Implications of oxidative stress in chronic kidney disease: a review on current concepts and therapies

Moderate levels of endogenous reactive oxygen species (ROS) are important for various cellular activities, but high levels lead to toxicity and are associated with various diseases. Levels of ROS are maintained as a balance between oxidants and antioxidants. Accumulating data suggest that oxidative stress is a major factor in deterioration of renal function. In this review, we highlight the possible mechanism by which oxidative stress can lead to chronic kidney disease (CKD). This review also describes therapies that counter the effect of oxidative stress in CKD patients. Numerous factors such as upregulation of genes involved in oxidative phosphorylation and ROS generation, chronic inflammation, vitamin D deficiency, and a compromised antioxidant defense mechanism system cause progressive detrimental effects on renal function that eventually lead to loss of kidney function. Patients with renal dysfunction are highly susceptible to oxidative stress, as risk factors such as diabetes, renal hypertension, dietary restrictions, hemodialysis, and old age predispose them to increased levels of ROS. Biomolecular adducts (DNA, proteins, and lipids) formed due to reaction with ROS can be used to determine oxidative stress levels. Based on the strong correlation between oxidative stress and CKD, reversal of oxidative stress is being explored as a major therapeutic option. Xanthine oxidase inhibitors, dietary antioxidants, and other agents that scavenge free radicals are gaining interest as treatment modalities in CKD patients.

Magnetic resonance imaging of dilated cardiomyopathy: prognostic benefit of identifying late gadolinium enhancement in Asian patients

INTRODUCTION@#Risk stratification in dilated cardiomyopathy (DCM) is imprecise, relying largely on echocardiographic left ventricular ejection fraction (LVEF) and severity of heart failure symptoms. Adverse cardiovascular events are increased by the presence of myocardial scarring. Late gadolinium enhancement (LGE) on cardiovascular magnetic resonance (CMR) imaging is the gold standard for identifying myocardial scars. We examined the association between LGE on CMR imaging and adverse clinical outcomes during long-term follow-up of Asian patients with DCM.@*METHODS@#Consecutive patients with DCM undergoing CMR imaging at a single Asian academic medical centre between 2005 and 2015 were recruited. Clinical outcomes were tracked using comprehensive electronic medical records and mortality was determined by cross-linkages with national registries. Presence and distribution of LGE on CMR imaging were determined by investigators blinded to patient outcomes. Primary endpoint was a composite of heart failure hospitalisations, appropriate implantable cardioverter-defibrillator shocks and cardiovascular mortality.@*RESULTS@#Of 86 patients, 64.0% had LGE (80.2% male; mean LVEF 30.1% ± 12.7%). Mid-wall fibrosis (71.7%) was the most common pattern of LGE distribution. Over a mean follow-up period of 4.9 ± 3.2 years, 19 (34.5%) patients with LGE reached the composite endpoint compared to 4 (12.9%) patients without LGE (p = 0.01). Presence of LGE, but not echocardiographic LVEF, independently predicted the primary endpoint (hazard ratio 4.15 [95% confidence interval 1.28-13.50]; p = 0.02).@*CONCLUSION@#LGE presence independently predicted adverse clinical events in Asian patients with DCM. Routine use of CMR imaging to characterise the myocardial substrate is recommended for enhanced risk stratification and should strongly influence clinical management.

Implications of oxidative stress in chronic kidney disease: a review on current concepts and therapies

Moderate levels of endogenous reactive oxygen species (ROS) are important for various cellular activities, but high levels lead to toxicity and are associated with various diseases. Levels of ROS are maintained as a balance between oxidants and antioxidants. Accumulating data suggest that oxidative stress is a major factor in deterioration of renal function. In this review, we highlight the possible mechanism by which oxidative stress can lead to chronic kidney disease (CKD). This review also describes therapies that counter the effect of oxidative stress in CKD patients. Numerous factors such as upregulation of genes involved in oxidative phosphorylation and ROS generation, chronic inflammation, vitamin D deficiency, and a compromised antioxidant defense mechanism system cause progressive detrimental effects on renal function that eventually lead to loss of kidney function. Patients with renal dysfunction are highly susceptible to oxidative stress, as risk factors such as diabetes, renal hypertension, dietary restrictions, hemodialysis, and old age predispose them to increased levels of ROS. Biomolecular adducts (DNA, proteins, and lipids) formed due to reaction with ROS can be used to determine oxidative stress levels. Based on the strong correlation between oxidative stress and CKD, reversal of oxidative stress is being explored as a major therapeutic option. Xanthine oxidase inhibitors, dietary antioxidants, and other agents that scavenge free radicals are gaining interest as treatment modalities in CKD patients.

The evaluation of QTc prolongation and QT dispersion in type 2 diabetes mellitus as an indicator of cardiac autonomic neuropathy

Background: Diabetes mellitus refers to group of metabolic disorders characterized by hyperglycemia due to an absolute or relative deficit in insulin production or action. Diabetes mellitus produces pathological changes in most organs of the body including heart, blood vessels, kidneys, nerves and eyes. Cardiovascular autonomic neuropathy (CAN) is a severely debilitating yet underdiagnosed complication of diabetes. Diabetes-associated cardiovascular autonomic neuropathy damages autonomic nerve fibers that innervate the heart and blood vessels causing abnormalities in heart rate and vascular dynamics.Methods: Total 80 cases of diabetes mellitus were selected. Cardiac autonomic neuropathy in them was diagnosed by a series of tests recommended by Ewing et al, which include - Valsalva ratio, Deep Breath Test, Heart rate response to standing, Postural Hypotension, SHGT Increase in diastolic BP on sustained hand grip. They were divided into 2 groups A and B depending on presence or absence of cardiac autonomic neuropathy. ECG was done to calculate QTc and QTd.Results: In group A mean QTc was 0.344 sec and in group B in patients with mild CAN mean QTc was 0.432, moderate CAN mean QTc was 0.444, and in patients of severe CAN mean QTc was 0.481. p value was 0.001 that it is highly significant. Means more was degree of CAN more was prolongation of QT and similarly more the degree of CAN more was QTd.Conclusions: Diagnosis of cardiac autonomic neuropathy by battery of cardiac autonomic function tests is a comlex procedure. The prolongation of QTc interval and more specifically QTd interval on ECG is a marker in diagnosis of cardiac autonomic neuropathy which can be easily evaluated.

A myriad of electrocardiographic findings associated with digoxin use

Digoxin is a commonly prescribed drug in the management of heart failure and atrial fibrillation. Despite its widespread use, most clinicians have little experience with recognising clinical signs and symptoms that might suggest a potentially lethal drug toxicity. We herein describe two cases with specific reference to the electrocardiographic changes induced by digoxin and discuss the predisposing factors for toxicity, recognition of possible toxicity and treatment approaches.

Electrocardiography findings and clinical presentation in Ebstein's anomaly

Ebstein's anomaly is a congenital malformation characterised by tricuspid valve pathology with right heart enlargement. Cases of Ebstein's anomaly can vary widely in severity, anatomy and presentation. In this article, we presented three cases of Ebstein's anomaly and discussed the presentation as well as electrocardiographic (ECG) changes. Patients may first present to their primary care physicians with cardiac symptoms such as reduced effort tolerance together with an abnormal ECG. ECG changes suggestive of right heart enlargement are important in the initial consideration and eventual formal diagnosis of the condition.

Prevalence of insulin resistance in cirrhosis of liver

Background: Liver plays a central role in glucose homeostasis. Chronic liver disease is associated with an increased incidence of insulin resistance (IR) and Diabetes Mellitus. Diabetes that develops as a complication of cirrhosis of liver is known as 慔epatogenous diabetes (HD)�. This study was conducted to study the prevalence of insulin resistance in liver cirrhosis.Methods: One Hundered (100) non-diabetic patients of liver cirrhosis considering the inclusion and exclusion criteria and visiting both indoor and outpatient department of medicine, SGRDIMSAR were included in the study. All cirrhotic patients irrespective of etiology were subjected to fasting plasma glucose level and fasting plasma insulin levels and insulin resistance was calculated by HOMA-IR method. Study was statistically analyzed.Results: 79 out of 100 patients were found to have insulin resistance and increase in prevalence with grades of child pugh score were noted.Conclusions: Keeping in view the results of the study, we conclude that FPG and HbA1c are not sufficient in detecting glucose metabolism disorders in cirrhosis. As insulin resistance can be used as an important prognostic marker in patients with cirrhosis of liver, serum insulin levels can be recommended as routine investigation in these patients. Diabetes mellitus increases the risk of HCC in cirrhosis patients. So, by early detection of diabetes mellitus by calculating insulin resistance with HOMA-IR method we can prevent progression of disease to development into HCC.

High-grade atrioventricular block

Atrioventricular (AV) block is an AV conduction disorder that can manifest in various settings, with varying symptomaticity and severity. The electrocardiogram is a key diagnostic tool for management, and careful interpretation is necessary to institute the correct management. We described two cases of patients with bradycardia due to AV blocks and discussed the electrocardiogram interpretation and management.

Can you interpret the ECG under stress?

Stress (Takotsubo) cardiomyopathy (SC) is a cardiomyopathy characterised by transient myocardial dysfunction, commonly triggered by a surge in catecholamine. Electrocardiographic features may mimic other conditions, such as myocardial infarction. We presented two cases of SC and reviewed the electrocardiographic features of this disease entity.

Rhythmic chaos: irregularities of computer ECG diagnosis

Diagnostic errors can occur when physicians rely solely on computer electrocardiogram interpretation. Cardiologists often receive referrals for computer misdiagnoses of atrial fibrillation. Patients may have been inappropriately anticoagulated for pseudo atrial fibrillation. Anticoagulation carries significant risks, and such errors may carry a high cost. Have we become overreliant on machines and technology? In this article, we illustrate three such cases and briefly discuss how we can reduce these errors.

Improvement in left ventricular function assessed by tissue Doppler imaging after aortic valve replacement for severe aortic stenosis

<p><b>INTRODUCTION</b>The effects of reduction of left ventricular (LV) systemic afterload following aortic valve replacement (AVR) for severe aortic valve stenosis (AS) were investigated, using echocardiography and tissue Doppler imaging (TDI).</p><p><b>METHODS</b>We compared the preoperative and postoperative echocardiographic assessments of 23 patients with severe AS who had undergone isolated AVR (n = 13) or concomitant AVR with coronary artery bypass grafting (CABG) (n = 10). Conventional echocardiographic evaluations and TDI at the lateral mitral annulus were performed.</p><p><b>RESULTS</b>Echocardiography was performed at a median of 120 (interquartile range: 66-141) days after AVR. There was significant reduction in aortic transvalvular mean pressure gradient after AVR. Although LV dimensions, mass and ejection fraction remained unchanged, LV diastolic and systolic functions improved (as observed on TDI). Early diastolic (E'), late diastolic (A') and systolic (S') mitral annular velocities increased significantly (p < 0.05). There was significant improvement in TDI-derived parameters among the patients who had isolated AVR, while among the patients who had concomitant AVR with CABG, only S' had significant improvement (p = 0.028).</p><p><b>CONCLUSION</b>TDI was able to detect improvements in LV systolic and diastolic function after AVR for severe AS. There was less improvement in the TDI-derived diastolic parameters among patients who underwent concomitant AVR with CABG than among patients who underwent isolated AVR.</p>

Electrocardiography series. Narrow QRS-complex tachycardia: part 2

We discuss two cases of incessant atrial tachycardia (AT), including the presentation and clinical course. It is important to differentiate AT from other causes of supraventricular tachycardia, such as atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular reentrant tachycardia (AVRT), as it would have implications on clinical management. Electrocardiographic features of AT, especially the presence of an AV Wenckebach phenomenon with 'grouped beating', are critical for differentiating AT from AVRT and AVNRT. It is also vital to identify the P waves and their relations to QRS on electrocardiography, as this would aid in the differentiation of various supraventricular tachycardias.