Reversible Myocardial Ischemia Research Articles

Coronary Artery Embolization After Successful Surgical Ablation of Atrial Fibrillation

A 63-year-old woman was urgently transferred to our institution from a regional hospital with no facilities for cardiac catheterization after she presented with sudden-onset nausea and left arm pain associated with transient inferior ST-segment elevation and lateral ST-segment depression on ECG. Seven weeks earlier, she had undergone elective 3-vessel coronary artery bypass grafting when an abnormal dipyridamole 99mTc-sestamibi scan demonstrated reversible myocardial ischemia but normal left ventricular function. Surgical cryoablation (box lesion isolation of the pulmonary veins, with targeted ablation of the left atrium and left atrial appendage) was also successfully performed to treat persistent atrial fibrillation (AF). Postoperatively, she underwent anticoagulation therapy with warfarin; enoxaparin was also administered until her international normalized ratio was ≥2.0. Continuous telemetry confirmed that normal sinus rhythm was maintained during her entire postoperative stay. She continued taking warfarin on discharge, and her international normalized ratio was monitored regularly. Her comorbidities included type 2 diabetes mellitus, …

Single Resting hsTnT Level Predicts Abnormal Myocardial Stress Test in Acute Chest Pain Patients With Normal Initial Standard Troponin

The goal of this study was to determine the ability of a single, resting high-sensitivity troponin T (hsTnT) measurement to predict abnormal myocardial perfusion imaging (MPI) in patients presenting with acute chest pain to the emergency department (ED). HsTnT assays precisely detect very low levels of troponin T, which may be a surrogate for the presence and extent of myocardial ischemia. We included all patients from the ROMICAT I (Rule Out Myocardial Infarction Using Computer Assisted Tomography) trial, an observational cohort study, who underwent both single-photon emission computed tomography (SPECT)-MPI stress testing and 64-slice computed tomography angiography (CTA) and in whom hsTnT measurements were available. We assessed the discriminatory value of hsTnT for abnormal SPECT-MPI and the association of reversible myocardial ischemia by SPECT-MPI and the extent of coronary atherosclerosis by CTA to hsTnT levels. Of the 138 patients (mean age 54 ± 11 years, 46% male), 19 (13.7%) had abnormal SPECT-MPI. Median hsTnT levels were significantly different between patients with normal and abnormal SPECT-MPI (9.41 pg/ml [interquartile range (IQR): 5.73 to 19.20 pg/ml] vs. 4.89 pg/ml [IQR: 2.34 to 7.68 pg/ml], p = 0.001). Sensitivity of 80% and 90% to detect abnormal SPECT-MPI was reached at hsTnT levels as low as 5.73 and 4.26 pg/ml, respectively. Corresponding specificity was 62% and 46%, and negative predictive value was 96% and 96%, respectively. HsTnT levels had good discriminatory ability for prediction of abnormal SPECT-MPI (area under the curve: 0.739, 95% confidence interval: 0.609 to 0.868). Both reversible myocardial ischemia and the extent of coronary atherosclerosis (combined model r(2) = 0.19 with partial of r(2) = 0.12 and r(2) = 0.05, respectively) independently and incrementally predicted the measured hsTnT levels. In patients with acute chest pain, myocardial perfusion abnormalities and coronary artery disease are predicted by resting hsTnT levels. Prospective evaluations are warranted to confirm whether resting hsTnT could serve as a powerful triage tool in chest pain patients in the ED before diagnostic testing and improve the effectiveness of patient management.

Intermediate-Term Prognostic Value of Reversible Perfusion Deficit Diagnosed by Adenosine CMR: A Prospective Follow-Up Study in a Consecutive Patient Population

The aim of this study was to assess the hypothesis that cardiac magnetic resonance (CMR) myocardial perfusion imaging can provide incremental prognostic value over other risk factors regarding the prediction of major cardiovascular events in a large, consecutive, and thereby unselected population of patients presenting with stable angina pectoris. Recently, it has been shown that CMR provides good short-term prognosis in patients with stable coronary heart disease. Reversible myocardial ischemia can be assessed using a combination of perfusion and late gadolinium enhancement imaging. Data concerning intermediate-term prognostic information, especially on major clinical endpoints such as cardiac death or myocardial infarction, are limited. From 2003 to 2007, consecutive patients with stable angina pectoris who underwent adenosine perfusion CMR were enrolled unless they met the predefined exclusion criteria. Myocardial perfusion imaging by adenosine stress and late gadolinium enhancement was assessed using a 1.5-T whole-body CMR scanner. Follow-up information concerning the combined endpoint of cardiac death, nonfatal myocardial infarction, and stroke was obtained from patients, general practitioners, or treating hospitals, respectively. In our study, 1,229 consecutive patients were enrolled. The mean follow-up period was 4.2 ± 2.1 years. During this time, 88 primary endpoints occurred. In patients with reversible perfusion deficits, significantly more cardiac deaths (p < 0.0001) and nonfatal myocardial infarctions (p = 0.001) were observed than in the control group. On multivariate analysis, reversible perfusion deficit was the strongest independent predictor for an event, with a 3-fold increased risk. Moreover, the absence of a perfusion deficit was shown to exhibit high negative predictive value. Adenosine perfusion CMR provides excellent risk stratification and intermediate-term prognostic value in patients with stable coronary artery disease. The presence of a myocardial perfusion deficit is an incremental prognostic risk factor over other risk factors.

Evaluation of myocardial infarction patients after coronary revasculation by dual-phase multi-detector computed tomography: Now and in future

Multidetector-row computed tomography (MDCT) has become one of the major tools in diagnosing and evaluating patients with coronary artery disease in recent years. In selected patients, MDCT has been shown to provide more reliable accuracy in detection of stent patency than invasive coronary angiography. Chiou et al reported a delicate infarcted myocardium at-risk score. According to their results, the MDCT-based myocardium at-risk score had a good correlation with the thallium 201 ST-segment elevation myocardial infarction-based summed difference score (r = 0.841, P < 0.001). They claimed that dual-phase MDCT is useful in detecting different patterns of obstructive lesions and the extent of myocardium at risk. In this commentary, we discuss the current status of the clinical application of MDCT in patients with myocardial infarction in relation to evaluating the myocardial perfusion defect, detecting reversible myocardial ischemia, assessing myocardial viability, estimating target lesion restenosis, and calculating of fractional flow reserve from MDCT.

Chronic cardiac chest pain

Complaints of chest discomfort and pain is one of the most common causes of patients seeking help in primary care with 20 –40% of the general population affected by chest pain during their lifetime. The incidence of unspecific chest pain ranges from 10 in the 20 –29 yr old to 30 per 1000 person-years in the 70– 79 yr old, 1 and in any given year, one-fifth of the population will experience chest pain. Although the majority of cases are benign and short lived, with only a minority of patients consulting their doctor, acute new or new-onchronic chest pain still accounts for an estimated 700 000 annual emergency department attendances and a quarter of medical emergency admissions in England and Wales. 2 With 8% of men and 3% of women aged between 55 and 64 and 14% of men and 8% of women aged between 64 and 74 suffering from angina, 3 medical staff will repeatedly encounter patients with chest pain. At the acute presentation, it is important to establish the presence of ischaemic heart disease, such as acute coronary syndrome (ACS), warranting urgent medical or surgical intervention. Whereas treatment of newly diagnosed coronary artery disease (CAD) and angina follows wellestablished medical and surgical pathways, a number of patients with established angina, however, fail to respond to medical therapy or are unsuitable for surgical intervention. Such refractory angina is defined as chronic when lasting more than 3 months. Chronic refractory angina is characterized by reversible myocardial ischaemia in the presence of progressive CAD difficult to control by a combination of medical therapy, percutaneous coronary intervention (PCI), and coronary artery bypass graft surgery (CABG). 4 Additionally, the patients often have impaired left ventricular function, renal impairment, and diabetes. Although it would be anticipated that this group of patients would become even smaller with continued advancements in medical technology, data suggest a continued European yearly incidence of 30–50 000 chronic refractory angina patients. 4 Even after coronary revascularization, surveys suggest between 19% and 38% of the patients remain troubled by angina 12 months after intervention. 5 As some of these patients will present in chronic pain clinics and for noncardiac surgery, anaesthetists will be required to assist in their management.

Troponin I Measured by a High-Sensitivity Assay in Patients with Suspected Reversible Myocardial Ischemia: Data from the Akershus Cardiac Examination (ACE) 1 Study

Whether cardiac troponin concentrations are increased by reversible myocardial ischemia is controversial. Differences in the structure of cardiac troponin I (cTnI) and cTnT may have implications for diagnostic utility. cTnI was measured with a prototype high-sensitivity (hs) assay in 198 patients referred for myocardial perfusion imaging (MPI) before exercise stress testing, immediately after, and 1.5 and 4.5 h later. We categorized patients according to MPI results and compared hs-cTnI concentrations with hs-cTnT concentrations. Baseline hs-cTnI was higher in patients with reversible myocardial ischemia (n = 19) vs the other patients (n = 179): median 4.4 (quartiles 1-3: 2.3-7.1) vs 2.5 (1.4-4.3) ng/L, P = 0.003. Baseline hs-cTnI and hs-cTnT concentrations were correlated (r = 0.46, P < 0.001) and the areas under the ROC curve for hs-cTnI and hs-cTnT in diagnosing reversible ischemia were similar: 0.71 vs 0.69, P = 0.77. Whereas hs-cTnI increased immediately after exercise (P < 0.001 vs baseline measurements) in patients without ischemia, it increased after 4.5 h in patients with reversible ischemia (P = 0.01). The increment in hs-cTnI concentrations was comparable between groups; thus, measuring hs-cTnI after exercise stress testing did not improve diagnostic accuracy over baseline measurements, and hs-cTnI concentrations were not found to be associated with reversible myocardial ischemia in multivariate analysis. By linear regression analysis, age, male sex, history of hypertension, angiotensin-converting enzyme inhibitor use, and lower left ventricular ejection fraction were associated with higher baseline hs-cTnI concentrations. In patients referred to MPI, hs-cTnI concentrations were not closely associated with reversible myocardial ischemia, but rather were influenced by variables associated with structural alterations of the myocardium.

Calcium antagonists in myocardial ischemia/reperfusion—update 2012

The present article briefly reviews the processes underlying excitation-contraction coupling in cardiomyocytes and vascular smooth muscle cells, their perturbations during reversible and irreversible myocardial ischemia and reperfusion, notably the pathogenetic role of increased intracellular calcium concentrations, and finally the beneficial effects of calcium antagonists on the impairment of coronary vasomotor tone, on cardiac contractile dysfunction and on myocardial infarction.

Diagnostic utility of a single-epitope sandwich B-type natriuretic peptide assay in stable coronary artery disease: Data from the Akershus Cardiac Examination (ACE) 1 Study

ObjectivesTo assess the merit of a novel single-epitope sandwich (SES) assay specific to the stable part of BNP in patients with reversible myocardial ischemia as post-translational modifications of BNP may influence assay performance. Design and methodsWe measured BNP concentration by a conventional assay and the SES-BNP assay in 198 patients referred for myocardial perfusion imaging (MPI). BNP concentration was determined before and immediately after exercise stress testing, and 1.5 and 4.5h later. Patients were categorized according to MPI results. ResultsBNP concentration was higher with both assays at all time points in patients with reversible myocardial ischemia (n=19) compared to the other patients (n=179). Measuring BNP after stress testing or calculating the changes in BNP concentration did not improve diagnostic accuracy compared to baseline measurements: SES-BNP: AUC 0.71 (95% CI 0.58–0.84) vs. conventional BNP: 0.71 (0.59–0.83), p=0.96. By linear regression analysis, reversible myocardial ischemia was significantly associated with baseline SES-BNP concentration (p=0.043), but not with measurements by the conventional assay (p=0.089). In multivariate logistic regression models, only baseline measurement with the SES-BNP assay was significantly associated with reversible myocardial ischemia: odds ratio [logarithmical transformed BNP] 2.00 (95% CI 1.16–3.47), p=0.013. The SES-BNP assay, but not the conventional BNP assay, reclassified a significant proportion of the patients towards their correct category on top of the best clinical model of our data set: NRI=0.47, p=0.04. ConclusionsThe SES-BNP assay was significantly associated with reversible myocardial ischemia as assessed by several statistical indices, while a conventional BNP assay was not.

141 Cardiac troponin reflects silent myocardial ischaemia in patients with stable coronary artery disease

BackgroundCardiac troponin is an independent predictor of cardiovascular mortality in patients with stable coronary artery disease, yet the factors that determine circulating troponin concentration in these patients are not known....

Cardiac troponin T levels and exercise stress testing in patients with suspected coronary artery disease: the Akershus Cardiac Examination (ACE) 1 study

Whether reversible ischaemia in patients referred for exercise stress testing and MPI (myocardial perfusion imaging) is associated with changes in circulating cTn (cardiac troponin) levels is controversial. We measured cTnT with a sensitive assay before, immediately after peak exercise and 1.5 and 4.5 h after exercise stress testing in 198 patients referred for MPI. In total, 19 patients were classified as having reversible myocardial ischaemia. cTnT levels were significantly higher in patients with reversible myocardial ischaemia on MPI at baseline, at peak exercise and after 1.5 h, but not at 4.5 h post-exercise. In patients with reversible ischaemia on MPI, cTnT levels did not change significantly after exercise stress testing [11.1 (5.2–14.9) ng/l at baseline compared with 10.5 (7.2–16.3) ng/l at 4.5 h post-exercise, P=0.27; values are medians (interquartile range)]. Conversely, cTnT levels increased significantly during testing in patients without reversible myocardial ischaemia [5.4 (3.0–9.0) ng/l at baseline compared with 7.5 (4.6–12.4) ng/l, P<0.001]. In conclusion, baseline cTnT levels are higher in patients with MPI evidence of reversible myocardial ischaemia than those without reversible ischaemia. However, although cTnT levels increase during exercise stress testing in patients without evidence of reversible ischaemia, this response appears to be blunted in patients with evidence of reversible ischaemia. Mechanisms other than reversible myocardial ischaemia may play a role for acute exercise-induced increases in circulating cTnT levels.

Adenosine Stress High-Pitch 128-Slice Dual-Source Myocardial Computed Tomography Perfusion for Imaging of Reversible Myocardial Ischemia

Background— Coronary computed tomography angiography (CTA) enables accurate anatomic evaluation of coronary artery stenosis but lacks information about hemodynamic significance. The aim of this study was to evaluate 128-slice myocardial CT perfusion (CTP) imaging with adenosine stress using a high-pitch mode, in comparison with cardiac MRI (CMR). Methods and Results— Thirty-nine patients with intermediate to high coronary risk profile underwent adenosine stress 128-slice dual source CTP (128×0.6 mm, 0.28 seconds). Among those, 30 patients (64±10 years, 6% women) also underwent adenosine stress CMR (1.5T). The 2-step CTP protocol consisted of (1) adenosine stress-CTP using a high-pitch factor (3.4) ECG-synchronized spiral mode and (2) rest-CTP/coronary-CTA using either high-pitch (heart rate &lt;63 bpm) or prospective ECG-triggering (heart rate &gt;63 bpm). Results were compared with CMR and with invasive angiography in 25 patients. The performance of stress-CTP for detection of myocardial perfusion defects compared with CMR was sensitivity, 96%; specificity, 88%; positive predictive value (PPV), 93%; negative predictive value (NPV), 94% (per vessel); and sensitivity, 78%; specificity, 87%; PPV, 83%; NPV, 84% (per segment). The accuracy of stress-CTP for imaging of reversible ischemia compared with CMR was sensitivity, 95%; specificity, 96%; PPV, 95%; and NPV, 96% (per vessel). In 25 patients who underwent invasive angiography, the accuracy of CTA for detection of stenosis &gt;70% was (per segment): sensitivity, 96%; specificity, 88%; PPV, 67%; and NPV, 98.9%. The accuracy improved from 84% to 95% after adding stress CTP to CTA. Radiation exposure of the entire stress/rest CT protocol was only 2.5 mSv. Conclusions— Adenosine-induced stress 128-slice dual-source high-pitch myocardial CTP allows for simultaneously assessment of reversible myocardial ischemia and coronary stenosis, with good diagnostic accuracy as compared with CMR and invasive angiography, at a very low radiation exposure.

Serum high-sensitivity C-reactive protein, amyloid-associated protein and N-terminal proBNP levels do not predict reversible myocardial ischaemia

The aim of this study was to detect any relationship between serum high-sensitivity C-reactive protein (hs-CRP), serum amyloid-associated protein (SAA) and N-terminal pro B-type natriuretic peptide (NT-proBNP) levels, and reversible myocardial ischaemia during cardiovascular exercise tests and to determine whether these biomarkers could predict transient myocardial ischaemia. Ninety-six patients (36 women, 60 men, mean age 57 ± 8.5 years) were included in the study. Venous blood samples were taken from patients before and 15 minutes after exercise testing. SAA and hs-CRP were analysed using immunonephelometric assays (Dade-Behring, BN II, Marburg, Germany). NT-proBNP (pg/ml) was determined using the immulite 1 000 chemiluminescence immunoassay system (Siemens Medical Solution Diagnostics, Deerfiled, USA). Forty-eight patients (18 women, 30 men) with positive exercise tests were allocated to the exercise-positive group and 48 (18 women, 30 men) with negative exercise tests were put in the exercise-negative group. Coronary angiography was performed on all patients in the exercise-positive group. There was no difference between the levels of hs-CRP, SAA and NT-pro-BNP before and after exercise testing in both of the exercise groups. Serum levels of hs-CRP, SAA and NT-proBNP could not predict the occurrence of reversible myocardial ischaemia during exercise. Large-scale clinical studies are needed to clarify the status of hs-CRP, SAA and NT-proBNP with exercise.

Epicardial hematoma and myocardial ischemia following application of Starfish stabilizer: an uncommon complication of the device

The Starfish heart positioning device allows excellent cardiac positioning and hemodynamic stability during off-pump coronary artery bypass graft surgery. Herein, we present a patient in whom the use of this device caused epicardial hematoma as the result of an injured epicardial vein, an uncommon complication of this device. In this patient, regional left ventricular wall motion abnormality on transesophageal echocardiography and a ST-T change on electrocardiogram occurred secondary to the development of the epicardial hematoma. These signs completely disappeared upon removal of the hematoma. These findings suggested that the hematoma resulted in reversible myocardial ischemia.

Nonischemic&amp;nbsp;ST segment elevation in hypertrophic cardiomyopathy due to chest wall deformity from kyphoscoliosis

A 57-year-old male was admitted with suspected acute coronary syndrome. He reported experiencing moderate chest pain when walking during the day prior to admission, but had very prominent ST segment elevations in the precordial electrocardiography (EKG) leads. A physical examination revealed remarkable severe kyphoscoliosis with chest deformity. The patient's cardiac troponin levels remained normal, while cardiac ultrasound and magnetic resonance imaging of the chest confirmed hypertrophic cardiomyopathy (HCM) with severe thickening of the interventricular septum. Ischemic heart disease was ruled out by myocardial perfusion imaging with (99m)Tc-MIBI during rest and dipyridamole-induced stress without showing irreversible or reversible myocardial ischemia. Our diagnosis was that the chest pain was noncardiac in origin and that the pronounced ST segment elevations in the precordial EKG leads reflected the severely hypertrophic interventricular septum through the normally thick left ventricular free wall. The patient's chest wall deformity brought his septum and the ventricular free wall nearly parallel to the left side of the chest wall, allowing for complete expression of the reciprocal EKG pattern of septal hypertrophy. We suggest that EKG findings should always be interpreted with the chest wall shape being kept in mind.

Cardiac Raynaud's phenomenon induced by cold provocation as a predictor of long‐term left ventricular dysfunction and remodelling in systemic sclerosis: 7‐year follow‐up study

The clinical importance of cold-induced reversible myocardial ischaemia, known as cardiac Raynaud's phenomenon (C-Raynaud), has not been established in systemic sclerosis (SSc). This prospective study investigated the impact of C-Raynaud on long-term irreversible left ventricular (LV) functional and morphologic deterioration in SSc. Fifty-one SSc patients with no clinical evidence of cardiac involvement were prospectively followed up for 7.1 +/- 2.2 years. Systolic LV dysfunction was defined as a LV ejection fraction <50%. Left ventricular remodelling was defined as an increase in LV volume during follow-up of more than 20% compared with baseline values. At the initial evaluation, C-Raynaud was found in 15 patients (29.4%). Of these, eight patients had severe C-Raynaud. None of the patients had systolic LV dysfunction. At the final evaluation, five patients had developed systolic LV dysfunction. In four of these five patients, the development of systolic LV dysfunction was associated with LV remodelling. At multivariate analysis, severe C-Raynaud was a strong independent determinant of the development of long-term systolic LV dysfunction. This study documents for the first time that severe C-Raynaud is a strong long-term predictor of systolic LV dysfunction in SSc patients. Detection of C-Raynaud is clinically important for identifying SSc patients at high risk of cardiac deterioration at latent stage.

Multimodality Noninvasive Imaging for Assessment of Congenital Heart Disease

Major advances in the field of pediatric cardiology and cardiac surgery over the last several decades have led to a dramatic improvement in survival rates for most forms of congenital heart disease (CHD). For example, hypoplastic left heart syndrome, a previously lethal defect, now has early survival rates up to 90% at major centers.1 These improved outcomes have produced a growing population of survivors with complex CHD who are now reaching adulthood (Figure 1). During this period, improvements in surgical and medical treatments have been accompanied by developments in diagnostic modalities. Echocardiography has replaced catheterization as the primary diagnostic modality, and it is now uncommon for newborn infants to undergo catheterization for purely diagnostic purposes. Although echocardiography remains the bedrock of noninvasive cardiac imaging, the array of diagnostic modalities and techniques available continue to grow and this has spawned the specialty of “noninvasive cardiac imaging” and the need for the “cardiac imager” to be adept in all the different modalities. Figure 1. Percentage of patients under the age of 1 year (grey bars) and over the age of 18 years (black bars) undergoing echocardiography at Children’s Hospital Boston from 1983 through 2006. Note the reverse trends of these age groups reflecting the steady increase in the proportion of adult patients with congenital heart disease. Although the absolute number of infants undergoing echocardiography during this time period has increased, their proportion has steadily declined. Echocardiography, cardiac magnetic resonance (CMR), and cardiac computed tomography (CCT) are the primary modalities used for noninvasive cardiac imaging in patients with CHD. Nuclear scintigraphy is used in selected circumstances. The Table summarizes the strengths and weaknesses of each modality. Figure 2 shows temporal trends in utilization for the various noninvasive cardiac imaging techniques at our center. It is clear that echocardiography is the most frequently …

Validation of Magnetic Resonance Myocardial Perfusion Imaging With Fractional Flow Reserve for the Detection of Significant Coronary Heart Disease

Magnetic resonance myocardial perfusion imaging (MRMPI) has a number of advantages over the other noninvasive tests used to detect reversible myocardial ischemia. The majority of previous studies have generally used quantitative coronary angiography as the gold standard to assess the accuracy of MRMPI; however, only an approximate relationship exists between stenosis severity and functional significance. Pressure wire-derived fractional flow reserve (FFR) values <0.75 correlate closely with objective evidence of reversible ischemia. Accordingly, we have compared MRMPI with FFR. One hundred three patients referred for investigation of suspected angina underwent MRMPI with a 1.5-T scanner. The stress agent was intravenous adenosine (140 microg . kg(-1) . min(-1)), and the first-pass bolus contained 0.1 mmol/kg gadolinium. In the following week, coronary angiography with pressure wire studies was performed. FFR was recorded in all patent major epicardial coronary arteries, with a value <0.75 denoting significant stenosis. MRMPI scans, analyzed by 2 blinded observers, identified perfusion defects in 121 of 300 coronary artery segments (40%), of which 110 had an FFR <0.75. We also found that 168 of 179 normally perfused segments had an FFR > or = 0.75. The sensitivity and specificity of MRMPI for the detection of functionally significant coronary heart disease were 91% and 94%, respectively, with positive and negative predictive values of 91% and 94%. MRMPI can detect functionally significant coronary heart disease with excellent sensitivity, specificity, and positive and negative predictive values compared with FFR.

Effect of interleukin 6 deficiency on the expression of Bcl-2 and Bax in the murine heart

Interleukin 6 (IL-6) is a pleiotropic cytokine that is highly expressed in response to ischemia and reperfusion. It has dichotomous roles in the heart, functioning both as an inflammatory mediator as well as a protective agent. The aim of this study was to evaluate the effect of IL-6 deficiency on the expression of apoptotic regulatory proteins under both baseline conditions and following induction of ischemia and reperfusion in the mouse heart. C57BL/6J IL-6−/−TMKopf (IL6KO) and C57BL/6J mice (WT) were subjected to 30 minutes of local reversible myocardial ischemia in vivo or a sham operation. The expression of Bcl-2, Bax and STAT3 in the heart was assessed by western blotting. Under both baseline conditions and following the sham operation, IL-6 deficiency was associated with reduced expression of Bcl-2 and Bax. The TUNEL-FITC, Evans blue and tetrazolium chloride staining of the hearts following ischemia and reperfusion revealed similar injury in operated IL6KO and WT animals. There was increased STAT3 phosphorylation in operated mice regardless of the genotype. Bcl-2 and Bax expression was also comparable between the mouse strains following ischemia and reperfusion. In summary, these results indicated that IL-6 deficiency affected the basal expression of apoptotic regulators, but this did not profoundly alter the extent of reperfusion injury or apoptosis in the mouse heart following ischemia and reperfusion.

Phaeochromocytoma and reversible myocardial ischaemia in a 23-year old female

Background: Phaeochromocytoma is a rare neuroendocrine tumour with highly variable clinical presentation including serious and potentially lethal cardiovascular complications. Aim: To present a case of myocardial ischaemia in Phaeochromocytoma which was reversed after surgery. Setting: University of Port Harcourt Teaching Hospital (UPTH). Case report: A young female undergraduate aged 23 years presented with recurrent blackouts, paroxysmal hypertension which was resistant to several anti- hypertensive drugs and marked postural drop was referred from a private clinic to UPTH. Rest electrocardiogram (ECG) showed ischaemic changes and right axis deviation. Ultrasound scan and computerised tomographic (CT) scan showed a mass on the anteromedial portion of the left kidney with centrally located cystic areas. The 24-hour urine level of vanillyl mandelic acid (VMA) was normal. The tumour was excised by open surgery and histopathological findings confirmed Phaeochromocytoma. The ECG changes reversed after surgical excision. There was no recurrence or metastasis postoperatively after a long term follow up of 5 years. Her blood pressure remained normal postoperatively without taking antihypertensive medication. Conclusion: Phaeochromocytoma is a catecholamine secreting neuroendocrine tumour with a high cardiovascular morbidity and mortality. ECG features of myocardial ischaemia can be reversed by surgical intervention. Keywords: Phaeochromocytoma, Reversible myocardial ischaemia, Surgical interventionPort Harcourt Medical Journal Vol. 2 (3) 2008: pp. 263-267

Highly Sensitive Cardiac Troponin T Values Remain Constant after Brief Exercise- or Pharmacologic-Induced Reversible Myocardial Ischemia

Using a new precommercial high-sensitivity cardiac troponin T (hsTnT) assay, we evaluated whether hsTnT increases after reversible myocardial ischemia. In 195 patients undergoing nuclear stress testing (ST) using single-photon emission computed tomography (SPECT) for suspected ischemic heart disease, we measured hsTnT before and 18 min, 4 h, and 24 h after the stress test. Thirty patients were excluded before ST because of cardiac troponin T (cTnT) >30 ng/L (0.03 mug/L) as measured by the fourth-generation commercial test. Another 65 patients were excluded because of a combination of fixed and reversible perfusion defects (PDs) after SPECT. We studied 18 patients with reversible PDs, 41 patients with fixed PDs, and 41 patients without any PDs. Of these 100 patients, 61 received dynamic ST and 39 pharmacological ST. Median baseline hsTnT concentrations (25th, 75th percentile) were comparable in patients with reversible, fixed, and no PDs [5.57 (2.47, 12.60), 8.01 (4.55, 12.44), and 6.90 (4.63, 10.59) ng/L, respectively]. After ST, median hsTnT concentrations did not change in the reversible, fixed, or no PD groups from baseline to 18 min [-0.41 (-0.81, 0.01), 0.01 (-0.75, 0.79), and 0.36 (-0.42, 1.01) ng/L] or from baseline to 4 h [-0.56 (-1.82, 0.74), 0.24 (-0.60, 1.45), and 0.23 (-0.99, 1.15) ng/L]. Median baseline hsTnT concentrations tended to be higher in patients undergoing pharmacological vs dynamic ST; however, there were no significant increases in hsTnT concentrations after either type of ST. Elevation of cTnT is rather a consequence of irreversible myocyte death than reversible myocardial ischemia after exercise or pharmacologic myocardial ischemia.