Myocardial Infarction in the Absence of Obstructive Coronary Artery Disease (MINOCA): a Review of the Present and Preview of the Future.

PURPOSE OF REVIEW: The syndrome of myocardial infarction in the absence of obstructive coronary artery disease (MINOCA) is not uncommon and has multiple potential coronary etiologies. With the use of more sensitive cardiac biomarkers and advanced cardiovascular imaging, MINOCA presentations have gain increasing attention among researchers and cardiologists. Despite the presence of a myocardial infarction and elevated future risk, many patients are sent home with little or no cardio-protective treatment and no explanation for their symptoms. In this review, we emphasized the importance of MINOCA treatment based on the underlying etiology. RECENT FINDINGS: As there are multiple pathophysiological mechanisms potentially involved in MINOCA, it should be considered a working diagnosis until there is a better understanding regarding the underlying cause. It is critical to use multimodality imaging when treating patients with MINOCA to help determine the underlying etiology and rule out mimics of MINOCA, so that therapies appropriate to the etiology can be provided. A more systematic approach to managing patients with MINOCA should result in better treatment and an improved prognosis for these patients.

The Imaging Toolbox to Assess Patients with Suspected Myocardial Infarction in the Absence of Obstructive Coronary Artery Disease (MINOCA).

PURPOSE OF REVIEW: This paper will review myocardial infarction with non-obstructive coronary arteries (MINOCAs) briefly, and then focus on the imaging tools that should be employed when caring for patients with suspected MINOCA. RECENT FINDINGS: Diagnostic imaging has a critical role in assessing patients with suspected or confirmed MINOCA. The extent at which these diagnostic tests are used in any given patient will depend on the clinical acumen for the underlying condition, as well as the available resources. There are myriad conditions that can lead to MINOCA; further testing to exclude other underlying causes of myocardial injury is crucial. Cardiovascular imaging may assist in identifying the etiological cause in cases where MINOCA remains the most likely diagnosis. A systematic approach to the diagnostic assessment will help to uncover the underlying diagnosis, guide therapy, and provide the patient and their families with appropriate feedback.

Stress cardiomyopathy: Provoked chaotic T-wave lability.

Potentially lethal arrhythmia, occurring at presentation or during hospitalization, are a part of the clinical spectrum of stress cardiomyopathy. There is significant association between the catecholamine provoked nonalternating beat to beat fluctuations in T-wave morphology, termed T-wave lability (TWL), and the clinical risk of arrhythmia. We report four patients with diagnosis of stress cardiomyopathy, in whom serial electrocardiography showed macrovoltage nonalternating fluctuations in T-wave morphology.

Acute stent thrombosis: Should preventative measures start in the emergency department?

Stent thrombosis is a potentially life threatening condition caused by several factors or a combination factors, such as resistance to platelet agents and type of anticoagulation used as well as stent types. We report a case of acute thrombosis and discuss potential areas of intervention with literature review.

Hyperthermia and severe rhabdomyolysis from synthetic cannabinoids.

Synthetic cannabinoids (SC) have exploded on to the scene. With this rise in SC use, the number of complications and potential adverse effects are also well documented in the literature and is on the rise. The most frequently cited side effects are behavioral in nature and range for severe agitation to psychosis and delirium. We report a case of hyperthermia with severe rhabdomyolysis from SC use.

When a seizure is not a real seizure!

We report here 2 cases of methadone induced Torsades de Pointes with a clinical presentation mimicking convulsive seizures in a substance abuser. These cases highlight the importance of being aware of methadone-induced Torsades de Pointes and the occasional atypical clinical presentations of this condition.

Looking at diabetic ketoacidosis through electrocardiogram window!

BACKGROUND: Initial serum potassium (K+) in diabetic ketoacidosis (DKA) often does not reflect the true amount of total body K+ storage, and it is not a good predictor of subsequent hypokalemia. In this study, we tested the hypothesis that a deficiency of the total body K+ storage can be detected initially on surface electrocardiography (ECG). METHOD: Medical records of 350 patients with a diagnosis of DKA were reviewed. Data regarding serial basic metabolic panels, arterial blood gases, serum ketones, and total K+ replacement that patient received during admission were collected. We compared biochemical findings for patients with and without QTU corrected (QTUc) prolongation by using the t test. Patients who were taking medications known to affect QTUc or cause ST-T changes were excluded. RESULTS: After exclusion criteria, 61 patients were enrolled in this study. In 38 patients (62.9%), QTUc was more than or equal to 450 milliseconds. Patients with prolonged QTc received statistically more K+ supplementation during admission (P = .014). They also had lower serum K+ level during their hospital course (P = .002) compared to patients with normal QTUc intervals. No significant difference was found between initial serum K+, calcium, glucose, anion gap, acidosis, age, or heart rate between these 2 groups. CONCLUSION: The significant relationship between K+ depletion and the ECG changes observed in this study deserves further consideration. Our findings confirm the concept that the ECG is an easy and reliable tool for early diagnosis of hypokalemia in patients with DKA.

Synthetic Cannabinoids and Their Effects on the Cardiovascular System.

BACKGROUND: In the past couple of years, there has been an outbreak of synthetic cannabinoid (SC) use in major cities in the United States. Patients can present with various symptoms affecting the central nervous and cardiovascular systems. The effects of endocannabinoid on contractility and Ca(2+) signaling have been shown through both cannabinoid receptors and a direct effect on ion channels. These effects result in abnormalities in ionotropy, chronotropy, and conduction. CASE REPORT: Here we report on two cases of SC abuse and abnormalities in the cardiovascular system. These cases raise concerns about the adverse effects of SCs and the possibility of QTc prolongation and subsequent complications when using antipsychotic medication in the presence of SC abuse. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Given the rise in SC use and the potential effect on the cardiovascular system, physicians need to be mindful of potential cardiac complications, such as QTc prolongation and torsade de pointe, especially when administering medications that have the potential to cause QTc prolongation.

Hazards with ordering troponin in patients with low pretest probability of acute coronary syndrome.

BACKGROUND: In clinical practice, we progressively rely on biomarkers, without estimating the pretest probability. There is not enough support for the use of cardiac troponin (cTn) I in the management of noncardiac patients. We studied the rate at which this test was ordered, the prevalence of detection of a positive result in noncardiac patients, and the impact of this incidental finding on clinical management. METHODOLOGY: Patients admitted from December 2011 to 2013 to our community hospital with diagnosis of noncardiac disease who had positive cTn were included. Data collected included final diagnosis, patient disposition, cardiac monitoring, cardiology consult, and cardiac biomarker testing. RESULTS: Cardiac troponin I was ordered for 1700 patients in our emergency department. Seven hundred fifty patients had a positive cTn. Of the 750 patients, 412 had a positive cTn without any clinical suspicion of an acute coronary syndrome. An incidental finding of a positive cTn leads to ordering of cTn on average 4 times during admission, cardiac monitoring of 379 (91.99%) patients for at least 1 day, and a cardiac consultation for 268 (63.65%) of these patients. None of these patients was candidates for an invasive cardiac intervention. Seventy-eight (19.17%) patients were admitted to the cardiac care unit and subsequently transferred to the medical intensive care unit. CONCLUSIONS: A positive cTn in patients diagnosed with a nonacute coronary syndrome was associated with increased cardiac biomarker testing, telemetry monitoring, and cardiology consults. This study supports adherence to national guidelines for the use of cTn, to reduce hospital cost and resource utilization.

Underestimated and unreported prolonged QTc by automated ECG analysis in patients on methadone: can we rely on computer reading?

BACKGROUND: Recognition of prolonged corrected QT (QTc) interval is of particular importance, especially when using medications known to prolong QTc interval. Methadone can prolong the QTc interval and has the potential to induce torsades de pointes. OBJECTIVE: The objective of this study is to investigate the accuracy of computerized ECG analysis in correctly identifying and reporting QTc interval in patients on methadone. METHODS: We conducted a retrospective review of ECGs in the Muse electronic database of patients on methadone who are above 18 years old between January 2012 and December 2013 at an urban community hospital. ECGs were analyzed by the Marquette 12SL ECG Analysis Program (GE'Healthcare) reviewed by a cardiologist. RESULTS: A total of 826 ECGs of patients on methadone were examined manually for the QTc interval, of which 625 (75.7%) had QTc less than 470 ms, 149 (18%) had QTc between 470-499 ms and 52 (6.3%) had QTc more than 499 ms. QTc between 470-499 ms was underestimated by machine in 19 (12.8%) ECGs and QTc more than 499 ms was underestimated in 10 (19.6%) when compared to manually calculated QTc. QTc prolongation was underreported in 63 ECGs (48.5%) of those whose QTc between 470-499 ms and in 1 ECG (2.4%) of those whose QTc was more than 499 ms. CONCLUSIONS: QTc can be underestimated or unreported by the computer analysis. Physicians not only should calculate QTc manually but also examine the actual QTc value displayed on the report before concluding that this parameter is normal, especially in patients who are at risk of QTc prolongation.