Fear Potentiated Startle in Children With Autism Spectrum Disorder: Association With Anxiety Symptoms and Amygdala Volume

Atypical responses to fearful stimuli and the presence of various forms of anxiety are commonly seen in children with autism spectrum disorder (ASD). The fear potentiated startle paradigm (FPS), which has been studied both in relation to anxiety and as a probe for amygdala function, was carried out in 97 children aged 9-14 years including 48 (12 female) with ASD and 49 (14 female) with typical development (TD). In addition, exploratory analyses were conducted examining the association between FPS and amygdala volume as assessed with magnetic resonance imaging in a subset of the children with ASD with or without an anxiety disorder with available MRI data. While the startle latency was increased in the children with ASD, there was no group difference in FPS. FPS was not significantly associated with traditional Diagnostic and Statistical Manual (DSM) or "autism distinct" forms of anxiety. Within the autism group, FPS was negatively correlated with amygdala volume. Multiple regression analyses revealed that the association between FPS and anxiety severity was significantly moderated by the size of the amygdala, such that the association between FPS and anxiety was significantly more positive in children with larger amygdalas than smaller amygdalas. These findings highlight the heterogeneity of emotional reactivity associated with ASD and the difficulties in establishing biologically meaningful probes of altered brain function. LAY SUMMARY: Many children with autism spectrum disorder (ASD) have additional problems such as anxiety that can greatly impact their lives. How these co-occurring symptoms develop is not well understood. We studied the amygdala, a region of the brain critical for processing fear and a laboratory method called fear potentiated startle for measuring fear conditioning, in children with ASD (with and without an anxiety disorder) and typically developing children. Results showed that the connection between fear conditioning and anxiety is dependent on the size of the amygdala in children with ASD.

High Psychopathology Subgroup in Young Children With Autism: Associations With Biological Sex and Amygdala Volume

OBJECTIVE

The aims of this study were to identify a subset of children with autism spectrum disorder (ASD) and co-occurring symptoms of psychopathology, and to evaluate associations between this subgroup and biological sex and amygdala volume.

METHOD

Participants included 420 children (ASD: 91 girls, 209 boys; typically developing controls: 57 girls, 63 boys). Latent profile analysis was used to identify ASD subgroups based on symptoms of psychopathology, adaptive functioning, cognitive development, and autism severity. Differences in the proportions of girls and boys across subgroups were evaluated. Magnetic resonance imaging scans were acquired (346 children); amygdala volumes were evaluated in relation to subgroups and problem behavior scores.

RESULTS

Three ASD subgroups were identified. One group was characterized by high levels of psychopathology and moderate impairment on other measures (High Psychopathology Moderate Impairments [HPMI], comprising 27% of the sample). The other two subgroups had lower symptoms of psychopathology but were differentiated by high and low levels of impairment on other measures. A higher proportion of girls were classified into the HPMI subgroup (40% of girls versus 22% of boys). Relative to controls, amygdala volumes were enlarged only in the HPMI subgroup. There was a positive association between right amygdala volume and internalizing behaviors in girls but not in boys with ASD.

CONCLUSION

A higher proportion of girls with ASD faced greater challenges with psychopathology, suggesting a need for closer evaluation and potentially earlier intervention to help improve outcomes. Amygdala enlargement was associated with co-occurring symptoms of psychopathology, and sex-specific correlations with symptoms were observed.

Understanding Hippocampal Development in Young Children With Autism Spectrum Disorder

OBJECTIVE

We examined growth trajectories of hippocampal volume (HV) in early childhood in a longitudinal cohort of male and female participants with autism spectrum disorder (ASD) and typically developing (TD) individuals, and investigated HV in those with large brains. Relations between factors potentially associated with hippocampal size and growth were investigated.

METHOD

Participants received 1 to 3 structural magnetic resonance imaging scans between ages 25 and 80 months (unique participants: ASD, n =200; TD, n =110; total longitudinal scans, n = 593). HV growth during this period was examined using mixed-effects linear models. Associations between early HV and growth rates, and IQ and adaptive functioning, were evaluated.

RESULTS

After accounting for cerebral hemisphere volume, male participants exhibited larger left and right HV than female participants. Hippocampal growth rates did not differ by sex. In children with larger hemisphere volumes, male and female participants with ASD had relatively larger HV than TD participants of similar hemisphere volume. This effect was present in a broader group than only those with disproportionate megalencephaly (male participants with large cerebral volumes relative to body size). Right hippocampi were larger than left hippocampi in both groups and sexes. Right versus left volume differences were greater for ASD. After adjusting for hemisphere volume, male participants with ASD showed a significant positive association between right hippocampal growth and adaptive behavior.

CONCLUSION

HV was relatively greater in ASD in analyses adjusting for hemisphere volume, whereas only subtle differences were observed in HV and growth between participants with ASD and TD participants in unadjusted analyses, suggesting that ASD involves atypical coupling between HV and brain size.

In pursuit of neurophenotypes: The consequences of having autism and a big brain

A consensus has emerged that despite common core features, autism spectrum disorder (ASD) has multiple etiologies and various genetic and biological characteristics. The fact that there are likely to be subtypes of ASD has complicated attempts to develop effective therapies. The UC Davis MIND Institute Autism Phenome Project is a longitudinal, multidisciplinary analysis of children with autism and age-matched typically developing controls; nearly 400 families are participating in this study. The overarching goal is to gather sufficient biological, medical, and behavioral data to allow definition of clinically meaningful subtypes of ASD. One reasonable hypothesis is that different subtypes of autism will demonstrate different patterns of altered brain organization or development i.e., different neurophenotypes. In this Commentary, we discuss one neurophenotype that is defined by megalencephaly, or having brain size that is large and disproportionate to body size. We have found that 15% of the boys with autism demonstrate this neurophenotype, though it is far less common in girls. We review behavioral and medical characteristics of the large-brained group of boys with autism in comparison to those with typically sized brains. While brain size in typically developing individuals is positively correlated with cognitive function, the children with autism and larger brains have more severe disabilities and poorer prognosis. This research indicates that phenotyping in autism, like genotyping, requires a very substantial cohort of subjects. Moreover, since brain and behavior relationships may emerge at different times during development, this effort highlights the need for longitudinal analyses to carry out meaningful phenotyping. Autism Res 2017, 10: 711-722. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

Long-term follow-up of right ventricular monomorphic extrasystoles

OBJECTIVES

The purpose of this study was to verify in a long-term follow-up whether frequent monomorphic right ventricle extrasystoles may progress to arrhythmogenic right ventricular dysplasia (ARVD).

BACKGROUND

Frequent monomorphic right ventricle extrasystoles are generally considered benign. However, in patients with this pattern, cardiac magnetic resonance (MR) has recently shown anatomical and functional abnormalities of the right ventricle.

METHODS

Sixty-one patients who had been classified by noninvasive examinations as having frequent idiopathic right ventricle ectopy were contacted after 15 +/- 2 years (12 to 20) and submitted to clinical examination, electrocardiogram (ECG), Holter monitoring, stress test, signal averaged ECG, echocardiography and, in 11 patients, cardiac MR. The primary end point was to ascertain the presence of cases of sudden death or progression to ARVD.

RESULTS

At the end of the follow-up, 55 patients were alive; six died, none of sudden death; eight stated to be well but refused further examinations. The 47 patients examined had normal ECG; in 24 patients (51%), extrasystoles were no longer present at Holter monitoring; late potentials were present in up to 15% of the patients; the right ventricle was normal at echocardiography. In 8 of 11 patients (73%), cardiac MR showed focal fatty replacement and other abnormalities of the right ventricle.

CONCLUSIONS

In this long-term follow-up study, no patient died of sudden death nor developed ARVD; two-thirds of the patients were asymptomatic, and, in half of the patients, ectopy had disappeared. Focal fatty replacement in the right ventricle was present in most.

Comparison of defibrillation thresholds using monodirectional electrical vector versus bidirectional electrical vector

BACKGROUND

Currently, two main lead configurations are used for implantable cardioverter-defibrillators (ICD). One generates a monodirectional electrical vector by using the can surface as an active part (hot can) together with a right ventricular defibrillation coil. The other one (TRIAD) produces a bidirectional electrical vector by adding a proximal defibrillation electrode on the same lead. The purpose of this prospective study was to determine whether there is a difference between these configurations in terms of the acute defibrillation threshold (DFT). The secondary objective was to evaluate the possible sequential effect of successive arrhythmia induction and defibrillation shocks on the final DFT value.

METHODS

In 44 patients (37 males, 7 females, mean age 59.18 +/- 12.05 years; mean ejection fraction 35.21 +/- 11.69%), a Hot Can Ventak family ICD (Guidant, St. Paul, MN, USA) was implanted in a left pectoral pocket. During the implant procedure, step-down to failure DFT testing was performed twice in each patient using the two different above-mentioned configurations: the bidirectional and the monodirectional. The first configuration to be tested was determined by a 1:1 randomization by center.

RESULTS

The step-down DFT protocol was followed in 35 patients. The average DFT was 8.6 +/- 4.0 J for TRIAD and 10.4 +/- 4.3 J for the monodirectional (p = 0.009) lead configuration; this represents a 16.3% decrease in the DFT using a bidirectional configuration. Furthermore, no relationship between the final DFT and the number of ventricular fibrillation inductions and shocks received was observed, confirming the secondary objective.

CONCLUSIONS

Compared to the monodirectional electrical vector, the bidirectional electrical vector is clearly more beneficial for the patient.

Italian experience with AutoCapture in conjunction with a membrane lead. Pacesetter Automatic Control of Energy and Membrane Automatic Threshold Evaluation (Pacemate) Study Group

AutoCapture is a programmable feature of the Pacesetter Microny SR + 2425T VVIR pacemaker, which provides for the automatic capture verification, increase in output in the presence of noncapture and threshold searching, with adjustment of output settings. The effectiveness of this unit in conjunction with the Membrane models 1400T and 1401T bipolar endocardial leads was studied in 54 patients followed at 19 Italian Centers. The patients were randomized at the time of implantation to receive either the model 1400T or the 1401T lead. The electrodes in these leads are covered by a Nafion membrane, which was either impregnated (model 1400T) or not-impregnated (model 1401T) with steroid. This paper reports the data collected over the first six weeks postimplantation. The results of the automatic capture function was compared to the capture threshold measured using the Vario technique at the time of predischarge evaluations, and weeks 1,2, and 6 of postimplant follow-up. The reliability and effectiveness of the pulse generator-lead system allowed for consistent pacing at very low outputs and safety preserved at a programmed output only 0.3 V above the capture threshold.

[Idiopathic ventricular tachycardia with onset in the verapamil-sensitive left ventricle: the clinical characteristics and long-term follow-up of 37 patients]

BACKGROUND

Idiopathic verapamil-responsive left ventricular tachycardia (IVRLVT) is a rare, well known form of ventricular tachycardia. Issues concerning long-term prognosis, drug prophylaxis and non-pharmacological therapy are rarely reported in the literature. We report the long-term follow-up, the efficacy of various drugs in the prophylaxis and the role of catheter ablation in a large group of patients with IVRLVT.

METHODS AND RESULTS

This retrospective study involves 37 patients with a mean age of 28.3 +/- 14.8 years at first IVRLVT episode. The tachycardia morphology was typically with a right bundle-branch block configuration in all cases, with left axis deviation in 33 and right axis deviation in 5 (one patient had the 2 morphologies). Four patients had a mitral valve prolapse; the remaining 33 patients had neither clinical nor echocardiographic signs of heart disease. Only sporadic ventricular extrasystoles were detected at Holter monitoring in 73% of cases; 30% of patients had positive criteria for the presence of late potentials at signal averaged ECG. During electrophysiologic study, the tachycardia could be easily induced in 91% of patients. Mean follow-up is 7.3 +/- 4.7 years; all patients are alive at the end of follow-up. A mean of 2.3 +/- 1.2 drugs was prescribed in 35 patients (94.6%); betablockers were effective in 66% of the cases, verapamil in 20%, class I drugs in 22%, class III drugs in 15%. Both the 2 patients, who never received prophylaxis, and the 4 who stopped medication, utilize verapamil in case of recurrences. Eight patients were submitted to catheter ablation, with DC shock the first 2 patients, with RF energy from the third on; all but one (with DC shock) were successfully cured.

CONCLUSIONS

Long-term follow-up confirmed the good prognosis of this form of ventricular tachycardia; a new insight that has been addressed about prophylaxis is the high efficacy of betablockers in preventing relapse and the poor efficacy of verapamil per os in chronic prophylaxis. Radiofrequency catheter ablation is effective and safe, using the earliest ventricular potential and the pace-mapping reproducing the same morphology of the tachycardia in all the 12 leads as a marker to identify the site of RF application, and may be proposed to all patients suffering from frequent episodes of IVRLVT.

Idiopathic verapamil-responsive left ventricular tachycardia: clinical characteristics and long-term follow-up of 33 patients

Long-term prognosis, pharmacological prophylaxis and transcatheter ablation in a large group of patients with idiopathic verapamil-responsive left ventricular tachycardia (IVRLVT) are reported in this study. Thirty-three patients with a mean age of 27 +/- 16 years at their first IVRLVT episode, were studied retrospectively. Ventricular tachycardia was of the right bundle branch block morphology in all cases, with left axis deviation in 29 and right axis deviation in five (one patient had the two morphologies). Mitral valve prolapse was present in four patients; no heart disease was found in the remaining 29. Ventricular tachycardia could be electrophysiologically induced in 90% of the patients; Holter monitoring showed only sporadic ventricular extrasystoles in 76%; late potentials were found in 33% of the cases. At the end of a follow-up of 5.7 +/- 4.7 years, no patient had died. Thirty-one patients (94%) received a mean of 2.5 +/- 1.2 drugs; beta-blockers were effective in 71% of the cases, verapamil in 25%, class 1 drugs in 22%, class 3 drugs in 18%. Two patients who never received prophylaxis and four in whom it was stopped, were controlled with verapamil in case of recurrence. Six patients underwent catheter ablation; two with DC shock in whom it was successful in one, and four with radiofrequency energy, with a total success rate. The good prognosis of IVRLVT has been confirmed in a long-term follow-up; a new finding is the high efficacy of beta-blockers for prophylaxis. Radiofrequency transcatheter ablation is an effective and safe therapy for patients with symptoms not controlled by drug treatment.

Associated cardiac lesions in patients with radiation-induced complete heart block

We investigated the clinical, electrophysiological, haemodynamic and angiographic aspects of four patients (two men and two women, aged 31-46 years) who developed complete heart block 13-20 years after therapeutic irradiation of the chest for Hodgkin's disease. The initial cardiac symptom was syncope in three, effort intolerance in one. The electrocardiogram recorded third-degree atrioventricular block in three patients, right bundle branch block and posterior fascicular block in one. The electrophysiological study, performed in three cases, showed that the block was infranodal in two. Three patients had significant coronary arterial stenoses, that involved the ostia in two. All patients had mild-to-moderate aortic and mitral regurgitation. One patient had haemodynamic signs of constriction. Another patient had recurrent pericardial effusions. All had echocardiographic evidence of a thickened pericardium. Cardiac involvement can be extensive in patient with radiation-induced heart block. Because coronary artery disease can be particularly severe, coronary angiography appears to be warranted in such patients.

Catheter ablation of accessory pathways in patients with Wolff-Parkinson-White syndrome

PATIENTS

Fifty-two patients with Wolff-Parkinson-White syndrome underwent transcatheter ablation. All patients were symptomatic. Eighteen had documented episodes of atrial fibrillation, 14 of which also had reentrant tachycardias; the remaining 34 had only episodes of reentrant tachycardias. Forty-nine patients had both anterograde and retrograde conduction through the accessory pathway; 3 had retrograde conduction alone; 2 patients had 2 accessory pathways and 1 had 3. All patients were resistant or intolerant to at least 2 antiarrhythmic drugs.

METHODS

All patients were treated with radiofrequency current. Ablation was considered successful if the anterograde and retrograde conduction were completely abolished. Ablation was considered unsuccessful if ablation of only 1 pathway in patients with 2 or more accessory pathways and/or modification of the accessory pathway conduction without interruption was achieved.

RESULTS

Accessory pathway ablation was successfully performed in 46 out of 52 patients (88%). Fifty out of 56 accessory pathways were effectively ablated (89%). Thirty-eight required a single session of ablation and 8 additional patients were successfully ablated during a second session. The number of radiofrequency current applications ranged from 2 to 13 (mean 4.1 +/- 2.5). The mean duration of the sessions was 4.30 +/- 1.50 hours (range 2.30 to 9). The mean radiation exposure for session was 55 +/- 25 minutes (range 20 minutes to 2.30 hours). Complications were observed in 2 out of 52 patients. One patient had a transient II degree type 1 atrioventricular block; another patient with severe arterial hypertension had a mild hemorrhagic stroke with complete neurological remission. FOLLOW-UP. Forty-five out of the 46 patients in whom ablation was successful were asymptomatic for arrhythmias during a mean follow-up of 8 months (range 4 to 16), without antiarrhythmic treatment, and without reappearance of preexcitation. One patient showed reappearance of preexcitation at electrocardiogram one month after the ablation, followed by an episode of reentrant tachycardia; this patient underwent a second successful ablation session.

CONCLUSIONS

Our results show that ablation techniques have high success rates with no serious complications.

[Nonpharmacological therapy of supraventricular arrhythmia]

Between 1985 and 1990, 1242 patients with supraventricular arrhythmias were followed-up at our Institution. Six hundred and twenty patients had atrial fibrillation or flutter; 7 of them (1%) underwent modulation of atrioventricular conduction. Four hundred and twenty-eight patients had ventricular preexcitation; in 23 (5%) surgical or transcatheter ablation of an accessory pathway were performed. Atrioventricular node reentrant tachycardias were diagnosed in 111 patients; 8 patients (7%) underwent antitachycardia pacemaker implantation. Surgical and catheter ablative techniques eliminate the substrate of the tachycardia; death and complete A-V block (paraseptal pathways) are at this moment rarely reported. Antitachycardia pacemakers do not offer a definitive therapy. For their safeness and effectiveness they are still indicated in patients with A-V node reentrant tachycardias, until technological development will reduce the risks of ablative techniques.

[A case of pericarditis in acute brucellosis]

A case of brucellosis pericarditis in a patient affected with acute brucellosis hospitalized in the Infectious Disease Department of Asti Hospital is described. During the hospitalization, the patient revealed (in addition to the classical symptoms and signs), a modest shooting pain in the chest and typical electrocardiographic alterations confirmed by an echocardiography that revealed slight pericardial effusion at both front and rear, subsequently and by steroid and specific antibiotic therapies. The real possibility of finding this complication, considered so rare in the literature, in cardiovascular brucellosis is pointed out as is the capacity of modern echocardiographic research to confirm and reinforce diagnosis and consequently also the description of modest pericardial effusions with unclear symptoms and electrocardiographic signs that were once practically ignored when the pericardial involvement often escaped a clinical identification, being concealed by the most important signs of the primary infection.

No evidence of platelet activation during atrial pacing in subjects with stable angina

Platelet behaviour (activation) in ischemic heart disease (stable angina) during pacing-induced tachycardia was studied. ECG was recorded during the trial. Ischemic heart disease (IHD) subjects had 75% or more narrowing of the luminal diameter of a coronary artery, demonstrated by coronary angiography. Eight subjects needing cardiac catheterism because of supraventricular rhythm disturbances with no evidence of IHD were studied as controls. Beta-thromboglobulin (beta-tg) and platelet factor 4 (PF4) were studied as platelet activation markers; beta-tg and PF4 were evaluated before atrial pacing in peripheral venous blood and, by catheterism, before and at maximum pacing rate in coronary venous sinus (CVS) and in ascending aorta (AA). Catheterism and blood withdrawals were performed in order to reduce platelet activation in vivo. No significant difference in platelet activation between IHD patients and control group in peripheral venous blood were found. No trans-myocardial gradient neither in IHD subjects nor in controls were observed. In conclusion, no platelet activation in IHD patients during pacing-induced tachycardia could be observed.

Severe electrocardiographic abnormalities during arfonad administration

Severe and reversible electrocardiographic abnormalities (first degree atrioventricular block, left bundle branch block, ventricular fibrillation), were induced by the administration of Arfonad in a patient with type III acute aortic dissection previously chronically treated with alpha-methyl-dopa. Any other possible cause of the electrocardiographic changes was excluded on the basis of clinical findings and laboratory studies. The explanation of the electrocardiographic abnormalities induced by Arfonad are not readily apparent, also on careful review of the literature. We suggest a strict electrocardiographic monitoring during Arfonad administration especially in patients with cardiac conduction defects and previous administration of cardiac cathecholamines depleting drugs.