ST-segment Changes In Electrocardiogram Research Articles

High-magnesium exposure to bullfrog heart causes ST segment elevation.

Hypermagnesemia occurs in elderly people or patients with renal insufficiency after excessive ingestion of magnesium-containing laxatives. In addition to typical electrocardiogram (ECG) findings caused by conduction defects, changes in the ST segments and T waves are also observed in patients with severe hypermagnesemia. This suggested the involvement of similar pathophysiology to acute myocardial infarction, as we previously demonstrated using burn-induced subepicardial injury model in frog hearts. In the present study, by exposing the bullfrog heart to high-magnesium solution, we reproduced prominent ST segment changes in ECG as actually observed in patients with severe hypermagnesemia. In addition to the great increase in the T waves, the ECG showed a marked elevation of the ST segments and the cardiac action potential demonstrated a marked shift of the resting membrane potential to the depolarized side. High-magnesium exposure did not affect the abundance of Na+/K+-ATPase proteins. However, the pharmacological stimulation of Na+/K+-ATPase activity by insulin quickly retrieved the elevated ST segments in ECG. From these results, the functional blockade of Na+/K+-ATPase activity by magnesium ions was thought to be responsible for generating the potassium concentration gradient and the subsequent ST segment changes.

The Significance of Dynamics of ST Segment Changes When Assessing the Effectiveness of Mechanical Reperfusion of the Myocardium in Hyperglycaemic Patients with Acute Myocardial Infarction with Persistent ST-Segment Elevation

Background: The coexistence of coronary heart disease and consequently, acute myocardial infarction with persistent ST-segment elevation (STEMI) and glucose metabolism disorders is well known. Still, glucose metabolism disorders in the STEMI population are not fully understood. We know that diabetes mellitus (DM) is a factor disabling the function of microcirculation, which in turn may affect the outcome of coronary intervention. The aim of this study was to evaluate the dynamics of ST-segment changes in ECG (electrocardiogram) in STEMI (ST-segment elevation myocardial infarction) patients with co-existing hyperglycaemia compared to those with normoglycaemia treated with a percutaneous coronary intervention (PCI), as well as to determine this parameter in the assessment of reperfusion effectiveness. Methods: The study included 92 patients with the diagnosis of STEMI enrolled in the PCI treatment and was divided into groups based on the glucose levels on admission (reactive hyperglycaemia): a group with higher glucose levels on admission (Glc ≥ 7.8 mmol/L, n = 46), a group with lower glucose levels on admission (Glc < 7.8 mmol/L, n = 46) and into groups based on the concentration of HbA1c: a group with a lower HbA1c level (<6.5% (48 mmol/mol), n=71) and a group with a higher level (≥6.5%, n=21). Results: On admission, there were no significant differences in terms of clinical characteristics between the groups of patients with normoglycemia and reactive hyperglycaemia. After PCI, the patients with normoglycemia had significantly higher (p = 0.021) dynamics of changes in the resolution of ST-segment elevation in ECG expressed in an indicator of sum STR (resolution of ST-elevation). A degree of resolution of ST elevation in ECG was significantly (p = 0.021) dependent on the level of blood glucose – higher the blood glucose level, weaker the resolution. The patients with glucose levels ≥7.8 mmol/L had significantly higher levels of CK and CK-MB during the first 48 hours of hospitalization. There was a statistically significant difference in the mean length of hospitalization between individuals from the group with lower and higher blood glucose levels on admission (p = 0.028). A 4-month follow-up revealed no significant difference in the incidence of major adverse cardiovascular events (MACE) in the study groups (p = 0.063). A 4-year follow-up of patients with higher levels of blood glucose on admission showed a higher incidence of MACE (p = 0.01). The patients with HbA1c ≥ 6.5% were older (p = 0.004), had a greater BMI > 30kg/m2 (p=0.019) and the lower ejection fraction of the left ventricle (p = 0.003) compared to those with the HbA1c levels <6.5%. The incidence of MACE in 4-month and 4-year follow-up was comparable in the study population.

Our first encounter with a COVID-19 patient in cardiology ward: Lessons learned

COVID-19 is an ongoing global pandemic caused by a betacoronavirus named SARS-CoV-2. Within few months after the first index case is identified in Wuhan city of China, it attained a global pandemic status due to its unique epidemiology and pathophysiology. It typically presents with signs and symptoms of viral pneumonia. Patients with cardiac disease are at increased risk of COVID disease and create a diagnostic dilemma in differentiating from respiratory illnesses for the cardiologists. Furthermore, ST-segment changes in electrocardiogram and troponin elevation which form a key diagnostic point in the diagnosis of acute coronary syndromes are frequently seen in COVID-19 patients. This is a matter of utmost concern as the diagnostic dilemma caused may lead to many patients who may not have epicardial coronary artery disease that may be taken up for invasive angiography. Moreover, the prejudice caused by the COVID-19 is leading to fewer admissions for acute coronary syndromes and fewer primary percutaneous transluminal coronary angioplasty leading to inappropriate management of deserving patients with genuine acute coronary syndromes. These patients form a very important chunk of population as on the one hand, they are more likely to spread the infection if they are improperly triaged, and on the other hand, they are less likely to receive proper guideline-directed treatment of cardiovascular syndromes increasing the mortality from primary cardiac pathology. The following case highlights the above-mentioned issues faced in triaging and treating a patient who presented a diagnostic dilemma. Our patient a 53-year-old lady who is a known case of chronic coronary syndrome with effort-induced angina on exertion for the last 4 months on medical management presented to the emergency department, after being rejected admission by three hospitals, with features of chest pain at rest 5 days prior to admission associated with dyspnea and nonproductive cough along with elevated troponin and ST elevation. She was initially diagnosed as acute coronary syndrome with acute heart failure and was taken up to the cardiology ward where a proper clinical examination suggesting right middle lobe localized crackles and chest X-ray findings prompted the suspicion of COVID-19, testing for which by a viral RNA-based test came as positive. This case illustrated the unique challenge posed by the COVID-19 for the cardiologist and the importance of clinical examination and a high index of suspicion needed along with prompt isolation of any suspected case. She was shifted to the COVID ward from where she was discharged after 5 weeks.

Cardioprotective Effect of Selective Estrogen Receptor Modulator Raloxifene Are Mediated by Heme Oxygenase in Estrogen-Deficient Rat.

Estrogens and raloxifene (RAL) have beneficial effects on certain cardiovascular indices in postmenopausal women characterized by estrogen deficiency. Heme oxygenase (HO) activity is increased by 17β-estradiol (E2) and RAL in estrogen-deficient rat resulting in vasorelaxation mediated by carbon monoxide. We determined the expressions of HO in cardiac and aortic tissues after ovariectomy (OVX) and subsequent RAL or E2 treatment. We investigated the effects of pharmacological inhibition of HO enzyme on the arginine vasopressin- (AVP-) induced blood pressure in vivo, the epinephrine- and phentolamine-induced electrocardiogram ST segment changes in vivo, and the myeloperoxidase (MPO) enzyme activity. When compared with intact females, OVX decreased the HO-1 and HO-2 expression, aggravated the electrocardiogram signs of heart ischemia and the blood pressure response to AVP, and increased the cardiac MPO. E2 and RAL are largely protected against these negative impacts induced by OVX. The pharmacological inhibition of HO in E2- or RAL-treated OVX animals, however, restored the cardiovascular status close to that observed in nontreated OVX animals. The decreased expression of HO enzymes and the changes in blood pressure ischemia susceptibility and inflammatory state in OVX rat can be reverted by the administration of E2 or RAL partly through its antioxidant and anti-inflammatory roles.

Coronary arterial disease after electroconvulsive therapy: a case report

Objectives Unipolar depression (UPD) is a leading cause of global burden of diseases, particularly among the elderly, whose treatment may be challenging. In such cases, ECT is often recommended due to its safety and efficacy. This report presents a case of a 67-year-old male inpatient that developed a rare cardiac complication during ECT. Methods Clinical case report with patient’s consent and bibliographic review. Results A 67-year-old male inpatient with recurrent severe psychotic depression was hospitalized and ECT was indicated after failure of the pharmacological treatment. A comprehensive clinical pre-evaluation revealed only nonspecific ST-segment changes in electrocardiogram. During the 7th ECT session, it was observed transitory ST-segment depression followed by a discrete increase of plasma troponin I. Severe tri-vessel coronary artery stenosis was found and a percutaneous coronary angioplasty was performed, with satisfactory psychiatric and cardiac outcomes. Conclusions Unipolar depression (UPD) and cardiovascular disease are often coexistent conditions, especially among the elderly. In the current case, myocardial ischemia was detected lately during ECT therapy and its treatment allowed the UPD treatment to be completed adequately.

Relation between Oral Health Status and Electrocardiogram ST Segment Changes in a Group of Patients with Myocardial Infarction.

Background and aims. Only half to two-thirds of cardiovascular diseases can be explained by the classic risk factors. It is believed that chronic oral inflammation is a potent risk factor for systemic diseases. Studies show that electrocardiogram ST segment changes can be predictive of myocardial infarction outcome. In this study the relation between electrocardio-gram ST segment changes and oral health is evaluated. Materials and methods. In this cross-sectional study, thirty-six patients (14 females and 22 males) with myocardial infarction were enrolled. Oral health indices including DMFT index, probing depth, clinical attachment loss and bleeding on probing were recorded for each patient. DMFT index, PD, CAL as continuous variables and BOP as a categorical variable were compared with ST segment changes by independent t-test and chi-squared test, respectively (α=0.05). Results. DMFT index, BOP and PD revealed no statistically significant relation with ST segment groups. CAL showed a statistically significant difference within ST segment groups (P=0.003, OR=1.68). Conclusion. Clinical attachment loss was significantly higher in patients with ST segment depression, while no correla-tion was seen between probing depth, bleeding on probing and DMFT index with ST segment elevation or depression.

Importance of the Exercise Test Follow-up Programme for Patients with Coronary Artery Disease who Underwent Percutaneous Coronary Intervention

Importance of the Exercise Test Follow-up Programme for Patients with Coronary Artery Disease who Underwent Percutaneous Coronary Intervention The clinical course and prognosis of coronary heart disease (CHD) can be modified favourably with percutaneous coronary intervention (PCI) in combination with medication. A follow-up programme was developed in the Latvian Centre of Cardiology, which included a stress electrocardiogram for patients after PCI. This is the first study in Latvia, and provides wide opportunities to evaluate functional status of patients, treatment effectiveness, possible risks and prognosis after PCI. Exercise tests are widely used for the evaluation and diagnostics of CHD. This method has been successfully implemented in diagnostics of restenosis in coronary arteries, a process which pathophysiologically differs from primary atherosclerosis. A total of 7,300 patients with CHD were followed-up in one year after PCI. An exercise test was conducted one, three, six and twelve months after PCI. Clinical and functional status of patients and risk of restenosis were evaluated and corrections in medications were made. Seventeen percent of patients had chest pain and 13% had significant ST-segment changes in electrocardiogram. Restenosis of coronary arteries in angiography were established in 6.4%. In half of those patients above restenosis was diagnosed early — three to six months after PCI. We established a patient subgroup (22%) with "silent" ischemia (positive exercise test without chest pain), out of whom 41% had restenosis. For left main (LM) disease patients 50% of all restenosis diagnoses also were diagnosed early (three to six month after PCI). Restenosis was associated with ST-segment deviation in the exercise electrocardiogram. A lower Robinson index (RI) was registered in the same group of patients. A focussed follow-up programme performing exercise test allows to determine timely possible risk of restenosis, to adapt medication doses, to reduce risk factors and to influence positively patients' compliance.

Early thrombolysis by recombinant tissue-plasminogen activator is beneficial to the ischemic myocardium.

We examined the effect of coronary thrombolysis by recombinant tissue-plasminogen activator (rtPA) on infarct size using a thrombin-induced thrombosis model of open-chest anesthetized dog. Occlusive thrombus was induced by injection of thrombin (100 U) in the left anterior descending coronary artery (LAD). The intravenous infusion of rtPA (10 micrograms/kg/min) was started at 30 min (30 min-ischemia group) or at 60 min (60 min-ischemia group) after the formation of thrombus, and was continued for 30 min. Spontaneous thrombolysis was not observed in the 360 min-ischemia (vehicle-treated) group. Intravenous infusion of rtPA elicited thrombolysis within 30 min in all the dogs except in one in the 60 min-ischemia group. The infarct size was significantly reduced by rtPA-induced thrombolysis. The shorter the duration of the ischemia, the longer the effect of the drug, and the infarct size after thrombolysis was smaller in the 30 min-ischemia group than in the 60 min-ischemia group. Ischemia-induced changes in ST-segment of electrocardiogram (ECG) were significantly ameliorated after thrombolysis in both 60 min- and 30 min-ischemia group. These results suggest that early reperfusion of coronary thrombosis by rtPA is beneficial to the ischemic myocardium.