Psychobiological characteristics of dissociative identity disorder: a symptom provocation study.

BACKGROUND: Dissociative identity disorder (DID) patients function as two or more identities or dissociative identity states (DIS), categorized as 'neutral identity states' (NIS) and 'traumatic identity states' (TIS). NIS inhibit access to traumatic memories thereby enabling daily life functioning. TIS have access and responses to these memories. We tested whether these DIS show different psychobiological reactions to trauma-related memory. METHODS: A symptom provocation paradigm with 11 DID patients was used in a two-by-two factorial design setting. Both NIS and TIS were exposed to a neutral and a trauma-related memory script. Three psychobiological parameters were tested: subjective ratings (emotional and sensori-motor), cardiovascular responses (heart rate, blood pressure, heart rate variability) and regional cerebral blood flow as determined with H(2)(15)O positron emission tomography. RESULTS: Psychobiological differences were found for the different DIS. Subjective and cardiovascular reactions revealed significant main and interactions effects. Regional cerebral blood flow data revealed different neural networks to be associated with different processing of the neutral and trauma-related memory script by NIS and TIS. CONCLUSIONS: Patients with DID encompass at least two different DIS. These identities involve different subjective reactions, cardiovascular responses and cerebral activation patterns to a trauma-related memory script.

Diurnal variation of ventricular repolarization in a large family with LQT3-Brugada syndrome characterized by nocturnal sudden death.

BACKGROUND: In patients with long-QT syndrome type 3 (LQT3), symptoms occur particularly at rest or during sleep. As to the underlying mechanism, excessive prolongation of the QT interval at slow heart rates probably plays a role. OBJECTIVES: The purpose of the present study was to investigate QT interval prolongation unrelated to heart rate comparing nighttime and daytime in a family with features of both LQT3 and Brugada syndrome. METHODS: The study group consisted of 38 carriers of the mutant gene (SCN5A, 1795insD) and 30 noncarrier family members, who served as controls. Holter monitoring was performed with beat-to-beat QT interval measurement. In addition, in a subset of subjects, an exercise test and a pacing test (carriers only) with measurement of the RT interval were performed. RESULTS: In carriers, the slope between heart rate and QT interval was significantly steeper during nighttime (0:00 a.m. to 6:00 a.m.) than during daytime (8:00 a.m. to 22:00 p.m.) (regression coefficient -6.18 and -2.80, respectively), (p=0.03),no such effect being observed in the noncarriers. Further, the RT interval was markedly shorter during recovery than during exercise in carriers but not in noncarriers. In contrast, during AAI pacing in the carriers, RT interval shortening along with increasing heart rate was followed by a comparable prolongation of the RT interval along with subsequent decreasing heart rate. CONCLUSIONS: In this large LQT3-Brugada syndrome family, carriers of the mutant gene (SCN5A, 1795insD) are characterized by diurnal variation of ventricular repolarization by exhibiting QT interval prolongation, which is more pronounced during nighttime compared with daytime, even when taking into account differences in heart rate. The autonomic nervous system appears to play a role in mediating this effect. This observation may be of relevance for explaining the high incidence of nocturnal sudden death in this family, but this remains to be proven. In addition, whether our findings also apply to other families with LQT3 is uncertain.

Does flecainide regain its antiarrhythmic activity after electrical cardioversion of persistent atrial fibrillation?

OBJECTIVES: The purpose of this study was to evaluate the hypothesis that presumed reversion of electrical remodeling after cardioversion of atrial fibrillation (AF) restores the efficacy of flecainide. BACKGROUND: Flecainide loses its efficacy to cardiovert when AF has been present for more than 24 hours. Most probably, the loss is caused by atrial electrical remodeling. Studies suggest electrical remodeling is completely reversible within 4 days after restoration of sinus rhythm (SR). METHODS: One hundred eighty-one patients with persistent AF (median duration 3 months) were included in this prospective study. After failure of pharmacologic cardioversion by flecainide 2 mg/kg IV (maximum 150 mg in 10 minutes) and subsequent successful electrical cardioversion, we performed intense transtelephonic rhythm monitoring three times daily for 1 month. In case of AF recurrence, a second cardioversion by flecainide was attempted as soon as possible. RESULTS: AF recurred in 123 patients (68%). Successful cardioversion by flecainide occurred only when SR had been maintained for more than 4 days (7/51 patients [14%]). Failure to cardiovert was associated with a prolonged duration of the recurrent AF episode and concurrent digoxin use. Multivariate logistic regression confirmed that successful cardioversion was determined by digoxin use (odds ratio [OR] 0.093, P = .047) and by the interaction between the duration of SR and the (inverse) duration of recurrent AF (OR 6.499, P < .001). When flecainide was administered within 10 hours after AF onset and the duration of SR was greater than 4 days, the success rate was 58%. CONCLUSIONS: Flecainide recovers its antiarrhythmic action after cardioversion of AF. However, successful pharmacologic cardioversion occurs only after SR has lasted at least 4 days and is expected only for recurrences having duration of a few hours. Immediate pharmacologic cardioversion of AF recurrence may be a worthwhile strategy for management of persistent AF.

Clustering of RR intervals predicts effective electrical cardioversion for atrial fibrillation.

INTRODUCTION: Atrial fibrillation (AF) is characterized by an irregularly irregular ("random") heart beat. However, controversy exists whether the ventricular rhythm in AF is truly random. We investigated randomness by constructing three-dimensional RR interval plots (3D plots), allowing identification of "clustering" of RR intervals. It was hypothesized that electrical cardioversion (ECV) would be more effective in AF patients with clustering, because clustering might reflect a higher degree of organization of atrial fibrillatory activity. METHODS AND RESULTS: The study group consisted of 66 patients (44 men and 22 women; mean age 68 +/- 11 years), who were referred for ECV because of persistent AF. Twenty-four-hour Holter recordings were used to construct 3D plots by plotting each RR interval (x axis) against the previous RR interval (y axis) and the number of occurrences of each of these x,y combinations (z axis). A clustering index was calculated as the percentage of beats within the peaks in the 3D plot. Based on the 3D plots, clustering of RR intervals was present in 31 (47%) of the 66 patients. ECV was effective in restoring sinus rhythm in 29 (94%) of these 31 patients, whereas sinus rhythm was restored in only 25 (71%) of the remaining 35 patients without clustering (P = 0.020). The clustering index ranged from <2% in the 12 patients with failed ECV to >8% in the 32 patients with sinus rhythm at the end of the study (4 weeks after the ECV); the clustering index in the 22 patients with a relapse of AF after effective ECV was intermediate (P = 0.034 and P = 0.042, respectively). CONCLUSION: This study indicates that ECV is more effective in restoring sinus rhythm in AF patients with clustering compared to patients in whom no clustering is apparent on 3D plots. In addition, the degree of clustering appears to be predictive of the overall outcome of ECV; the higher the degree of clustering, the higher the likelihood of sinus rhythm at follow-up.

Pharmacological treatment of young children with permanent junctional reciprocating tachycardia.

Our objective was to assess the efficacy of pharmacological treatment in reducing the incidence of permanent junctional reciprocating tachycardia in young children, or to bring the mean heart rate over 24 h to a normal level. We included 21 children with a median age of 0.05 year seen with permanent junctional reciprocating tachycardia over the period 1990 through 2001. Of these children, two had abnormal left ventricular function. Follow-up visits were made at least every 6 months. We registered the presence of the tachycardia over 24 h, the mean heart rate over 24 h, and cardiac function. Treatment was started with propafenone alone, or in combination with digoxin as the first choice. Treatment was effective in 14 cases (67%), with either complete disappearance of the tachycardia after discontinuation of medication, or continuation in sinus rhythm with medication; partially effective in 4 cases (20%) when the mean heart rate over 24 h on the last Holter recording was less than 1 standard deviation above the normal for age; but was not effective in the remaining 3 cases (14%). In 3 patients treated with propafenone, or 13 given propafenone and digoxin, treatment was effective in 12 (75%), partially effective in 2 (13%), and ineffective in the other 2 (13%). All 21 children had a normal left ventricular function at the end of follow-up. The median duration of follow-up was 2.4 years. Permanent junctional reciprocating tachycardia had disappeared spontaneously in one-third of the children, 5 being less than 1 year old. Adverse effects, seen in 5 cases, were mild or asymptomatic. No signs of proarrhythmia were registered. Pharmacological treatment, either with propafenone alone, or in combination with digoxin, is safe and effective in young children with permanent junctional reciprocating tachycardia. The mean heart rate is normalized, and cardiac function is restored and preserved. Radiofrequency ablation may be delayed to a safer age, with the arrhythmia disappearing spontaneously in one-third.

Diagnostic performance of various QTc interval formulas in a large family with long QT syndrome type 3: Bazett's formula not so bad after all...

BACKGROUND: Recently, we identified a novel mutation of SCN5A (1795insD) in a large family with LQTS3. The aim of this study was to assess whether the various proposed corrections of the QT interval to heart rate help to improve the identification of carriers of the mutant gene. METHODS: The study group consisted of 101 adult family members: 57 carriers and 44 noncarriers (mean age 44.6 +/- 14.6 and 40.3 +/- 12.8 years, respectively). In all individuals a 12-lead ECG, exercise ECG, and 24-hour Holter ECG were obtained. RESULTS: Correction for heart rate significantly improved the diagnostic performance of the QT interval. Diagnostic performance of the Bazett formula was similar to that of the newer formulas (Fridericia, Hodges, Framingham, and a logarithmic formula). At a cut-off value of 440 ms, the Bazett corrected QT interval was associated with a sensitivity and specificity of 90% and 91%, respectively. Using the 24-hour Holter ECG, a prolonged QTc at heart rates less than 60 beats/min was almost pathognomonic for genetic mutation (sensitivity and specificity both 99%), whereas the QTc calculated at the lowest heart rate using Bazett's formula provided full discrimination. CONCLUSION: In the present family, the resting ECG gave a good indication about the presence or absence of genetic mutation but a 24-hour Holter recording was mandatory to ascertain the diagnosis. In the diagnosis of this form of LQTS3, Bazett's formula was at least as good as other proposed corrections of the QT interval to heart rate.