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Spontaneous Onset (spontaneous + onset)
Selected AbstractsSpontaneous Onset of Ventricular Fibrillation during Atrioventricular Nodal Reentrant TachycardiaJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2009CHRISTIAN VON BARY M.D. No abstract is available for this article. [source] Electrophysiological Differences of the Spontaneous Onset of Paroxysmal and Persistent Atrial FibrillationPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 3 2007STEFAN WEBER M.D. Background: Information about the spatiotemporal organization of atrial activity at the onset of atrial fibrillation (AF) is still limited. Methods: AF mapping was performed in 30 patients with AF (mean age 53 ± 9 years, 26 males) by deploying a noncontact mapping balloon in the left atrium (LA). Twenty-four patients had paroxysmal AF and six patients had persistent AF. Three types of AF episodes were analyzed: nonsustained AF (lasting , 30 seconds), sustained AF (lasting > 30 seconds, with spontaneous conversion or requiring internal cardioversion and subsequent stable sinus rhythm), and persistent AF episodes (stable sinus rhythm lasting , 1 minute after cardioversion). Results: A total of 101 spontaneous AF onset episodes were analyzed. Analysis of AF onset showed that there was a progressive shortening of the initial cycle lengths from nonsustained episodes to sustained episodes and to persistent AF episodes. There was an earlier and more rapid reduction in the cycle lengths from persistent episodes to sustained episodes and to nonsustained episodes of AF (P < 0.05 for persistent vs sustained and for sustained vs nonsustained episodes). The development of multiwavelet activity and disorganization of conduction occurred earlier in persistent and sustained episodes than in nonsustained AF episodes. LA size was greater in patients with persistent AF episodes compared with patients with sustained or nonsustained AF episodes. Conclusions: Electrophysiological events that develop at the onset of AF seem to be different in different types of AF. A more rapid degeneration into the fibrillatory activity was observed in persistent and sustained AF than in nonsustained AF episodes. [source] Electrophysiologic and electrocardiographic characteristics of focal atrial tachycardia arising from superior tricuspid annulusINTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 7 2008J. X. Yin Summary Objectives:, This study describes the electrophysiologic and electrocardiographic characteristics of focal atrial tachycardia (AT) arising from superior tricuspid annulus in six (1.9%) patients of a consecutive series of 320 patients. Methods:, Six patients (mean age 42 ± 22 years) with a mean cycle length of 326 ms of a consecutive series of 320 patients undergoing radiofrequency ablation for focal AT were mapped. Results:, During electrophysiologic study, tachycardia could be induced in five patients with programmed atrial extrastimuli while a spontaneous onset and offset with ,warm-up and cool-down' phenomenon was seen in the other patient. During tachycardia, P-wave morphology in Lead I, II, III and aVF was upright in all the six patients. The precordial leads were dominantly negative or isoelectric in V1,V2 and positive in V5,V6 with a transition at V3 or V4. Moreover, the tachycardia was sensitive to intravenous administration of adenosine triphosphate in five of six patients. Conclusions:, Radiofrequency ablation was performed successfully in all patients (mean 4.5 ± 1.2 applications). No recurrence of AT was observed after a mean follow-up of 8 ± 6 months. Thus, AT arising from superior tricuspid annulus is rare. Radiofrequency ablation of this kind of AT is safe and effective. [source] Electrophysiologic characteristics and radiofrequency ablation of focal atrial tachycardia arising from para-Hisian regionINTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 3 2007Y. Zhou Summary This study describes the electrophysiologic characteristics and radiofrequency ablation of focal atrial tachycardia (AT) arising from para-Hisian region in 14 (6.0%) patients of a consecutive series of 224 patients patients. Inverted or biphasic P wave in V1 and uncharacteristic P wave in inferior leads were observed during tachycardia, suggesting that there isn't a characteristic P-wave morphology for para-Hisian AT. During electrophysiological study, tachycardia could be induced with programmed atrial extrastimuli in 11 patients while a spontaneous onset and offset with ,warm-up and cool-down' phenomenon were seen in other three patients. Moreover, the tachycardias were sensitive to intravenous administration of adenosine triphosphate in all patients. On the basis of these findings, the mechanism is suggestive of triggered activity or micro-reentry, but automaticity cannot be conclusively excluded. Radiofrequency energy was delivered to the earliest site of atrial activation during AT. Ablating energy was carefully titrated, starting at 5 W and increasing gradually upto a maximum of 40 W, to achieve the ceasing of tachycardia. The long-term outcome was a 100% success rate in these 14 patients and there were no irreversible complications associated with ablation. Thus, the mapping and ablation of focal AT arising from para-Hisian region is safe and effective, delivery of radiofrequency energy in a titrated manner and continuous monitoring of atrioventricular (AV) conduction advocated to minimise the risk of damage to the anterograde AV conduction. [source] Nonlinear Analysis of Heart Rate Variability: Fractal and Complexity Measures of Heart Rate BehaviorANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 2 2000Juha S. Perkiömäki M.D. Many new methods of analyzing heart rate (HR) variability have been developed to describe the features in HR behavior that cannot be detected by traditional time- and frequency-domain methods. Some of the new methods, such as analysis of fractal correlation properties and complexity of HR dynamics, have provided clinically useful information in various patient populations. Importantly, some fractal analysis methods are better risk predictors of mortality than traditional HR variability measures, and analysis of complexity of HR dynamics has been shown to predict the spontaneous onset of atrial fibrillation. New analysis methods based on nonlinear dynamics are a promising tool for better understanding of normal and abnormal HR behavior. More work will be needed to establish the clinical applicability of traditional and new analysis methods of HR variability. [source] Impact of intrapartum epidural analgesia on breast-feeding durationAUSTRALIAN AND NEW ZEALAND JOURNAL OF OBSTETRICS AND GYNAECOLOGY, Issue 5 2003Jennifer J. Henderson Abstract Background: ,Although the labour and delivery outcomes of epidural analgesia have been investigated extensively, the effects on breast-feeding success are not clearly identified. Aim: To investigate the effects of intrapartum epidural analgesia on breast-feeding duration. Methods: Nulliparous women enrolled in a randomised trial investigating labour and delivery outcomes of intrapartum epidural analgesia were asked about breast-feeding outcomes. Breast-feeding duration was ascertained by a self-report at 2 and 6 months post-partum. Breast-feeding outcomes were analysed as a prospective observational study because of high cross-over rates (43.4%) in the original randomised controlled trial. Results: A total of 992 women were recruited to the trial with 690 (69.6%) receiving epidural analgesia in labour. Breast-feeding was initiated by 95% (n = 946). At 2 and 6 months, 625 (63.5%) and 401 (40.7%), respectively, were still breast-feeding. Intrapartum analgesia (trend P -value = 0.036), mode of delivery (P < 0.001), age (P < 0.001), education (P < 0.001), and smoking in pregnancy (P < 0.001) showed univariate associations with breast-feeding duration. In the subgroup of women with spontaneous onset of labour and vaginal deliveries, after controlling for other obstetric and demographic factors, epidural analgesia but not narcotic analgesia was significantly associated with reduced breast-feeding duration (adjusted hazard ratio 1.44, 95% confidence interval 1.04,1.99). Conclusions: Nulliparous women have a high use of epidural analgesia in labour. Nulliparous women who choose epidural analgesia are more likely to breast-feed for shorter durations. Further exploration of the factors underlying this association should be undertaken. [source] Low saliva progesterone concentrations are associated with spontaneous early preterm labour (before 34 weeks of gestation) in women at increased risk of preterm deliveryBJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 11 2009GCL Lachelin Saliva progesterone and oestriol concentrations were determined weekly from 24 weeks of gestation in women at increased risk of preterm delivery. Samples were analysed from 28 women with spontaneous onset of labour and delivery before 37 weeks of gestation, and 64 who delivered at term. Saliva progesterone was lower in the 12 women delivering before 34 weeks than in those delivering later, between 34 and 37 weeks (P = 0.007) or at term (P = 0.009). Measurement of saliva progesterone may be of value in the prediction of early preterm labour and in determining which women might benefit from progesterone supplementation. [source] Association between lactate in vaginal fluid and time to spontaneous onset of labour for women with suspected prelabour rupture of the membranesBJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 12 2006E Wiberg-Itzel Objectives, To assess whether lactate determination in vaginal fluid is associated with, and can predict, onset of labour for women with suspected prelabour rupture of the membranes (PROM). Design, Prospective observational study. Setting, Labour ward at Soder Hospital, Stockholm, Sweden. Population, Women with suspected PROM after 34 weeks of gestation, who later had spontaneous onset of labour (n= 179). Methods, All women underwent a speculum examination and a test for determining lactate concentration in vaginal fluid. We used logistic regression to estimate the association between lactate concentration in vaginal fluid and time to onset of labour. Main outcome measures, Time from examination to onset of labour (cervix ,4 cm), within 24 hours and 48 hours. Results, The median time interval between examination and spontaneous onset of labour was 8.4 hours for women with ,high' lactate (,4.5 mmol/l) and 54 hours for those with ,low' lactate concentrations (<4.5 mmol/l). Among 86 women with high lactate concentrations, 76 (88%) had started labour within 24 hours compared with 20 of 93 (22%) women with low lactate concentrations (OR 27.7, 95% CI 12.2,63.3). After checking for the effect of visible amniotic fluid, the corresponding odds were still substantially increased (OR 13.5, 95% CI 5.3,34.3). Conclusions, High lactate concentration (,4.5 mmol/l) in vaginal fluid can be used to predict whether a woman with suspected PROM will commence spontaneous onset of labour within 24 or 48 hours. 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