Psychogenic pseudosyncope: Not always a diagnosis of exclusion.

BACKGROUND: Psychogenic pseudosyncope (PPS) frequently mimics syncope. The aim of this study was to assess the prevalence and clinical features of PPS and its relationship to vasovagal syncope (VVS). METHODS: We examined retrospectively the medical records of 1,401 consecutive patients referred to a syncope unit. We identified patients who had the final diagnosis of PPS. In these patients, we retrieved the initial diagnosis made during their first visit and the subsequent tests performed leading to the final diagnosis. RESULTS: Fourteen (1.0%) patients (mean age 35 ± 14; 11 females) were diagnosed as having PPS: seven had a diagnosis of PPS alone and seven had both VVS and PPS. High frequency of attacks (53 ± 35 attacks during the previous year), prolonged loss of consciousness (minutes to > 1 hour), and a history of psychiatric disorders characterized PPS patients. Tilt test reproduced a PPS attack in the presence of normal blood pressure and heart rate in seven patients (50%), and induced VVS in another three patients who had the final diagnosis of both PPS and VVS. In two patients, one or more events occurred during the clinic visits and were directly witnessed by the clinic personnel. CONCLUSIONS: We have shown that 1% of referrals to a syncope unit have the final diagnosis of PPS and that up to 50% of cases presented with a different initial diagnosis, namely VVS. Our findings suggest that causality between syncope and psychiatric disorders is likely bidirectional. The presence of a multidisciplinary team is important to address this often unrecognized relationship.

Risk Stratification for Arrhythmic Events in Patients With Asymptomatic Pre-Excitation: A Systematic Review for the 2015 ACC/AHA/HRS Guideline for the Management of Adult Patients With Supraventricular Tachycardia: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society.

OBJECTIVE: To review the literature systematically to determine whether noninvasive or invasive risk stratification, such as with an electrophysiological study of patients with asymptomatic pre-excitation, reduces the risk of arrhythmic events and improves patient outcomes. METHODS: PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials (all January 1, 1970, through August 31, 2014) were searched for randomized controlled trials and cohort studies examining noninvasive or invasive risk stratification in patients with asymptomatic pre-excitation. Studies were rejected for low-quality design or the lack of an outcome, population, intervention, or comparator of interest or if they were written in a language other than English. RESULTS: Of 778 citations found, 9 studies met all the eligibility criteria and were included in this paper. Of the 9 studies, 1 had a dual design-a randomized controlled trial of ablation versus no ablation in 76 patients and an uncontrolled prospective cohort of 148 additional patients-and 8 were uncontrolled prospective cohort studies (n=1594). In studies reporting a mean age, the range was 32 to 50 years, and in studies reporting a median age, the range was 19 to 36 years. The majority of patients were male (range, 50% to 74%), and <10% had structural heart disease. In the randomized controlled trial component of the dual-design study, the 5-year Kaplan-Meier estimates of the incidence of arrhythmic events were 7% among patients who underwent ablation and 77% among patients who did not undergo ablation (relative risk reduction: 0.08; 95% confidence interval: 0.02 to 0.33; P<0.001). In the observational cohorts of asymptomatic patients who did not undergo catheter ablation (n=883, with follow-up ranging from 8 to 96 months), regular supraventricular tachycardia or benign atrial fibrillation (shortest RR interval >250 ms) developed in 0% to 16%, malignant atrial fibrillation (shortest RR interval ≤250 ms) in 0% to 9%, and ventricular fibrillation in 0% to 2%, most of whom were children in the last case. CONCLUSIONS: The existing evidence suggests risk stratification with an electrophysiological study of patients with asymptomatic pre-excitation may be beneficial, along with consideration of accessory-pathway ablation in those deemed to be at high risk of future arrhythmias. Given the limitations of the existing data, well-designed and well-conducted studies are needed.

Clinical Characteristics and Outcome of Patients with Situational Syncope Compared to Patients with Vasovagal Syncope.

BACKGROUNDS: The purpose of the study was to assess the clinical outcome of patients with situational syncope (SS) compared to patients with vasovagal syncope (VVS). METHODS: We assessed the prevalence, patients' characteristics, and outcome of consecutive patients with SS and VVS who presented to the Faint and Fall Clinic (University of Wisconsin) between January 2013 and December 2015. RESULTS: SS was found in 55/1,401 (4.0%) syncope patients with follow-up data available in 47 patients: defecation (n = 16), micturition (n = 15), cough (n = 10), swallow (n = 3), laughter (n = 1), sneeze (n = 1), and cough plus laughter (n = 1). Over the same time period, 252/1,401 patients (18%) were diagnosed with VVS with follow-up data available in 171 patients. Compared with VVS patients, SS patients were older, more likely to be male, had a higher prevalence of hypertension, had an absence of prodromes, and experienced more injuries at the time of syncope (P = 0.01 for all). During a mean follow-up duration of 15.4 ± 9.1 months, syncope recurred in 5/47 (10.6%) patients with SS and 16/171 (9.4%) patients with VVS. The recurrence rates at 1 year and 2 years were 20% (95% SE ± 13) and 40% (95% SE ± 20) for the SS group, and 23% (95% SE ± 13) and 43% (95% SE ± 20) for the VVS group (P = 0.6). No patient died. CONCLUSIONS: We have shown in a large cohort of consecutive patients with syncope that SS is a relatively infrequent form of reflex syncope with different clinical characteristics but similar recurrence rate to VVS.

Cardiac Arrest in Pregnancy: A Scientific Statement From the American Heart Association.

This is the first scientific statement from the American Heart Association on maternal resuscitation. This document will provide readers with up-to-date and comprehensive information, guidelines, and recommendations for all aspects of maternal resuscitation. Maternal resuscitation is an acute event that involves many subspecialties and allied health providers; this document will be relevant to all healthcare providers who are involved in resuscitation and specifically maternal resuscitation.

Long-Term Outcome of Patients with Bifascicular Block and Unexplained Syncope Following Cardiac Pacing.

BACKGROUND: According to the ACC/AHA/HRS guidelines, cardiac pacing is reasonable in patients with bifascicular block (BF-B) and syncope when other causes have been excluded. The purpose of this study was to assess the long-term outcome of patients with BF-B and unexplained syncope following cardiac pacing. METHODS AND RESULTS: Between 2009 and 2015, we identified 43 consecutive patients (mean age of 78 ± 12 years, 64% males) who presented with syncope and BF-B and had received a pacemaker (PM). During a mean follow-up period of 31 ± 21 months, syncope recurred in seven patients (16%): 7% (95% standard error [SE] ± 3%) at 1 year and 18% (95% SE ± 7%) at 5 years. At univariable analysis, the only predictor of syncope recurrence was empiric pacing (P = 0.03). There were no syncope recurrences in the 12 patients who received a PM following a positive electrophysiological study (EPS) and the five patients with documentation of paroxysmal atrioventricular block (AVB) during cardiac monitoring (insertable loop recorder [ILR]), (EPS/ILR Group, n = 17) compared to seven of 26 (27%) patients who received empiric pacing (Empiric Group, n = 26; P = 0.02). Progression to high-degree AVB was documented during follow-up in 16 (37%) patients: nine of 17 (53%) patients in the EPS/ILR Group and seven of 26 (27%) patients in the Empiric Group (P = 0.11). There were no injuries reported during ILR monitoring. CONCLUSIONS: We have shown that syncope recurs not infrequently in patients with BF-B who received pacing for syncope. Nearly one in four patients who had empiric pacing suffered syncope recurrence compared to no recurrences in patients who received a PM following a positive EPS or documentation of transient AVB.

The pathophysiologic mechanisms associated with hypotensive susceptibility.

INTRODUCTION: Patients with vasovagal syncope (VVS) and positive tilt table test (TTT) were not found to benefit from pacing in the ISSUE-3 trial despite the presence of spontaneous asystole during monitoring. "Hypotensive susceptibility" unmasked by TTT was reported as a possible explanation. The purpose of this study was to assess the pathophysiologic mechanisms associated with hypotensive susceptibility. METHODS: 366 consecutive patients with the diagnosis of VVS who also had TTT were identified. Baroreflex gain (BRG) in addition to blood pressure (BP) and heart rate (HR) responses during the first 20 min of TTT were analyzed and compared between patients with positive TTT (n = 275, 75 %) and negative TTT (n = 91, 25 %). RESULTS: The mean BRG was similar between the groups (12.5 ± 6.3 versus 12.4 ± 6.3 ms/mmHg, p = 0.72); however, an age-dependent decrease was noted (17.6 ± 4.8, 15.0 ± 6.0, 10.6 ± 4.2, 10.3 ± 6.4 and 9.9 ± 8.5 ms/mmHg for patients <21, 21-40, 41-60, 61-80 and >80 years old, respectively; p < 0.001). In addition, we saw a main effect of age on the type of response with a greater prevalence of a vasodepressor response in older subjects (p < 0.001). During the first 20 min of TTT, BP was similar in patients with tilt-positive VVS when compared with patients with tilt-negative VVS; however, HR was significantly lower. CONCLUSION: BRG is similar in tilt-positive VVS patients when compared with tilt-negative VVS patients. An age-dependent decrease in BRG was noted with a higher prevalence of a vasodepressor response seen in older patients. The clinical significance of the blunted HR response in tilt-positive VVS remains to be determined.

"Vasovagal" response during ventricular fibrillation: incidence and implications.

BACKGROUND: The purpose of this study was to assess the relationship between changes in sinus node cycle length (SNCL) during ventricular fibrillation (VF) and the peripheral changes in blood pressure (BP) and sympathetic nerve activity (SNA) in human subjects. We hypothesized that patients with no SNCL shortening during VF have a vasovagal-like response with a greater decrease in BP and SNA when compared to patients with SNCL shortening. METHODS: SNCL, BP, and SNA recordings were attempted in 24 patients undergoing the implantation of a dual-chamber implantable defibrillator. Changes were measured during the first 5 seconds of VF and compared with the 5 seconds prior to VF induction. RESULTS: SNCL shortened during VF in nine patients (mean%∆SNCL = -12 ± 8%) and remained unchanged or lengthened in seven patients (mean%∆SNCL = 7 ± 7%). Eight patients had ventriculoatrial (VA) conduction prohibiting assessment of SNCL changes. In patients with SNCL shortening, the %∆MBP (mean BP) was -47 ± 6% compared to -58 ± 8% in patients with no SNCL shortening (P < 0.01). In patients with VA conduction, the %∆MBP was -54 ± 3%. SNA recordings were successfully obtained in four patients. When compared to baseline, SNA increased by 34 ± 30% in two patients with SNCL shortening, decreased by 25% in one patient with SNCL lengthening, and by 90% in the fourth patient with VA conduction. CONCLUSIONS: We have shown that patients with no SNCL shortening have a significantly greater decrease in MBP during VF when compared to patients with SNCL shortening. The underlying mechanism appears to be reflex mediated with a vasovagal-like response in patients with no SNCL shortening.

Mechanisms of sinus node cycle length changes during ventricular fibrillation.

OBJECTIVE: We have previously shown that up to one-third of patients develop no change or an increase in sinus node cycle length (SNCL) during ventricular fibrillation (VF). The purpose of the present study was to investigate the mechanism of SNCL changes during VF in a swine model. We hypothesized that changes in SNCL during VF are vagally-mediated. METHODS: In 33 anesthetized pigs DC current was used to induce VF for 10 s followed by defibrillation. SNCL changes were assessed during VF and compared to baseline. Animals that had ventriculo-atrial conduction during VF were excluded. Post-defibrillation, the pigs were randomized to receive atropine, propranolol, atropine + propranolol or placebo followed by repeat VF induction and measurement of SNCL changes. RESULTS: Ventriculo-atrial conduction was present in 14 pigs prohibiting SNCL measurements. In the remaining 19 animals, 10 demonstrated SNCL shortening (S-Group) and 9 demonstrated non-shortening (NS-Group). Atropine decreased the absolute change in SNCL from 51.2 to 26.6 ms (n = 6; p = 0.03). It attenuated the SNCL shortening previously observed in the S-Group (-99.2 ms versus -47.9 ms, p = 0.04) and reversed the SNCL prolongation initially observed in the NS-Group (27.1 ms versus -6.5 ms, p = 0.13). Similarly, atropine + propranolol decreased the absolute change in SNCL from 33.3 to 12.2 ms (n = 4; p = 0.05). No significant changes were noted with propranolol or placebo. INTERPRETATION: The SNCL changes during VF appear to be vagally-mediated. The clinical implications vis-à-vis defibrillation threshold and future device programming await future studies.

Management of arrhythmia syndromes during pregnancy.

PURPOSE OF REVIEW: To discuss the diagnosis and management of maternal arrhythmias occurring during pregnancy. RECENT FINDINGS: When necessary, current technology allows implantation of arrhythmia management devices and performing catheter ablation procedures with little or no risk from radiation exposure to the fetus. SUMMARY: A variety of cardiac rhythm disturbances can occur during pregnancy, ranging from benign ectopy to life-threatening arrhythmias. In patients with normal hearts and minimally symptomatic arrhythmias, only reassurance is necessary. The quality of the data on managing more serious arrhythmias in pregnancy is somewhat limited, yet with a clear understanding of the maternal hemodynamic changes associated with pregnancy, and the appropriate antiarrhythmic therapies available, almost all cases can be treated successfully. The decision to treat should be based on careful consideration of risk and benefits, yet, when therapy is deemed necessary, it should be administered promptly and with confidence. Drug therapy should be avoided during the first trimester if possible and drugs with the longest record of safety are preferred. The decision to pursue an invasive strategy is complicated by the potential for procedural risks. Yet, the state of modern technology is such that invasive strategies, when justified, can be carried out effectively.

Effect of dronedarone on clinical end points in patients with atrial fibrillation and coronary heart disease: insights from the ATHENA trial.

AIMS: This study aimed to assess safety and cardiovascular outcomes of dronedarone in patients with paroxysmal or persistent atrial fibrillation (AF) with coronary heart disease (CHD). Coronary heart disease is prevalent among AF patients and limits antiarrhythmic drug use because of their potentially life-threatening ventricular proarrhythmic effects. METHODS AND RESULTS: This post hoc analysis evaluated 1405 patients with paroxysmal or persistent AF and CHD from the ATHENA trial. Follow-up lasted 2.5 years, during which patients received either dronedarone (400 mg twice daily) or a double-blind matching placebo. Primary outcome was time to first cardiovascular hospitalization or death due to any cause. Secondary end points included first hospitalization due to cardiovascular events. The primary outcome occurred in 350 of 737 (47%) placebo patients vs. 252 of 668 (38%) dronedarone patients [hazard ratio (HR) = 0.73; 95% confidence interval (CI) = 0.62-0.86; P = 0.0002] without a significant increase in number of adverse events. In addition, 42 of 668 patients receiving dronedarone suffered from a first acute coronary syndrome compared with 67 of 737 patients from the placebo group (HR = 0.67; 95% CI = 0.46-0.99; P = 0.04). CONCLUSION: In this post hoc analysis, dronedarone on top of standard care in AF patients with CHD reduced cardiovascular hospitalization or death similar to that in the overall ATHENA population, and reduced a first acute coronary syndrome. Importantly, the safety profile in this subpopulation was also similar to that of the overall ATHENA population, with no excess in proarrhythmias. The mechanism of the cardiovascular protective effects is unclear and warrants further investigation.

Effect of dronedarone on cardiovascular events in atrial fibrillation.

BACKGROUND: Dronedarone is a new antiarrhythmic drug that is being developed for the treatment of patients with atrial fibrillation. METHODS: We conducted a multicenter trial to evaluate the use of dronedarone in 4628 patients with atrial fibrillation who had additional risk factors for death. Patients were randomly assigned to receive dronedarone, 400 mg twice a day, or placebo. The primary outcome was the first hospitalization due to cardiovascular events or death. Secondary outcomes were death from any cause, death from cardiovascular causes, and hospitalization due to cardiovascular events. RESULTS: The mean follow-up period was 21+/-5 months, with the study drug discontinued prematurely in 696 of the 2301 patients (30.2%) receiving dronedarone and in 716 of the 2327 patients (30.8%) receiving placebo, mostly because of adverse events. The primary outcome occurred in 734 patients (31.9%) in the dronedarone group and in 917 patients (39.4%) in the placebo group, with a hazard ratio for dronedarone of 0.76 (95% confidence interval [CI], 0.69 to 0.84; P<0.001). There were 116 deaths (5.0%) in the dronedarone group and 139 (6.0%) in the placebo group (hazard ratio, 0.84; 95% CI, 0.66 to 1.08; P=0.18). There were 63 deaths from cardiovascular causes (2.7%) in the dronedarone group and 90 (3.9%) in the placebo group (hazard ratio, 0.71; 95% CI, 0.51 to 0.98; P=0.03), largely due to a reduction in the rate of death from arrhythmia with dronedarone. The dronedarone group had higher rates of bradycardia, QT-interval prolongation, nausea, diarrhea, rash, and an increased serum creatinine level than the placebo group. Rates of thyroid- and pulmonary-related adverse events were not significantly different between the two groups. CONCLUSIONS: Dronedarone reduced the incidence of hospitalization due to cardiovascular events or death in patients with atrial fibrillation. (ClinicalTrials.gov number, NCT00174785.)