Comparison of biochemical markers for the detection of minimal myocardial injury: superior sensitivity of cardiac troponin--T ELISA

Enzymes as indispensable markers in disease diagnosis

Enzymes have been used for disease diagnosis for many decades; however, advancements in technology like ELISA and flow cytometry-based detection have significantly increased their use and have increased the sensitivity of detection. Technological advancements in recombinant enzyme production have increased enzymatic stability, and the use of colorimetric-based and florescence-based assays has led to their increased use as biomarkers for disease detection. Enzymes like acid phosphatase, cathepsin, lactate dehydrogenase, thymidine kinase and creatine kinase are indispensable markers for diagnosing cancer, cardiovascular diseases and others. This minireview summarizes various enzymes used in disease diagnosis, their metabolic role, market value and potential as disease markers across various metabolic and other disorders.

High Prevalence of Bovine Cardiac Cysticercosis in Upper Egypt: An Epidemiological and Histopathological Study

Bovine cysticercosis is categorized as a serious parasitic zoonotic infestation. The infection is mainly caused by the tapeworm Taenia saginata, which infects cattle and humans. The larval stage, Cysticercus bovis (C. bovis), is found in the skeletal and cardiac muscles of infected cattle. Despite its potential public health concern, few studies have been conducted on cardiac cysticercosis in Upper Egypt. This study investigates the prevalence, epidemiology, and impact of cardiac cysticercosis in Upper Egypt, emphasizing how histopathological changes in cardiac muscle and physiological parameters might be associated with the infection. From December 2022 to October 2023, a total of 941 animals from Assiut province, Upper Egypt, were slaughtered and their cardiac muscles were examined for the presence of C. bovis. Cysts were classified as viable or degenerated through macroscopic inspection. The overall prevalence of C. bovis infected hearts made up 10.8% of the total examined. The highest prevalence rate was in the summer season followed by spring; winter had the lowest infections. The histopathological examination of infected tissues revealed immune cell infiltration around Cysticercus-infected areas. Additionally, Bax immunostaining demonstrated the apoptotic effect of cysticercosis. Regarding the measured physiological parameters, there were non-significant changes in plasma levels of total protein and albumin in cattle infected with cysticercosis compared with control animals. Moreover, there was a significant decrease in total antioxidant capacity (TAC) combined with a significant increase in lipid peroxide (Malondialdehyde) (MDA), troponin T, and lactate dehydrogenase (LDH) activity in infected animals. The present work documented a set of epidemiological and pathological findings, revealing that C. bovis is a potentially harmful parasite and can cause significant health problems in both cattle and humans.

Shareef L. Levels of cardiac troponin-T and LDL-C to HDL-C ratio of hospitalized COVID-19 patients: A case-control study

Background: People with coronavirus disease 2019 (COVID-19) are frequently at higher risk of developing cardiovascular and metabolic disorders, which are strongly related to the development of long-term illness and higher mortality. These effects may be caused by several interrelated processes, including the IL-6 driven cytokine storm or uncontrolled angiotensin II stimulation. In addition, the direct viral infection of cardiac myocytes is thought to cause cardiac injury because it increases metabolic demand, activates the immune system, and causes vasculature disruption. The objective of this study was to determine whether there is a relationship between cardiac troponin-T (cTnT) and low-density lipoprotein cholesterol (LDL-C) to high-density lipoprotein cholesterol (HDL-C) ratio values with COVID-19. Methods: During the data collection stage, 90 participants were included, 45 healthy controls and 45 hospitalized patients diagnosed with COVID-19 using reverse transcription-quantitative PCR (RT-qPCR). Each participant provided 5 ml venous blood to begin analyzing cTnT and LDL-C:HDL-C ratio levels in their blood to see whether there is an association between the level of any of these markers and COVID-19 infection using SPSS version 23. Results: This research reported a significant rise in the measured values of cTnT and LDL-C:HDL-C ratio in patients' blood compared to controls, with P-values of 0.025 and 0.000, respectively, in which alpha values < 0.05, These biomarkers hold the promise in predicting COVID-19 severity, and early treatment may help reduce complications. Conclusions: Due to the fact that cTn is a diagnostic marker of disease activity and a strong independent predictor of negative events, its usage in emergency rooms may well be advantageous. If cTn is elevated, hospitalization may be indicated. A difference in the blood LDL-C:HDL-C ratio of COVID-19 patients demonstrated an association with the illness. Because lipid studies are inexpensive and reliable to do, they may aid clinicians in identifying the severity of COVID-19.

Role of Cardiac Biomarkers in the Assessment of Acute Cerebrovascular Accident

Background  Stroke (cerebrovascular accident) has for long been a global burden in terms of its morbidity and mortality. Serum levels of cardiac enzymes such as creatine kinase-MB (CK-MB) component, troponin T, and brain natriuretic peptide have been found to be elevated among the patients with stroke and also serve to prognosticate these patients. The serum levels of these enzymes correlate directly to the severity of stroke in these patients.

Objective  Elevated cardiac enzymes among patients with acute cerebrovascular accidents are not uncommon despite the patients not having any cardiac problems. We aimed to identify the occurrence of elevated cardiac enzymes among patients with acute stroke and their correlation with the severity of stroke.

Materials and Methods  Our study included 100 patients of acute stroke with no previous history of cardiac ailments. Serum levels of troponin I and CK-MB were analyzed among these patients using enzyme-linked immunosorbent assay method within the first 2 hours of admission. Patients outcome during the hospital stay were analyzed. Stroke severity was assessed using the National Institute of Health Stroke score (NIHS score) and the modified Rankin Score (mRS). The cardiac enzyme levels were correlated with these scores.

Results  Twenty-eight percent of patients had elevated troponin I, while 72% patients had normal levels with the mean values of 10.36 to 106.54 ng/mL and 0.00 to 0.02 ng/mL, respectively. CK-MB levels were found elevated among 14% patients and normal among 86% patients with mean values of 5.8 to 124.36 and 0.0 to 4.3 ng/mL, respectively. Among the six patients who succumbed to death, three patients had increased troponin I and four had elevated CK-MB. NIHS scores of 21.0357±6.79 and 105.277±5.564 were seen in patients with elevated and normal troponin I, whereas NIHS scores of 20.4285±8.658 and 11.8721±9.273 were seen among patients with increased and normal CK-MB, respectively. The mRS scores were 4.3214±0.367, 2.4305±1.374, 4.2143±1.412, and 2.756±1.749 ng/mL among the patients with elevated and normal troponin I and CK-MB, respectively.

Conclusion  The mean values of cardiac enzymes troponin I and CK-MB were higher among patients with higher scores of NIHS and mRS. Among them, troponin I was very significant and it may serve as an early biomarker for the severity of stroke and hint on early cardiac evaluation among these patients.

The effect of malaria and anti-malarial drugs on skeletal and cardiac muscles

Malaria remains one of the most important infectious diseases in the world, being a significant public health problem associated with poverty and it is one of the main obstacles to the economy of an endemic country. Among the several complications, the effects of malaria seem to target the skeletal muscle system, leading to symptoms, such as muscle aches, muscle contractures, muscle fatigue, muscle pain, and muscle weakness. Malaria cause also parasitic coronary artery occlusion. This article reviews the current knowledge regarding the effect of malaria disease and the anti-malarial drugs on skeletal and cardiac muscles. Research articles and case report publications that addressed aspects that are important for understanding the involvement of malaria parasites and anti-malarial therapies affecting skeletal and cardiac muscles were analysed and their findings summarized. Sequestration of red blood cells, increased levels of serum creatine kinase and reduced muscle content of essential contractile proteins are some of the potential biomarkers of the damage levels of skeletal and cardiac muscles. These biomarkers might be useful for prevention of complications and determining the effectiveness of interventions designed to protect cardiac and skeletal muscles from malaria-induced damage.

High-sensitivity troponin T as a marker of myocardial injury after radiofrequency catheter ablation

Background

The aim of our study was to monitor radiofrequency catheter ablation-induced myocardial damage by measuring high-sensitivity cardiac troponin T (hs-cTnT).

Methods

Serum concentrations of hs-cTnT (Elecsys 2010 system, Roche) were measured in 73 healthy blood donors and serially in 27 patients who had samples taken both before and 24 h after radiofrequency ablation (RFA) for atrioventricular nodal re-entry tachycardia (AVNRT), atrial fibrillation (AF) or right atrial flutter (AFL).

Results

Significant increases of hs-cTnT were seen in patients after RFA (AVNRT: P = 0.0115, AF: P = 0.0011, AFL: P = 0.0009). Postprocedural serum hs-cTnT correlated with the number of radiofrequency applications and with the duration of RFA procedure. Spearman's coefficient of rank correlation ( r) were as follows: hs-cTnT versus RFA duration: r = 0.771 ( P < 0.001); hs-cTnT versus number of pulses: r = 0.708 ( P < 0.001). Patients with the diagnosis of AVNRT had lower serum hs-cTnT concentration after RFA compared with AFL ( P < 0.0001) and AF ( P < 0.0001) patients.

Conclusions

Our data indicate that RFA causes a significant increase of serum hs-cTnT concentration that could be used to monitor myocardial injury.

Diverse morphological lesions and serious arrhythmias with hemodynamic insults occur in the early myocardial contusion due to blunt impact in dogs

To investigate the morphology and hemodynamics of the early myocardial contusion, an animal model of cardiac contusion was established by impact to the precordial region at sternum at velocity of 10.0m/s with a mechanical elastic-cord propelled impactor in 19 dogs. The electrocardiogram and both the left and right intra-ventricular pressures were recorded continuously throughout the experiment. Histological and immunohistochemical examinations of myoglobin, creatine kinase-MB and fibrinogen were conducted. At the moment of impact, abrupt over-pressures within the left and right ventricles occurred with concomitant serious arrhythmias followed by variety of cardiac conduction disorders and depressed left and right ventricular systolic pressures during the observation times. Histologically, lesions of myocardial contusions were identified at subepicardial, myocardial or subendocardial layer as interstitial hemorrhage, disruption or coagulative necrosis as well as contraction band necrosis of the muscle fibers, which might be categorized into the hemorrhagic, necrotized and mixed forms. The three forms of lesions were found to exist independently, or co-existed in a heart. However, severity of the lesions varied greatly with different parts even within a heart. Intravascular thromboses were occasionally discovered post-impact. Immunohistochemically, loss of myoglobin and creatine kinase-MB from cardiac cells, and accumulation of fibrinogen at the cell membranes were detected 5min post-impact. The intracellular accumulation of fibrinogen increased with extension of post-impact intervals. Our results indicate that diverse morphological lesions concomitant with hemodynamic compromise and serious, even fatal arrhythmias occur in the early myocardial contusion, and intravascular thromboses are occasionally produced, suggesting that traumatic myocardial ischemic lesion may be induced due to blunt impact to the precordial region.

Elevated cardiac troponin T in hemodialysis patients receiving more intravenous iron sucrose

Elevated cardiac troponin T (cTnT) has been associated with shorter survival in hemodialysis patients. Moreover, intravenous (IV) iron treatment has been held responsible for oxidative stress and accelerated atherosclerosis in these patients. In the present study, we investigated the relationship between cTnT concentration, IV iron treatment, and parameters of iron status. In addition, parameters of oxidative stress, inflammation, and atherosclerosis were evaluated. Predialysis blood samples of 78 chronic hemodialysis patients were analyzed for cTnT, malondialdehyde, creatine kinase (CK), and CK-isoenzyme MB (CK-MB). In addition, the mean value of predialysis serum samples collected during the last year, were considered for homocysteine, ferritin, iron, iron binding capacity, blood cell counts, blood urea nitrogen, creatinine, albumin, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), calcium, phosphate, iPTH, cholesterol, and triglyceride. The quantity of IV iron sucrose administered during the last two years was counted from the patients' files. Echocardiography, all events related to ischemic heart disease, and urine volume were also recorded. Elevated cTnT levels (> or =0.10 ng/mL) were found in 18 patients (23.1%). The amount of iron administered was 2264+/-1871 mg with a range 0-7000 mg. Patients with elevated cTnT levels received more IV iron than those with normal cTnT (3692+/-1771 vs. 1761+/-1595 mg, p<0.001). The serum ferritin level was higher in patients with elevated cTnT (median levels; 477 vs. 288 ng/mL; P<0.05). Patients with elevated cTnT were longer on dialysis compared to those with normal levels (median times; 35.5 vs. 15 months, P<0.01) and regression analysis identified the amount of administered iron as an independent factor for elevated cTnT (P<0.01). Intravenous iron treatment and high ferritin concentration are related to high cTnT level, which has previously been incriminated as a survival marker in hemodialysis patients.

Results of exercise testing at a mean age of 10 years after neonatal arterial switch operation

AIM

This prospective follow-up study investigated long-term exercise capacity at a mean age of 10 y after neonatal arterial switch operation for transposition of the great arteries in a large group of homogeneous unselected children.

METHODS

56 asymptomatic children, aged 7.9-14.3 y (10.5 +/- 1.6, mean +/- SD), were examined with respect to exercise tolerance, electrocardiographic (ECG) response and activity of biochemical markers for myocardial injury. The protocol included standard electrocardiography, M-mode and two-dimensional echocardiography at rest, a Bruce walking treadmill test to voluntary exhaustion, and determination of cardiac troponin I and T, creatine kinase and myoglobin from venous blood samples at rest and 4 h after exercise. Heart rate, blood-pressure response to exercise stress and endurance time were compared with published results of age-matched normal children.

RESULTS

54 patients (96.4%) had normal exercise capacity; a reduction in 2 patients was not due to cardiac disease. Heart rate and systolic blood pressure rose significantly between rest and peak exercise and did not differ from normal controls, whereas diastolic blood pressure was lower. ECG remained normal at rest and on exercise in 54 children (96.4%). Serum values of cardiac troponin I and T, creatine kinase and myoglobin were normal at rest and after exercise in all patients.

CONCLUSION

The study demonstrates excellent long-term exercise capacity after neonatal arterial switch operation. Exercise testing is a useful and non-invasive screening method to detect patients with clinically relevant exercise-induced myocardial ischaemia and should be routinely performed in growing patients.

The diagnostic value of troponin T and myoglobin levels in acute myocardial infarction: a study in Turkish patients

This study compares the diagnostic value of troponin T (TnT) and myoglobin with creatinine kinase (CK) for myocardial infarction (MI) in a tertiary care centre in a developing nation. The study group comprised 33 acute myocardial infarction patients and 27 healthy controls. Receiver operating characteristic curves for TnT, myoglobin and CK were drawn and areas under the curve calculated. At admission, myoglobin levels had greater diagnostic sensitivity than TnT or CK levels. After 2 h, myoglobin and TnT had equal sensitivity and specificity, whereas CK still had lower sensitivity than myoglobin and TnT. After 4 h there was no difference between the tests. It was concluded that myoglobin levels on admission and TnT at 2 h had the greatest diagnostic rate, whereas all the tests were similar after 4 h for MI.

Cardiac troponin T and myocardial injury during routine cardiac catheterisation in children

BACKGROUND

This study aims to investigate whether intracardiac catheterization produces myocardial damage on pediatric heart.

METHODS

Five blood samples were collected (basal, immediate post procedure, at 4, 12 and 24 h after the procedure) for troponin T and creatine kinase MB (CKMB) from 48 consecutive patients (age: 5.34+/-6.03 years). The effect of age, duration of procedure, pulmonary hypertension, cyanosis, and medication taken for congestive heart failure on the levels of troponin T and CKMB were sought.

RESULTS

The increase in CKMB (basal CKMB: 3.93+/-3.70 ng/ml; peak CKMB: 8.68+/-10.89 ng/ml; P<0.0001) and troponin levels (basal troponin: 0.002+/-0.003 ng/ml; peak troponin: 0.11+/-0.23 ng/ml; P<0.0001) over time was significant in the study group. Additionally younger patients (</=1 year), patients with pulmonary hypertension (mean pulmonary artery pressure >25 mmHg), longer procedure time (>30 min), and patients taking anti-congestive heart failure therapy had significantly higher levels of CKMB and troponin (P>0.05).

CONCLUSION

All patients undergoing cardiac catheterization are under risk of myocardial injury, and younger patients with pulmonary hypertension and especially with compensated cardiac failure have increased risk of myocardial damage, and need to be handled carefully.

Significance of assessment of serum cardiac troponin I and interleukin-8 in scorpion envenomed children

In the present study, 41 children in Upper Egypt were admitted to Pediatric Intensive Care Unit, Assiut University Hospital, for scorpion envenomation. They were compared with 15 apparently healthy children of matching age as controls. The victims and controls were subjected to complete clinical examination, full blood count and arterial blood gases analysis. According to severity of scorpion envenomation, 17 children had manifestations of severe envenomation and clinical signs of toxic myocarditis (severe cases), 14 children had moderate manifestations of envenomation without clinical evidence of carditis (moderate cases) and 10 cases showing only mild symptoms of envenomation (mild cases). The serum levels of cardiac troponin I (cTnI) and interleukin-8 (IL-8) beside the enzymatic activities of creatine phosphokinase (CPK), CPK-isoenzyme-MB (CPK-MB) and lactate dehydrogenase (LDH) were determined once for mild cases and controls on admission and twice for severe and moderate cases on admission and after 24. Electrocardiography and measurements of echocardiographic (Echo) of % fractional shortening of left ventricule (% SF), left ventricular ejection fraction (LVEF) and cardiac chambers dilatation were done for severe and moderate cases. All the envenomed victims showed significantly higher mean values of CPK, CPK-MB, LDH, and IL-8 on admission in comparison to control group. cTnI was not detectable in the sera of control group as well as patients of mild envenomation. The mean values of CPK, CPK-MB, LDH, and IL-8 were significantly higher in severe cases while only IL-8 and CPK-MB were significantly higher in moderate cases in comparison with mild cases. The mean values of IL-8, cTnI, CPK, CPK-MB and LDH were significantly higher in severe cases both on admission and on follow-up comparing with moderate cases. The case fatality rate was 12.5% and all were from severe cases with toxic myocarditis. The non-survivors victims showed significant higher mean values of only cTnI on admission and both cTnI and IL-8 on follow up in comparison to the survivors. Significant reduction of % SF and LVEF were noticed among the non-survivors in comparison to survivors. The cTnI showed 100% specificity and sensitivity for diagnosis of myocardial injury in relation to Echo finding in the envenomed victims. In severe cases, cTnI was positively correlated with IL-8 while negatively correlated with %SF and LVEF. In conclusion, cTnI is a specific marker for diagnosis of myocardial injury in scorpion envenomation while other biochemical markers did not show such specificity. Also, IL-8 may be involved in the pathogenesis of myocardial injury of scorpion envenomation. Both cTnI and IL-8 may be useful to forecast the fatal outcome in scorpion envenomation.

Myocardial damage in falciparum malaria detectable by cardiac troponin T is rare

OBJECTIVES

To estimate the prevalence of myocardial damage in falciparum malaria by serum concentration of cardiac troponin T.

METHODS

Retrospective study of stored sera and patient files; assessment of acute myocardial damage by serum concentration or activity of cardiac troponin T, creatine kinase, creatine kinase MB and myoglobin and by routine electrocardiography.

RESULTS

A total of 161 patients with falciparum malaria were included in the study; troponin T was elevated in one case (0.6%), no CK-MB elevations were found, myoglobin was elevated in 10 of 161 patients (6.2%), all of whom were elderly and had concomitant elevated serum concentration levels of cystatin C; ECG abnormalities were seen in 23 patients.

CONCLUSION

Assessed by troponin T, myocardial damage in falciparum malaria is rare.

Creatine kinase-MB elevation after stroke is not cardiac in origin: comparison with troponin T levels

BACKGROUND AND PURPOSE

Creatine kinase-MB (CK-MB) increases in some patients with stroke, with no clear evidence of an acute coronary syndrome. Its elevations have been suggested to represent a biological marker for stroke-related myocardial injury. Troponin T has superior sensitivity and specificity to CK-MB in revealing minor myocardial injury. Therefore, we studied troponin T levels after stroke to determine whether troponin T increases in parallel to CK-MB.

METHODS

We made daily measurements of CK-MB, myoglobin, total creatine kinase (total CK), and troponin T levels up to day 5 in 32 patients with large hemispheric infarction and with no history of coronary heart disease. The daily enzyme levels were compared with those of a control group of 22 patients with neurological diseases other than stroke.

RESULTS

Serum CK-MB, myoglobin, and total CK levels were elevated above the cutoff value in 11, 26, and 20 patients with stroke, respectively. These enzyme levels gradually increased within the first 3 days and declined afterward. Troponin T did not exceed the reference range in any patients. One patient had elevated myoglobin and 3 had elevated total CK in the control group. The difference between groups was significant for CK-MB, myoglobin, and total CK at various time points.

CONCLUSIONS

Troponin T, a more specific biochemical marker of myocardial injury, does not increase after stroke. Normal troponin T along with elevated CK-MB signifies that CK-MB is not the biological marker for myocytolysis. CK-MB elevations in stroke patients are likely to be noncardiac in origin.

Heart-type fatty acid binding protein (hFABP) in the diagnosis of myocardial damage in coronary artery bypass grafting

OBJECTIVES

Heart-type fatty acid binding protein (hFABP) is an intracellular molecule engaged in the transport of fatty acids through myocardial cytoplasm and has been used as a rapid marker of myocardial infarction. However, its value in the evaluation of perioperative myocardial injury has not yet been assessed.

METHODS

32 consecutive patients undergoing coronary artery bypass grafting were included in a prospective, randomized study using standardized operative procedures and myocardial protection. Three patients with perioperative myocardial infarction were added. Serial blood samples were taken preoperatively, before ischemia, 5 and 60 min after declamping, 1 and 6 h postoperatively and on postoperative days 1, 2 and 10 and were tested for hFABP, creatine kinase isoenzyme MB (CKMB) and troponin I (TnI).

RESULTS

Hospital mortality was zero. The kinetics of the biochemical parameters revealed a typical pattern for each marker. In routine patients, hFABP levels peaked as early as 1 h after declamping, whereas CKMB and TnI peaked only 1 h after arrival in the intensive care unit. Patients with perioperative infarction displayed peak levels some hours later in all marker proteins. Peak serum levels of hFABP correlated significantly with peak levels of CKMB (r=0.436, P=0.011) and TnI (r=0.548, P=0.001), indicating the degree of myocardial damage.

CONCLUSIONS

hFABP is a rapid marker of perioperative myocardial damage and peaks earlier than CKMB or TnI. The kinetics of marker proteins in serial samples immediately after reperfusion is more suitable for the detection of perioperative myocardial infarction than a fixed cut-off level.

Cardiac troponin I predicts myocardial dysfunction in aneurysmal subarachnoid hemorrhage

OBJECTIVES

We studied the incidence of myocardial injury in aneurysmal subarachnoid hemorrhage (SAH) using the more sensitive cardiac troponin I (cTnI) assay, correlated changes in cTnI with creatine kinase, MB fraction (CK-MB), myoglobin, and catecholamine metabolite assays, and examined the predictive value of changes in cTnI for myocardial dysfunction.

BACKGROUND

Myocardial injury in aneurysmal SAH as evidenced by elevated CK-MB fraction has been reported. Little published data exist on the value of cTnI measurements in aneurysmal SAH.

METHODS

Thirty-nine patients were studied for seven days. Clinical cardiovascular assessment, electrocardiographic (ECG), echocardiography, cTnI, CK, CK-MB and CK-MB index, myoglobin and 24-h urinary catecholamine assays were performed in all patients. The ECG abnormalities were defined by the presence of ST-T changes, prolonged QT intervals, and arrhythmias. An abnormal echocardiogram was defined by the presence of wall-motion abnormalities and a reduced ejection fraction. The severity of SAH was graded clinically and radiologically.

RESULTS

Eight patients demonstrated elevations in cTnI (upper limit of normal is 0.1 microg/liter with the immunoenzymatic assay and 0.4 microg/liter with the sandwich immunoassay), while five had abnormal CK-MB levels (upper limit of normal is 8 microg/liter). Patients with more severe grades of SAH were more likely to develop a cTnI leak (p < 0.05). Patients with cTnI elevations were more likely to demonstrate ECG abnormalities (p < 0.01) and manifest clinical myocardial dysfunction (p < 0.01) as evidenced by the presence of a gallop rhythm on auscultation and clinical or radiological evidence of pulmonary edema as compared to those with CK-MB elevations. The sensitivity and specificity of cTnI to predict myocardial dysfunction were 100% and 91%, respectively, whereas the corresponding figures for CK-MB were 60% and 94%, respectively. Elevations in myoglobin levels (upper limit of normal <70 microg/liter) and urinary catecholamine metabolites (urinary vanilmandelate/creatinine ratio upper limit of normal, 2.6) are a nonspecific finding.

CONCLUSIONS

Measurements of cTnI reveal a higher incidence of myocardial injury than predicted by CK-MB in aneurysmal SAH, and elevations of cTnI are associated with a higher incidence of myocardial dysfunction. Thus, cTnI is a highly sensitive and specific indicator of myocardial dysfunction in aneurysmal SAH.