Primary angioplasty in patient with ST-segment elevation myocardial infarction in the setting of intentional carbon monoxide poisoning

Practical Recommendations for the Evaluation and Management of Cardiac Injury Due to Carbon Monoxide Poisoning

Carbon monoxide (CO) is a relatively frequent cause of poisoning evaluated in emergency departments. The risk of neurologic injuries, such as cognitive, psychological, vestibular, and motor deficits, is 25% to 50%. However, the risk of cardiac injuries should also be considered. Among patients with CO poisoning, the mortality in patients with myocardial injury is approximately 3 times greater than that in patients without myocardial injury. In large-scale studies, up to 69.2% of patients with acute CO poisoning exhibiting elevated troponin I levels and no underlying cardiovascular illnesses had late gadolinium enhancement on cardiac magnetic resonance, suggesting covert CO-induced myocardial fibrosis. Myocardial damage can be evaluated using electrocardiography, echocardiography, computed tomography, and cardiac magnetic resonance. This paper offers recommendations for cardiac evaluations based on our collective experience of managing >2,000 cases of acute CO poisoning with supporting information taken from peer-reviewed published reports on CO poisoning.

Association of carbon monoxide poisoning with cardiovascular disease risk: A systematic review and meta-analysis

Objective

This study aims to provide an updated overview of the relationship between carbon monoxide poisoning (COP) and cardiovascular disease.

Methods

A systematic literature search was conducted in PubMed, Embase, Cochrane, and Web of Science databases up to September 2023. The association between COP patients and cardiovascular adverse events was examined and summarized. The outcomes included arrhythmia, coronary heart disease, heart failure, myocardial infarction, major adverse cardiovascular events (MACE), carboxyhaemoglobin percent (COHB%), Pondus Hydrogenii (PH) electrocardiography (ECG) parameters.

Results

Eight eligible articles, involving a total of 251,971 patients, were included for evidence synthesis. The analysis revealed a heightened incidence of MACE in patients with COP. Additionally, COP exhibited an impact on specific ECG parameters. The incidence of MACE after COP was found to be similar in Korean and Chinese populations, and there was no significant effect of gender or underlying diseases on MACE incidence following COP. The incidence of MACE after COP did not differ significantly in individuals aged 50 years and older.

Conclusions

Considering the observed heterogeneity and potential biases in the selected studies, emergency physicians should be aware of the increased likelihood of cardiovascular events in patients diagnosed with COP.

Carbon monoxide poisoning: A problem uniquely suited to a medicinal inorganic chemistry solution

Carbon monoxide poisoning is one of the most common forms of poisoning in the world. Although the primary mode of treatment, oxygen therapy, is highly effective in many cases, there are instances in which it is inadequate or inappropriate. Whereas oxygen therapy relies on high levels of a low-affinity ligand (O2) to displace a high-affinity ligand (CO) from metalloproteins, an antidote strategy relies on introducing a molecule with a higher affinity for CO than native proteins (Kantidote,CO > Kprotein,CO). Based on the fundamental chemistry of CO, such an antidote is most likely required to be an inorganic compound featuring an electron-rich transition metal. A review is provided of the protein-, supramolecular complex-, and small molecule-based CO poisoning antidote platforms that are currently under investigation.

Carbon monoxide intoxication with a CO-Hb of 30% while smoking waterpipe: a case report

Carbon monoxide (CO) poisoning is a significant public health issue and a considerable economic burden in developed countries. While the majority of non-fire-related CO poisonings are attributed to gas heating, there are several other less recognized sources that should be considered in the initial differential diagnosis.The patient in this case was a 21-year-old who experienced a brief episode of loss of consciousness and was subsequently admitted to the Emergency department. Upon evaluation, the patient was diagnosed with CO poisoning, which necessitated hyperbaric oxygen therapy to mitigate the effects of this toxic exposure.Despite exhibiting harmful symptoms initially, the patient stated in a phone interview two and a half years post-incident that they have not experienced any enduring effects such as cardiac arrhythmia or concentration deficits. While their understanding of the risks associated with waterpipe smoking has increased, it has not influenced any major changes in their waterpipe smoking habits.

Rare Causes of Acute Coronary Syndrome: Carbon Monoxide Poisoning

Acute coronary syndrome (ACS) is a spectrum of clinical and paraclinical disorders arising from an imbalance of oxygen demand and supply to the myocardium. The most common cause is atherosclerosis; however, other rare causes such as carbon monoxide (CO) poisoning should be considered. Through tissue hypoxia and direct cell injury, CO poisoning can lead to a broad spectrum of cardiac disorders, especially ACS. Materials and Methods. We have conducted a retrospective study in the Toxicology Department of Saint Spiridon Emergency University Hospital, including all patients admitted through the emergency department with CO poisoning. We divided the cohort into event group (myocardial injury) and non-event group (patients without myocardial injury) and performed a subset analysis of the former. Results. A total of 65 patients were included, 22 in the event and 43 in the non-event group. The severity of poisoning did not correlate with myocardial injury; however, 50% of the event group had severe poisoning with carboxyhaemoglobin ≥ 20%. Cardiac enzyme markers (troponin and creatin-kinase MB) had a statistically significant increase in the event group compared to the non-event group (p < 0.05). Most of the patients in the STEMI (50%) and NSTEMI (66.7%) groups had severe CO intoxication. The STEMI group had a mean age of 27.7 years old and no comorbidities. Conclusions. Myocardial injury can develop in CO poisoning irrespective of the severity of poisoning, and it can be transient, reversible, or permanent. Our study introduces new information on adverse cardiac events in patients with CO poisoning, focusing on the ACS. We found that the severity of CO poisoning plays an important role in developing myocardial injury, as 50% of patients in the event group were severely intoxicated. While in-hospital mortality in our study was low, further prospective studies should investigate the long-term mortality in these patients.

Global burden analysis and AutoGluon prediction of accidental carbon monoxide poisoning by Global Burden of Disease Study 2019

Accidental carbon monoxide poisoning (ACOP) is the most common occupational toxic disease, but related data are scarce or non-existent in many countries. This article investigates the global burden of ACOP based on the Global Burden of Disease Study 2019 (GBD 2019) and the World Bank database. In our study, numbers and age-standardized rates of ACOP prevalence, incidence, deaths, disability-adjusted life years (DALYs), years lived with disability (YLDs), and years of life lost (YLLs) were analyzed at global, regional, and national level. Besides, the estimated annual percentage change (EAPC) of age-standardized rates were calculated by generalizing the linear model. Age, sex, and Socio-demographic Index (SDI) are included to access their internal relevance. Globally, in 2019, there were approximately 0.97 million ACOP incidence cases (95% CI 0.66 million to 1.4 million), and 41,142 (95% UI 32,957 to 45,934) people died from it. Compared with 1990, the morbidity and mortality of ACOP in 2019 are on a downward trend. By sexes, from 1990 to 2019, females have higher morbidity and lower mortality. This correlation enables us to evaluate the level and status of public health services in various countries. We also evaluated the correlation between ACOP and economic parameters and use newly released machine learning tool-AutoGluon to predict the epidemiology of ACOP. The results of this study can be used by the health authorities to consider the burden of ACOP that could be addressed with preventive and therapeutic measures.

Carbon Monoxide Poisoning and Developing Ischemic Heart Disease: A Nationwide Population-Based Nested Case-Control Study

Although there are several case reports showing that carbon monoxide (CO) poisoning causes ischemic heart disease (IHD), no large-scale epidemiological studies have shown a significant association between the two. To investigate the association between CO poisoning and IHD, a nested case-control study of 28,113 patients who experienced CO poisoning and 28,113 controls matched by sex and age was performed using the nationwide health database of South Korea. Based on a conditional logistic regression, there was a significantly higher risk of IHD among the CO poisoning group than among the control group (adjusted hazard ratio [HR], 2.16; 95% confidence interval [CI], 1.87–2.49). The risk of IHD after CO poisoning was higher among the younger age group under 40 years (adjusted HR, 4.85; 95% CI, 3.20–7.35), and it was much greater among those with comorbidities (adjusted HR, 10.69; 95% CI, 2.41–47.51). The risk of IHD was the highest within the first two years after CO poisoning (adjusted HR, 11.12; 95% CI, 4.54–27.22). Even if more than six years had passed, the risk was still significantly higher than among the control group (adjusted HR, 1.55; 95% CI, 1.27–1.89). The analyses imply that CO poisoning is associated with an increased risk of IHD.

Veno-venous extracorporeal blood phototherapy increases the rate of carbon monoxide (CO) elimination in CO-poisoned pigs

BACKGROUND AND OBJECTIVES

Carbon monoxide (CO) inhalation is the leading cause of poison-related deaths in the United States. CO binds to hemoglobin (Hb), displaces oxygen, and reduces oxygen delivery to tissues. The optimal treatment for CO poisoning in patients with normal lung function is the administration of hyperbaric oxygen (HBO). However, hyperbaric chambers are only available in medical centers with specialized equipment, resulting in delayed therapy. Visible light dissociates CO from Hb with minimal effect on oxygen binding. In a previous study, we combined a membrane oxygenator with phototherapy at 623 nm to produce a "mini" photo-ECMO (extracorporeal membrane oxygenation) device, which improved CO elimination and survival in CO-poisoned rats. The objective of this study was to develop a larger photo-ECMO device ("maxi" photo-ECMO) and to test its ability to remove CO from a porcine model of CO poisoning.

STUDY DESIGN/MATERIALS AND METHODS

The "maxi" photo-ECMO device and the photo-ECMO system (six maxi photo-ECMO devices assembled in parallel), were tested in an in vitro circuit of CO poisoning. To assess the ability of the photo-ECMO device and the photo-ECMO system to remove CO from CO-poisoned blood in vitro, the half-life of COHb (COHb-t_1/2 ), as well as the percent COHb reduction in a single blood pass through the device, were assessed. In the in vivo studies, we assessed the COHb-t_1/2 in a CO-poisoned pig under three conditions: (1) While the pig breathed 100% oxygen through the endotracheal tube; (2) while the pig was connected to the photo-ECMO system with no light exposure; and (3) while the pig was connected to the photo-ECMO system, which was exposed to red light.

RESULTS

The photo-ECMO device was able to fully oxygenate the blood after a single pass through the device. Compared to ventilation with 100% oxygen alone, illumination with red light together with 100% oxygen was twice as efficient in removing CO from blood. Changes in gas flow rates did not alter CO elimination in one pass through the device. Increases in irradiance up to 214 mW/cm² were associated with an increased rate of CO elimination. The photo-ECMO device was effective over a range of blood flow rates and with higher blood flow rates, more CO was eliminated. A photo-ECMO system composed of six photo-ECMO devices removed CO faster from CO-poisoned blood than a single photo-ECMO device. In a CO-poisoned pig, the photo-ECMO system increased the rate of CO elimination without significantly increasing the animal's body temperature or causing hemodynamic instability.

CONCLUSION

In this study, we developed a photo-ECMO system and demonstrated its ability to remove CO from CO-poisoned 45-kg pigs. Technical modifications of the photo-ECMO system, including the development of a compact, portable device, will permit treatment of patients with CO poisoning at the scene of their poisoning, during transit to a local emergency room, and in hospitals that lack HBO facilities.

Prevalence of myocardial injury requiring percutaneous coronary intervention after acute carbon monoxide poisoning

OBJECTIVE

More than one-third of patients with moderate to severe acute carbon monoxide (CO) poisoning had myocardial injury. However, the ratio of acute CO patients necessitating percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) remains unknown. This study aimed to examine the prevalence of myocardial injury requiring PCI or CABG in patients with CO poisoning.

METHODS

This was a nationwide retrospective cohort study, using the Japanese Diagnosis Procedure Combination inpatient database focusing on the period between 2010 and 2017. We extracted data on patients diagnosed with CO poisoning and determined the prevalence of cases presenting with myocardial injury requiring PCI or CABG.

RESULTS

We identified 9091 eligible patients. Within this patient pool, eight patients underwent PCI within 2 days of admission. No patients required CABG. The prevalence of subsequent PCI was 0.09% (8/9091). The patients who required PCI had a significantly higher median age than those who did not (75 vs. 52 years of age, respectively). Patients requiring PCI were older and were more likely to have underlying comorbidities such as hypertension and diabetes mellitus.

CONCLUSION

The present study reported a low prevalence of myocardial injury requiring PCI in acute CO poisoning patients. Although myocardial injury due to coronary artery occlusion would be a very rare presentation in the setting of acute CO poisoning, coronary occlusion should be taken into consideration for elderly patients and/or patients who have coronary risk factors.

Risk factors for venous thromboembolism after carbon monoxide poisoning: A nationwide population-based study

Introduction:

The risk of venous thromboembolism increases after acute carbon monoxide poisoning. However, studies on the characteristics of patients who develop venous thromboembolism after carbon monoxide poisoning are rare. The aim of this study was to identify the risk factors for venous thromboembolism within 3 months after carbon monoxide poisoning.

Methods:

This is a population-based study that employed nationwide claims data from South Korea. Among the carbon monoxide poisoning patients (⩾18 years), the characteristics of the groups with and without venous thromboembolism (pulmonary embolism or deep vein thrombosis) were identified. All the significant variables in the univariable analysis were included in the multivariable logistic regression to determine the risk factors for venous thromboembolism occurrence.

Results:

Among the 24,232 carbon monoxide poisoning patients, 130 subjects developed venous thromboembolism within 90 days of their carbon monoxide poisoning diagnosis. The significant risk factors for venous thromboembolism in the multivariable analysis were age (adjusted odds ratio (aOR) = 1.01; 95% confidence interval (CI) = 1.003–1.03), intensive care unit admission (aOR = 3.80; 95% CI = 2.34–6.12), length of stay (aOR = 1.02; 95% CI = 1.0001–1.04), congestive heart failure (aOR = 2.17; 95% CI = 1.36–3.42), and cancer (aOR = 1.94; 95% CI = 1.10–3.22). The adjusted odds ratios for intensive care unit admission for patients with pulmonary embolism and deep vein thrombosis were 3.05 (95% CI = 1.61–5.61) and 5.60 (95% CI = 2.89–10.90), respectively.

Conclusion:

Patients with older age, intensive care unit admission, a longer length of stay, congestive heart failure, or cancer are at greater risk of developing venous thromboembolism after carbon monoxide poisoning. In particular, intensive care unit admission was the strongest risk factor for venous thromboembolism, pulmonary embolism, and deep vein thrombosis. Monitoring and administering prophylactic treatments to prevent venous thromboembolism would be helpful in high-risk in carbon monoxide poisoning patients.

A neuroglobin-based high-affinity ligand trap reverses carbon monoxide-induced mitochondrial poisoning

Carbon monoxide (CO) remains the most common cause of human poisoning. The consequences of CO poisoning include cardiac dysfunction, brain injury, and death. CO causes toxicity by binding to hemoglobin and by inhibiting mitochondrial cytochrome c oxidase (CcO), thereby decreasing oxygen delivery and inhibiting oxidative phosphorylation. We have recently developed a CO antidote based on human neuroglobin (Ngb-H64Q-CCC). This molecule enhances clearance of CO from red blood cells in vitro and in vivo Herein, we tested whether Ngb-H64Q-CCC can also scavenge CO from CcO and attenuate CO-induced inhibition of mitochondrial respiration. Heart tissue from mice exposed to 3% CO exhibited a 42 ± 19% reduction in tissue respiration rate and a 33 ± 38% reduction in CcO activity compared with unexposed mice. Intravenous infusion of Ngb-H64Q-CCC restored respiration rates to that of control mice correlating with higher electron transport chain CcO activity in Ngb-H64Q-CCC-treated compared with PBS-treated, CO-poisoned mice. Further, using a Clark-type oxygen electrode, we measured isolated rat liver mitochondrial respiration in the presence and absence of saturating solutions of CO (160 μm) and nitric oxide (100 μm). Both CO and NO inhibited respiration, and treatment with Ngb-H64Q-CCC (100 and 50 μm, respectively) significantly reversed this inhibition. These results suggest that Ngb-H64Q-CCC mitigates CO toxicity by scavenging CO from carboxyhemoglobin, improving systemic oxygen delivery and reversing the inhibitory effects of CO on mitochondria. We conclude that Ngb-H64Q-CCC or other CO scavengers demonstrate potential as antidotes that reverse the clinical and molecular effects of CO poisoning.

Incidence Rate and Predictors of Globus Pallidus Necrosis after Charcoal Burning Suicide

Objective: This study examined predictors of globus pallidus necrosis as there was a paucity of literature of globus pallidus necrosis resulted from carbon monoxide poisoning after charcoal burning suicide. Methods: A total of 67 patients who had attempted charcoal burning suicide were recruited and stratified into two subgroups based on either presence (n = 40) or absence (n = 27) of globus pallidus necrosis. Demographic, clinical, laboratory, and radiographic data were obtained for cross-sectional analysis. All patients were followed to investigate the risks for mortality. Results: The patients aged 36.8 ± 11.1 years (67.2%) were male. Patients with globus pallidus necrosis were younger (p = 0.044) and had less hypertension (p = 0.015) than patients without globus pallidus necrosis. Furthermore, patients with globus pallidus necrosis suffered from severer medical complications, i.e., fever (p = 0.008), acute myocardial injury (p = 0.022), acute rhabdomyolysis (p = 0.022), and neuropsychiatric symptoms (p < 0.001) than patients without globus pallidus necrosis. Moreover, patients with globus pallidus necrosis received less hyperbaric oxygen therapy than without necrosis (p = 0.024). Two patients (3.0%) died on arrival. In a multivariable regression model, it was revealed that acute myocardial injury (odds ratio 4.6, confidence interval 1.1–18.9, p = 0.034) and neuropsychiatric symptoms (odds ratio 8.0, confidence interval 2.0–31.4, p = 0.003), decreased blood bicarbonate level (odds ratio 0.8, confidence interval 0.7–1.0, p = 0.032), and younger age (odds ratio 0.9, confidence interval 0.9–1.0, p = 0.038) were significant predictors for globus pallidus necrosis. Conclusion: Although patients who had attempted charcoal burning suicide had a low mortality rate (3.0%), globus pallidus necrosis was not uncommon (59.7%) in this population. Further studies are warranted.

Transient ST Segment Elevation Caused by Intracoronary Thrombus after Acute Carbon Monoxide Poisoning

Carbon monoxide (CO) poisoning is the most common cause of death and injury among all poisonings. Myocardial injury is detected in one-third of CO poisonings. In this Case Report, a previously healthy 41-year-old man was referred for CO poisoning. The initial electrocardiogram (ECG) showed 1mm ST segment elevation in leads DII, DIII, and aVF. As the patient did not describe chest pain and had no cardiac symptoms, ECG was repeated 10 minutes later and it was seen that ST segment elevation disappeared. As the patient had a transient ST segment elevation and elevated high-sensitive Tn-T (HsTn-T), the patient was transferred to the coronary angiography laboratory. The patient's left coronary system was normal, but a thrombus image narrowing the lumen by approximately 60% was observed in the right coronary artery. Intravenous tirofiban was administered for 48 hours. Control coronary angiography showed continuing thrombus formation and a bare metal stent was successfully implanted. This is the first reported case with transient ST segment elevation associated with acute coronary thrombus caused by CO poisoning. It may be recommended that patients with CO poisoning should be followed-up with a 12-lead ECG monitor or 24-hour ECG Holter monitoring, even if they show no cardiac symptoms and echocardiography shows no wall motion abnormality. Early coronary angiography upon detection of such dynamic ECG changes in these recordings as ST segment elevation can reduce the risk of myocardial infarction (MI) and mortality in these patients.

Variant angina induced by carbon monoxide poisoning: A CARE compliant case report

RATIONALE

Carbon monoxide (CO) poisoning can cause severe damage to the nervous system, and can also cause serious damage to organs, such as the heart, kidneys, and lungs. CO damage to myocardial cells has been previously reported. This can lead to serious complications, such as myocardial infarction.

PATIENT CONCERNS

A 47-year-old female patient complained of sudden chest pain for 30 minutes. Before admission, the patient had non-radiating burning chest pain after inhalation of soot.

DIAGNOSIS

An electrocardiogram showed that myocardial ischemia was progressively aggravated, manifested by progressive ST-segment elevation, and accompanied by T wave inversion and other changes. No obvious coronary stenosis was observed in a coronary angiographic examination. Therefore, the patient was considered to have developed variant angina resulting from CO poisoning-induced coronary artery spasm.

INTERVENTIONS

The patient was treated with drugs for improving blood circulation and preventing thrombosis, and underwent hyperbaric oxygen therapy.

OUTCOMES

Clinical symptoms relieved after the treatment.

LESSONS

Findings from this case suggest that CO can cause coronary artery spasm and it is one of the predisposing factors of variant angina. For these patients, hyperbaric oxygen therapy can improve blood circulation and prevent formation of thrombus and encephalopathy.

Non-ST elevation myocardial infarction induced by carbon monoxide poisoning: A case report

RATIONALE

Acute myocardial infarction is a rare complication of carbon monoxide poisoning. there is often no chest pain and other typical manifestations. We report a patient with mild carbon monoxide poisoning who had acute dyspnea as the earliest symptom and was later diagnosed with non-ST elevation myocardial infarction (NSTEMI) and acute left heart failure.

PATIENT CONCERNS

A 73-year-old woman complained of dizziness and fatigue with shortness of breath after carbon monoxide intoxication.

DIAGNOSES

This patient had a clear history of carbon monoxide poisoning, acute respiratory distress, bilateral lung dry and moist rale, chest X-ray showed bilateral pulmonary edema, Electrocardiograph indicated general depression of the ST segment of the leads in the chest, cardiac troponin I (CTNI) increased progressively, cardiac ultrasonography indicated abnormal ventricular wall movement, coronary angiography suggested left main trunk and 3-vessel lesions, suggesting diagnosis acute carbon monoxide poisoning, acute coronary syndrome, acute left heart failure.

INTERVENTIONS

She was treated with a high concentration of oxygen, an inhibitor of platelet aggregation (aspirin plus clopidogrel), an anticoagulant (low molecular weight heparin), an antimicrobial (ceftizoxime), an expectorant (mucosolvan), diuresis (furosemide and spironolactone), and myocardial support (Metoprolol). Coronary angiography and stent placement were performed 8 days later.

OUTCOME

On the 10th day after onset of the condition, echocardiography was performed, which showed that cardiac function was improved. Mild segmental wall motion abnormality was observed on echocardiography. After 14 days, the patient had recovered well and was discharged without chest tightness, chest pain, dizziness, headache, or unresponsiveness.

LESSONS

This case suggests that the symptoms of carbon monoxide poisoning are complex and diverse. It can be manifested as a primary hypoxic symptom, or cause the exacerbation of underlying diseases due to hypoxia. Therefore, patients with carbon monoxide poisoning should actively seek comprehensive cardiac examination to ensure early diagnosis. Whenever necessary, coronary angiography and stent implantation should be performed to improve the likelihood of the patient's survival.

Pulmonary Phototherapy to Treat Carbon Monoxide Poisoning in Rats

BACKGROUND

Carbon monoxide (CO) poisoning is a common cause of poison-related mortality. CO binds to hemoglobin in the blood to form carboxyhemoglobin (COHb), impairing oxygen delivery to peripheral tissues. Current treatment of CO-poisoned patients involves oxygen administration to rapidly remove CO and restore oxygen delivery. Light dissociates CO from COHb with high efficiency. Exposure of murine lungs to visible laser-generated light improved the CO elimination rate in vivo. The aims of this study were to apply pulmonary phototherapy to a larger animal model of CO poisoning, to test novel approaches to light delivery, and to examine the effect of chemiluminescence-generated light on the CO elimination rate.

METHODS

Anesthetized and mechanically ventilated rats were poisoned with CO and subsequently treated with air or oxygen combined with or without pulmonary phototherapy delivered directly to the lungs of animals at thoracotomy, via intrapleural optical fibers or generated by a chemiluminescent reaction.

RESULTS

Direct pulmonary phototherapy dissociated CO from COHb reducing COHb half-life by 38%. Early treatment with phototherapy in critically CO poisoned rats improved lactate clearance. Light delivered to the lungs of rats via intrapleural optical fibers increased the rate of CO elimination without requiring a thoracotomy, as demonstrated by a 16% reduction in COHb half-life. Light generated in the pleural spaces by a chemiluminescent reaction increased the rate of CO elimination in rats breathing oxygen, reducing the COHb half-life by 12%.

CONCLUSIONS

Successful application of pulmonary phototherapy in larger animals and humans may represent a significant advance in the treatment of CO-poisoned patients.

Carbon Monoxide Poisoning: Pathogenesis, Management, and Future Directions of Therapy

Carbon monoxide (CO) poisoning affects 50,000 people a year in the United States. The clinical presentation runs a spectrum, ranging from headache and dizziness to coma and death, with a mortality rate ranging from 1 to 3%. A significant number of patients who survive CO poisoning suffer from long-term neurological and affective sequelae. The neurologic deficits do not necessarily correlate with blood CO levels but likely result from the pleiotropic effects of CO on cellular mitochondrial respiration, cellular energy utilization, inflammation, and free radical generation, especially in the brain and heart. Long-term neurocognitive deficits occur in 15-40% of patients, whereas approximately one-third of moderate to severely poisoned patients exhibit cardiac dysfunction, including arrhythmia, left ventricular systolic dysfunction, and myocardial infarction. Imaging studies reveal cerebral white matter hyperintensities, with delayed posthypoxic leukoencephalopathy or diffuse brain atrophy. Management of these patients requires the identification of accompanying drug ingestions, especially in the setting of intentional poisoning, fire-related toxic gas exposures, and inhalational injuries. Conventional therapy is limited to normobaric and hyperbaric oxygen, with no available antidotal therapy. Although hyperbaric oxygen significantly reduces the permanent neurological and affective effects of CO poisoning, a portion of survivors still have substantial morbidity. There has been some early success in therapies targeting the downstream inflammatory and oxidative effects of CO poisoning. New methods to directly target the toxic effect of CO, such as CO scavenging agents, are currently under development.

Incidence and patterns of cardiomyopathy in carbon monoxide-poisoned patients with myocardial injury

OBJECTIVES

Sustained myocardial injury is a significant predictor of mortality in carbon monoxide (CO) poisoning. There are few reports in the literature regarding the presence of CO-induced cardiomyopathy from early stages in the emergency department (ED). We prospectively investigated the early incidence of CO-induced cardiomyopathy and its patterns in patients with cardiomyopathy.

MATERIALS AND METHODS

During a 10-month period, transthoracic echocardiography (TTE) was performed in 43 consecutive patients with CO poisoning and myocardial injury, which was defined as elevated high-sensitive troponin I within 24 h after ED arrival. Measurements of left ventricular ejection fraction and wall motion abnormalities were performed to evaluate cardiac function. If a patient had CO-induced cardiomyopathy, we measured cardiac function at the time of patient admission, day 1, day 2, and once within seven days of hospitalization.

RESULTS

The incidence of cardiomyopathy was as high as 74.4% (32 of 43 patients) in CO-poisoned patients with myocardial injury based on initial ED results. Echocardiographic patterns included non-cardiomyopathy (25.6%), global dysfunction (51.2%), and Takotsubo-like cardiomyopathy (23.2%). Patients in the global dysfunction group had significantly more normalized cardiac dysfunction within 72 h than did those in the Takotsubo-like cardiomyopathy group (81.8% vs. 22.2%, p = 0.001).

DISCUSSION AND CONCLUSION

Patients with CO poisoning and myocardial injury experienced cardiomyopathy, including reversible global dysfunction and a Takotsubo-like pattern. Investigation of cardiomyopathy needs to be considered in patients with CO poisoning and myocardial injury.

Carbon monoxide poisoning and subsequent cardiovascular disease risk: a nationwide population-based cohort study

Carbon monoxide (CO) poisoning is considered one of the most crucial health concerns. Few studies have investigated the correlation between CO poisoning and the risk of developing cardiovascular diseases (CVDs). Therefore, we conducted a population-based, longitudinal cohort study in Taiwan to determine whether patients with CO poisoning are associated with higher risk of developing subsequent CVDs, including arrhythmia, coronary artery disease (CAD) and congestive heart failure (CHF). This retrospective study used the National Health Insurance Research Database. The study cohort comprised all patients aged ≥20 years with a diagnosis of CO poisoning and hospitalized during 2000 to 2011 (N = 8381), and the comparison cohort comprised randomly selected non-CO-poisoned patients (N = 33,524) frequency-matched with the study cohort by age, sex, and the year of index date. Each patient was individually tracked to identify those who develop CVD events during the follow-up period. Cox proportional hazards regression model was performed to calculate the hazard ratios of CVDs after adjusting for possible confounders. The overall incidences of arrhythmia, CAD, and CHF were higher in the patients with CO poisoning than in the controls (2.57 vs 1.25/1000 person-years, 3.28 vs 2.25/1000 person-years, and 1.32 vs 1.05/1000 person-years, respectively). After adjusting for age, sex, and comorbidities, the patients with CO poisoning were associated with a 1.83-fold higher risk of arrhythmia compared with the comparison cohort, and nonsignificantly associated with risk of CAD and CHF. CO-poisoned patients with coexisting comorbidity or in high severity were associated with significantly and substantially increased risk of all 3 CVDs. CO poisoning is associated with increased risk of subsequent development of arrhythmia. Future studies are required to explore the long-term effects of CO poisoning on the cardiovascular system.