An unusual cause of recurrent syncope in a patient with implantable cardioverter defibrillator

Electromagnetic interferences (EMI) deriving from electrical devices may affect implantable cardioverter defibrillators (ICD). Improved algorithms have been developed in order to minimize adverse effects. However, caution should be still recommended in ICD recipients when handling electrical devices. Here we describe the case of an ICD patient with recurrent syncopal episodes due to inhibition of pacing by oversensing of electrical noise from a not properly grounded washing machine.     

Usefulness of tilt testing in children with syncope: a survey of pediatric electrophysiologists

The role of tilt table testing as a diagnostic modality in children with unexplained syncope is unclear. We sent a questionnaire to members of the Pediatric and Congenital Electrophysiology Society to assess the current practice pattern. Of the 186 members, 97 (52%) replied. Twenty four percent of the pediatric electrophysiologists have completely stopped doing tilt table tests and of those performing the tests, a majority (76%) did < 10 tests/yr (median=3 tilts/yr, range 0-100/yr). Of those performing the test, 95% rarely or never accepted direct referrals from the general practioners and 62% felt that the frequency of tilt table tests being performed had decreased since they had started practicing. The median usefulness of the test was rated at 3 (range 1-9) on a scale of 1 to 10 with 10 being very useful. A majority (68%) felt they rarely or never altered treatment based on the results of the tilt test. Wide variability was noted in the test protocol including the tilt angle, tilt duration, use of pharmacologic agents and the duration of fasting prior to the test. We therefore conclude that there is significant lack of standardization in tilt table tests performed in children. Tilt table testing, as perceived by pediatric electrophysiologists, is of limited utility and progressively less used in children with syncope.     

Diagnostic dilemma of cardiac syncope in pediatric patients

Aims

Syncope is defined as temporary loss of consciousness and postural tone resulting from an abrupt transient decrease in cerebral blood flow. The present work aimed at determining how diagnostic tests are used in the evaluation of pediatric syncope at a tertiary pediatric referral center and to report on the utility and the yield of these tests.

Settings and Design

Retrospective study conducted at a tertiary referral arrhythmolology service

Methods and Material

The clinical charts of 234 pediatric patients presenting with a primary complaint of syncope with an average age of 7.48 ± 3.82(3.5-16) years were reviewed by the investigators.

Statistical analysis used

Statistical Package of social science (SPSS) version 9,0 was used for analysis of data.

Results

The commonest trigger for syncope in the study population was early following exercise (n=65) and the commonest prodrome was palpitation, noted in 25 patients. A murmur was present in 19 of our patients (8.3%) while 10.7% (n=25) had abnormal ECGs. Of the 106 echocardiograms done, 14 (13.2%) were abnormal. Only two of them were missed by ECG. All patients were offered ambulatory 24 hour ECG. One patient with sick sinus syndrome was diagnosed only with Holter.

Conclusions

Clues to the presence of cardiac syncope may include acute onset of syncope, frequent episodes, low difference between blood pressure readings in supine and erect positions (after standing for 2 minutes) and most importantly an abnormal 12 lead ECG. Transthoracic echo and Holter monitoring have low yield in pediatric syncope.     

Use of a novel pacing mode to achieve biventricular pacing in a patient with recurrent atrial lead dislodgement after CRT-D implantation

Cardiac resynchronization therapy device (CRT-P and CRT-D) implantation has increased tremendously with increasing operator experience, eligible patients and expansion of indications. Refinements in devices and algorithms now aid physicians to improve biventricular pacing and optimize CRT. We report a case in which an interesting device program was used to achieve biventricular pacing after repeated dislodgement of the atrial lead in a patient implanted with CRT-D.     

Randomized Prospective Comparison of Two Protocols for Head-up Tilt Testing in Patients with Normal Heart and Recurrent Unexplained Syncope

BackgroundThis randomized study was aimed to compare the diagnostic value of two head-up tilt testing protocols using sublingual nitroglycerin for provocation in patients with recurrent unexplained syncope and normal heart.MethodsThe patients with normal findings in physical examination, electrocardiography and echocardiography were randomly submitted to one of upright tilt test protocols. The only difference between two protocols was that nitroglycerin was administered after a five minute resting phase in supine position during protocol B. We also considered eighty normal persons as the control group.ResultsOut of 290 patients that underwent tilt testing, 132 patients were in group A versus 158 patients in group B. Both groups had an identical distribution of clinical characteristics. Tilt test was positive in 79 patients in group A (25 in passive phase, 54 in active phase) versus 96 patients in group B (43 in passive phase, 53 in active phase). There was no significant difference between results in two groups (P value = 0.127). Forty cases were tested with protocol A and forty underwent tilt testing with protocol B. Tilt test was positive in 4 cases with protocol A versus 3 cases in protocol B. The positive rates of tilt testing with protocol A was 60% while it was 61% in protocol B. The specificity of testing with protocol A was 90% and it was 92.5% in protocol B.ConclusionsAccording to our data, adding a period of rest and returning to supine position before nitroglycerin administration had no additional diagnostic yield.     

儿童直立调节试验对不明原因晕厥的诊断价值

目的:探讨直立倾斜试验对儿童不明原因晕厥的诊断价值,为临床诊断提供科学依据。方法:对208例不明原因晕厥的儿童给予进行直立倾料试验检查,持续进行心电监护监测,记录其血压、心率变化,分析试验结果。结果:145例(69.71%)出现阳性的血管迷走神经反应,73例(50.34%)为血管抑制型反应;19例(13.10%)呈心脏抑制型反应;53例(36.55%)为混合型反应型,并且诱发因子多为持久站立。结论:不明原因晕厥患者在直立倾斜试验中以血管迷走反应为主,持久站立是血管迷走神经性晕厥的主要诱因。     

Ultrastructural evidence of GABA-ergic inhibition and glutamatergic excitation in the pacemaker nucleus of the gymnotiform electric fish,Hypopomus

The medullary pacemaker nucleus of Hypopomus triggers each electric organ discharge (EOD) by a single command pulse. It consists of electrotonically coupled pacemaker cells, which generate the rhythm, and relay cells, which follow the pacemaker cells and excite the spinal motoneurons of the electric organ. The pacemaker cells receive two inputs from the complex of the diencephalic prepacemaker nucleus (PPn), a GABA-ergic inhibition and a glutamatergic excitation. Relay cells, on the other hand, receive two glutamatergic inputs, one from a subnucleus of the PPn, the PPn-C, and a second from the sublemniscal prepacemaker nucleus (SPPn).We have labelled afferents to the pacemaker nucleus by injecting HRP to specific sites of the prepacemaker complex. By using immunogold-labelled antibodies and en-grid staining techniques, we demonstrated GABA and glutamate immunoreactivity in labelled synaptic profiles of ultra-thin sections of the pacemaker nucleus. The two types of synapses were interspersed on the surfaces of pacemaker cells, with GABA-immunoreactive synapses apparently representing the GABA-mediated input of the PPn-I, an inhibitory subdivision of the PPn, and glutamate-immunoreactive synapses representing the input of the PPn-G, an excitatory subdivision of the PPn. Only glutamate-immunoreactive synapses were found on relay cells.Abbreviations AMPA -Amino-3-hydroxy-5-methylisoxazole-4-propionic acid - CP central posterior nucleus - EOD electric organ discharge - GABA -aminobutyric acid - GAD L-glutamate decarboxylase - HRP horseradish peroxidase - JAR jamming avoidance response - NMDA N-methyl-D-aspartate - PPn (diencephalic) prepacemaker nucleus - SPPn sublemniscal prepacemaker nucleus     

Bifurcation analysis and effects of changing ionic conductances on pacemaker rhythm in a sinoatrial node cell model

The electrical excitation (action potential generation) of sinoatrial node (cardiac pacemaker) cells is directly related to various ion channels (pore-forming proteins) in cell membranes. In order to analyze the relation between action potential generation and ion channels, we use the Yanagihara-Noma-Irisawa (YNI) model of sinoatrial node cells, which is described by the Hodgkin-Huxley-type equations with seven variables. In this paper, we analyze the global bifurcation structure of the YNI model by varying various conductances of ion channels, and examine the effects of these conductance changes on pacemaker rhythm (frequency of action potential generation). The coupling effect on pacemaker rhythm is also examined approximately by applying external current to the YNI model.     

心脏起搏与电生理学技术和方法的回顾与展望

回顾了心脏电生理方法学和器械进步的早期基石,并阐述了以导管和起搏技术为特点的心内电生理学若干标志性新方法、新领域、新进展。进而展望了心脏电生理方法学的若干发展方向。     

Risk of death and recurrent ventricular arrhythmias in survivors of cardiac arrest concurrent with acute myocardial infarction

Aims

Cardiac arrest (CA) is an indication for defibrillator (ICD) implantation unless it occurs in the context of an acute myocardial infarction (AMI). We investigated the ventricular arrhythmia (VA)-free survival of patients resuscitated from CA in the setting of AMI.

Methods

We reviewed a database of 1600 AMI and CA survivors from which 48 patients were identified as having concurrent CA and AMI (CA+AMI group). Those patients were matched by age, gender, race, and left ventricular ejection fraction (LVEF) to 96 patients with AMI but no CA (AMI group) and 48 patients with CA but no AMI (CA group).

Results

Patients and controls were followed for 3.9±3.2 years. Patients in the 3 groups had similar baseline characteristics (age 63±14 yrs, 78% men, 98% white, 53% with CAD, LVEF 33±14%). The 5-year VA-free survival was 67%, 92%, and 80% for the CA+AMI, AMI, and CA groups, respectively, p<0.001.

Conclusion

Patients with concurrent CA and AMI are at high risk of recurrent VA, with VA-free survival rates significantly worse than those of patients with AMI but no CA, and comparable to those of patients with CA outside the context of an AMI. Accordingly, these patients should be considered for ICD implantation.     

A cytogenetic study of couples with recurrent spontaneous abortions and infertile patients with recurrent IVF/ICSI failure

PURPOSE:

This study was conducted to determine the frequency and contribution of chromosomal abnormalities in miscarriages and in couples with recurrent in vitro fertilization/intra cytoplasmic sperm injection (IVF/ICSI) failure.

MATERIALS and METHODS:

A total of 221 individuals; 79 with three or more recurrent spontaneous abortions and 142 with at least three IVF/ICSI failures. Chromosomal analysis from peripheral blood lymphocytes was performed according to standard cytogenetic methods using G-banding technique.

RESULTS:

Abnormal karyotype was found in 21 (9.50%) individuals. Of these 21 subjects, 4 (19.04%) exhibited sex chromosomal abnormalities and 17 (80.96%) had autosomal abnormalities. Male partners had significantly higher chromosomal abnormalities (5.88%) than of females (3.61%). These abnormalities were also higher in patients with recurrent spontaneous abortions than with IVF/ICSI failure (P < 0.05).

CONCLUSIONS:

These data may be indicative that chromosomal abnormalities are involved more in spontaneous abortions than in recurrent IVF/ICSI failure. Cytogenetic analysis could be valuable for these couples when clinical data fail to clarify the cause.     

结扎冠状动脉后快速起搏方法建立急性心功能不全动物模型

目的探讨建立急性心功能不全动物模型的可行性。方法完全结扎犬前降支,进行快速右室起搏,使心输出量(CCO)较基础状态稳定地下降50%,分别测定基础及心输出量下降状态下的血压(AP)、血氧(SaO2)、平均右房压(mRAP)、平均肺毛压(mPCWP)、系统血管阻力(SVR)、心腔大小、左室射血分数(LVEF)、血浆肾素活性(PRA)、内皮素(ET)、尿量(UO)、血肌酐(Scr)、肌酐清除率(Ccr)。结果结扎LAD和快速右室起搏后,CCO较基础状态均稳定地下降50%,CCO降低后,AP、SaO2显著下降,mRAP、mPCWP、SVR显著升高;心脏各腔室明显扩大,LVEF显著降低;PRA、ET、Scr明显升高,UO、Ccr明显下降。结论结扎冠状动脉前降支及快速右心室起搏可成功制作急性心功能不全的动物模型。     

Comparison of RFFIT tests with different standard sera and testing procedures

The World Health Organization (WHO) standard assay for determining antibody level is the rapid fluorescent focus inhibition test (RFFIT) and is used to determine the degree of immunity after vaccinatio...     

Perioperative kinetics of endocan in patients undergoing cardiac surgery with and without cardiopulmonary bypass

IntroductionEndothelial Specific Molecule-1 or endocan is a novel biomarker associated with the development of acute lung injury (ALI) in response to a systemic inflammatory state such as trauma. Acute Respiratory Distress syndrome (ARDS), a severe form of ALI is a devastating complication that can occur following cardiac surgery due to risk factors such as the use of cardiopulmonary bypass (CPB) during surgery. In this study we examine the kinetics of endocan in the perioperative period in cardiac surgical patients.MethodsAfter ethics approval, we obtained informed consent from 21 patients undergoing elective cardiac surgery (3 groups with seven patients in each group: coronary artery bypass grafting (CABG) with the use of CPB, off-pump CABG and complex cardiac surgery). Serial blood samples for endocan levels were taken in the perioperative period (T0: baseline prior to induction, T1: at the time of heparin administration, T2: at the time of protamine, T2, T3, T4 and T5 at 1, 2, 4 and 6 h following protamine administration respectively). Endocan samples were analysed using the enzyme-linked immunosorbent assay (ELISA) method. Statistical analysis incorporated the use of test for normality.ResultsOur results reveal that an initial rise in the levels of serum endocan from baseline in all patients after induction of anaesthesia. Patients undergoing off-pump surgery have lower endocan concentrations in the perioperative period than those undergoing CPB. Endocan levels decrease following separation from CPB, which may be attributed to haemodilution following CPB. Following administration of protamine, endocan concentrations steadily increased in all patients, reaching a steady state between 2 and 6 h. The baseline endocan concentrations were elevated in patients with hypertension and severe coronary artery disease.ConclusionBaseline endocan concentrations are higher in hypertensive patients with critical coronary artery stenosis. Endocan concentrations increased after induction of anaesthesia and decreased four hours after separation from CPB. Systemic inflammation may be responsible for the rise in endocan levels following CPB.     

Loss of consciousness and convulsion induced by a ventricular tachycardia mimicking epilepsy in a patient with noncompaction cardiomyopathy: a case report

Convulsions and loss of consciousness can be caused by, among other things, arrhythmias, conduction disorders or epilepsy. In clinical practice it can be difficult to distinguish between these causes of syncope, even for well-trained specialists. Patients with cardiac syncope have a substantial risk of subsequent sudden death. We present a patient with previously unknown noncompaction cardiomyopathy in whom syncope induced by ventricular tachycardia was misinterpreted as epilepsy. We present this case report in order to underline the necessity for cardiological assessment in patients with assumed mild epilepsy or syncope of unknown origin.     

A review of toxicity testing protocols and endpoints with Artemia spp.

Artemia spp. is an historically popular biological model still requiring an official internationally based standardization. Several endpoints are currently available. Short-term acute endpoints include biomarker (acetylcholinesterase; heat stress proteins; lipid peroxidation; thiobarbituric acid reactive substances; thioredoxin reductase; glutathione-peroxidase; glutathione S-transferase; glutathione reductase; aldehyde dehydrogenase; and adenylpyrophosphatase and Fluotox), hatching (dry biomass, morphological disorders and size), behavioral (swimming speed and path length), teratogenicity (growth), and immobilization (meaning mortality after 5–30 s observation). Long-term chronic tests focus on growth, reproduction and survival or mortality after 7–28 d exposure from larval to adulthood stage. We analyzed each test looking at its endpoint, toxicant and experimental design including replicates, exposure time, number of exposed cysts or organisms and their relative life stage, exposure conditions during hatching and testing (salinity, pH, light intensity, aeration dilution media, and food supply), type of testing chambers, and quality assurance and quality control criteria. Similarities and differences between the identified approaches were highlighted. Results evidenced that hatching 24 h short-term and 14 d long-term mortality are the most promising Artemia spp. protocols that should go forward with international standardization.