16.5%), pelvis and sacral (16.5%), inflammatory central nervous system (10%) lesions and peripheral neuropathies (6.7%). Neurological level of injury was between the lumbar and the sacral level. All spinal cord lesions were lesions of the conus medullaris. Patients also complained of lower urinary tract symptoms (70%), sexual (63.3%) and bowel (60%) disorders. In most cases, the urodynamic diagnosis was neurogenic bladder with peripheral abnormalities and the electromyographic diagnosis was distal neuropathy.

CONCLUSION

Radicular pain occurring during micturition, defecation or orgasm is a rare condition. The most common underlying lesion seems to be radiculopathy, from lumbar to sacral spine. The presence of these symptoms, in the absence of any known neurological condition, should suggest the practitioner a radiculopathy in most of the cases. In consequence, appropriate additional tests should be offered to these patients.

SIGNIFICANCE

Few data are available on sciatica during micturition, defecation or orgasm. This study underlines the need for appropriate tests if a patient complaint from this type of symptom. Indeed, the most common underlying lesion is a radiculopathy but can also be a lesion of conus medullaris.

Cardiac cephalalgia: severe, non-exertional headache presenting as unstable angina

Cardiac cephalalgia is a migraine-like headache that occurs during episodes of myocardial ischaemia. Clinical characteristics of the headache vary widely but are often severe in intensity, worsen with reduced myocardial perfusion and resolve with reperfusion. It can present along with typical symptoms of angina pectoris, although not always. We present a 64-year-old man with a 6-month history of severe, non-exertional headaches occurring with increasing frequency. A resting ECG showed ST elevation in the inferior leads. His serum troponin I was not elevated. Coronary angiography showed severe stenosis of his right coronary artery, which was successfully stented by percutaneous coronary intervention. He remains headache free at 2-year follow-up.

Chest pain as a manifestation of hypokalemia in a pediatric patient

Patients presenting to the emergency department with chest pain are common and a cause of significant concern to patients and families and physicians alike. The causes of chest pain are myriad. These causes span diverse categories including cardiovascular, respiratory, abdominal and gastrointestinal, musculoskeletal, psychiatric, hematologic and oncologic, and neurologic Thull-Freedman (2010) [1]. These diverse etiologies present a diagnostic and management challenge to the ER physician who is tasked to minimize unnecessary diagnostics while not missing any significant disease. Multiple reviews have discussed the various etiologies of chest pain in the pediatric patient presenting to the ER but none of these recent reviews has included hypokalemia as a cause of chest pain Talner and Carboni (2000), Cava and Sayger (2004), Ringstrom and Freedman (2006), Foy and Filippone (2015), Yeh and Yeh (2015) [2-6]. Additionally, no reviews of hypokalemia describe this condition presenting with chest pain (Mandal, 1997; Gennari, 2002; Medford-Davis and Rafique, 2014 [7-9]). This case report describes a pediatric patient who presents with chest pain that was attributed to hypokalemia. This report attempts to make practitioners aware that hypokalemia may present with chest pain and to encourage ER providers to include this in the differential diagnosis.

Anatomy and physiology of phrenic afferent neurons

Large-diameter myelinated phrenic afferents discharge in phase with diaphragm contraction, and smaller diameter fibers discharge across the respiratory cycle. In this article, we review the phrenic afferent literature and highlight areas in need of further study. We conclude that 1) activation of both myelinated and nonmyelinated phrenic sensory afferents can influence respiratory motor output on a breath-by-breath basis; 2) the relative impact of phrenic afferents substantially increases with diaphragm work and fatigue; 3) activation of phrenic afferents has a powerful impact on sympathetic motor outflow, and 4) phrenic afferents contribute to diaphragm somatosensation and the conscious perception of breathing. Much remains to be learned regarding the spinal and supraspinal distribution and synaptic contacts of myelinated and nonmyelinated phrenic afferents. Similarly, very little is known regarding the potential role of phrenic afferent neurons in triggering or modulating expression of respiratory neuroplasticity.

Neurotrophin receptors in the pathogenesis, diagnosis and therapy of neurodegenerative diseases

In the last few years, exciting properties have emerged regarding the activation, signaling, mechanisms of action, and therapeutic targeting of the two types of neurotrophin receptors: the p75^NTR with its intracellular and extracellular peptides, the Trks, their precursors and their complexes. This review summarizes these new developments, with particular focus on neurodegenerative diseases. Based on the evolving knowledge, innovative concepts have been formulated regarding the pathogenesis of these diseases, especially the Alzheimer's and two other, the Parkinson's and Huntington's diseases. The medical progresses include original procedures of diagnosis, started from studies in mice and now investigated for human application, based on innovative classes of receptor agonists and blockers. In parallel, comprehensive studies have been and are being carried out for the development of drugs. The relevance of these studies is based on the limitations of the therapies employed until recently, especially for the treatment of Alzheimer's patients. Starting from well known drugs, previously employed for non-neurodegenerative diseases, the ongoing progress has lead to the development of small molecules that cross rapidly the blood-brain barrier. Among these molecules the most promising are specific blockers of the p75^NTR receptor. Additional drugs, that activate Trk receptors, were shown effective against synaptic loss and memory deficits. In the near future such approaches, coordinated with treatments with monoclonal antibodies and with developments in the microRNA field, are expected to improve the therapy of neurodegenerative diseases, and may be relevant also for other human disease conditions.