[Cardiac diagnostic techniques in dialysis patients]

The field of cardiovascular disease in patients with dialysis has seen a tremendous increase in the number and diversity of diagnostic techniques available. Therefore, the newer methods have added new types of information to our diagnostic area. The plain chest roentgenogram and electrocardiogram are still simple and important tests. The other noninvasive procedures such as echocardiography, radionuclide techniques, CT and MRI supply important additional information concerning cardiac anatomy and function, but invasive cardiac catheterization remains the only method for accurately measuring intracardiac pressures and cineangiography is still necessary for defining the anatomy of the coronary arteries. Recently, the determination of natriuretic peptides (ANP,BNP), noradrenaline and troponin is added to evaluate cardiac function. The purpose of this paper discusses the use of these techniques in patients with dialysis.

Cardiac Troponin T in Obstructive Sleep Apnea

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is associated with nocturnal angina and ST-segment depression, which are relieved by treatment with continuous positive airway pressure (CPAP). We tested the hypothesis that severe nocturnal hypoxia in patients with OSA causes myocyte necrosis as evidenced by increases in cardiac troponin T.

DESIGN

Prospective cohort study.

SETTING

Cardiovascular physiology and sleep research laboratory.

PARTICIPANTS

Fifteen male volunteers with coronary artery disease (CAD) and moderate or severe OSA (apnea-hypopnea index [AHI] > 15).

MEASUREMENTS AND RESULTS

Polysomnography and measurement of serum cardiac troponin T before sleep, after 4 h of untreated OSA, and in the morning after 4 h of treatment with CPAP. The mean AHI for the group was 41 (SD 16), and the mean oxygen saturation nadir during sleep was 83% (SD 8%). All measurements of cardiac troponin T were < 0.010 ng/mL.

CONCLUSIONS

Despite the fact that some patients with OSA may experience nocturnal ischemia, this study shows that patients with severe OSA and coexisting CAD do not have nightly episodes of myocardial injury detectable by the current-generation cardiac troponin T assay.

Troponins in children and neonates

Cardiac troponin T and cardiac troponin I--the biochemical markers of myocardial injury--are characterized by high specificity and sensitivity in comparison with other markers used in the past.

CONCLUSION

Troponins have been studied in a wide range of clinical settings. Some of them are unique to paediatric care, but many questions, mainly concerning laboratory limitations and data interpretation in paediatrics, are still open to debate.

[Cardiac troponin I and T: specific biomarkers of cardiomyocyte]

PURPOSE

Cardiac troponin I and troponin T have replaced creatine kinase MB (CK-MB) for the diagnosis of cardiomyocyte necrosis. Cardiac specificity of these new markers leads to a change in our practice.

CURRENT KNOWLEDGE AND KEY POINTS

Following necrosis, intracellular proteins are released into blood. This easy concept overlaps a biological complexity since troponins are released as complexes leading to various cut-off values depending on the assay used, as least for cardiac troponin I. The increase in both specificity and analytical sensitivity of these markers reached to propose a new definition of myocardial infarction. The diagnosis of acute coronary syndrome is a clinical based diagnosis, the use of troponin contributing to their classification. Finally, pathological processes leading to cardiac injury may induce an increase in the cardiac troponin level.

FUTURE PROSPECTS AND PROJECTS

Troponin standardization is a challenge for the near future leading to better follow-up of patients and comparison between cohorts.

Postmortem proteolysis is reduced in transgenic mice overexpressing calpastatin1,2

Using both in vitro and in vivo approaches, numerous studies have provided evidence that mu-calpain is responsible for postmortem proteolysis. This paper reports the effect of overexpression of calpastatin on postmortem proteolysis in transgenic mice. Transgenic mice (n = 8) with a human calpastatin gene, whose expression was driven by the human skeletal muscle actin promoter, were killed along with control nontransgenic littermates (n = 5). Hind limbs were removed and stored at 4 degrees C, and muscle samples were dissected at 0, 1, 3, and 7 d postmortem and analyzed individually. At time 0, active human calpastatin was expressed in transgenic murine skeletal muscle at a level 370-fold greater (P < 0.001) than calpastatin in control mice. Although the native isoform of this protein was degraded with storage, at 7 d postmortem, approximately 78% of at-death activity remained, indicating that degraded calpastatin retains activity. Calpain (mu- and m-) expression was unaffected (P > 0.05) by the transgene as assessed by immunoreactivity at d 0. Over 7 d, 33% of at-death 80-kDa isoform immunoreactivity of mu-calpain was lost in transgenics compared to an 87% loss in controls, indicating that autolysis of mu-calpain was slowed in transgenic mice. Desmin degradation was also inhibited (P < 0.05) in transgenics when compared to controls. Control mice lost 6, 78, and 91% of at-death native desmin at 1, 3, and 7 d postmortem, respectively; conversely, transgenic mice lost only 1, 3, and 17% at the same times. A similar trend was observed when examining the degradation of troponin-T. Interestingly, m-calpain seemed to undergo autolysis in control mice, which in postmortem tissue is indicative of proteolysis. Further investigation revealed that both mu- and m-calpain are active postmortem in normal murine skeletal muscle. In conclusion, a high level of expression of active calpastatin was achieved, which, by virtue of its inhibitory specificity, was determined to be directly responsible for a decrease in postmortem proteolysis.

"Affinity-proteomics": direct protein identification from biological material using mass spectrometric epitope mapping

We describe here a new approach for the identification of affinity-bound proteins by proteolytic generation and mass spectrometric analysis of their antibody bound epitope peptides (epitope excision). The cardiac muscle protein troponin T was chosen as a protein antigen because of its diagnostic importance in myocardial infarct, and its previously characterised epitope structure. Two monoclonal antibodies (IgG1-1B10 and IgG1-11.7) raised against intact human troponin T were found to be completely cross reactive with bovine heart troponin T. A combination of immuno-affinity isolation, partial proteolytic degradation (epitope excision), mass spectrometric peptide mapping, and database analysis was used for the direct identification of Tn T from bovine heart cell lysate. Selective binding of the protein was achieved by addition of bovine heart cell lysate to the Sepharose-immobilised monoclonal antibodies, followed by removal of supernatant material containing unbound protein. While still bound to the affinity matrix the protein was partially degraded thereby generating a set of affinity-bound, overlapping peptide fragments comprising the epitope. Following dissociation from the antibody the epitope peptides were analysed by matrix assisted laser desorption-ionisation (MALDI) and electrospray-ionisation (ESI) mass spectrometry. The peptide masses identified by mass spectrometry were used to perform an automated database search, combined with a search for a common "epitope motif". This procedure resulted in the unequivocal identification of the protein from biological material with only a minimum number of peptide masses, and requiring only limited mass-determination accuracy. The dramatic increase of selectivity for identification of the protein by combining the antigen-antibody specificity with the redundancy of peptide sequences renders this "affinity-proteomics" approach a powerful tool for mass spectrometric identification of proteins from biological material.

Pericardial fluid level of heart-type cytoplasmic fatty acid-binding protein (H-FABP) is an indicator of severe myocardial ischemia

BACKGROUND

Heart-type cytoplasmic fatty acid-binding protein (H-FABP) has been reported as a sensitive and specific marker for the early diagnosis of acute myocardial infarction. Our hypothesis was that serum or pericardial fluid levels of H-FABP can reflect not only myocardial infarction but also myocardial ischemia.

METHODS

A total of 34 patients with unstable angina, who had anginal symptoms and/or ST-changes in ECG monitoring within 24 h before operation, were classified into group A (n=17), and those without these symptoms and changes into group B (n=17). Blood and pericardial fluid samples were obtained immediately after median sternotomy, and serum and pericardial fluid levels of creatine kinase-MB, cardiac troponin-T, and H-FABP were measured.

RESULTS

Serum H-FABP levels were slightly elevated compared with their normal values in both groups. While they showed no difference between groups A and B (group A vs. B: 8.5+/-1.0 vs. 7.1+/-0.7 ng/ml, P=0.25), pericardial fluid levels of H-FABP were significantly higher in group A than in group B (16.3+/-2.0 vs. 9.6+/-1.0 ng/ml, P=0.0046). H-FABP showed a weak correlation between its serum levels and pericardial fluid levels (r=0.40).

CONCLUSIONS

Pericardial fluid levels of H-FABP reflect myocardial ischemia occurring within 24 h of their measurements. H-FABP may be secreted into the interstitial space by increased permeability of the myocardial cell membrane associated with severe myocardial ischemia. Thus, pericardial fluid reflects pathophysiological conditions of cardiomyocytes more sensitively than circulating blood.

Troponin T as a marker of differentiation revealed by proteomic analysis in renal arterioles

Renovascular hypertension is characterized by stenosis of the renal artery and high plasma renin levels. The renal phenotype is characterized by high levels of renin in the hypoperfused kidney due to the recruitment of renin-producing cells along the afferent arterioles. This increase in myoepithelioïd cells is due mainly to the differentiation of existing smooth muscle cells with acquisition of a secretory phenotype. To understand the molecular mechanisms involved in this recruitment, we used the established rat model of renovascular hypertension known as the two-kidney, one-clip model in the Lewis rat. Renal arterioles were isolated using magnetized iron suspension. Differential proteomic analysis was performed using 2-D polyacrylamide gel electrophoresis followed by mass spectrometry. Comparative analysis of soluble proteins extracted from afferent arterioles of clipped and contralateral kidneys showed 14 proteins significantly differentially expressed by at least a factor of 2. These proteins were identified by mass spectrometry. The most striking protein revealed by proteomics is troponin T, which is down-regulated in the afferent arterioles of the clipped kidney. Confocal microscopy showed that troponin T is specific of the smooth muscle phenotype and absent in the myoepithelioïd phenotype. Our data suggest that troponin T is only present in renal smooth muscle cells.

Comparison of cardiac troponin T and I in healthy men and in aortic valve replacement

Troponins are of outstanding importance for the diagnosis of myocardial infarction. Cardiac troponin T (cTnT) and the various cardiac troponin I (cTnI) assays differ with respect to method comparison, diagnostic sensitivity and diagnostic specificity. To understand the differences in the diagnostic behavior of troponin assays, AccuTnI and Elecsys Troponin STAT were used in a group of healthy men and in the follow-up of patients with aortic valve replacement (AVR). Within the healthy subjects AccuTnI was able to differentiate two subgroups from each other, whereas the cTnT concentrations of all subjects were below the detection limit. In AVR patients, cTnT and cTnI correlated sufficiently, if the postoperative periods were taken into consideration. There was a rapid increase in cTnI within 24 h. In contrast, a broad peak was evident for cTnT between 48 and 120 h. The results emphasize more the differences in the release of cTnI and cTnT from the cytoplasm and the thin filaments of the cardiomyocytes than the modifications of the troponins circulating in the blood.

[Levels of troponin I, tropoinin T, isoenzyme MB creatine kinase and myoglobins in blood serum for perioperative diagnosis of myocardial infarction in patients after coronary artery bypass graft surgery with extracorporeal circulation]

We studied plasma levels of troponin I (cTnI), troponin T (cTnT), creatine kinase MB (CKMBmass) and myoglobin (MB) in patients undergoing coronary artery bypass surgery with extracorporeal circulation and cardioplegia. In group 1 (25 patients without perioperative myocardial infarction) plasma levels of all markers studied were elevated after operation. In group 2 (24 patients with perioperative myocardial infarction) plasma concentrations of all markers exceeded several times levels observed in patients without myocardial infarction with maximal value for MB at 12 hours after operation; for cTnI and CKMBmass at 16 hours after surgery and for cTnT at 32 hours after the end of operation. ROC curves show cut-off value for CKMBmass 20.3 ng/ml (sensitivity 79% and specificity 89%); for cTnI cut-off value was 0.8 ng/ml (sensitivity 80% and specificity 94%) for cTnT the cut-off value was 0.41 ng/ml (sensitivity 86% and specificity 88%) and for MB the cut-off value was 419 ng/ml (sensitivity 85% and specificity 70%).

CONCLUSION

All markers studied are reliable biochemical tests for perioperative myocardial infarction, however, the analysis of ROC curves suggested that cTnI and cTnT might be more useful for diagnosis of perioperative myocardial infarction after conventional coronary artery bypass surgery.

Inhibition of δ-Protein Kinase C Protects Against Reperfusion Injury of the Ischemic Heart In Vivo

Background— Current treatment for acute myocardial infarction (AMI) focuses on reestablishing blood flow (reperfusion). Paradoxically, reperfusion itself may cause additional injury to the heart. We previously found that δ-protein kinase C (δPKC) inhibition during simulated ischemia/reperfusion in isolated rat hearts is cardioprotective. We focus here on the role for δPKC during reperfusion only, using an in vivo porcine model of AMI.

Methods and Results— An intracoronary application of a selective δPKC inhibitor to the heart at the time of reperfusion reduced infarct size, improved cardiac function, inhibited troponin T release, and reduced apoptosis. Using 31 P NMR in isolated perfused mouse hearts, we found a faster recovery of ATP levels in hearts treated with the δPKC inhibitor during reperfusion only.

Conclusions— Reperfusion injury after cardiac ischemia is mediated, at least in part, by δPKC activation. This study suggests that including a δPKC inhibitor at reperfusion may improve the outcome for patients with AMI.

Effects of ischemic preconditioning on myocardial protective on cardiac surgery: possibility of ischemic preconditioning and adenosine administration

SUBJECT

We evaluated the efficacy for concomitant use of ischemic preconditioning (IPC) and cardioplegic arrest with adenosine premedication on myocardial protection.

METHODS

Twenty-one pigs were divided into three groups: 1) control group, 2) IPC group which had IPC, 3) IPC+adenosine triphosphate (ATP) group which had an administration of 140 gamma of ATP (Adetphos, Kowa, Tokyo, Japan) during IPC. IPC was employed by 3 minutes of aortic cross clamping and 5 minutes of reperfusion. After cardioplegic arrest, the hemodynamical state was observed during 60 minutes of reperfusion. Serum adenosine, troponin-T, E-max, and Tau (the time constant of early diastolic left ventricular pressure decay) were compared.

RESULTS

Serum adenosine levels and at the end of IPC and 60 minutes reperfusion were significantly higher in the IPC and IPC+ATP groups than the control group. Comparison of the myocardial contractile force indicator E-max showed that the IPC and IPC+ATP groups showed significantly higher recovery rates of myocardial contractile force than the control group. Tau was the lowest in the IPC+ATP group than the other groups. In the histopathological study, the control group showed widely distributed hypercontraction bands and waving degeneration of myofibrils. On the other hand, the structure of myofibrils was well preserved in the IPC and IPC+ATP groups.

CONCLUSIONS

The concomitant use of IPC enhanced the effect of a myocardial protective solution. However, the administration of adenosine during IPC did not show any further advantage than IPC along. (Ann Thorac Cardiovasc Surg 2003; 9: 307-13)

Expression of nitric oxide synthase immunoreactivity in the human female intramural striated urethral sphincter

PURPOSE

While we have recently detected neuronal nitric oxide synthase (nNOS) immunoreactivity in a heterogeneous population of human male urethral striated muscle, to our knowledge the association of nNOS in the female counterpart is unknown. We investigated the association of nNOS with female urethral striated muscle and re-investigated muscle fiber types.

MATERIALS AND METHODS

Cryostat sections were taken from the middle third of 4 human female urethras. Nicotinamide adenine dinucleotide phosphate diaphorase histochemistry and nNOS immunohistochemistry were performed. Muscle fiber types were identified by myofibrillar adenosine triphosphatase histochemistry and fast twitch troponin T immunohistochemistry. The association between nNOS immunoreactivity and muscle fiber type was analyzed.

RESULTS

Positive staining for nicotinamide adenine dinucleotide phosphate diaphorase histochemistry and nNOS immunoreactivity were recognized in the sarcolemma of 43.9% of female urethral striated muscle fibers. Immunoreactivity for fast twitch troponin T immunohistochemistry was demonstrated by 2% of the striated fibers. The use of myofibrillar adenosine triphosphatase showed that all fibers darkly stained uniformly at a pH of 9.6, 4.6 and 4.3, suggesting that they were myofibrillar intermediate muscle fibers. The results allowed the differentiation of 2 subgroups of fibers, namely smaller fibers (modal diameter 10.1 to 15.0 microm.) without nNOS immunoreactivity and larger fibers (modal diameter 15.1 to 20.0 microm.) with nNOS immunoreactivity.

CONCLUSIONS

To our knowledge female urethral striated muscle has for the first time been found to consist of myofibrillar intermediate fibers and nNOS was positively localized in the sarcolemma of a subgroup of the fibers. This study provides a basis for further investigation into female urethral striated sphincter function and changes in pathological conditions.

Importance of preanalytical handling of samples for measurement of cardiac troponin T in coronary effluent from isolated rat hearts

The isolated, buffer-perfused heart is probably the most widely used model in experimental heart research, and the coronary effluent is often analysed for markers of myocardial injury. Adsorption to surrounding materials may be a serious problem of protein measurements in solutions with low protein concentrations. The aims of the present study were to investigate the importance of the preanalytical phase when measuring cardiac troponin T (cTnT) in a buffer perfusate and to investigate whether addition of albumin to the effluent might increase recovery of cTnT and improve the assay. Coronary effluent was collected in tubes of different materials and in tubes with 40 g/L bovine albumin, and then frozen. cTnT was analysed at different time points after withdrawal from the freezer. cTnT was 2.3-119 times higher in effluent with albumin. In effluent without albumin, cTnT concentration declined to 2% of the initial concentration after two episodes of freezing and thawing. The cTnT loss could not be prevented by using polystyrene or siliconized glass, but was partially inhibited in effluent with albumin. Furthermore, creatine kinase and lactate dehydrogenase levels were higher in effluent with albumin. The within-series coefficient of variation for cTnT was markedly improved when using effluent with albumin.

P19 embryonal carcinoma cells: a suitable model system for cardiac electrophysiological differentiation at the molecular and functional level

OBJECTIVE

Murine P19 embryonal carcinoma (EC) cells can differentiate into spontaneously beating cardiomyocytes in vitro and have revealed important insight into the early molecular processes of cardiomyocyte differentiation. We assessed the suitability of the P19 cell model for studying cardiac ion channel regulation at the molecular and functional level.

METHODS

P19 cells were induced to differentiate towards cardiomyocytes. mRNAs for cardiac markers and ion channels were determined by RT-PCR at six timepoints during the differentiation process. Action potentials and individual ion currents were measured by whole cell patch clamp.

RESULTS

Ion channel mRNA expression of several channels is temporally regulated during differentiation, while others show little or no regulation. L-type calcium and transient outward channels are expressed from very early on, while sodium and delayed and inward rectifier channels are upregulated at somewhat later stages during differentiation, which mirrors the in vivo murine cardiomyocyte differentiation during embryogenesis. Spontaneous cardiomyocyte action potentials exhibit a low upstroke velocity, which often can be enhanced by hyperpolarizing the cells, hence activating thusfar dormant ion channels to contribute to the action potential upstroke. Action potential duration decreases considerably during the differentiation of spontaneously beating cells. In late stages, non-beating myocytes can be found which only generate action potentials upon electrical stimulation. Their shape is comparable to neonatal/juvenile ventricular mouse myocytes in culture. Finally, we show that P19-derived cardiomyocytes display a very complete set of functional ion channels.

CONCLUSION

P19 cells represent a powerful model to study the regulation of myocardial electrophysiological differentiation at the molecular and functional level.

Protein carbonyl groups as biomarkers of oxidative stress

Oxidative stress, an imbalance toward the pro-oxidant side of the pro-oxidant/antioxidant homeostasis, occurs in several human diseases. Among these diseases are those in which high levels of protein carbonyl (CO) groups have been observed, including Alzheimer's disease (AD), rheumatoid arthritis, diabetes, sepsis, chronic renal failure, and respiratory distress syndrome. What relationships might be among high level of protein CO groups, oxidative stress, and diseases remain uncertain.The usage of protein CO groups as biomarkers of oxidative stress has some advantages in comparison with the measurement of other oxidation products because of the relative early formation and the relative stability of carbonylated proteins. Most of the assays for detection of protein CO groups involve derivatisation of the carbonyl group with 2,4-dinitrophenylhydrazine (DNPH), which leads to formation of a stable dinitrophenyl (DNP) hydrazone product. This then can be detected by various means, such as spectrophotometric assay, enzyme-linked immunosorbent assay (ELISA), and one-dimensional or two-dimensional electrophoresis followed by Western blot immunoassay. At present, the measurement of protein CO groups after their derivatisation with DNPH is the most widely utilized measure of protein oxidation.

Laboratory tests in the diagnosis of pulmonary embolism

The diagnosis of pulmonary embolism (PE) requires objective testing. However, all imaging techniques have their own limitations and costs and cannot be performed in every patient with suspected PE. After decades of unfruitful research, several laboratory tests have been evaluated for suspected PE, the most promising being the D-dimer test. As a general rule, the specificity of D-dimers is too low to confirm PE. Conversely, several (but not all) D-dimer assays have a high sensitivity for diagnosing PE. Outcome studies indicate that the Vidas D-dimer and SimpliRED D-dimer can be used safely to withdraw anticoagulation when the pretest probability of PE is low (SimpliRED) or when it is low or moderate (Vidas). These results may however not apply to other D-dimer assays and clinicians should know the characteristics of the test used in their hospital. Blood gas analysis does not have sufficient sensitivity and specificity to confirm or exclude PE, but it may be used to evaluate the clinical probability of PE before other testing is done. The diagnostic value of the alveolar dead space fraction in patients with suspected PE is currently investigated. Initial data suggest that it needs to be combined with a D-dimer test to safely exclude PE. Brain natriuretic peptide and cardiac troponin have limited usefulness for diagnosing PE, but both tests may identify patients with a poor prognosis, in whom more aggressive treatment may be warranted.

Myocardial tissue troponins T and I. An immunohistochemical study in experimental models of myocardial ischemia

BACKGROUND

Cardiac troponins T (cTnT) and I (cTnI) are proven diagnostic and risk stratification biomarkers in patients with acute coronary syndromes. To date, no immunohistochemical studies have been performed which allow visualization of the time course and pattern of myocardial troponin egress from the myocardium during the early evolution of ischemic injury in experimental systems.

METHODS

We studied archival formalin-fixed, paraffin-embedded myocardium from 50 experimental animals (dogs, pigs and rats) that had undergone permanent coronary occlusion (n = 34) for 0.5-6 h or occlusion of 0.75-6 h followed by reperfusion (n = 16). Histologic sections that included ischemic and nonischemic myocardium were studied by immunohistochemistry with three different antibodies to human cTnI and one to cTnT, using a standard avidin-biotin-peroxidase system.

RESULTS

All antibodies detected cTnT or cTnI in normal myocardium and its loss from necrotic myocardium, in some cases as early as 30 min after coronary occlusion, before histologic evidence of necrosis was present. Loss was nonuniform, being greater at the periphery of the infarcts then at their central regions. Usually, loss of cTnT appeared greater than loss of cTnI. With reperfusion, findings were similar to those after permanent occlusion, except that there was a greater contrast between loss at the periphery compared to the loss in the central region. Considerable residual staining persisted for hours after occlusion, indicating delayed release over time, concordant with sustained serum elevations in patients with acute myocardial infarction. No loss of staining was observed in nonnecrotic myocardium.

CONCLUSIONS

Immunohistochemical staining using antibodies to human cTnT and cTnI can be used to visualize cardiac troponins and document their loss in histologic sections of myocardium in different animal species. Loss of cTnT and cTnI occurs very early following ischemic injury and may precede histologic evidence of necrosis, but does not occur in myocardium that is not necrotic. Immunohistochemical staining of hearts for cTnT and cTnI can assist in the often difficult recognition of myocardial necrosis at autopsy, in patients suspected of dying from acute myocardial ischemia.

Does the discharge ECG provide additional prognostic insight(s) in non-ST elevation ACS patients from that acquired on admission?

BACKGROUND

Although the prognostic value of admission ST changes in patients with non-ST elevation acute coronary syndrome (ACS) is established, the utility of the discharge ECG is unknown. Accordingly, using the PARAGON-B Troponin substudy, we assessed the prevalence of ST depression on both admission and discharge ECG, the likelihood of developing new Q-waves at discharge and the additional prognostic value of these changes.

METHODS AND RESULTS

Nine hundred and eighteen patients were studied; 542 patients (59%) had admission ST downward arrow > or =1mm and 376 patients (41%) did not and their 6-month mortality was 4.4 vs 0.8%, P=0.002, respectively. Of patients with ST downward arrow on admission, 320 (59%) normalized their ST segment at discharge. Of patients without ST downward arrow on admission, 35 (9.3%) developed new ST downward arrow at discharge. Patients with persistent ST downward arrow on discharge had a higher 6-month mortality (6.0 vs 0.9%), (re)MI (16.3 vs 7.4%), and death/(re)MI (20.0 vs 8.3%) than those who never had ST downward arrow (all P< or =0.002). Two hundred and fifty-six patients had Q-waves on admission whereas by discharge 320 had Q-waves. Patients with Q-waves on discharge vs those without had a higher mortality (4.8 vs 1.9%), (re)MI (13.8 vs 8.3%), and death/(re)MI (16.4 vs 9.6%) at 6 months (all P< or =0.021).

CONCLUSIONS

This study highlights that the dynamic ECG changes which occur between admission and discharge in non-ST elevation ACS patients allows further risk stratification in determining the likelihood of 6-month death and/or re(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.