Decoupling speciation and extinction reveals both abiotic and biotic drivers shaped 250 million years of diversity in crocodile-line archosaurs.

Whereas living representatives of Pseudosuchia, crocodylians, number fewer than 30 species, more than 700 pseudosuchian species are known from their 250-million-year fossil record, displaying far greater ecomorphological diversity than their extant counterparts. With a new time-calibrated tree of >500 species, we use a phylogenetic framework to reveal that pseudosuchian evolutionary history and diversification dynamics were directly shaped by the interplay of abiotic and biotic processes over hundreds of millions of years, supported by information theory analyses. Speciation, but not extinction, is correlated with higher temperatures in terrestrial and marine lineages, with high sea level associated with heightened extinction in non-marine taxa. Low lineage diversity and increased speciation in non-marine species is consistent with opportunities for niche-filling, whereas increased competition may have led to elevated extinction rates. In marine lineages, competition via increased lineage diversity appears to have driven both speciation and extinction. Decoupling speciation and extinction, in combination with ecological partitioning, reveals a more complex picture of pseudosuchian evolution than previously understood. As the number of species threatened with extinction by anthropogenic climate change continues to rise, the fossil record provides a unique window into the drivers that led to clade success and those that may ultimately lead to extinction.

Ecological Transitions and the Shape of the Decapod Tree of Life.

Understanding the processes that shaped the distribution of species richness across the Tree of Life is a central macroevolutionary research agenda. Major ecological innovations, including transitions between habitats, may help to explain the striking asymmetries of diversity that are often observed between sister clades. Here, we test the impact of such transitions on speciation rates across decapod crustaceans, modeling diversification dynamics within a phylogenetic framework. Our results show that, while terrestrial lineages have higher speciation rates than either marine or freshwater lineages, there is no difference between mean speciation rates in marine and freshwater lineages across Decapoda. Partitioning our data by infraorder reveals that those clades with habitat heterogeneity have higher speciation rates in freshwater and terrestrial lineages, with freshwater rates up to 1.5 times faster than marine rates, and terrestrial rates approximately four times faster. This averaging out of marine and freshwater speciation rates results from the varying contributions of different clades to average speciation rates. However, with the exception of Caridea, we find no evidence for any causal relationship between habitat and speciation rate. Our results demonstrate that while statistical generalizations about ecological traits and evolutionary rates are valuable, there are many exceptions. Hence, while freshwater and terrestrial lineages typically speciate faster than their marine relatives, there are many atypically slow freshwater lineages and fast marine lineages across Decapoda. Future work on diversification patterns will benefit from the inclusion of fossil data, as well as additional ecological factors.

Eye movements show similar adaptations in temporal coordination to movement planning conditions in both people with and without cerebral palsy.

The effects of cerebral palsy on movement planning for simple reaching tasks are not well understood. Movement planning is complex and entails many processes which could be affected. This study specifically sought to evaluate integrating task information, decoupling movements, and adjusting to altered mapping. For a reaching task, the asynchrony between the eye onset and the hand onset was measured across different movement planning conditions for participants with and without cerebral palsy. Previous research shows people without cerebral palsy vary this temporal coordination for different planning conditions. Our measurements show similar adaptations in temporal coordination for groups with and without cerebral palsy, to three of the four variations in planning condition tested. However, movement durations were still longer for the participants with cerebral palsy. Hence for simple goal-directed reaching, movement execution problems appear to limit activity more than movement planning deficits.

Infarct size and left ventricular remodelling after preventive percutaneous coronary intervention.

OBJECTIVE: We hypothesised that, compared with culprit-only primary percutaneous coronary intervention (PCI), additional preventive PCI in selected patients with ST-elevation myocardial infarction with multivessel disease would not be associated with iatrogenic myocardial infarction, and would be associated with reductions in left ventricular (LV) volumes in the longer term. METHODS: In the preventive angioplasty in myocardial infarction trial (PRAMI; ISRCTN73028481), cardiac magnetic resonance (CMR) was prespecified in two centres and performed (median, IQR) 3 (1, 5) and 209 (189, 957) days after primary PCI. RESULTS: From 219 enrolled patients in two sites, 84% underwent CMR. 42 (50%) were randomised to culprit-artery-only PCI and 42 (50%) were randomised to preventive PCI. Follow-up CMR scans were available in 72 (86%) patients. There were two (4.8%) cases of procedure-related myocardial infarction in the preventive PCI group. The culprit-artery-only group had a higher proportion of anterior myocardial infarctions (MIs) (55% vs 24%). Infarct sizes (% LV mass) at baseline and follow-up were similar. At follow-up, there was no difference in LV ejection fraction (%, median (IQR), (culprit-artery-only PCI vs preventive PCI) 51.7 (42.9, 60.2) vs 54.4 (49.3, 62.8), p=0.23), LV end-diastolic volume (mL/m2, 69.3 (59.4, 79.9) vs 66.1 (54.7, 73.7), p=0.48) and LV end-systolic volume (mL/m2, 31.8 (24.4, 43.0) vs 30.7 (23.0, 36.3), p=0.20). Non-culprit angiographic lesions had low-risk Syntax scores and 47% had non-complex characteristics. CONCLUSIONS: Compared with culprit-only PCI, non-infarct-artery MI in the preventive PCI strategy was uncommon and LV volumes and ejection fraction were similar.

Highly automatic quantification of myocardial oedema in patients with acute myocardial infarction using bright blood T2-weighted CMR.

BACKGROUND: T2-weighted cardiovascular magnetic resonance (CMR) is clinically-useful for imaging the ischemic area-at-risk and amount of salvageable myocardium in patients with acute myocardial infarction (MI). However, to date, quantification of oedema is user-defined and potentially subjective. METHODS: We describe a highly automatic framework for quantifying myocardial oedema from bright blood T2-weighted CMR in patients with acute MI. Our approach retains user input (i.e. clinical judgment) to confirm the presence of oedema on an image which is then subjected to an automatic analysis. The new method was tested on 25 consecutive acute MI patients who had a CMR within 48 hours of hospital admission. Left ventricular wall boundaries were delineated automatically by variational level set methods followed by automatic detection of myocardial oedema by fitting a Rayleigh-Gaussian mixture statistical model. These data were compared with results from manual segmentation of the left ventricular wall and oedema, the current standard approach. RESULTS: The mean perpendicular distances between automatically detected left ventricular boundaries and corresponding manual delineated boundaries were in the range of 1-2 mm. Dice similarity coefficients for agreement (0=no agreement, 1=perfect agreement) between manual delineation and automatic segmentation of the left ventricular wall boundaries and oedema regions were 0.86 and 0.74, respectively. CONCLUSION: Compared to standard manual approaches, the new highly automatic method for estimating myocardial oedema is accurate and straightforward. It has potential as a generic software tool for physicians to use in clinical practice.

Microvascular Resistance Predicts Myocardial Salvage and Infarct Characteristics in ST-Elevation Myocardial Infarction.

BACKGROUND: The pathophysiology of myocardial injury and repair in patients with ST-elevation myocardial infarction is incompletely understood. We investigated the relationships among culprit artery microvascular resistance, myocardial salvage, and ventricular function. METHODS AND RESULTS: The index of microvascular resistance (IMR) was measured by means of a pressure- and temperature-sensitive coronary guidewire in 108 patients with ST-elevation myocardial infarction (83% male) at the end of primary percutaneous coronary intervention. Paired cardiac MRI (cardiac magnetic resonance) scans were performed early (2 days; n=108) and late (3 months; n=96) after myocardial infarction. T(2)-weighted- and late gadolinium-enhanced cardiac magnetic resonance delineated the ischemic area at risk and infarct size, respectively. Myocardial salvage was calculated by subtracting infarct size from area at risk. Univariable and multivariable models were constructed to determine the impact of IMR on cardiac magnetic resonance-derived surrogate outcomes. The median (interquartile range) IMR was 28 (17-42) mm Hg/s. The median (interquartile range) area at risk was 32% (24%-41%) of left ventricular mass, and the myocardial salvage index was 21% (11%-43%). IMR was a significant multivariable predictor of early myocardial salvage, with a multiplicative effect of 0.87 (95% confidence interval 0.82 to 0.92) per 20% increase in IMR; P<0.001. In patients with anterior myocardial infarction, IMR was a multivariable predictor of early and late myocardial salvage, with multiplicative effects of 0.82 (95% confidence interval 0.75 to 0.90; P<0.001) and 0.92 (95% confidence interval 0.88 to 0.96; P<0.001), respectively. IMR also predicted the presence and extent of microvascular obstruction and myocardial hemorrhage. CONCLUSION: Microvascular resistance measured during primary percutaneous coronary intervention significantly predicts myocardial salvage, infarct characteristics, and left ventricular ejection fraction in patients with ST-elevation myocardial infarction. (J Am Heart Assoc. 2012;1:e002246 doi: 10.1161/JAHA.112.002246).

Is there still a role for preoperative 12-lead electrocardiography?

BACKGROUND: Twelve-lead electrocardiography is a standard preoperative investigation for patients undergoing major surgery. There is uncertainty and debate over the usefulness of this test for stratifying postoperative cardiac risk. The aim of this study was to investigate the correlation between an abnormal electrocardiogram (ECG) and the postoperative cardiac event rate. METHODS: A prospective single-center observational cohort study in patients undergoing major noncardiac surgery was performed. ECGs were analyzed at the end of the study by a cardiologist and a clinician blinded to the clinical outcomes. The primary endpoints were a major adverse cardiac event (MACE), defined as nonfatal myocardial infarction or cardiac death, and perioperative mortality. RESULTS: A total of 345 patients were included, who had undergone aortic surgery 25.8%, lower limb bypass 29.0%, amputation 25.2%, or laparotomy 20.0%. An abnormal ECG was present in 141 (40.9%) patients. MACE occurred in 46 (13.3%) cases. Patients with an abnormal ECG had a significantly higher incidence of MACE (21.6 vs. 8.3%, P < 0.001). Multivariate analysis showed that left ventricular strain and a prolonged QTc interval (>440 ms) were independent predictors of postoperative adverse events. Among patients with no prior history of ischemic heart disease, those with an abnormal ECG had a higher MACE rate (20.3%) than those patients with a normal ECG (8.6%) (P = 0.01). CONCLUSION: Preoperative electrocardiography is a useful screening test for predicting perioperative cardiac events. Patients with an abnormal ECG but without a prior history of heart disease are a high-risk group potentially amenable to intervention and risk reduction.

Bright-blood T(2)-weighted MRI has high diagnostic accuracy for myocardial hemorrhage in myocardial infarction: a preclinical validation study in swine.

BACKGROUND: Myocardial hemorrhage after myocardial infarction (MI) usually goes undetected. We investigated the diagnostic accuracy of bright-blood T(2)-weighted cardiac MRI for myocardial hemorrhage in experimental MI. METHODS AND RESULTS: MI was created in swine by occluding the left anterior descending (n=10) or circumflex (n=5) coronary arteries for 90 minutes followed by reperfusion for ≤3 days (n=2), 10 days (n=7), or 60 days (n=6). MRI was performed at 1.5 T, using bright-blood T(2)-prepared steady-state free-precession, T(2)* and early (1 minute) and late (10-15 minutes) gadolinium enhancement (EGE, LGE, respectively) MRI. Left ventricular sections and histology were assessed for hemorrhage by an experienced cardiac pathologist blinded to the MRI data. Hypointense regions on T(2)-weighted and contrast-enhanced MRI were independently determined by 3 cardiologists experienced in MRI who were also blinded to the pathology results. Eighty ventricular pathological sections were matched with MRI (n=68 for EGE MRI). All sections with evidence of MI (n=63, 79%) also exhibited hyperintense zones consistent with edema on T(2)-weighted MRI and infarct on LGE MRI. Myocardial hemorrhage occurred in 49 left ventricular sections (61%) and corresponded with signal voids on 48 T(2)-weighted (98%) and 26 LGE-MRI (53%). Alternatively, signal voids occurred in the absence of hemorrhage in 3 T(2)-weighted (90% specificity) and 5 LGE MRI (84% specificity). On EGE MRI, 27 of 43 cases of early microvascular obstruction corresponded with hemorrhage (63% sensitivity), whereas 5 of 25 defects occurred in the absence of hemorrhage (80% specificity). The positive and negative predictive values for pathological evidence of hemorrhage were 94% and 96% for T(2)-weighted, 84% and 55% for LGE MRI, and 85% and 56% for EGE MRI. CONCLUSIONS: Bright-blood T(2)-weighted MRI has high diagnostic accuracy for myocardial hemorrhage.

Bright-blood T2-weighted MRI has higher diagnostic accuracy than dark-blood short tau inversion recovery MRI for detection of acute myocardial infarction and for assessment of the ischemic area at risk and myocardial salvage.

BACKGROUND: T2-Weighted MRI reveals myocardial edema and enables estimation of the ischemic area at risk and myocardial salvage in patients with acute myocardial infarction (MI). We compared the diagnostic accuracy of a new bright-blood T2-weighted with a standard black blood T2-weighted MRI in patients with acute MI. METHODS AND RESULTS: A breath-hold, bright-blood T2-weighted, Acquisition for Cardiac Unified T2 Edema pulse sequence with normalization for coil sensitivity and a breath-hold T2 dark-blood short tau inversion recovery sequence were used to depict the area at risk in 54 consecutive acute MI patients. Infarct size was measured on gadolinium late contrast enhancement images. Compared with dark-blood T2-weighted MRI, consensus agreements between independent observers for identification of myocardial edema were higher with bright-blood T2-weighted MRI when evaluated per patient (P<0.001) and per segment of left ventricle (P<0.001). Compared with bright-blood T2-weighted MRI, dark-blood T2-weighted MRI underestimated the area at risk compared with infarct size (P<0.001). The 95% limits of agreement for interobserver agreements for the ischemic area at risk and myocardial salvage were wider with dark-blood T2-weighted MRI than with bright-blood T2-weighted MRI. Bright blood enabled more accurate identification of the culprit coronary artery with correct identification in 94% of cases compared with 61% for dark blood (P<0.001). CONCLUSIONS: Bright-blood T2-weighted MRI has higher diagnostic accuracy than dark-blood T2-weighted MRI. Additionally, dark-blood T2-weighted MRI may underestimate area at risk and myocardial salvage.