Reperfusion strategies in the emergency treatment of ST-segment elevation myocardial infarction

Prevalence and determinants of delays in care among premature deaths due to acute cardiac conditions and stroke in residents of a district in India

Background

Lack of timely care is a predictor of poor outcomes in acute cardiovascular emergencies including stroke. We assessed the presence of delay in seeking appropriate care among those who died due to cardiac/stroke emergencies in a community in northern India and identified the reasons and determinants of this delay.

Methods

We conducted a social audit among all civil-registered premature (30-69 years) deaths due to acute cardiac event or stroke in the district. The three-delays model was used to qualitatively classify the delays in care-seeking-deciding to seek care, reaching the appropriate health facility (AHF) and initiating definitive treatment. Based on the estimated time from symptom onset to reaching AHF, we classified patients as early (reached within one hour) or delayed arrivers. We used mixed-effect logistic regression with postal code as a random effect to identify determinants of delayed arrival.

Findings

Only 10.8% of the deceased reached an AHF within one hour. We noted level-1 delay in 38.4% (60% due to non-recognition of seriousness); level-2 delay in 20% (40% due to going to an inappropriate facility) and level-3 delay in 10.8% (57% due to lack of affordability). Patients with a monthly family income of >270US$ (aOR 0.44; 95% CI 0.21-0.93) were less and those staying farther from AHF (aOR 1.12; 95% CI 1.01-1.25 for each Km) were more likely to have delayed arrival in AHF.

Interpretation

A small proportion of patients with cardiac and stroke emergencies reach health facility early with delays at multiple levels. Addressing the reasons for delay could prevent these deaths.

Funding

: Indian Council of Medical Research, New Delhi, India.

Prophylactic administration of rosmarinic acid ameliorates depression-associated cardiac abnormalities in Wistar rats: Evidence of serotonergic, oxidative, and inflammatory pathways

Psychiatric disorders and associated cardiac comorbidities have increased the risk of mortality worldwide. Researchers reported that depression increases the possibility of future cardiac abnormalities by approximately 30%. Therefore, there is an unmet need to develop therapeutic interventions to treat depression and associated cardiac abnormalities. The present study was conducted to evaluate the prophylactic effect of rosmarinic acid (RA) against chronic unpredictable stress (CUS)-induced depression associated cardiac abnormalities in Wistar rats. The CUS paradigm, which comprised several stressors, was employed for 40 days to induce depressive-like behavior and associated cardiac abnormalities in rats. Along with CUS, RA at a dose of 25 and 50 mg/kg was administered orally to two groups of animals for 40 days. Behavioral tests (forced swim test and sucrose consumption test) and molecular biomarkers (corticosterone and serotonin) were performed. Electrocardiography was performed before CUS (Day 0), Day 20, and Day 40 to study electrocardiogram parameters. Furthermore, changes in body weight, organ weight, tissue lipid peroxidation, glutathione, catalase, cTn-I, MMP-2, and proinflammatory cytokines (TNF-α and IL-6) were estimated. Our results showed that RA treatment caused a reduction in immobility period, adrenal hyperplasia, corticosterone level, tissue lipid peroxidation, cTn-I, MMP-2, proinflammatory cytokines, and QRS complex duration, while an increase in sucrose consumption, brain serotonin level, T-wave width, glutathione, and catalase activity as compared with the CUS-control group. The results of our study proved that RA administration ameliorates CUS-induced depression-associated cardiac abnormalities in rats via serotonergic, oxidative, and inflammatory pathways.

Evaluation of rosmarinic acid against myocardial infarction in maternally separated rats

Depression and coronary heart diseases are the common comorbid disorder affecting humans globally. The present study evaluated the effectiveness of rosmarinic acid (RA) against myocardial infarction (MI) in comorbid depression induced by maternal separation in rats. Maternal stress is one of the childhood crises that may be a potential risk factor for coronary heart disease in later part of life. As per protocol, 70-80% of pups were separated daily for 3 h between postnatal day 1 (PND1) and postnatal day 21 (PND21). Forced-swim test, sucrose preference test, and electrocardiography were performed during the experiment. Body weight was measured on PND0, PND35, and PND55. Orally rosmarinic acid (25 mg/kg and 50 mg/kg) and fluoxetine (10 mg/kg) was done from PND35 to PND55. On PND53 and PND54, isoproterenol (100 mg/kg, subcutaneously) was administered to induce myocardial infarction. On PND55, blood was collected and animals sacrificed, and plasma corticosterone, brain-derived neurotrophic factor, cardiac biomarkers, interleukine-10, and anti-oxidant parameters were measured. Rosmarinic acid and fluoxetine ameliorated the maternal separation-induced increase in immobility period, anhedonia, body weight, ST elevation, corticosterone, creatine kinase-MB (CK-MB), and lactate dehydrogenase (LDH). At the same time, both drugs elevated the tissue levels of BDNF, IL-10, glutathione, and superoxide dismutase activity. This study provides the first experimental evidence that maternal stress is an independent risk factor of cardiac abnormalities in rats. Moreover, maternal stress synergistically increases the severity of cardiac abnormalities induced by isoproterenol. Interestingly, fluoxetine and rosmarinic acid effectively ameliorated behavioral anomalies and myocardial infarction in maternally separated rats. Schematic representation of possible molecular mechanism of action of rosmarinic acid against MS-induced myocardial infarction. RA, rosmarinic acid; MS, maternal separation; PND, postnatal days; ISO, isoproterenol; BDNF, brain-derived neurotrophic factor; GSH, glutathione; SOD, superoxide dismutase; IL-10, interleukin-10; MI, myocardial infarction.

The cardioprotective effect of rosmarinic acid on acute myocardial infarction and genes involved in Ca2+ homeostasis

Acute myocardial infarction (AMI) is a common cause of hospitalisation and high mortality due to lethal arrhythmias. Sarcoplasmic reticulum Ca2+ ATPase (SERCA2) and ryanodine receptor (RyR2) regulate the cytosolic Ca2+ ion concentration. Rosmarinic acid (RA) is one of the most common caffeic esters in Rosmarinus officinalis. The present study was conducted to test the hypothesis whether RA can protect cardiac function against AMI and arrhythmias induced by isoproterenol through the regulatory effect of SERCA2 and RyR2 gene expression. To this aim, male Sprague-Dawley rats were allocated into in vivo and ex vivo studies and received RA (10, 15, and 30 mg/kg; 14 days). AMI was induced by two consecutive subcutaneous injections of 100 mg/kg isoproterenol. Blood pressure (BP), heart rate, electrocardiography (ECG) parameters, plasma levels of cardiac biomarkers, and antioxidative enzymes were evaluated (in vivo study). Cardiac functions were measured in isolated hearts using Langendorff set up. Gene expressions of SERCA2 and RyR2 were measured in left ventricular heart. Isoproterenol administration showed a significant decline in BP, QRS voltage, activities of antioxidant enzymes, cardiac function, and gene expressions of SERCA2 and RyR2. The results also indicated a significant increase in heart rate, ST-elevation, cardiac biomarkers, and antioxidant enzymes. RA at 30 mg/kg dosage showed the best effect on the improvement of the mentioned factors. This study suggests that RA has potent cardioprotective effects against AMI and arrhythmia, which may be due to its ability to enhance expression of plasma antioxidant enzymes and genes involved in Ca2+ homeostasis SERCA2 and RyR2. The protective role of RA is also possibly related to its antiadrenergic effects.

Effect of vitamin D on isoprenaline-induced myocardial infarction in rats: possible role of peroxisome proliferator-activated receptor-γ

Infarct-like lesion induced by isoprenaline is a well-known model to study myocardial infarction (MI). Vitamin D has been shown to have anti-inflammatory and antioxidant effects. Recent studies highlighted cross talk between vitamin D and peroxisome proliferator-activated receptor gamma (PPAR-γ). The present study was designed to investigate the effect of pretreatment with vitamin D on the isoprenaline-induced infarct-like lesion in rats and the role of PPAR-γ as a novel mechanism in vitamin-D-mediated cardioprotective effect. Markers chosen to assess cardiac damage included serum level of creatine kinase (CK), lactate dehydrogenase (LDH), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6). Cardiac contents of malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GSH) were also assessed. Furthermore, ECG monitoring and measurement of injury extension were carried out. Isoprenaline increased the level of cardiac enzymes, as well as inflammatory and oxidative stress biomarkers. In addition, it produced ST-segment elevation. Pretreatment with vitamin D significantly improved previous parameters. The prior treatment with bisphenol A diglycidyl ether (BADGE), a PPAR-γ antagonist, significantly attenuated the protective effect of vitamin D. In conclusion, vitamin D can be demonstrated as a promising cardioprotective agent in MI and PPAR-γ significantly contributes toward vitamin-D-mediated protection.

Tomato lycopene attenuates myocardial infarction induced by isoproterenol: electrocardiographic, biochemical and anti-apoptotic study

OBJECTIVE

To assess the protective effects of lycopene on electrocardiographic, hemodynamic, biochemical and apoptotic changes in isoproterenol induced myocardial infarction.

METHODS

Myocardial infarction was induced in rats by subcutaneous injection of isoproterenol (200 mg/kg) for two consecutive days at an interval of 24 h. Rats were treated with lycopene (10 mg/kg/day, p.o.) for a period of 30 days and isoproterenol (ISO) was injected on the 29th and 30th day. At the end of experiment i.e. on the 31st day electrocardiographic, hemodynamic, biochemical and apoptotic changes were monitored from control and experimental groups.

RESULTS

ISO injected rats showed a significant alteration in electrocardiograph pattern and hemodynamic changes (i.e. systolic, diastolic and mean arterial pressure). It also showed significant increase in C-reactive protein, myeloperoxidase, nitrite levels and Caspase-3 protease activity. In addition, it also exhibited alteration in the levels of electrolytes (Na(+), K(+) and Ca(2+)), vitamin E, uric acid and serum protein. Gel electrophoresis of ISO injected rats showed increase in DNA fragmentation. Triphenyl tetrazolium chloride staining of the heart section shows increase area of infarction in ISO injected rats. Pre-co-treatment with lycopene significantly prevented the ISO induced alteration in ECG, haemodynamic, biochemical and apoptotic changes.

CONCLUSIONS

The present result shows that treatment of lycopene in ISO injected rats significantly attenuates induced myocardial infarction.

Evaluation of Cardioprotective Effect of 3,5,3'-Tri-iodo-L-thyronine in Isoproterenol-Induced Cardiotoxicity

T(3) (3,5,3'-triiodothyronine) has drawn relatively little attention in relation to cardiovascular (CVS) diseases. The present study was designed to evaluate the cardioprotective action of T(3) in isoproterenol-(ISO-) induced cardiac toxicity. Female Wistar rats were exposed with ISO (100 mg/kg, body weight, subcutaneously) for 2 days at the interval of 24 h followed by T(3) (3 μg/kg, body weight, orally) treatment for 3 days. Positive control rats received only ISO (100 mg/kg, body weight, subcutaneously) for 2 days at the interval of 24 hrs. Control group animals received normal saline as a vehicle. As expected, ISO-induced significant changes were observed in low-density lipoprotein, total cholesterol, ALT, CK-MB to TCK ratio, and prolongation of QT interval in electrocardiogram, which is toward normalization after T(3) treatment. Lower heart weight, upregulation of cardiac myosin heavy chain alpha (MHC-α), and reduced inflammatory cell infiltration, myonecrosis, vacuolar changes, and a trend toward normal cardiac muscle fiber architecture in microscopic examination of cardiac tissue further support the cardioprotective effect of T(3).

Hospitals with and without percutaneous coronary intervention capability: considerations for treating acute coronary syndromes

The crucial aim in the emergency management of patients presenting with chest pain is the identification of acute coronary syndromes (ACS) and the initiation of appropriate treatment. Institution-specific triage to initial medical or interventional therapies is influenced by the availability of percutaneous coronary intervention (PCI) facilities. Although the use of invasive strategies has increased, most US hospitals do not have PCI facilities. Pharmacological management is an integral part of all treatment strategies, regardless of the availability of interventional capability. Given the growing importance of invasive management strategies, a therapy that is compatible with both medical and invasive therapy options is becoming increasingly important. Aspirin and clopidogrel are recommended for patients with ACS regardless of the conservative or invasive management strategy. With enoxaparin, patients with ACS can seamlessly transition from the medical management phase to the interventional management phase without the need for introducing a second anticoagulant in the cardiac catheterization laboratory. Fondaparinux can be used for patients with ACS treated medically, but should not be used alone during PCI because of the risk of catheter thrombosis. Bivalirudin can be used in non-ST-segment elevation myocardial infarction patients who are managed invasively.

Acute coronary syndrome

Acute coronary syndrome (ACS) is the umbrella term for the clinical signs and symptoms of myocardial ischemia: unstable angina, non-ST-segment elevation myocardial infarction, and ST-segment elevation myocardial infarction. This article further defines ACS and the conditions it includes; reviews its risk factors; describes its pathophysiology and associated signs and symptoms; discusses variations in its diagnostic findings, such as cardiac biomarkers and electrocardiographic changes; and outlines treatment approaches, including drug and reperfusion therapies.

Cardioprotective effect of 'Khamira Abresham Hakim Arshad Wala' a unani formulation in isoproterenol-induced myocardial necrosis in rats

The present study was designed to investigate whether Khamira Abresham Hakim Arshad Wala (KAHAW), a preparation of Unani System of Medicine, is able to attenuate the isoproterenol (ISO)-induced myocardial necrosis on the basis of its effects on hemodynamic, antioxidant, histopathological and ultrastructural parameters. Male Wistar albino rats were administered KAHAW (200, 400 and 800mg/kg/day, orally) or vehicle for 14 days with concurrent ISO administration (85mg/kg, subcutaneously, 2 doses at 24h interval) on 13th and 14th day. On the 15th day, vehicle+ISO-treated rats exhibit cardiac dysfunctions as indicated by decrease in systolic, diastolic, and mean arterial pressures, reduction in both maximum positive and maximum negative rates of developed left ventricular pressure (+/-LVdp/dt) and an increase in left ventricular end-diastolic pressure (LVEDP). Biochemical analysis of their heart homogenate presented reduced levels of enzymes viz., superoxide dismutase (SOD), catalase (CAT), lactate dehydrogenase (LDH), creatine kinase-MB (CK-MB) isoenzyme. A marked reduction in reduced glutathione (GSH) levels along with increase in levels of thiobarbituric acid reactive substances (TBARS) was also observed in rat myocardium. Myocardial necrosis, edema and inflammation were evident from the light microscopic and ultrastructural changes. KAHAW at dose of 800mg/kg/day significantly reversed majority of hemodynamic and antioxidant derangements. The protective role of KAHAW on ISO-induced myocardial necrosis was further confirmed by histopathological and ultrastructural examination. There was no significant change in heart rate in all experimental groups. KAHAW per se groups showed no significant change when compared with vehicle control group. The study results thus demonstrated the cardioprotective potential of KAHAW against ISO-induced myocardial necrosis and associated oxidative stress.

Fondaparinux sodium: a review of its use in the management of acute coronary syndromes

Fondaparinux sodium (Arixtra) is a synthetic, sulfated pentasaccharide, selective factor Xa inhibitor that is indicated in Europe for preventing thrombus formation in patients with acute coronary syndromes (ACS; the focus of this review), including those with ST-segment elevation myocardial infarction (STEMI), non-STEMI (NSTEMI), or unstable angina.The large (n = 20,078), well designed OASIS-5 trial showed that subcutaneous fondaparinux 2.5 mg/day for <or=8 days was noninferior to subcutaneous enoxaparin 1 mg/kg twice daily (once daily in those with renal dysfunction) in reducing death or ischemic events at 9 days and the efficacy was maintained for up to 6 months (study end) in patients with unstable angina or NSTEMI. During this time, major bleeding occurred in fewer fondaparinux than enoxaparin recipients, resulting in a benefit: risk balance favoring fondaparinux. The incidence of death or reinfarction at 30 days was significantly lower in recipients of subcutaneous fondaparinux 2.5 mg/day than in those who received usual care (including unfractionated heparin [UFH] treatment as indicated) in patients with STEMI in the large (n > 12,000) OASIS-6 trial. There were no differences in the incidence of major bleeding between these groups, resulting in a benefit : risk balance favoring fondaparinux. The specificity and selectivity of fondaparinux, combined with its long half-life and 100% bioavailability, allows once-daily anticoagulation without the need for monitoring activated clotting time. Subcutaneous fondaparinux was noninferior to enoxaparin treatment in patients with unstable angina or NSTEMI, and was more effective than usual care in those with STEMI. Fondaparinux has a favorable tolerability profile, particularly with regard to the risk of major bleeding, and limited data suggest that it is more cost effective than enoxaparin in the short term. Thus, overall, clinical evidence suggests that fondaparinux has a valuable place in the treatment of patients with ACS.