Reversible cardiac failure in an adolescent after prolonged exposure to carbon monoxide

Frontal QRS-T angle as a predictive marker for myocardial damage in acute carbon monoxide poisoning

INTRODUCTION

The present study was undertaken to investigate the prognostic value of the frontal QRS-T angle associated with adverse cardiac outcomes in patients with carbon monoxide (CO) poisoning in early stages in the emergency department.

MATERIALS AND METHODS

The data of 212 patients with CO poisoning who were admitted to the ED between January 2010 and May 2020 were retrospectively analyzed. The frontal QRS-T angle was obtained from the automatic reports of the EKG device.

RESULTS

Compared to patients without myocardial damage, among patients with myocardial damage, statistically high creatinine, creatine kinase MB, cardiac troponin I, and frontal QRS-T angle values were found (p < 0.001 for all parameters), while the saturation of arterial blood pH and arterial oxygen values were found to be lower (p = 0.002 and p < 0.001, respectively). The frontal QRS-T angle values were correlated with creatine kinase, creatine kinase-MB, cardiac troponin I, and oxygen saturation (SpO₂) in arterial blood (r = 0. 232, p = 0.001; r = 0. 253, p = < 0.001; r = 0. 389, p = < 0.001; r = -0. 198, p = 0.004, respectively). The optimum cut-off value of the frontal QRS-T angle was found to be 44.5 (area under the curve: 0.901, 95% confidence interval: 0.814-0.988, sensitivity: 87%, specificity: 84%).

CONCLUSIONS

The frontal QRS-T angle, a simple and inexpensive parameter that can be easily obtained from 12-lead surface electrocardiography, can be used as an early indicator in the detection of myocardial damage in patients with CO poisoning.

Carbon monoxide-induced cardiomyopathy

BACKGROUND

Previous reports demonstrated mechanisms of cardiac toxicity in acute carbon monoxide (CO) poisoning. Still, none established CO-induced cardiomyopathy (CMP) as a clinical entity. The aim of this study is to investigate CO-induced CMP in patients with acute CO poisoning in terms of its epidemiology, clinical characteristics, and prognosis.

METHODS AND RESULTS

A retrospective study was conducted on consecutive patients who were diagnosed with acute CO poisoning at the emergency department of Ajou University Hospital during the period of 62 month. Six hundred and twenty-six patients were diagnosed with acute CO poisoning. During the initial echocardiography, 19 patients were abnormal: (1) global hypokinesia/akinesia (n=7), (2) regional wall hypokinesia/akinesia [n=12; takotsubo type (n=6), reverse takotsubo type (n=2), non-specific type (n=4)]. The ejection fraction (EF) was 36.3±13.5% (from 15% to 55%) and less than 45% for 14 patients. In the follow-up echocardiography performed within 12 days after the initial performance, most patients were found to have cardiac wall motion abnormalities, and their EF had returned to normal (ie, EF ≥50%).

CONCLUSIONS

CO-induced CMP was identified in 3.04% (n=19) of all patients (n=626). It might not be too critical in acute clinical courses of acute CO poisoning because the prognosis seems favorable. Considering the common factors between CO-induced CMP and takotsubo CMP, myocardial stunning subject to a catecholamine surge most likely plays a central role in the development of CO-induced CMP.

Transient left ventricular systolic dysfunction associated with carbon monoxide toxicity

Carbon monoxide (CO) is one of well known chemical asphyxiants which cause tissue hypoxia with prominent neurologic and cardiovascular injury. Cardiac dysfunction after CO poisoning can be presented as two clinical patterns. One is transient global left ventricular (LV) dysfunction and the other is LV dysfunction with regional wall motion abnormalities. In this case report, we present a case with transient LV systolic dysfunction caused by intentional exposure to CO. After conservative treatment including high concentration of oxygen, the patient recovered completely without any complication.

Serum levels of NT-ProBNP as an early cardiac marker of carbon monoxide poisoning

Acute carbon monoxide (CO) poisoning may cause cardiotoxicity. The natriuretic peptides, including atrial natriuretic peptide, brain natriuretic peptide (BNP), N-BNP, and NT-proBNP (N-terminal pro brain natriuretic peptide), are endogenous cardiac hormones that may be secreted upon myocardial stress. The aim of this study was to assess the plasma NT-proBNP level in acute CO poisoning and to compare it with healthy control. After approval by the ethical committee, 15 healthy controls and 15 patients admitted to the Gaziantep University Hospital (Gaziantep, Turkey) between January 2005 and July 2005 with the diagnosis of carbon monoxide poisoning were studied. Echocardiography was performed to all patients. Serum NT-proBNP, creatine kinase (CK), creatine kinase-MB (CK-MB), and troponin-T were also analyzed, along with the carboxyhemoglobin (COHb) level. The correlation between serum NT-proBNP and COHb level was investigated. Electrocardiography (ECG) was performed to all patients and healthy controls, and the results were compared. Differences in troponin, CK, and CK-MB levels were not statistically significant between groups (p > 0.05). The level of NT-proBNP and COHb were found to be increased in the study group. There was a positive correlation between the COHb and the NT-proBNP (r = 0.829, p < 0.01), and between the COHb and the CK (r = 0.394, p < 0.01). There was no difference between groups in other parameters, all of which were within normal range. Thus, in this study we showed that the plasma NT-proBNP level may contribute to the early diagnosis of cardiotoxicity in patients with carbon monoxide poisoning.

Cardiogenic shock complicating acute carbon monoxide poisoning despite neurologic and metabolic recovery

We report the cases of 2 previously healthy young patients with acute carbon monoxide intoxication who deteriorated to cardiogenic shock in the face of apparent metabolic and neurologic recovery. Prolonged exposure to sublethal levels of carbon monoxide (>24 hours, carboxyhemoglobin level of 20.4% and 22.6%) and massive binding of the toxin to myocardial myoglobin and mitochondrial cytochrome chain enzymes might explain their protracted cardiac failure. The good response to inotropic agents and the findings of repeated echocardiographic studies support the probable diagnosis of myocardial stunning. Complete cardiac recovery was observed in both patients.

Carbon monoxide cardiotoxicity

Cardiac dysfunction including arrhythmias and myocardial ischemia have often been reported in carbon monoxide poisoning; scattered punctiform hemorrhages throughout the heart have been documented in autopsy samples. An appropriate diagnostic approach is crucial to assess carbon monoxide cardiac damage. This evaluation may be confounded by several factors, including the absence of overt symptoms and of specific ischemic changes in the electrocardiogram. In experimental studies, laboratory animals can develop cardiac changes similar to those seen in humans and therefore proved to be useful models to study the effects and the mechanisms of cardiac damage due to carbon monoxide. These investigations, as well as others performed in vitro, provide support for a direct action of carbon monoxide on the heart, in addition to systemic hypoxia produced by carboxyhemoglobin formation. This review focuses on the diagnostic aspects of carbon monoxide cardiotoxicity. Experimental results obtained in animals and in vitro models are also discussed.

Cardiac damage in pediatric carbon monoxide poisoning

BACKGROUND

Cardiovascular disorders including myocardial ischemia and heart failure have been described in both laboratory animals and humans following carbon monoxide poisoning. Carbon monoxide cardiotoxicity may be clinically occult and often remains undiagnosed because of the lack of overt symptoms and specific ischemic changes in the electrocardiogram. Routine myocardial necrosis markers have low diagnostic efficiency, particularly in patients with concomitant skeletal muscle necrosis or multiple organ failure complicating carbon monoxide poisoning. Carbon monoxide-induced cardiotoxicity has been investigated rarely in children.

CASE REPORT

This paper describes carbon monoxide poisoning in a 12-year-old child who suffered from occult cardiac damage despite mild symptoms and low carboxy hemoglobin concentrations. Myocardial and mitral valve dysfunctions were observed, suggesting an ischemia-like syndrome. Cardiac damage was completely reversible within 1 month.

CONCLUSION

This case report supports that a prolonged carbon monoxide exposure can cause cardiac damage in children even in the absence of specific symptoms, cerebral failure and high carboxyhemoglobin concentrations.