Prior History Of Syncope Research Articles

THerapy Efficacy in Short or long-coupled idiopathic ventricular fibrillation: an International Survey (THESIS)

Abstract Background A recent review of 86 patients with short or long-coupled premature ventricular complex (SLC-PVC) initiating idiopathic ventricular fibrillation (IVF) found high success rate in arrhythmia control with quinidine (QND) (83%) or radiofrequency ablation (RFA) (70.8%). Purpose To compare the efficacy of QND vs. RFA therapy in a large patient cohort with SLC-IVF. Methods THESIS included 287 patients with SLC-IVF screened from 58 centers and 1 multicenter group in 22 countries across 4 continents. The study cohort included 146 (50.9%) males, aged 39+14 years at the time of IVF documentation. Therapy groups were defined according to the first therapy given. Therapy success was defined as no VF recurrence. Results Patients presented after aborted cardiac arrest, ICD shocks, syncope, aborted cardiac arrest + arrhythmic storm, arrhythmic storm, palpitations, seizures or were asymptomatic in 121 (42%), 51(18%), 42(14.6%), 27 (9.4%), 23 (8%), 8 (2.8%), 6 (2.1%) and 9 (3.1%), respectively. Fifty-three patients (18.5%) had a prior history of syncope. Eleven (3.8%) patients required ECMO support. Mean shortest and longest coupling interval which triggered VF in the same patient were 304.9+82ms and 341.2+94.1ms, respectively. VF initiation with "long" coupled PVC (coupling interval >350ms) was observed in 41 (18.1%) patients, and VF initiation with both short and long coupled PVC was documented in 30 (13.2%) others. RFA was performed in 112 patients and QND was given to 68 patients. Patients were followed during a mean follow-up of 84.8+64.5 months. Therapy success was achieved in the RFA or QND group in 69 (62.2%) and 49 (71%) patients, respectively (p=0.29). The RV Purkinje was the main targeted ablation site in 46 (47.4%) patients. Treatment success varied according to the site of origin (SOO) of the PVC which triggered VF. Therapy success was higher with QND when PVC SOO based on ECG, was the RV inflow tract (81.3% vs. 57.7%, p=0.048) or when the SOO was not available (67.9% vs 36.4%, p=0.064), and when the coupling interval/QT ratio was <1 (75.5% vs. 57.5%, p=0.03), Figures 1,2. A higher success rate with ablation compared with QND was seen with LV- SOO compared with RV-SOO (82.1% vs 60.3%, p=0.019). Similarly, successful ablation was achieved in 83.3% (n=24) vs. 55.9% (n=68) patients with LV and RV-SOO respectively; p=0.004. One patient expired of sudden cardiac death due to misdiagnosis, while wearing a subcutaneous -ICD, without any drug or ablation therapy. Conclusions SLC-IVF strikes males and females equally. SLC-PVCs triggering the arrhythmia mainly arise from the RV Purkinje system. QND and RFA have similar efficacy in arrhythmia control. Quinidine has a higher treatment success rate in patients with PVC-SOO in the RV inflow area and in those with coupling interval/QT<1.Figure 1Treatment success by SOOFigure 2Treatment success by CI/QT

Syncope in patients with diagnosed with hypertrophic cardiomyopathy: risk of ventricular tachycardia, cardiac arrest and death

Abstract Funding Acknowledgements Type of funding sources: None. Background Hypertrophic cardiomyopathy (HCM) is a common genetic cardiovascular disorder; however, detection rates remain low. While most patients are only mildly symptomatic, some develop serious complications such as heart failure (HF), atrial fibrillation (AF), and sudden cardiac death (SCD). Given the possibility of severe outcome, a large focus is put on early detection and prevention of possible HCM related complications. Syncope has long been one of these factors associated with increased risk of SCD, however little concrete data on the impact and consequences of prior syncope in a large HCM population exist. Objectives To determine the risk of ventricular tachycardia (VT), cardiac arrest (CA) and death in patients with HCM and prior history of syncope compared to HCM patients without syncope. Methods All patients aged ≥16 years diagnosed with HCM from 2005 - 2018 were identified in the Danish National Registers and included at first time diagnosis. All admissions or prior presentation of syncope were registered and analyzed for the outcome of a combined endpoint comprising occurrence of VT, CA or death. The association between HCM, syncope and the combined endpoint were investigated using multivariable cox proportional-hazard analysis adjusted for gender, age, and comorbidities. Cumulative incidence of the combined endpoint was calculated using the Aalen-Johansen estimator. Results In this study 3,856 HCM patients were included (median age 68 years [IQR 56-78]) with near equal gender distribution (males 53%, females 47%). Overall 361 (9%) of patients had a registered contact for syncope prior to HCM diagnosis. A total of 1356 patients (35%) reached the combined endpoint. Of those patients with prior syncope 163 patients (45%) reached the endpoint, compared to 1193 patients (34%) who had no registered syncope prior to HCM diagnosis. Univariate analysis showed a significantly increased risk (HR 1.5 (CI 1.3-1.8) p = <0.001) of patients in the syncope group of VT, CA and death, however in multivariate analysis adjusted for gender, age and comorbidities this difference did not prove significant (HR 1.1 (CI 0.9-1.3) p = 0.35) (Figure 1). Subgroup analysis revealed a striking disparity between male and female HCM patients with prior syncope in their risk of reaching the combined endpoint. Adjusted for age and comorbidities, males were at a significantly increased risk of ventricular tachycardia, cardiac arrest and death (HR 1.6 (CI 1.1-2.2) p = 0.008) (Figure 2). Conclusion Although there was a significant increased rate of HCM patients with prior syncope reaching the combined endpoint of ventricular tachycardia, cardiac arrest and death, multivariate analysis showed this association to be mainly driven by comorbidity and age. In this cohort males with prior syncope were at a significantly higher risk of reaching the combined endpoint. More research will be needed to explore this disparity.

Short-Coupled Idiopathic Ventricular Fibrillation: A Literature Review With ExtendedFollow-Up.

Idiopathic ventricular fibrillation is responsible for approximately 5%-7% of cases of aborted cardiac arrest. Recent studies have shown that short-coupled ventricular premature complexes are present at the onset of idiopathic ventricular fibrillation in 6.6%-17% of patients. The present review provided information on 86 patients with short-coupled malignant ventricular arrhythmias that were reported as case reports or small patient series during the last 70 years. In 75% of the 81 cases published during the last 40 years, extended information and follow-up (from 2.63 ± 4.5 years to 10.67±7.8 years; P< 0.001, between the original publication to the latest update) could be obtained from the authors. The review shows that short-coupled malignant ventricular arrhythmias occurred almost equally in males and females, at the mean age of 40 years. A tendency for later occurrence of the arrhythmia by 4 years was observed in females. A prior history of syncope was noted in 45.3% of the patients, whereas arrhythmic storm occurred in 42% at presentation. The most common mode of revelation of short-coupled malignant ventricular arrhythmias was syncope (53.5%), followed by aborted cardiac arrest (26.7%) and recurrent arrhythmic event after prior implantable-cardioverter defibrillator implantation for idiopathic ventricular fibrillation (17.4%). For the first time, short-coupled malignant arrhythmias exhibiting "not-so-short" coupling intervals (≥350milliseconds) were found in a significant proportion of patients (17.4%). Duringlong-term follow-up, quinidine yielded a slightly higher success rate in arrhythmia control than ablation. Largerstudies are necessary to assess the best strategy for the management of this potentially lethal arrhythmia.

P1879Characterization of cardiac diagnostic care pathways by indication and physician specialty in a real-world dataset of 314,554 patients

Abstract Background A variety of modalities exist for diagnosing cardiac arrhythmias via ambulatory ECG recording. These can range from short-term (i.e. ≤48 hours) holter monitoring, medium-term external monitoring for up to 30 days, and long-term monitoring via an implantable cardiovascular monitor (ICM). Purpose To quantify the prevalence of different diagnostic care pathways for cardiac arrhythmias in a large, real-world dataset. Methods A de-identified database of aggregated EHR data from 2015–2017 was used to identify patients with any procedure or service received for an ambulatory cardiac diagnostic monitor. Three categories of diagnostic monitoring technologies were identified: (1) Holter monitoring for up to 48 hours, (2) External ECG and event monitoring for up to 30 days via external loop recorder, mobile cardiac telemetry (MCT), or other external ECG recording device, and (3) ICMs. Patients with their first monitor in 2015 or later were selected. The number of patients that had their initial monitor in each of the different categories were quantified, as well as the number that followed a care pathway progression from shorter-term to longer-term monitoring. Patients were grouped by clinical history (syncope or ischemic stroke diagnosis codes in the 6 months prior) as well as by whether they had a clinical interaction with an electrophysiologist (EP) at any point in their care pathway. Results A total of 314,554 patients were identified with a mean follow-up duration of 340.1±232.5 days. The initial monitor type used across all patients was 68.8% holter, 27.7% extended holter/MCT/external loop recorder, and 3.5% ICMs. 5.1% of all patients received multiple categories of monitoring. 50,812 patients had a prior history of syncope, 46.4% of which were seen by an EP. 28,374 patients had a prior history of ischemic stroke, with 50.9% seen by an EP. The figure shows that patients seen by an EP are more likely to receive ICMs than those not seen by an EP (20.6% vs. 3.8% for syncope; 25.3% vs. 5.7% for stroke; both p&lt;0.001). Patients seen by an EP are also more likely to receive multiple categories of progressively-longer monitoring than those not seen by an EP (10.4% vs. 4.6% for syncope; 8.3% vs. 4.0% for stroke; both p&lt;0.001). Conclusion Cardiac diagnostic care pathways for syncope and ischemic stroke are significantly different between those patients that are seen by an EP versus those that are not. Relatively few patients overall received multiple types of cardiac diagnostic monitoring. Acknowledgement/Funding Medtronic

Are cardiac patients in Saudi Arabia provided adequate instructions when they should not drive?

ABSTRACTObjective:Driving capability can be significantly affected by different heath disorders; cardiovascular diseases (CVDs) should be considered when assessing patients for medical fitness to drive (MFTD). The aim of this study was to evaluate the awareness of Saudi patients about driving recommendations and to assess the incidence of motor vehicle accidents (MVAs) among cardiac patients.Materials and Methods:We conducted a cross-sectional survey-based study. Male patients diagnosed with CVDs and who were visiting outpatient departments were invited to complete a questionnaire regarding their awareness of driving recommendations. Patients’ demographics, clinical diagnosis, echocardiography parameters, and time-to-CVD diagnosis were all obtained from the patients’ medical records. Women were excluded because it was illegal for women to drive in Saudi Arabia during the study period.Results:In total, 800 men were included, with a mean age of 54 ± 12 years. Driving counseling had been provided to 241 participants (30%). Of these, 207 (25%) were advised not to drive for a period of between one week and six months. Five percent of the patients had a history of MVAs during the follow-up period of 6.2 ± 4 years. We found that the presence of a dyspnea ≥2, according to the New York Heart Association (NYHA), and a history of loss of consciousness (syncope/pre-syncope) were significantly associated with accidents (46% vs. 20%, P < 0.0001 and 41% vs. 10%, P < 0.0001, respectively).Conclusion:Patient–physician discussion about MFTD was only performed with 30% of the patients with CVDs in Saudi Arabia. Dyspnea NYHA class ≥2 or a prior history of syncope were significantly associated with the incidence of MVAs.

Cocaine-Induced Brugada Pattern.

Background:Brugada phenocopies are clinical entities etiologically distinct from congenital Brugada syndrome; differentiation is crucial for management.Case:A 29 year-old male with a history of cocaine abuse, brought in by Emergency Medical Services (EMS) after he was found unresponsive and given naloxone. He was found altered but arousable with verbal stimuli. He reported snorting a white powder to get “high”. He denied family history of sudden death or previous history of syncope. His ECG on presentation showed coved, ≥2 mm ST elevation with T-wave inversion in V2 consistent with Brugada EKG pattern (Figure 1). His troponin was trending up with elevated creatinine 1.6 mg/dl, liver enzymes and lactic acid, and urine toxicology was positive for cocaine.Decision-making:The presentation of altered mental status is multifactorial: metabolic derangement, drugs misuse and Brugada. Finding Brugada EKG pattern should be investigated to differentiate congenital Brugada syndrome and Brugada phenocopies. This patient has no family history of sudden death and no prior history of syncope. Serial EKG showed a gradual resolution of the coved and ST elevation in V2.Conclusion:our case demonstrates the importance of careful history taking including family history, as well as serial ECGs and treating the possible underlying etiology such as drugs abuse or electrolytes abnormality. It is also warranted to differentiate between Brugada phenocopies from congenital Brugada syndrome because therapeutic strategies are quite different with each diagnosis.

Prevalence of spontaneous type I ECG pattern, syncope, and other risk markers in sudden cardiac arrest survivors with Brugada syndrome.

A spontaneous type I electrocardiogram (ECG) pattern and/or unheralded syncope are conventionally used as risk markers for primary prevention of sudden cardiac arrest/death (SCA/SCD) in Brugada syndrome (BrS). In this study, we determine the prevalence of conventional and newer markers of risk in those with and without previous aborted SCA events. All patients with BrS were identified at our institute. History of symptoms was obtained from medical tests or from interviews. Other markers of risk were also obtained, such as presence of (1) spontaneous type I pattern, (2) fractionated QRS (fQRS), (3) early repolarization (ER) pattern, (4) late potentials on signal-averaged ECG (SAECG), and (5) response to programmed electrical stimulation. In 133 patients with Bars, 10 (7%) patients (mean age=39±11 years; nine males) were identified with a previous ventricular fibrillation/ventricular tachycardia episode (n=8) or requiring cardio-pulmonary resuscitation (n=2). None of these patients had a prior history of syncope before their SCA event. Only two (20%) patients reported a history of palpitations or dizziness. None had apneic breathing and three (30%) patients had a family history of SCA. From their ECGs, a spontaneous pattern was only found in one (10%) of these patients. Further, 10% of patients had fQRS, 17% had late potentials on SAECG, 20% had deep S waves in lead I, and 10% had an ER pattern in the peripheral leads. No significant differences were observed in the non-SCA group. The majority of BrS patients with previous aborted SCA events did not have a spontaneous type I and/or prior history of syncope. Conventional and newer markers of risk appear to only have limited ability to predict SCA.

Recurrent syncope is not an independent risk predictor for future syncopal events or adverse outcomes

Almost 20% of patients with syncope will experience another event. It is unknown whether recurrent syncope is a marker for a higher or lower risk etiology of syncope. The goal of this study is to determine whether older adults with recurrent syncope have a higher likelihood of 30-day serious clinical events than patients experiencing their first episode. MethodsThis study is a pre-specified secondary analysis of a multicenter prospective, observational study conducted at 11 emergency departments in the US. Adults 60 years or older who presented with syncope or near syncope were enrolled. The primary outcome was occurrence of 30-day serious outcome. The secondary outcome was 30-day serious cardiac arrhythmia. In multivariate analysis, we assessed whether prior syncope was an independent predictor of 30-day serious events. ResultsThe study cohort included 3580 patients: 1281 (35.8%) had prior syncope and 2299 (64.2%) were presenting with first episode of syncope. 498 (13.9%) patients had 1 prior episode while 771 (21.5%) had >1 prior episode. Those with recurrent syncope were more likely to have congestive heart failure, coronary artery disease, previous diagnosis of arrhythmia, and an abnormal ECG. Overall, 657 (18.4%) of the cohort had a serious outcome by 30 days after index ED visit. In multivariate analysis, we found no significant difference in risk of events (adjusted odds ratio 1.09; 95% confidence interval 0.90–1.31; p = 0.387). ConclusionIn older adults with syncope, a prior history of syncope within the year does not increase the risk for serious 30-day events.

Electro and Echocardiographic Profile of Young American Navy Recruits Presented with Syncope

Background: The etiology of syncope in young adults is poorly defined and most studies reveal benign etiologies. However, case reports suggest that exercise-related syncope, even in young patients, can be a harbinger of sudden cardiac death. We aim to determine the characteristics of young adults presenting with syncope in a diverse population of navy recruits. Methods: A retrospective chart review was performed on all Navy recruits who presented with a complaint of syncope to the Captain James A. Lovell Federal Health Care Center (JALFHCC) between June 1, 2006 and May 31, 2013. There was a total of 154 charts. Demographics and clinical data, along with Electrocardiogram (EKG), telemetry, and echocardiographic findings were recorded. Variables were compared between the subjects with abnormal cardiac profile and subjects with normal cardiac results. Results: The sample size of 154 included 95 males and 59 females. There were 13 (8.4%) subjects who were found to have concerned cardiac findings; 9 were males (9.5% of males) and 4 were females (6.8% of females). Compared to those without cardiac findings, there were no significant differences in age (20.2 ± 3.8 vs. 20.2 ± 2.5 years), body mass index (25.8 ± 2.8 vs. 24.7 ± 3.5), prior history of syncope (23 vs. 21%), or presence of exertional syncope (77 vs. 63%). Conclusion: A significant proportion of young American navy recruits have evidence of concerning electro and echocardiographic findings. We did not find any clinical profile predicting such findings although there was a statistically insignificant, but noticeable trend towards exertional syncope in those who had concerning cardiac abnormalities.

Risk of syncope during work

Little is known regarding the overall prevalence of syncope in a population of workers and the risk of occurrence during working time. A total of 452 consecutive workers (mean age: 46 ± 9 years) were invited to answer an anonymous questionnaire. They had been employed for 22 ± 10 years for a total of 9765 years worked. In the cohort, 160 subjects (35%) reported a total of 465 episodes of syncope during their lives; 64 (14%) suffered a syncopal episode after the start of employment, but only 26 (5.7%) reported syncope at work, 7 (1.5%) having had 2 episodes, and 1 (0.2%) 3 episodes (total: 36 episodes). The risk of syncope during work was 4.6 times higher for those who had a prior history of syncope [18 of 138 (13%)] than for those who did not [8 of 314 (3%), P = 0.001]. The occurrence of syncope during work for the patients with a history of syncope was one syncopal episode in every 99 years worked and for those who had already had an episode during work, one episode in every 16 years worked. Only one patient experienced minor trauma as a consequence of syncope during work and three were referred to the emergency department. All patients continued their employment without any problems. The prevalence of syncope during work is low and its impact is benign. The probability of syncope during work is higher for subjects with a history of syncope.

Predictors of Hospitalization in Patients with Syncope Assisted in Specialized Cardiology Hospital

BackgroundRisk stratification of a syncopal episode is necessary to better differentiate patients needing hospitalization of those who can be safely sent home from the emergency department. Currently there are no strict guidelines from our Brazilian medical societies to guide the cardiologist that evaluate patients in an emergency setting.ObjectivesTo analyze the criteria adopted for defining the need for hospitalization and compare them with the predictors of high risk for adverse outcome defined by the OESIL score that is already validated in the medical literature for assessing syncope.MethodsA cross-sectional study of patients diagnosed with syncope during emergency department evaluation at our institution in the year 2011.ResultsOf the 46,476 emergency visits made in that year, 216 were due to syncope. Of the 216 patients analyzed, 39% were hospitalized. The variables associated with the need of hospital admission were - having health care insurance, previous known cardiovascular disease, no history of prior stroke, previous syncope and abnormal electrocardiograms during the presentation. Patients classified in OESIL scores of 0-1 had a greater chance of emergency discharge; 2-3 scores showed greater association with the need of hospitalization. A score ≥ 2 OESIL provided an odds ratio 7.8 times higher for hospitalization compared to score 0 (p <0.001, 95% CI:4,03-15,11). In approximately 39% no etiological cause for syncope was found and in 18% cardiac cause was identified.ConclusionsFactors such as cardiovascular disease, prior history of syncope, health insurance, no previous stroke and abnormal electrocardiograms, were the criteria used by doctors to indicate hospital admission. There was a good correlation between the clinical judgment and the OESIL criteria for high risk described in literature.

Accessory myocardial pathway mimicking an inferior myocardial infarction after major vascular surgery

Accessory myocardial pathway mimicking an inferior myocardial infarction after major vascular surgery

Cerebrovascular blood flow during the near syncopal phase of head-up tilt test: a comparative study in different types of neurally mediated syncope

This study analyses the changes in cerebral blood flow (CBF) velocity occurring in the near syncopal phase of head-up tilt test (HUT) to determine whether their appearance during the premonitory symptoms permits the differentiation of the different types of haemodynamic response. Six hundred and nineteen patients aged 35.9 +/- 16.4 with a prior history of syncope (55%) or presyncope (45%) were studied. Head-up tilt test was positive in 585 patients. The test was interrupted before syncope, once hypotension was evident and CBF changed. A vasovagal reaction (VVR) was observed in 245 patients. They had a 59% fall in diastolic CBF velocity, whereas systolic CBF velocity decreased by 12%. Postural orthostatic tachycardia syndrome (POTS) was observed in 82, systolic and diastolic CBF velocity decreased 44 and 60%, respectively. A similar response was observed in 258 patients with the orthostatic intolerance (OI) pattern. No significant changes were observed in the negative group. Patients with VVR had changes in CBF velocity, which are different from those presented by patients with POTS and OI pattern. Cerebral blood flow monitoring is useful to increase the yield of HUT and may allow early interruption before syncope occurs, reducing patient discomfort.

Transcranial Doppler monitoring during head upright tilt table testing in patients with suspected neurocardiogenic syncope.

The aim of the present study was to evaluate the mechanism of cerebrovascular autoregulation in patients with neurocardiogenic syncope using bilateral transcranial Doppler (TCD) monitoring during head upright tilt table testing (HUT). Two hundred and six patients were prospectively studied. One hundred and fifty-nine subjects (77%) had a prior history of syncope and 47 (23%) had presyncope. Ninety-nine patients (48%) had syncope or presyncope during HUT with a 76% fall in diastolic middle cerebral artery blood flow velocity (D-MCA-BFV). Systolic MCA-BFV (S-MCA-BFV) fell by 33%. Deepening of the dicrotic notch in the Doppler waveform always preceded the fall in D-MCA-BFV. Patients without syncope or presyncope (n=96) had smaller changes in cerebral blood flow velocities during HUT and only twenty-two subjects had transient deepening of the dicrotic notch. Eleven subjects had presyncope during HUT due to an exaggerated response to nitrates with progressive arterial hypotension without bradycardia and changes during TCD monitoring that were intermediate between positive and negative HUT. In conclusion, patients with neurocardiogenic syncope have changes in cerebral blood flow during the event. TCD monitoring during HUT helps to assess these alterations.

Effets cardiaques du massage carotidien chez le sujet sain de plus de 50 ans. Évaluation des critères diagnostiques du syndrome du sinus carotidien

Objective. – To study the value and limitations of carotid sinus massage in healthy individuals older then 50 years of age, in order to assess the validity of the widely used criteria for the diagnosis of hypersensitive carotid sinus syndrome Methods. – Right and left carotid sinus massage was performed in 120 healthy individuals older then 50 years of age (74 males and 46 females aged 59 ± 7 years) who had no prior history of syncope, pre–syncope, or abnormal bradyarrythmia, during EKG monitoring. Results. – Hypersensitivity of the carotid sinus (HSCS) defined as a pause > 3 s, was found in 28 individuals (23,3 %). The pause was induced by right carotid sinus massage in 20 cases and by left carotid sinus massage in 8 cases. Patients demonstrating HSCS were older compared to those who did not develop a pause. One or multiple blocked P wave was seen in 16 cases when carotid sinus massage was performed on the left side compared to 8 with right carotid sinus massage. Conclusion. – In healthy individuals older then 50 years of age, it is not rare to induce a significant pause following carotid sinus massage. This limits the validity of the widely used criteria for the diagnosis of hypersensitive carotid sinus syndrome. Additional criteria are proposed to make this diagnosis in front of a brief loss of consciousness.

Head-up Tilt Test in Subjects with No History of Syncope or Presyncope

Background and Objectives:Head-up tilt test is increasingly being used to diagnose neurocardiogenic syncope. But the protocol of head-up tilt test has not been settled. The purpose of this study was to evaluate the effect of isoproterenol provocation during head-up tilt test in normal volunteers with no prior history of syncope or presyncope. Method:Head-up tilt test was performed with 53 volunteers (mean age 30±9 years, male 27, female 26) in the fasting state. After supine heart rate and blood pressure were obtained, each volunteer was tilted to the 70 degree upright position for 30 minutes using a motorized tilt table with a footboard. If the test was negative in the baseline tilt, intravenous isoproterenol infusion was started at 1 μ g/min and then increased by 1 μg/min every three minutes to a maximum of 5 μg/min while maintaining 70 degree upright position. The end points of test were positive response, intolerance to isoproterenol, heart rate >150 beat/min, and completion of the protocol. When an end point was reached, the volunteer was rapidly returned to the supine position. Results:Positive response to head-up tilt test was noted in 14 cases (26%). The pattern of positive response was vasodepressive in all cases. There was no significant side effect of isoproterenol. There was no significant difference between positive and negative response group in terms of age, sex, peak infusion rate of isoproterenol and hemodynamic response. The positive response rate at 2 μ g/min , 3 μg/min, 4 μg/min, and 5 μg/min of isoproterenol infusion was 1.9%, 9.7%, 23.7% and 32.5%, respectively. Conclusion:Head-up tilt test at 70 degree angle with isoproterenol infusion provided an adequate specificity. (Korean Circulation J 2000;30(7):841-846)

Impact of clinical history and electrophysiologic characterization of accessory pathways on management strategies to reduce sudden death among children with Wolff-Parkinson-White syndrome

Objectives. This study sought to determine whether the clinical and electrophysiologic criteria developed in adults also identify children with Wolff-Parkinson-White syndrome at risk for sudden death.Background. In adults with Wolff-Parkinson-White syndrome, a shortest RR interval <220 ms during atrial fibrillation is a sensitive marker for sudden death. However, because reliance on the shortest RR interval has a low positive predictive value, the clinical history has assumed a pivotal role in assessing risk. This approach has not been evaluated in children.Methods. We retrospectively evaluated 60 children ≤18 years old who underwent comprehensive electrophysiologic evaluation between 1979 and 1989 before undergoing operation for Wolff-Parkinson-White syndrome. Clinical and electrophysiologic data were analyzed after patients had been grouped by ther clinical presentation: high risk (cardiac arrest), intermediate risk (syncope or atrial fibrillation) or low risk (orthodromic reciprocating tachycardia alone).Results. Ten children had a clinical cardiac arrest (high risk); only one had a prior history of syncope or atrial fibrillation. Compared with the intermediate (n = 19) and low risk groups (n = 31), there were no differences in age ([mean ± SD] 14.8 ± 0.6 vs. 14.7 ± 0.6 vs. 14.5 ± 1.7 years), duration of symptoms (1.9 ± 0.5 vs. 4.1 ± 1.1 vs. 5.2 ± 0.8 years), incidence of congenital heart disease (30% vs. 26% vs. 32%), presence of multiple pathways (20% vs. 16% vs. 16%) or accessory pathway location. A shortest pre-excited RR interval <220 ms was found in 7 of 7 high risk patients (sensitivity 100%), 14 of 19 intermediate risk patients and 11 of 31 low risk patients (prevalence 35%).Conclusions. Cardiac arrest was the only distinguishing clinical feature between high and low risk groups and the first manifestation in 80% of the children of an accessory pathway that can precipitate a life-threatening arrhythmia. In this series, the largest reported to date of children with Wolff-Parkinson-White syndrome having a cardiac arrest, a shortest pre-excited RR interval <220 ms was more sensitive than clinical history for identifying those at risk for sudden death.

Sudden death in severe aortic stenosis following cardiac catheterization.

Five patients with critical aortic stenosis (aortic valve area 0.6 cm2 or less) died 2 days to 21 days following cardiac catheterization performed in anticipation of cardiac surgery. A sixth patient was successfully resuscitated for spontaneous ventricular fibrillation, and successful aortic valve replacement was accomplished. Two patients had prior history of syncope; one patient, of ventricular tachycardia; three patients, of pulmonary edema; and three patients, of crescendo angina. One patient had severe hypotension during maintenance hemodialysis for chronic renal failure. The mode of death was sudden but not witnessed in two patients. The terminal cardiac rhythms were slow junctional in one patient, idioventricular in one, ventricular tachycardia in one, and ventricular fibrillation in the fourth patient. We conclude that symptomatic patients with critical aortic stenosis should be monitored after cardiac catheterization, and surgery should be performed as soon as possible since sudden death is not unusual.