190: In how many patients with Wolff-Parkinson-White syndrome-related adverse presentation isoproterenol infusion was required to reproduce the arrhythmia?

Electrophysiological study is the main method for the detection of patients with a Wolff-Parkinson-White syndrome (WPW) at risk of adverse presentation (resuscitated ventricular fibrillation (VF), documented life-threatening arrhythmia): the protocol is debated. The purpose of the study was to look in how many patients with WPW-related adverse presentation, atrial fibrillation (AF) or atrial tachycardia with the shortest RR cycle length (CL) with 1/1 conduction over accessory pathway (AP)<250msec was induced in control state (CS) and when isoproterenol was required.Methods63 patients, mean age 38±18, were referred for WPW-related adverse presentation (VF 6, other 56). EPS included in CS atrial pacing and measurement of the shortest CL with 1/1 conduction over AP and programmed stimulation with 1 and 2 extrastimuli. AP effective refractory period (ERP) was determined. In absence of induction of a tachycardia with a CL <250msec, isoproterenol (0.02 to 1μg. min-1) was infused to increase sinus rate to 130bpm; the protocol was repeated.ResultsMean shortest CL conducted over AP was 223±30msec in CS, 192±25msec after isoproterenol. APERP was 225±29msec in CS, 191±19msec after isoproterenol. Atrioventricular orthodromic tachycardia (AVRT) was induced in 34 patients (54%), antidromic tachycardia (ATD) in 13 (21%), AF in 43 (68%). Criteria for a malignant form (induction of AF or ATD with a shortest CL <250mesc) were noted in 42 patients (67%) in CS and were obtained after isoproterenol in remaining 21 patients (33%). Among these patients, 12 had inducible tachycardia in CS (AVRT (n=6), ATD (n=3), AF (n=3) but the shortest CL was >240msec. A tachycardia was only induced after isoproterenol in 9 patients (14%).ConclusionsInfusion of isoproterenol should be systematic when WPW is evaluated. EPS performed only in CS missed at least 14% of patients at risk of life-threatening arrhythmias who had no inducible supraventricular tachyarrhythmia and 33% of patients with a WPW without the classical criteria for a malignant form. Isoproterenol increased the sensitivity of EPS for the detection of malignant form from 67 to 100%

092: Prognosis value of QRS duration in patients with heart disease and syncope

BackgroundPatients with heart disease (HD) and syncope are at high risk of sudden death. Implantable defibrillator (ICD) is recommended in patients with unexplained syncope and left ventricular ejection fraction (LVEF) < 30% or in patients with LVEF >30% and inducible ventricular tachycardia (VT).AimThe purpose of the study was to evaluate the prognostic significance of QRS duration measurement in patients with HD and syncope.Methods528 patients, 89 women and 439 men, mean age 65±12 years, were admitted for syncope. All of them had an HD, either ischemic HD (n=382) or left ventricular impairment of other origin (n=115). Holter monitoring, electrophysiological study and head-up tilt test were systematic. Filtered QRS duration was measured at signal-averaged ECG (Fidelity 2000 of Cardionics) (filter 40 Hz, noise level < 0.6 μV). The patients were followed from 3 months up to 18 years (mean 5 ±4 years).ResultsMean LVEF was 40±14%. Cardiac defibrillator was implanted in 73 patients. 30 patients died suddenly, 75 died from heart failure or were transplanted (n=9). Remaining patients are alive or died from non cardiac death (n= 8). The last group differed from group who died suddenly by an higher LVEF (42±14% vs 32±13) (p< 0.00001) and a shorter QRS duration (125±34 msec vs 144±31) (p< 0.026). They tended to be older (65±12 years vs 61±13) (p<0.09). The alive group differed also from group who died from heart failure by an higher LVEF (42±14% vs 33±13) (p< 0.001) and a shorter QRS duration (125±34 msec vs 141±31) (p< 0.0033). They tended to be younger (65±12 years vs 67±10) (p<0.08). Patients who died suddenly and those who died from heart failure had similar LVEF and QRS duration but patients who died suddenly are younger than patients who died from heart failure (p<0.01).ConclusionsLow LVEF is a classical risk of worse prognosis in patients with HD and syncope. A longer QRS duration is also a noninvasive and simple test of worse prognosis. A QRS duration more than 125 msec had a sensitivity of 73% and a specificity of 64% to predict cardiac mortality

Global Array-Based Transcriptomics from Minimal Input RNA Utilising an Optimal RNA Isolation Process Combined with SPIA cDNA Probes

Technical advances in the collection of clinical material, such as laser capture microdissection and cell sorting, provide the advantage of yielding more refined and homogenous populations of cells. However, these attractive advantages are counter balanced by the significant difficultly in obtaining adequate nucleic acid yields to allow transcriptomic analyses. Established technologies are available to carry out global transcriptomics using nanograms of input RNA, however, many clinical samples of low cell content would be expected to yield RNA within the picogram range. To fully exploit these clinical samples the challenge of isolating adequate RNA yield directly and generating sufficient microarray probes for global transcriptional profiling from this low level RNA input has been addressed in the current report. We have established an optimised RNA isolation workflow specifically designed to yield maximal RNA from minimal cell numbers. This procedure obtained RNA yield sufficient for carrying out global transcriptional profiling from vascular endothelial cell biopsies, clinical material not previously amenable to global transcriptomic approaches. In addition, by assessing the performance of two linear isothermal probe generation methods at decreasing input levels of good quality RNA we demonstrated robust detection of a class of low abundance transcripts (GPCRs) at input levels within the picogram range, a lower level of RNA input (50 pg) than previously reported for global transcriptional profiling and report the ability to interrogate the transcriptome from only 10 pg of input RNA. By exploiting an optimal RNA isolation workflow specifically for samples of low cell content, and linear isothermal RNA amplification methods for low level RNA input we were able to perform global transcriptomics on valuable and potentially informative clinically derived vascular endothelial biopsies here for the first time. These workflows provide the ability to robustly exploit ever more common clinical samples yielding extremely low cell numbers and RNA yields for global transcriptomics

Is Ablation of Atrial Flutter Always Safe?

International audienceBackground: Radiofrequency ablation of typical atrial flutter is largely used and is considered as safe. The purpose of the study was to evaluate the prevalence and the causes of severe adverse event (AE) following atrial flutter ablation.Methods: Ablation of typical flutter was performed by conventional method with an 8-mm-tip electrode catheter, a maximum power of 70 W, and a maximum target temperature of 70° for 60 seconds in 883 patients, (685 males and 198 females aged from 18 to 93 years [64 ± 11.5]; 664 had heart disease [HD]).Results: AE occurred in 44 patients (5%). AE was life threatening in 14 patients: poorly tolerated bradycardia (transient complete atrioventricular block [AVB] or sinus bradycardia [SB] <40 beats per minute) associated with cardiac shock and acute renal failure in five patients, tamponade (n = 1), bleeding leading to death (n = 1), various AE-related deaths (n = 2), ventricular tachycardia-related death (n = 1), definitive complete AVB (n = 3), and right coronary artery occlusion-related complete AVB (n = 1). Less serious AE occurred in 30 patients: transitory major SB or second- or third-degree AVB (n = 23), bleeding (n = 4), transient ischemic attack (n = 1), and various AE (n = 2). Most of the bradycardia was related to β-blockers or other antiarrhythmic drugs used to slow atrial flutter. Factors of AE were female gender (36% vs 22%, P < 0.02) and the presence of ischemic (P < 0.03) or valvular HD (P < 0.01).Conclusions: AE following atrial flutter ablation occurred in 5% of patients. Most of them are avoidable by control of anticoagulants and arrest of rate-control drugs used to slow the rate of atrial flutter

RNA yield from titrated HUVEC following RNA isolation using process A or process B.

<p>Cells were titrated over a range of 3000-200 cells per tube and each split equally into 6 aliquots for subsequent cell lysis and RNA isolation by either of two process (Process A or B). All resultant RNAs were quantified by reverse transcription of the entire yielded RNA and quantitative real-time PCR against a standard curve of known HUVEC total RNA input. The table shows mean total RNA yields (numbers in parenthesis  =  standard deviation from three technical replicates).</p

Low abundant probeset retention with decreasing RNA input levels.

<p>Data from the microarrays generated according to the workflow set out in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0017625#pone-0017625-g002" target="_blank">Figure 2</a> was filtered for those probe sets representing a family of proteins, G protein-coupled receptors (GPCR), known to be of low abundance and difficult to detect using microarrays. The signal intensity was set at a threshold of Log₂≥6 or Log₂≥7 to ensure analysis of probe sets demonstrating strong hybridisation and robust signal. Data plotted is the number of GPCR probe sets present with differing RNA input levels and the number of genes that are represented in parenthesis below the data point. When duplicate GeneChips were available only the probe sets passing threshold in both duplicates were included. Venn diagrams illustrate the overlap of common genes between GeneChips from titrated RNA input levels for either WT-Ovation FFPE or WT-One-Direct RNA amplification systems.</p

Quality metrics from test vascular endothelial biopsy sample cDNA probes generated by the WT-Ovation FFPE and WT-Ovation One-Direct RNA amplification systems.

<p>cDNA yield and microarray quality metrics generated from one vascular endothelial cell biopsy using either the WT-Ovation FFPE or One-Direct RNA amplification system. Quality metrics reflect Expression Console (Affymetrix) report data generated following MAS5.0 feature extraction.</p

Assessing GeneChip quality control metrics and the effects of cDNA probe quality using Principle Components Analysis.

<p>(<b>A</b>) MAS5.0 QC data generated in Expression Console (Affymetrix) displayed using PCA illustrates the majority of GeneChips (n = 64) clustering together within 2 standard deviations of the group mean. The PCA is coloured according to the sscDNA quality score designated to each sample. Of the small number of samples lying out with the 2 SD boundary, sscDNA quality does not appear to be responsible for the variation shown, with this being contributed by other experimental factors. (<b>B</b>) PCA visualisation of Affx control probes only, coloured by sscDNA quality score shows that a significant proportion of the variation is driven by quality of the sscDNA probes. (<b>C</b>) PCA visualisation including all probes reveals the distinct sub-groups of the cohort according to expressed transcriptome patterns, regardless of cDNA quality.</p