Functional Genomics for Plant Breeding 3.0.

Functional genomics, as a scientific discipline, has significantly transformed the landscape of plant breeding in recent years [...].

Neutral and Pectic Heteropolysaccharides Isolated from Opuntia joconostle Mucilage: Composition, Molecular Dimensions and Prebiotic Potential.

Opuntia joconostle is a semi-wild cactus cultivated for its fruit. However, the cladodes are often discarded, wasting the potentially useful mucilage in them. The mucilage is composed primarily of heteropolysaccharides, characterized by their molar mass distribution, monosaccharide composition, structural features (by vibrational spectroscopy, FT IR, and atomic force microscopy, AFM), and fermentability by known saccharolytic commensal members of the gut microbiota. After fractionation with ion exchange chromatography, four polysaccharides were found: one neutral (composed mainly of galactose, arabinose, and xylose) and three acidic, with a galacturonic acid content from 10 to 35%mol. Their average molar masses ranged from 1.8 × 105 to 2.8 × 105 g·mol-1. Distinct structural features such as galactan, arabinan, xylan, and galacturonan motifs were present in the FT IR spectra. The intra- and intermolecular interactions of the polysaccharides, and their effect on the aggregation behavior, were shown by AFM. The composition and structural features of these polysaccharides were reflected in their prebiotic potential. Lactobacilli and Bifidobacteria were not able to utilize them, whereas members of Bacteroidetes showed utilization capacity. The obtained data suggest a high economic potential for this Opuntia species, with potential uses such as animal feed in arid areas, precise prebiotic, and symbiotic formulations, or as the carbon skeleton source in a green refinery. Our methodology can be used to evaluate the saccharides as the phenotype of interest, helping to guide the breeding strategy.

Confounding factors leading to misdiagnosing ventricular tachycardia as supraventricular in the emergency room.

Studies conducted during the last 50 years have proposed electrocardiographic criteria and algorithms to determine if a wide QRS tachycardia is ventricular or supraventricular in origin. Sustained ventricular tachycardia is an uncommon reason for consultation in the emergency room. The latter and the complexity of available electrocardiographic diagnostic criteria and algorithms result in frequent misdiagnoses. Good hemodynamic tolerance of tachycardia in the supine position does not exclude its ventricular origin. Although rare, ventricular tachycardia in patients with and without structural heart disease may show a QRS duration <120 ms. Interruption of tachycardia by coughing, carotid sinus massage, Valsalva maneuver, or following the infusion of adenosine or verapamil should not discard the ventricular origin of the arrhythmia. In patients with regular, uniform, sustained broad QRS tachycardia, the presence of structural heart disease or A-V dissociation strongly suggest its ventricular origin. Occasionally, ventricular tachycardia can present with AV dissociation without this being evident on the 12-lead ECG. Cardiac auscultation, examination of the jugular venous pulse, and arterial pulse palpation provide additional clues for identifying A-V dissociation during tachycardia. This paper does not review the electrocardiographic criteria for categorizing tachycardia as ventricular but rather why emergency physicians misdiagnose these patients.

Miniseries 2-Septal and paraseptal accessory pathways-Part IV: Inferior paraseptal accessory pathways-lessons from surgical and catheter ablation.

Surgeons and electrophysiologists performing accessory pathway ablation procedures have used the term 'posteroseptal' region. This area, however, is neither septal nor posterior, but paraseptal and inferior; paraseptal because it includes the fibro-adipose tissues filling the pyramidal space and not the muscular septum itself and inferior because it is part of the heart adjacent to the diaphragm. It should properly be described, therefore, as being inferior and paraseptal. Pathways in this region can be ablated at three areas, which we term right inferior, mid-inferior, and left inferior paraseptal. The right- and left inferior paraseptal pathways connect the right and left atrial vestibules with the right and left paraseptal segments of the parietal ventricular walls. The mid-inferior paraseptal pathways take a subepicardial course from the myocardial sleeves surrounding the coronary sinus and its tributaries. Our review addresses the evolution of the anatomical concept of the inferior paraseptal region derived from surgical and catheter ablation procedures. We also highlight the limitations of the 12-lead electrocardiogram in identifying, without catheter electrode mapping, which are the pathways that can be ablated without a coronary sinus, or left heart approach.

Miniseries 2-Septal and paraseptal accessory pathways-Part III: Mid-paraseptal accessory pathways-revisiting bypass tracts crossing the pyramidal space.

The mid-paraseptal region corresponds to the portion of the pyramidal space whose right atrial aspect is known as the triangle of Koch. The superior area of this mid-paraseptal region is also para-Hisian, and is close to the compact atrioventricular node and the His bundle. The inferior sector of the mid-paraseptal area is unrelated to the normal atrioventricular conduction pathways. It is, therefore, a safe zone in which, if necessary, to perform catheter ablation. The middle part of the mid-paraseptal zone may, however, in some patients, house components of the compact atrioventricular node. This suggests the need for adopting a prudent attitude when considering catheter ablation in this area. The inferior extensions of the atrioventricular node, which may represent the substrate for the slow atrioventricular nodal pathway, take their course through the middle, and even the inferior, sectors of the mid-paraseptal region. In this review, we contend that the middle and inferior areas of the mid-paraseptal region correspond to what, in the past, was labelled by most groups as the 'midseptal' zone. We describe the electrocardiographic patterns observed during pre-excitation and orthodromic reciprocating tachycardia in patients with pathways ablated in the middle or inferior sectors of the region. We discuss the modification of the ventriculo-atrial conduction times during tachycardia after the development of bundle branch block aberrancy. We conclude that the so-called 'intermediate septal' pathways, as described in the era of surgical ablation, were insufficiently characterized. They should not be considered the surrogate of the 'midseptal' pathways defined using endocardial catheter electrode mapping.

Miniseries 2-Septal and paraseptal accessory pathways-Part II: Para-Hisian accessory pathways-so-called anteroseptal pathways revisited.

Surgeons, when dividing bypass tracts adjacent to the His bundle, considered them to be 'anteroseptal'. The area was subsequently recognized to be superior and paraseptal, although this description is not entirely accurate anatomically, and conveys little about the potential risk during catheter interventions. We now describe the area as being para-Hisian, and it harbours two types of accessory pathways. The first variant crosses the membranous septum to insert into the muscular ventricular septum without exiting the heart, and hence being truly septal. The second variant inserts distally in the paraseptal components of the supraventricular crest, and consequently is crestal. The site of ventricular insertion determines the electrocardiographic expression of pre-excitation during sinus rhythm, with the two types producing distinct patterns. In both instances, the QRS and the delta wave are positive in leads I, II, and aVF. In crestal pathways, however, the QRS is ≥ 140 ms, and exhibits an rS configuration in V1-2. The delta wave in V1-2 precedes by 20-50 ms the apparent onset of the QRS in I, II, III, and aVF. In the true septal pathways, the QRS complex occupies ∼120 ms, presenting a QS, W-shaped, morphology in V1-2. The delta wave has a simultaneous onset in all leads. Our proposed terminology facilitates the understanding of the electrocardiographic manifestations of both types of para-Hisian pathways during pre-excitation and orthodromic tachycardia, and informs on the level of risk during catheter ablation.

Advanced interatrial block: An electrocardiographic marker for stroke recurrence.

The presence of interatrial block (IAB) has been directly related to the appearance of various atrial tachyarrhythmias and therefore could be a risk factor for stroke. The objective of this study is to establish whether the presence of IAB could predict stroke recurrence in patients with a previous episode. METHODS: We included all patients discharged from our hospital in 2011 following treatment for stroke, excluding those of cardioembolic or lacunar etiology. For all patients we analyzed the ECG recordings, determined whether the patient presented cardiovascular risk factors, and determined the presence and type of IAB. An IAB was defined as partial if the P-wave duration was ≥120 ms, and advanced if the duration was ≥120 ms and presented biphasic morphology in the inferior leads. The primary endpoint was the recurrence of stroke and the secondary endpoint was the incidence of atrial tachyarrhythmias after the first episode. RESULTS: A total of 149 patients were identified (80 (71.5-86.0) years, 41% men). After a median follow-up of 3.96 (0.63-5.35) years, 54 deaths (36%) were observed, 27 patients (18%) had experienced stroke recurrence, and 20 (13%) had developed atrial tachyarrhythmias. On multivariate analysis, the presence of advanced IAB [HR: 2.3, 95% CI (1.0-5.5); p = 0.043] and diabetes [HR: 2.5, 95% CI (1.1-5.4); p = 0.018] were significantly associated with stroke recurrence. CONCLUSION: The presence of advanced IAB predicts the recurrence of stroke in patients with a previous episode. Further studies should be performed to investigate possible interventions.

Silent atrial fibrillation in pacemaker early post-implantation period: an unintentionally provoked situation?

Aims: Atrial high-rate episodes (AHREs) compatible with silent AF detected in pacemakers (PM) are related to an increased risk of stroke and silent ischaemic brain lesions (IBL) on CT scan. AHREs soon after PM implantation could be related with the procedure itself and the prognosis might be different. Methods and results: We analysed the incidence of AHREs >5 min and the presence of silent IBL in 110 patients (56% men, aged 75 ± 9 year-old) with PM and no history of AF, in relation to time from implantation (≤3 months vs. >3 months) and the atrial lead fixation (LF) (active vs. passive). Mean CHADS2 and CHA2DS2VASc scores were 1.9 ± 1.2 and 3.5 ± 1.5, respectively. Time from implantation was ≤3 months in 88 patients (80%). Active LF was used in 55 patients (50%). After 24 ± 9 months, AHREs were present in 40 patients (36.4%). CT-scan showed silent IBL in 26 patients (23.6%). The presence of AHREs at 3 months was more frequent in the patients with recent PM implantation (17% vs. 4.5%, P = 0.09) and significantly related to active LF (OR 5.36, 1.43-20.07; P < 0.05). The presence of silent IBL was related to the detection of AHREs during follow up (OR 3.12, 1.29-7.97; P < 0.05) but not with AHREs at first 3 months (OR 1.58, 0.49-5.05; P = 0.44). Conclusions: AHREs occur frequently during the first 3 months after PM implantation and could be related with procedure itself and the use of active LF. AHREs in this period might not be related to worse outcomes and should be interpreted cautiously.

CorVue algorithm efficacy to predict heart failure in real life: Unnecessary and potentially misleading information?

BACKGROUND: Heart failure (HF) hospitalizations have a negative impact on quality of life and imply important costs. Intrathoracic impedance (ITI) variations detected by cardiac devices have been hypothesized to predict HF hospitalizations. Although Optivol™ algorithm (Medtronic, Minneapolis, MN, USA) has been widely studied, CorVue™ algorithm's (St. Jude Medical, St. Paul, MN, USA) long-term efficacy has not been systematically evaluated in a "real-life" cohort. METHODS: CorVue™ was activated in implantable cardioverter defibrillator (ICD)/cardiac resynchronization therapy defibrillator (CRT-D) patients to store information about ITI measures. Clinical events (new episodes of HF requiring treatment and hospitalizations) and CorVue™ data were recorded every 3 months. Appropriate CorVue™ detection for HF was considered if it occurred in the 4 prior weeks to the clinical event. RESULTS: Fifty-three ICD/CRT-D (26 ICD and 27 CRT-D) patients (67 ± 1 years old, 79% male) were included. Device position was subcutaneous in 28 patients. At inclusion, mean left ventricular ejection fraction was 25 ± 7% and 27 patients (51%) were in New York Heart Association class I, 18 (34%) in class II, and eight (15%) in class III. After a mean follow-up of 17 ± 9 months, 105 ITI drops alarms were detected in 32 patients (60%). Only six alarms were appropriate (true positive) and required hospitalization. Eighteen patients (34%) presented 25 clinical episodes (12 hospitalizations and 13 emergency room/ambulatory treatment modifications). Nineteen of these clinical episodes (76%) remained undetected by the CorVue™ (false negative). Sensitivity of CorVue™ resulted in 24%, specificity was 70%, positive predictive value of 6%, and negative predictive value of 93%. CONCLUSIONS: CorVue™ showed a low sensitivity to predict HF events. Therefore, routinely activation of this algorithm could generate misleading information.

Inappropriate automatic mode switching episodes: What's the mechanism?

We present a case series of five patients reporting abnormal automatic mode switching (AMS) episodes during routinary cardiac defibrillator (ICD) and pacemaker (PM) follow-up. This non-previously described phenomenon was reported to St. Jude Medical (Abbott) Technical Support that confirmed the inappropriate automatic mode switching.