Three-dimensional speckle tracking

Two-dimensional speckle tracking is a useful technology. Nevertheless, it has some limitations because the heart has three dimensions. The recent development of three-dimensional speckle tracking technology provides a new diagnostic tool. By using this new method, a more complete and probably accurate evaluation of global and segmental left ventricular function may be performed. Three-dimensional speckle tracking is a promising tool to provide new insights into left ventricular function.     

Identifying patients without favourable long-term outcome among those with medically stabilized unstable angina and a negative dipyridamole stress echocardiogram

Aims: Patients with medically stabilized unstable angina anda negative stress echocardiogram have a favourable outcome asa whole. This study sought to identify which subsets of patientsare associated with serious events at long-term within thispopulation. Methods and results: We studied and followed-up 128 patients(mean 2.2 ± 1.3 years) with medically stabilized unstableangina and a negative dipyridamole stress echocardiogram. Cumulativesurvival rates were 98.2±1.3%, 96.0±2.2% and 93.2±3.2%,at 1, 2 and 4 years, respectively. Freedom from events (death,myocardial infarction, and revascularization) were 98.2±1.3%,96.0±2.2% and 86.3±6.0%, at 1, 2, and 4 years,respectively. Cumulative mortality rate was higher in men (3.6±2.5%,8.5±4.1%, and 12.2±5.4% at 1, 2, and 4 years,vs. 0% at the end of the follow-up in women; p = 0.034), andin those with previous myocardial infarction (4.3±4.3%,9.1±6.2%, and 18.2±2.3% at 1, 2 and 4 years, vs.1.1±1.1%, 2.9±2.1%, and 2.9±2.1% in thosewithout previous myocardial infarction, respectively; p = 0.047). Conclusion: Among patients with medically stabilized unstableangina and a negative dipyridamole stress echocardiogram, malegender and previous myocardial infarction are associated witha non-favourable outcome.     

Searching for new mechanisms of myocardial fibrosis with diagnostic and/or therapeutic potential

Myocardial fibrosis is the result of excessive fibrillar collagen synthesis and deposition without reciprocally balanced degradation. It causes cardiac dysfunction, arrhythmias, and ischaemia, and thereby determines the clinical course and outcome of cardiac patients even when adequately treated. Therefore, further research is needed to identify and better understand the factors that trigger and maintain the myocardial fibrotic response against different injuries in a variety of cardiac diseases. Here, we will focus on the following major areas of research: molecules that stimulate the differentiation of fibroblasts into myofibroblasts and subsequently alter collagen turnover (e.g. cardiotrophin‐1, galectin‐3, NADPH oxidases, and neutrophil gelatinase‐associated lipocalin), microRNA‐induced alterations of collagen gene expression, and matricellular protein‐ and lysyl oxidase‐mediated alterations of collagen cross‐linking and deposition.     

Regular theta‐firing neurons in the nucleus incertus during sustained hippocampal activation

This paper describes the existence of theta‐coupled neuronal activity in the nucleus incertus (NI). Theta rhythm is relevant for cognitive processes such as spatial navigation and memory processing, and can be recorded in a number of structures related to the hippocampal activation including the NI. Strong evidence supports the role of this tegmental nucleus in neural circuits integrating behavioural activation with the hippocampal theta rhythm. Theta oscillations have been recorded in the local field potential of the NI, highly coupled to the hippocampal waves, although no rhythmical activity has been reported in neurons of this nucleus. The present work analyses the neuronal activity in the NI in conditions leading to sustained hippocampal theta in the urethane‐anaesthetised rat, in order to test whether such activation elicits a differential firing pattern. Wavelet analysis has been used to better define the neuronal activity already described in the nucleus, i.e., non‐rhythmical neurons firing at theta frequency (type I neurons) and fast‐firing rhythmical neurons (type II). However, the most remarkable finding was that sustained stimulation activated regular‐theta neurons (type III), which were almost silent in baseline conditions and have not previously been reported. Thus, we describe the electrophysiological properties of type III neurons, focusing on their coupling to the hippocampal theta. Their spike rate, regularity and phase locking to the oscillations increased at the beginning of the stimulation, suggesting a role in the activation or reset of the oscillation. Further research is needed to address the specific contribution of these neurons to the entire circuit.