Dynamic directed interictal connectivity in left and right temporal lobe epilepsy.

OBJECTIVE There is increasing evidence that epileptic activity involves widespread brain networks rather than single sources and that these networks contribute to interictal brain dysfunction. We investigated the fast-varying behavior of epileptic networks during interictal spikes in right and left temporal lobe epilepsy (RTLE and LTLE) at a whole-brain scale using directed connectivity. METHODS In 16 patients, 8 with LTLE and 8 with RTLE, we estimated the electrical source activity in 82 cortical regions of interest (ROIs) using high-density electroencephalography (EEG), individual head models, and a distributed linear inverse solution. A multivariate, time-varying, and frequency-resolved Granger-causal modeling (weighted Partial Directed Coherence) was applied to the source signal of all ROIs. A nonparametric statistical test assessed differences between spike and baseline epochs. Connectivity results between RTLE and LTLE were compared between RTLE and LTLE and with neuropsychological impairments. RESULTS Ipsilateral anterior temporal structures were identified as key drivers for both groups, concordant with the epileptogenic zone estimated invasively. We observed an increase in outflow from the key driver already before the spike. There were also important temporal and extratemporal ipsilateral drivers in both conditions, and contralateral only in RTLE. A different network pattern between LTLE and RTLE was found: in RTLE there was a much more prominent ipsilateral to contralateral pattern than in LTLE. Half of the RTLE patients but none of the LTLE patients had neuropsychological deficits consistent with contralateral temporal lobe dysfunction, suggesting a relationship between connectivity changes and cognitive deficits. SIGNIFICANCE The different patterns of time-varying connectivity in LTLE and RTLE suggest that they are not symmetrical entities, in line with our neuropsychological results. The highest outflow region was concordant with invasive validation of the epileptogenic zone. This enhanced characterization of dynamic connectivity patterns could better explain cognitive deficits and help the management of epilepsy surgery candidates.

Different visual exploration of tool-related gestures in left hemisphere brain damaged patients is associated with poor gestural imitation.

According to the direct matching hypothesis, perceived movements automatically activate existing motor components through matching of the perceived gesture and its execution. The aim of the present study was to test the direct matching hypothesis by assessing whether visual exploration behavior correlate with deficits in gestural imitation in left hemisphere damaged (LHD) patients. Eighteen LHD patients and twenty healthy control subjects took part in the study. Gesture imitation performance was measured by the test for upper limb apraxia (TULIA). Visual exploration behavior was measured by an infrared eye-tracking system. Short videos including forty gestures (20 meaningless and 20 communicative gestures) were presented. Cumulative fixation duration was measured in different regions of interest (ROIs), namely the face, the gesturing hand, the body, and the surrounding environment. Compared to healthy subjects, patients fixated significantly less the ROIs comprising the face and the gesturing hand during the exploration of emblematic and tool-related gestures. Moreover, visual exploration of tool-related gestures significantly correlated with tool-related imitation as measured by TULIA in LHD patients. Patients and controls did not differ in the visual exploration of meaningless gestures, and no significant relationships were found between visual exploration behavior and the imitation of emblematic and meaningless gestures in TULIA. The present study thus suggests that altered visual exploration may lead to disturbed imitation of tool related gestures, however not of emblematic and meaningless gestures. Consequently, our findings partially support the direct matching hypothesis.

Details of left ventricular radial wall motion supporting the ventricular theory of the third heart sound obtained by cardiac MR.

OBJECTIVE Obtaining new details of radial motion of left ventricular (LV) segments using velocity-encoding cardiac MRI. METHODS Cardiac MR examinations were performed on 14 healthy volunteers aged between 19 and 26 years. Cine images for navigator-gated phase contrast velocity mapping were acquired using a black blood segmented κ-space spoiled gradient echo sequence with a temporal resolution of 13.8 ms. Peak systolic and diastolic radial velocities as well as radial velocity curves were obtained for 16 ventricular segments. RESULTS Significant differences among peak radial velocities of basal and mid-ventricular segments have been recorded. Particular patterns of segmental radial velocity curves were also noted. An additional wave of outward radial movement during the phase of rapid ventricular filling, corresponding to the expected timing of the third heart sound, appeared of particular interest. CONCLUSION The technique has allowed visualization of new details of LV radial wall motion. In particular, higher peak systolic radial velocities of anterior and inferior segments are suggestive of a relatively higher dynamics of anteroposterior vs lateral radial motion in systole. Specific patterns of radial motion of other LV segments may provide additional insights into LV mechanics. ADVANCES IN KNOWLEDGE The outward radial movement of LV segments impacted by the blood flow during rapid ventricular filling provides a potential substrate for the third heart sound. A biphasic radial expansion of the basal anteroseptal segment in early diastole is likely to be related to the simultaneous longitudinal LV displacement by the stretched great vessels following repolarization and their close apposition to this segment.

Changes in Left Ventricular Torsion Early Postoperatively After Aortic Valve Replacement and at Long-Term Follow-up.

OBJECTIVE In patients with aortic stenosis, left ventricular systolic torsion (pT) is increased to overcome excessive afterload. This study assessed left ventricular torsion before and immediately after surgical valve replacement and tested the instant effect of fluid loading. DESIGN Prospective, clinical single-center study. SETTING Intensive care unit of a university hospital. PARTICIPANTS 12 patients undergoing elective aortic valve replacement for aortic stenosis. INTERVENTIONS Echocardiography was performed on the day before surgery, within 18 hours after surgery including a fluid challenge, and after 2.5 years. MEASUREMENTS AND MAIN RESULTS pT decreased early postoperatively by 21.2% (23.4° ± 5.6° to 18.4° ± 6.9°; p = 0.012) and reached preoperative values at 2.5 years follow-up (24 ± 7). Peak diastolic untwisting velocity occurred later early postoperatively (13% ± 8% to 21% ± 9.4%; p = 0.019) and returned toward preoperative values at follow-up (10.2 ± 4.7°). The fluid challenge increased central venous pressure (8 ± 4 mmHg to 11 ± 4 mmHg; p = 0.003) and reduced peak systolic torsion velocity (138.7 ± 37.6/s to 121.3 ± 32/s; p = 0.032). pT decreased in 3 and increased in 8 patients after fluid loading. Patients whose pT increased had higher early mitral inflow velocity postoperatively (p = 0.04) than those with decreasing pT. Patients with reduced pT after fluid loading received more fluids (p = 0.04) and had a higher positive fluid balance during the intensive care unit stay (p = 0.03). Torsion after fluid loading correlated with total fluid input (p = 0.001) and cumulative fluid balance (p = 0.002). CONCLUSIONS pT decreased early after aortic valve replacement but remained elevated despite elimination of aortic stenosis. After 2.5 years, torsion had returned to preoperative levels.

Investigation of hemodynamics in an in vitro system simulating left ventricular support through the right subclavian artery using 4-dimensional flow magnetic resonance imaging.

OBJECTIVES Left ventricular assist devices are an important treatment option for patients with heart failure alter the hemodynamics in the heart and great vessels. Because in vivo magnetic resonance studies of patients with ventricular assist devices are not possible, in vitro models represent an important tool to investigate flow alterations caused by these systems. By using an in vitro magnetic resonance-compatible model that mimics physiologic conditions as close as possible, this work investigated the flow characteristics using 4-dimensional flow-sensitive magnetic resonance imaging of a left ventricular assist device with outflow via the right subclavian artery as commonly used in cardiothoracic surgery in the recent past. METHODS An in vitro model was developed consisting of an aorta with its supra-aortic branches connected to a left ventricular assist device simulating the pulsatile flow of the native failing heart. A second left ventricular assist device supplied the aorta with continuous flow via the right subclavian artery. Four-dimensional flow-sensitive magnetic resonance imaging was performed for different flow rates of the left ventricular assist device simulating the native heart and the left ventricular assist device providing the continuous flow. Flow characteristics were qualitatively and quantitatively evaluated in the entire vessel system. RESULTS Flow characteristics inside the aorta and its upper branching vessels revealed that the right subclavian artery and the right carotid artery were solely supported by the continuous-flow left ventricular assist device for all flow rates. The flow rates in the brain-supplying arteries are only marginally affected by different operating conditions. The qualitative analysis revealed only minor effects on the flow characteristics, such as weakly pronounced vortex flow caused by the retrograde flow via the brachiocephalic artery. CONCLUSIONS The results indicate that, despite the massive alterations in natural hemodynamics due to the retrograde flow via the right subclavian and brachiocephalic arteries, there are no drastic consequences on the flow in the brain-feeding arteries and the flow characteristics in the ascending and descending aortas. It may be beneficial to adjust the operating condition of the left ventricular assist device to the residual function of the failing heart.

Left atrial remodeling, early repolarization pattern, and inflammatory cytokines in professional soccer players

OBJECTIVES: Although regular physical exercise clearly reduces cardiovascular morbidity risk, long-term endurance sports practice has been recognized as a risk factor for atrial fibrillation (AF). However, the mechanisms how endurance sports can lead to AF are not yet clear. The aim of our present study was to investigate the influence of long-term endurance training on vagal tone, atrial size, and inflammatory profile in professional elite soccer players. METHODS: A total of 25 professional major league soccer players (mean age 24+/-4 years) and 20 sedentary controls (mean age 26+/-3 years) were included in the study and consecutively examined. All subjects underwent a sports cardiology check-up with physical examination, electrocardiography, echocardiography, exercise testing on a bicycle ergometer, and laboratory analysis [standard laboratory and cytokine profile: interleukin (IL)-6, tumor necrosis factor (TNF)-alpha, IL-8, IL-10]. RESULTS: Athletes were divided into two groups according to presence or absence of an early repolarization (ER) pattern, defined as a ST-segment elevation at the J-point (STE) >/=0.1mm in 2 leads. Athletes with an ER pattern showed significantly lower heart rate and an increased E/e' ratio compared to athletes without an ER pattern. STE significantly correlated with E/e' ratio as well as with left atrial (LA) volume. The pro-inflammatory cytokines IL-6, IL-8, TNF-alpha as well as the anti-inflammatory cytokine IL-10 were significantly elevated in all soccer players. However, athletes with an ER pattern had significantly higher IL-6 plasma levels than athletes without ER pattern. Furthermore, athletes with "high" level IL-6 had significantly larger LA volumes than players with "low" level IL-6. CONCLUSIONS: Athletes with an ER pattern had significantly higher E/e' ratios, reflecting higher atrial filling pressures, higher LA volume, and higher IL-6 plasma levels. All these factors may contribute to atrial remodeling over time and thus increase the risk of AF in long-term endurance sports.

Thrombus formation in the left ventricle after large myocardial infarction – assessment with cardiac magnetic resonance imaging

INTRODUCTION Left ventricular thrombus (LVT) formation may worsen the post-infarct outcome as a result of thromboembolic events. It also complicates the use of modern antiplatelet regimens, which are not compatible with long-term oral anticoagulation. The knowledge of the incidence of LVT may therefore be of importance to guide antiplatelet and antithrombotic therapy after acute myocardial infarction (AMI). METHODS In 177 patients with large, mainly anterior AMI, standard cardiac magnetic resonance imaging (CMR) including cine and late gadolinium enhancement (LGE) imaging was performed shortly after AMI as per protocol. CMR images were analysed at an independent core laboratory blinded to the clinical data. Transthoracic echocardiography (TTE) was not mandatory for the trial, but was performed in 64% of the cases following standard of care. In a logistic model, 3 out of 61 parameters were used in a multivariable model to predict LVT. RESULTS LVT was detected by use of CMR in 6.2% (95% confidence interval [CI] 3.1%-10.8%). LGE sequences were best to detect LVT, which may be missed in cine sequences. We identified body mass index (odds ratio 1.18; p = 0.01), baseline platelet count (odds ratio 1.01, p = 0.01) and infarct size as assessed by use of CMR (odds ratio 1.03, p = 0.02) as best predictors for LVT. The agreement between TTE and CMR for the detection of LVT is substantial (kappa = 0.70). DISCUSSION In the current analysis, the incidence of LVT shortly after AMI is relatively low, even in a patient population at high risk. An optimal modality for LVT detection is LGE-CMR but TTE has an acceptable accuracy when LGE-CMR is not available.

Patent Foramen Ovale Closure in Obstructive Sleep Apnea Improves Blood Pressure and Cardiovascular Function.

UNLABELLED Obstructive sleep apnea (OSA) is a frequent syndrome characterized by intermittent hypoxemia and increased prevalence of arterial hypertension and cardiovascular morbidity. In OSA, the presence of patent foramen ovale (PFO) is associated with increased number of apneas and more severe oxygen desaturation. We hypothesized that PFO closure improves sleep-disordered breathing and, in turn, has favorable effects on vascular function and arterial blood pressure. In 40 consecutive patients with newly diagnosed OSA, we searched for PFO. After initial cardiovascular assessment, the 14 patients with PFO underwent initial device closure and the 26 without PFO served as control group. Conventional treatment for OSA was postponed for 3 months in both groups, and polysomnographic and cardiovascular examinations were repeated at the end of the follow-up period. PFO closure significantly improved the apnea-hypopnea index (ΔAHI -7.9±10.4 versus +4.7±13.1 events/h, P=0.0009, PFO closure versus control), the oxygen desaturation index (ΔODI -7.6±16.6 versus +7.6±17.0 events/h, P=0.01), and the number of patients with severe OSA decreased significantly after PFO closure (79% versus 21%, P=0.007). The following cardiovascular parameters improved significantly in the PFO closure group, although remained unchanged in controls: brachial artery flow-mediated vasodilation, carotid artery stiffness, nocturnal systolic and diastolic blood pressure (-7 mm Hg, P=0.009 and -3 mm Hg, P=0.04, respectively), blood pressure dipping, and left ventricular diastolic function. In conclusion, PFO closure in OSA patients improves sleep-disordered breathing and nocturnal oxygenation. This translates into an improvement of endothelial function and vascular stiffening, a decrease of nighttime blood pressure, restoration of the dipping pattern, and improvement of left ventricular diastolic function. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT01780207.