The effect of left ventricular longitudinal strain on left atrial function and ventricular filling in hypertension.

AIM: To assess the relationship of global longitudinal strain during left atrial (LA) and left ventricular (LV) filling and emptying. MATERIALS AND METHODS: Using magnetic resonance imaging in 47 hypertensive patients, biplane global LV longitudinal strain was evaluated and related to LA and LV filling and emptying (by volumetric analysis), and to pulmonary vein and trans-mitral flow (by phase-contrast imaging). The results were compared to normal subjects. RESULTS: In hypertensive patients, reduced global longitudinal LV strain was associated with reduced LA reservoir (47 ± 10 versus 53 ± 9%, p<0.05), reduced LA conduit function (21 ± 9 versus 32 ± 11%, p<0.004), reduced LA early peak emptying rate (150 ± 77 versus 230 ± 88 ml/s, p=0.007), and slower early LV filling (373 ± 141 versus 478 ± 141 ml/s, p=0.03). LA peak filling rate showed a positive correlation to LV peak emptying rate (R=0.331, p=0.02). CONCLUSION: In hypertensive heart disease, impaired LV longitudinal systolic function causes reduced LA filling and emptying, and this leads directly to impaired LV filling and diastolic dysfunction.

The design and use of a simple device for the MRI assessment of changes in cardiovascular function by lower-body negative-pressure-simulated reduction of central blood volume.

AIM: To use a locally designed and simple lower-body negative-pressure (LBNP) device and 1.5 T magnetic resonance imaging (MRI) to demonstrate the ability to assess changes in cardiovascular function during preload reduction. These effects were evaluated on ventricular volumes and great vessel flow in healthy volunteers, for which there are limited published data. MATERIAL AND METHODS: After ethical review, 14 volunteers (mean age 33.9 ± 7 years, mean body mass index [BMI] 23.1 ± 2.5) underwent LBNP prospectively at 0, -5, -10, and -20 mmHg pressure, using a locally designed LBNP box. Expiratory breath-hold biventricular volumes, and free-breathing flow imaging of the ascending aorta and main pulmonary artery were acquired at each level of LBNP. RESULTS: At -5 mmHg, there was no change in aortic flow or left ventricular volumes versus baseline. Right ventricular output (p=0.013) and pulmonary net flow (p=0.026) decreased. At -20 mmHg, aortic and pulmonary net flow (p<0.001) decreased, as were left and right ventricular end diastolic volume (p<0.001) and left and right end systolic volumes (p=0.038 and p=0.003 respectively). CONCLUSIONS: Use of a MRI-compatible LBNP device is feasible to measure changes in ventricular volume and great arterial flow in the same experiment. This may enhance further research into the effects of preload reduction by MRI in a wide range of important cardiovascular pathologies.

Efficacy of percutaneous closure of patent foramen ovale: comparison among three commonly used occluders.

BACKGROUND: Percutaneous closure of patent foramen ovale (PFO) is standard treatment for patients with paradoxical embolism but studies examining the efficacy of the various occluders are lacking. OBJECTIVE: To evaluate short- and medium-term closure rates of three common occluders. METHODS: One hundred and sixty-six adults (47±12 (18-81 years)) were evaluated with transthoracic bubble echocardiography before and after PFO closure. Only patients with large PFOs were included (>30 bubbles in the left heart after Valsalva). RESULTS: Three occluders were used: Amplatzer (AGA Medical Corporation) (n=80, 48%), Gore Helex (n=48, 29%) and Premere TM (St Jude Medical) (n=38, 23%). One (0.6%) neurological event occurred during follow-up. At 6 months significant residual shunting after Valsalva was highest in the group that received the Helex (58.3%), and lower for Premere (39.5%) and Amplatzer (32.5%). At final follow-up residual shunting remained higher in patients with the Helex (33.3%) than in Premere (18.5%) and Amplatzer (11%). Amplatzer had a significantly lower residual shunt rate than Helex (p<0.05 at 6 months and final follow-up). The Premere had an intermediate residual shunt rate. Septal aneurysm also predicted residual shunting (RR=24.7, 95% CI: 8.2 to 74.4, p<0.0001). CONCLUSIONS: Percutaneous PFO closure is an efficacious progressive treatment but closure rates also depend on the presence of aneurysm and differ between occluders.

Possible therapeutic targets in cardiac myocyte apoptosis.

Since Kerr described programmed cell death (apoptosis) as a process distinct from necrosis, there have been many studies of apoptosis in disease, especially of immunological origin. Because cardiac myocytes are terminally differentiated cells, they have typically been assumed to die exclusively by necrosis. However, during the last decade this view has been challenged by several studies demonstrating that a significant number of cardiac myocytes undergo apoptosis in myocardial infarction, heart failure, myocarditis, arrhythmogenic right ventricular dysplasia, and immune rejection after cardiac transplantation, as well as in other conditions of stress. These are potentially relevant observations, because apoptosis--unlike necrosis--can be blocked or reversed at early stages. Specific inhibition of this process may confer a considerable degree of cardioprotection, but requires a thorough understanding of the underlying mechanisms. Recent progress includes a better understanding of the importance of mitochondria-initiated events in cardiac myocyte apoptosis, of factors inducing apoptosis in heart failure and during hypoxia, and of the dual pro-apoptotic and anti-apoptotic effects of hypertrophic stimuli such as beta-adrenoceptor agonists, angiotensin converting enzyme inhibitors, nitric oxide and calcineurin. The investigation of cytoprotective and apoptotic signal transduction pathways has revealed important new insights into the roles of the mitogen-activated protein kinases p38, extracellular signal regulated kinase and c-Jun N-terminal kinase in cardiac cell fate. Our present review focuses on the intracellular signal transduction pathways of cardiac myocyte apoptosis and the possibility of specific inhibition of the process.

[Definitions regarding medical errors]. / Definiciones respecto al error en medicina.

Medical errors can be defined as value laden facts, in relation to guidelines or expectations, to the responsibility involved, to the obligations abated, to the pertinence of excuses afforded because of complexity, compliance and prudence or its aggravation through recklessness. Due care is related to prevention and corresponding attitudes. Professionalism, continuous education and quality control systems to detect errors without dispensing inexcusable faults, are the main tools to avoid medical errors.