La serendipia en torno la fracción de eyección: una revisión de la historia, la casualidad y la cuasi-funcionalidad de una métrica aplaudida / A critical analysis of ejection fraction

Ejection fraction (EF) is defined by the ratio of end-systolic volume (ESV) and end-diastolic volume (EDV). The resulting fraction is a dimensionless number whose interpretation is ambiguous and most likely misleading. Despite this limitation, EF is widely accepted as a clinical marker of cardiac function. In this article we analyze the role of ESV, a fundamental variable of ventricular mechanics, compared with the popular EF. Common physiology-based mathematics can explain a simple association between EF and ESV. This concept is illustrated by a detailed analysis of the information obtained from angiocardiography, echocardiography and cardiac magnetic resonance studies. EF versus ESV produces a non-linear curve. For a small ESV, the EF approaches 100%, while for a large ESV, the EF gradually decreases toward zero. This elemental relationship is commonly observed in innervated natural hearts. Thus, the popularity of EF mostly derives from a fortuitous connection with the pivotal variable ESV. Alongside this finding, we unfold historical events that facilitated the emergence of EF as a result of serendipity. Our physiology-based approach denounces the circumstantial theories invoked to justify the importance of EF as an index of cardiac function, which are critically discussed. EF appears to be nothing more than a blessing in disguise. For this reason, we propose the ESV as a more logical metric for the analysis of ventricular function.

Estrés emocional relacionado con un terremoto como factor causante de un síndrome de takotsubo / Takotsubo syndrome associated with an earthquake. report of two cases

Takotsubo syndrome is an acute heart disease usually triggered by significant emotional or physical stress, very occasionally described in association with natural disasters such as earthquakes. Clinically, it simulates an acute myocardial infarction with similar symptoms, laboratory tests, and electrocardiographic changes. Coronary angiography shows the absence of significant coronary disease. We report two women, aged 71 and 80 years, and who developed a Takotsubo syndrome after an earthquake. In both, the syndrome was diagnosed with cardiac magnetic resonance imaging.

El rol de la resonancia magnética cardíaca en el diagnóstico diferencial entre miocarditis aguda e infarto agudo de miocardio con elevación del segmento ST

Background: Acute myocarditis frequently mimics an acute myocardial infarction, and its diagnosis is a clinical challenge. Aim: To describe the characteristics of cardiac magnetic resonance imaging in patients with acute myocarditis hospitalized with a diagnosis of ST-segment elevation myocardial infarction. Patients and Methods: Twenty-four patients aged 33 ± 11 years (21 men) with a definitive diagnosis of acute myocarditis hospitalized with a presumptive diagnosis of ST-segment elevation myocardial infarction, in whom a coronary angiogram excluded significant atherosclerotic coronary lesions, were included. Cardiac magnetic resonance imaging with cine-resonance images was performed to assess global and regional ventricular function, and to study myocardial tissue characteristics. T2-STIR sequences were used for the assessment of oedema and late gadolinium enhancement for necrosis/fibrosis. Results: Patients had high levels of total CK, CK-MB, troponin I, brain natriuretic peptide and C-reactive protein. Cardiac magnetic resonance imaging revealed myocardial edema and late gadolinium enhancement was identified in all patients. The edema was transmural in 86% and subepicardial in 14%. Enhancement was subepicardial in 74% of patients and intramural in 26%. It was located in the inferior and lateral walls of the left ventricle in 93%, without affecting the endocardium. In all patients, two of three Lake Louise criteria were met, and an acute myocarditis was diagnosed. Conclusions: Cardiac magnetic resonance imaging is the diagnostic method of choice for diagnosing acute myocarditis when it mimics an acute myocardial infarction.

Valor de la resonancia magnética cardíaca para el diagnóstico diferencial en pacientes con sospecha de infarto agudo de miocardio con elevación del segmento ST y arterias coronarias normales

Background: Patients hospitalized with suspected ST-segment elevation myocardial infarction (STEMI) who have normal coronary arteries (CAs) on invasive coronary angiography (ICA) may have an AMI or another acute cardiac disease that mimics it. Aim: To evaluate the usefulness of cardiac magnetic resonance imaging (CMRI) for diagnosing conditions resembling AMI with normal CAs. Material and Methods: We studied 424 consecutive patients admitted with suspected STEMI who underwent ICA. Those with normal CAs underwent CMRI involving cine-CMRI sequences to evaluate segmental wall motion, T2-weighted short-tau inversion-recovery imaging to detect oedema and delayed contrast enhancement (DCE) after gadolinium administration to identify necrosis/fibrosis. Patients with previous myocardial infarction were excluded. Results: Twenty-six patients (6.1%) had normal CAs. Definitive diagnosis after CMRI was acute myocarditis in 11 patients (42.3%) whose DCE was localized in the subepicardium or intramyocardially but not in the endocardium, AMI in nine patients (34.6%) who had subendocardial or transmural DCE, and Takotsubo cardiomyopathy (TCM) in six patients (23.1%), whose CMRI showed regional contractility abnormalities of the left ventricle and myocardial oedema but not DCE. Conclusions: Cardiac magnetic resonance imaging allows a precise diagnosis of acute myocardial infarction in patients with angiographically normal coronary arteries.

Transposición congénitamente corregida de grandes arterias en adultos asintomáticos diagnosticada circunstancialmente por ecocardiografía: casos clínicos / Asymptomatic congenitally corrected transposition of the great arteries: report of two cases

Congenitally corrected transposition of the great arteries is a rare congenital anomaly that can remain asymptomatic until adulthood, especially when there are no other associated congenital anomalies. We report two patients in their sixth decade of life with corrected transposition of the great arteries incidentally diagnosed by transthoracic echocardiography in a preventive medical check-up. The complementary use of cardiac computed tomography confirmed the diagnosis.

Terapia con células madre e insuficiencia cardiaca: aspectos éticos / Ethics of stem cell therapy for heart failure

Heart failure is one of the first diseases in which stem cells were used for regenerative medicine. Since 2001, many publications have shown that stem cell therapy has the potential to mitigate heart diseases, but there is no solid scientific evidence to fully support its clinical application at present. The future of regenerative medicine requires validated clinical trials with standardized platforms and transdisciplinary efforts to enable the development of safe and effective regenerative therapies to protect patients and to promote the ethical application of this new and highly promising therapy. Doctors and scientists have a responsibility to discuss with patients the current reality of regenerative therapies. They also have a responsibility to discourage the indiscriminate and commercial use of these therapies, which are sometimes based on false hopes, since their inappropriate use can harm vulnerable patients as well as research efforts. Although regenerative medicine may be the medicine of the future and might bring the hope of cure for chronic diseases, it is not yet ready for its wide clinical application.

Ventriculectomía parcial izquierda en un paciente con miocardiopatía dilatada terminal: ¿una alternativa para el trasplante cardíaco? / Partial left ventriculectomy for end stage dilated cardiomyopathy: report of one case

We present a case of a 60 year old male with end stage dilated cardiomyopathy in NYHA functional class IV in whom a partial left ventriculectomy was performed, a new surgical procedure developed in Brazil and done for the first time in Chile. Left ventricular size reduction produced an objective improvement on echocardiographic parameters of left ventricular function as well as in patient's NYHA functional class in the early post operative period

Insuficiencia renal aguda en pacientes con y sin sepsis: pronóstico y evolución / Acute renal failure in septic and non septic patients: prognostic and evolution

The purpose of this prospective study was to determine whether the course and prognosis of acute renal failure (ARF) in patients with and without sepsis are different. 252 (8 percent) of 3086 consecutive patients admited to a medical surgical intensive care unit (ICU) developed ARE. One hundred forty-nine (59 percent) were septic and 103 (41 percent) were non-septic. No differences were founded between groups regarding the incidence of oliguria, hyperkalemia, hypercatabolism, gastrointestinal bleeding, duration of oliguria and renal deficit, severity of azotemia, dialysis requirements and duration of stay in the hospital. There were statistically significant differences between septic and non septic patients with respect to hyponatremia (67.8 vs 54.4 percent, p<0.04), respiratory failure (68 vs 54 percent, p<0.04), and thrombocytopenia (64 vs 48 percent, p<0.02). Mortality in septic patients was higher than in non-septics (56 vs 42.7 percent, p<0.009). Factors associated with increased mortality in ARF septic patients were respiratory failure, metabolic acidosis and oliguria while in the non-septics they were hepatic dysfunction, hyperkalemia, respiratory failure and infection acquired during the course of renal failure. We conclude that ARF developing in septic patients has a higher mortality than that of non-septic patients, whereas the incidence of hypercatabolism and oliguria was not different between both groups