Syncope and ventricular arrhythmias in hypertrophic cardiomyopathy are not related to the derangement of coronary microvascular function

Non-sustained ventricular tachycardia on Holter and syncope have been considered risk factors for sudden death in hypertrophic cardiomyopathy. AIMS: In these patients the coronary vasodilator reserve is impaired despite normal coronaries, so we evaluated the correlation between the severity of coronary vasodilator reserve impairment and the occurrence of syncope and non-sustained ventricular tachycardia. METHODS AND RESULTS: Eighty-four patients with hypertrophic cardiomyopathy (62 males, age 43 +/- 12 years) had a two-dimensional echocardiographic study and a 48-h Holter. Myocardial blood flow was measured by positron emission tomography, at baseline and after dipyridamole, and the coronary vasodilator reserve was computed as dipyridamole myocardial blood flow/baseline myocardial blood flow. In 27 patients, subendocardial and subepicardial myocardial blood flow was measured in the septum and the subendocardial/subepicardial ratio was computed. Twenty of 84 patients had at least one syncopal episode, and 26 had at least one run of non-sustained ventricular tachycardia on Holter. Baseline and dipyridamole myocardial blood flow, coronary vasodilator reserve, and baseline and dipyridamole subendocardial/subepicardial myocardial blood flow ratio were similar in patients with and without syncope and with and without non-sustained ventricular tachycardia on Holter. However, patients with non-sustained ventricular tachycardia had larger left ventricular end-diastolic (47 +/- 6 vs 44 +/- 5 mm, P < 0.05) and end-systolic diameters (30 +/- 6 vs 27 +/- 4 mm, P < 0.05). CONCLUSIONS: (1) Coronary vasodilation is not more severely impaired in patients with hypertrophic cardiomyopathy and syncope or non-sustained ventricular tachycardia. (2) The left ventricle is more dilated in hypertrophic cardiomyopathy with non-sustained ventricular tachycardia.     

Exertional syncope in a patient with aortic stenosis and right coronary artery disease

A female with advanced aortic valvular stenosis and moderate right coronary artery disease experienced an exertional syncope during 24-h ambulatory electrocardiographic monitoring. A progressive bradycardia with 90-s sinus node arrest (cardio-inhibitory response) and premonitory angina pectoris with significant ST segment changes were demonstrated. Our report supports the concept of a neurocardiogenic (vasovagal) mechanism of exertional syncope in patients with aortic stenosis. The predominant left ventricular inferior-wall myocardial ischaemia in our patient might be an additional stimulus to left ventricular mechanoreceptors, resulting in a profound cardio-inhibitory response.     

Diagnosis of long QT syndrome with the help of atropine provoked ventricular tachycardia

A 49-year-old woman was admitted because of several syncopes during sports activity. She was appeared well, and the physical examination revealed no pathological findings, particularly no heart murmurs. The electrocardiogram had a normal PQ, QRS and the corrected QT (QTc)interval was 0.44 s. During the exercise test no arrhythmias were seen and the QTc was unchanged of 0.44 s, but 0.6 mg atropine injected intravenously provoked prolonged QTc = 0.49 s followed by nonsustained ventricular tachycardia. Electrophysiological examination and coronary arteriography showed no inducible arrhythmias and no presence of coronary artery disease. Beta-blocker treatment was started. During one year of observation she presented no syncope, and was still active in sports. It is concluded that patients presenting with syncope and an ECG with borderline QT prolongation should undergo several provocation trials, if simple stress test is initially negative, because undiagnosed patients without prophylactic treatment have a high mortality.     

pH sensitive properties of Tc(V)-DMS: analytical and in vitro cellular studies

Coronary arteries anomalies may be part of complex congenital malformations of the heart or be an isolated defect. In our anatomic collection of congenital heart disease, an isolated anomalous origin of coronary arteries was observed in 27 of 1,200 specimens (2.2%): left coronary artery from pulmonary trunk in five, origin from the wrong aortic sinus in 12 (both right and left coronary artery from the right sinus in four and from the left sinus in seven, left coronary artery from the posterior sinus in one), left circumflex branch from right aortic sinus or from very proximal right coronary artery in three, high takeoff of right coronary artery in three, stenosis of the coronary ostia attributable to valvelike ridge in four. In 16 (59%) patients (12 males and 4 females, age ranging from 2 months to 53 years; median, 14), the final outcome was sudden death; it occurred in all cases of left coronary artery origin from right aortic sinus, in 43% of right coronary artery origin from left aortic sinus, and in 40% of the left coronary artery from the pulmonary trunk. Sudden death was precipitated by effort in eight (50%) and was the first manifestation of the disease in eight (50%); previous symptoms consisted of recurrent syncope in four, palpitations in three, and chest pain in one. Five patients who died suddenly during effort were athletes. In conclusion, (1) more than half of our postmortem cases with anomalous origin of coronary arteries died suddenly, (2) all but two patients with sudden death had anomalous coronary artery origin from the aorta itself, (3) the fatal event was frequently precipitated by effort, (4) palpitations, syncope, and ventricular arrhythmias were the only prodromic symptoms and signs. Recognition during life of these coronary anomalies, by the use of noninvasive procedures, is mandatory to prevent the risk of sudden death and to plan surgical correction if clinically indicated.     

Esophageal patching for an unsuturable tracheoesophageal fistula

We report on the case of a 45-year-old man with recurrent syncope and angina with shortness of breath on exertion. Invasive and noninvasive diagnostic methods revealed severely stenosed bicuspid aortic valve, postductal coarctation of the aorta, and a coronary artery-descending aorta fistula. After surgical correction of the coarctation, ligation of the fistula, and aortic valve replacement, the patient's symptoms resolved.     

High-grade coronary stenosis due to a bronchogenic cyst

A 32-year-old woman without preceding illness or significant cardiovascular risk factors was admitted to hospital because of a syncope after physical exertion. Transoesophageal echocardiography, performed to exclude aortic dissection, showed as an incidental finding a cystic space-occupying mass, 5 x 6 cm in diameter, dorsal to the aortic root and main pulmonary artery. Exercise ECG had S-T segment depressions of about 0.3 mV, associated with anginal symptoms, so that inadequate coronary artery flow on exertion was suspected. Subsequent coronary angiography demonstrated a funnel-shaped 80% stenosis at the origin of the main left coronary artery, while all other coronary arteries were normal and smooth-walled. A causal connection between the two findings was assumed and quickly undertaken surgical intervention revealed an intrapericardial bronchogenic cyst which, presumably as a result of its size and location, had pressed on the main stem of the left coronary artery and caused the stenosis of its ostium. The cyst was completely resected and angioplasty of the coronary artery ostium was performed to ensure its patency. 3 months postoperatively the patient underwent an exercise test of up to 125 Watt without signs of ischaemia. This case presents a previously unreported complication of a bronchogenic cyst.     

Complex demodulation of cardiorespiratory dynamics preceding vasovagal syncope

BACKGROUND: The dynamic autonomic processes leading to vasovagal syncope are poorly understood. METHODS AND RESULTS: We used complex demodulation to continuously assess changes in respiration, R-R interval, and arterial pressure (blood pressure) variability during 60 degree head-up tilt in 25 healthy subjects with tilt-induced vasovagal syncope and 25 age-matched nonsyncopal control subjects. Coherence and transfer function analyses were used to examine the relation between respiration and R-R interval variability before syncope. Baseline blood pressure, R-R, and ventilation were similar between syncope subjects and control subjects. Syncope subjects experienced an increase in tidal volume and decrease in BP beginning 3 minutes before impending syncope (systolic blood pressure <80 mm Hg) necessitated termination of tilt. Approximately 90 seconds before syncope there was a sudden prolongation of R-R interval and increase in amplitude of high and low frequency R-R interval variability, indicating an abrupt enhancement of vagal tone. The increase in respiratory amplitude between 180 and 90 seconds before syncope was not accompanied by changes in R-R interval or R-R variability, suggesting a dissociation between respiration and the respiratory sinus arrhythmia. The coherence analysis showed fewer syncope subjects with coherence between respiratory and R-R interval variabilities and lower transfer magnitudes in syncope subjects compared with control subjects. Nonsyncopal subjects had no change in respiratory, R-R interval, or blood pressure dynamics during matched time periods before the time of syncope. CONCLUSIONS: Vasovagal syncope is preceded by a period of hyperpnea and cardiorespiratory decoupling followed by an abrupt increase in cardiovagal tone. Respiratory pumping without inspiratory cardiac slowing may partially counteract preload reduction until sudden bradycardia precipitates syncope.     

Prevalence of heart disease in older women in a nursing home

The prevalence of coronary artery disease (CAD) and the incidence of new coronary events are similar in older men and women. Independent risk factors for new coronary events in older women include age, prior CAD, cigarette smoking, hypertension, diabetes mellitus, high serum total cholesterol and triglycerides, and low serum high-density lipoprotein cholesterol. Older women have a higher prevalence of hypertension than older men. In older women with hypertension, echocardiographic left ventricular hypertrophy is a powerful independent predictor of new coronary events, atherothrombotic brain infarction, and congestive heart failure (CHF). Older women have a higher prevalence of rheumatic mitral stenosis and of mitral annular calcium than older men. Older women and men have a similar prevalence of valvular aortic stenosis, aortic regurgitation, mitral regurgitation, hypertrophic cardiomyopathy, and idiopathic dilated cardiomyopathy. The prevalence and incidence of CHF increase with age. The prevalence of normal left ventricular ejection fraction associated with CHF increases with age and is higher in older women than in older men. The prevalence of chronic atrial fibrillation increases with age and is similar in older men and women. Atrial fibrillation is an independent predictor of new coronary events and thromboembolic stroke in older women. Older women with unexplained syncope should have 24-hour ambulatory electrocardiograms to determine whether pauses > 3 seconds are present, requiring permanent pacemaker implantation.     

Intraluminal increase of superoxide anion following transient focal cerebral ischemia in rats

OBJECTIVES: We studied the triggering mechanism for neurally mediated syncope. BACKGROUND: Although increased transient sympathetic tone is thought to be necessary for the development of neurally mediated syncope, little is known about the triggering mechanism for neurally mediated syncope. METHODS: Plasma epinephrine (EP) and norepinephrine (NE) levels were assessed in 20 syncope patients during tilt test (80 degrees, 15 min) with and without isoproterenol (ISP, 0.01, 0.02 microg/kg/min). If syncope occurred, propranolol (0.1 mg/kg) was injected. RESULTS: Eight patients experienced syncope during tilting alone, and 9 patients required ISP for syncope. In the negative response without ISP, NE showed a small statistical 1.7-fold increase at end of tilting and EP did not change during tilting. When syncope occurred during tilting alone, a significant 11.7-fold increase in EP at syncope was registered concomitant with a small 2.5-fold increase in NE. When patients experienced syncope during tilting with ISP, a significant 5.0-fold increase in EP at syncope was registered concomitant with a small 1.7-fold increase in NE. In patients without ISP, propranolol did not interrupt syncope. In patients with ISP, six of eight receiving propranolol responded to tilting negatively. CONCLUSIONS: An increase of NE levels may result in inhibition of syncope and an EP surge may be a triggering mechanism for neurally mediated syncope. Comparatively low levels of EP may be enough to induce syncope during tilting with ISP compared with tilting alone. Propranolol is not effective in patients without ISP, but it frequently inhibits syncope in patients with ISP. Propranolol (0.1 mg/kg) may be insufficient to block the actions of high levels of circulating EP.     

Association of parental psychological and behavioral factors and children's syncope.

The authors examined the associations between parental variables and child syncope (fainting). Children ages 7 to 18 years undergoing tilt-table testing for neurocardiogenic syncope (NCS) at a pediatric cardiac center served as participants (N = 56). Results revealed that fathers' shortness of breath and overall psychological distress were significantly related to syncope frequency and emergency room (ER) visits for girls. Mothers' overall psychological distress, depressive symptoms, and shortness of breath were associated with boys' frequency of syncope and ER visits. Fathers' psychological factors were highly correlated with syncope for the children diagnosed negative for NCS. The frequency of children's syncope was higher in stepfamilies than in homes with both biological parents, and the correlations between children's syncope and the stepfathers' psychological symptoms were greater than for the children and their biological fathers in intact families. The role of parental psychological factors on child syncope is supported. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Micturition syncope

The micturition syncope is a special manifestation of the so called "situational syncopes". These reflex syncopes share efferent mechanisms with the neurocardiogenic, or vasovagal syncope. A case of a patient is reported, who presented with micturition syncope. The patient's tendency for vasovagal syncope was documented by a positive tilt table test. The uniform premonitory symptoms preceding the two fainting attacks indicated the relation between the episodes. The authors review the literature of the micturition syncope, and discuss the potential pathomechanisms.     

Syncope in children and adolescents

OBJECTIVES: The objectives of this study were to 1) define the incidence of syncope coming to medical attention among children and adolescents, 2) determine the outcome of syncope in these patients, and 3) determine changes over time in the evaluation and charges for evaluating this problem. BACKGROUND: Syncope occurs commonly in children and adolescents. However, the mid- and long-term outcome of children and adolescents who experience syncope is unknown. METHODS: Utilizing the Rochester Epidemiology Project, we determined the incidence, outcome and charges for medical evaluation for patients seeking medical attention for syncope during an early 5-year period (1950 to 1954) and a more recent 5-year period (1987 to 1991). RESULTS: The incidence of syncope coming to medical attention was 71.9 and 125.8/100,000 population for the early and more recent cohort, respectively. The incidence was higher for female than for male patients. The incidence peaked in 15- to 19-year old patients. Acute illness and noxious stimuli were associated with 24% and 23% of the episodes, respectively. Although long-term survival was not different from that of the general population, one child died suddenly, and another had hereditary prolonged QT interval syndrome. These were two of only six patients who had exertional syncope. Total charges for evaluation of syncope were similar in the two time periods. However, charges for testing procedures were greater for the more recent cohort. CONCLUSIONS: In general, syncope in children and adolescents is a benign event. Syncope occurring during exercise may identify patients with a potentially fatal condition. Detailed evaluation should be considered for patients who have syncope during exercise or who have a family history of syncope, sudden death, myocardial disease or arrhythmias. It may be prudent to obtain an electrocardiogram for all patients who seek medical attention for syncope.     

Parent and Child Psychological Factors in Pediatric Syncope and Other Somatic Symptoms.

The authors examined associations among parental and child adjustment, child syncope, somatic, and school problems. Participants were children (N = 56) ages 7-18 years with syncope. Measures included syncope severity, parental distress, and children's internalizing symptoms. For children diagnosed negative for neurocardiogenic syncope (NCS), their fathers' and their own psychological symptoms were positively associated with the severity of syncope, whereas their mothers' functioning was negatively associated with the severity of syncope. Also, for the negative NCS group, fathers' psychological functioning was associated with children's nonsyncope somatic complaints but not with their school problems. For the positive NCS group, few significant father-child associations were found, but several significant positive associations were revealed between mothers' psychological symptoms and their children's syncope as well as somatic and school problems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Syncope in patients with an implantable cardioverter-defibrillator: incidence, prediction and implications for driving restrictions

OBJECTIVES: This retrospective study was undertaken to provide information on occurrence, risk prediction and prevention of syncope in patients with an implantable cardioverter-defibrillator (ICD). BACKGROUND: ICDs effectively terminate ventricular tachycardia and fibrillation (VT/VF). Incapacitating symptoms, such as syncope, may still occur. METHODS: We performed a retrospective analysis of data from 421 patients (clinical history, outpatient chart reviews and episode data) with mean (+/-SD) follow-up of 26 +/- 18 months. RESULTS: Of 421 patients, 229 (54.4%) had recurrent VT/VF, and 62 (14.7%) had syncope. The actuarial survival rate free of VT/VF was 58%, 45% and 37% and that for survival free of syncope was 90%, 85% and 81% at 12, 24 and 36 months after implantation, respectively. Once VT/VF had occurred, 76%, 68% and 62% of patients remained free of syncope during the following 12, 24 and 36 months, and 68%, 64% and 56% remained free of second syncope 12, 24 and 36 months after first syncope, respectively. In cases of syncope, the mean cycle length (CL) of VT was 251 +/- 56 ms. A low baseline left ventricular ejection fraction (LVEF), induction of fast VT (CL <300 ms) during programmed ventricular stimulation and chronic atrial fibrillation (AF) were associated with an increased risk of syncope. If the LVEF was >40%, fast VT had not been induced, and patients had no chronic AF; 96%, 92% and 92% of patients remained free of syncope after 12, 24 and 36 months, respectively. Once patients had a VT recurrence, syncope during the first VT and a high VT rate were the strongest risk predictors of future syncope. CONCLUSIONS: Identification of patients with an ICD with a low and high risk of syncope seems to be feasible and might help as a guide to driving restrictions in such patients.     

Response to head-up tilt testing in patients with situational syncope

The results of head-up tilt testing were compared between 24 patients with situational syncope and 44 age-matched patients with typical vasovagal syncope. Patients with situational syncope showed poor positive responses, especially in the passive tilt results (8.3% vs. 39%, p = 0.0078).     

Paroxysmal atrial fibrillation: main cause of syncope in hypertrophic cardiomyopathy

The aim of this retrospective study was to determine the mechanism of syncope in idiopathic hypertrophic cardiomyopathy (HCM). An electrocardiographic study was undertaken in 43 patients with HCM: 27 (Group I) had a history of syncope and 16 (Group II) had no history of syncope but were investigated for conduction defects (n = 7) or unsustained ventricular tachycardia (VT) (n = 9). The stimulation protocol used programmed atrial pacing with 1 and 2 extrastimuli and ventricular pacing using up to 3 extrastimuli delivered at 2 sites. The following results were obtained: sustained atrial fibrillation (AF) (> 1 min) was induced in 21 patients in Group I (78%), 4 in Group II (25%); VT was induced in 3 patients in Group I (11%), and 3 in Group II (19%); infra-Hisian block was detected in 1 patient in Group I. The mechanism of syncope was elucidated in 23 patients in Group I (85%): one atrioventricular block 1 sinus node dysfunction, 18 atrial fibrillations, 2 associations of AF-VT and 1 VT. The authors conclude that the prevalence of inducible AF was higher in patients with HCA and syncope than in controls and HCM without syncope: this was the only detectable difference in 67% of patients with unexplained syncope. Paroxysmal AF could therefore explain malaise or syncope in up to 2/3 of cases of HCM.     

Use of an extended monitoring strategy in patients with problematic syncope. Reveal Investigators

BACKGROUND: The conventional investigation of patients who present with syncope involves short-term ECG monitoring or provocative testing with head-up tilt and electrophysiological testing. A symptom-rhythm correlation is often difficult to obtain during spontaneous syncope because of its sporadic, infrequent, and unpredictable nature. METHODS AND RESULTS: We used a prolonged monitoring strategy to determine the cause of syncope in 85 patients (age, 59+/-18 years; 44 men) with recurrent undiagnosed syncope with an implantable loop recorder capable of cardiac monitoring for up to 18 months. During a mean of 10.5+/-4.0 months of follow-up, symptoms recurred in 58 patients (68%) 71+/-79 days (2.3+/-2.6 months) after implantable loop recorder insertion. An arrhythmia was detected in 42% of patients who recorded a rhythm during recurrent symptoms, with bradycardia present in 18 and tachycardia in 3. Five of the 18 bradycardic patients and 2 additional sinus rhythm patients received a clinical diagnosis of neurally mediated syncope. Patients who experienced presyncope were much less likely to record an arrhythmia during symptoms compared with recurrence of syncope (24% versus 70%, P=0.0005). There were no adverse events associated with recurrent symptoms, and there were no sudden deaths. Inability to freeze after an event occurred in 8 patients, and pocket infection occurred in 3. CONCLUSIONS: The strategy of prolonged monitoring is effective and safe in patients with problematic syncope.     

Interaction of transresveratrol with plasma lipoproteins

OBJECTIVE: To determine electroencephalographic (EEG) changes occurring during syncope induced by headup tilt table testing. DESIGN: Prospective observational study. SETTING: Calgary General Hospital Syncope Clinic, Calgary, Alberta. PATIENTS: Eighteen patients with a history of recurrent syncope who developed syncope while undergoing diagnostic isoproterenol tilt table testing. INTERVENTIONS: Continuous EEGs were recorded in 18 sequentially consenting patients while they underwent diagnostic headup tilt table testing. MAIN RESULTS: Patients developed presyncope after 2.6 +/- 2.4 mins and syncope after 3.7 +/- 2.5 minutes. Systolic blood pressure dropped from 117 +/- 17 mmHg to 65 +/- 9 mmHg, and heart rate dropped from 124 +/- 26 beats/min to 65 +/- 27 beats/min. Fourteen patients developed presyncope, while five developed syncope without appreciable presyncope. Abnormal EEGs were recorded in 13 of 14 patients during presyncope and in 18 of 18 patients during syncope. No patients developed EEG abnormalities before the onset of presyncope, and the proportion of patients with EEG abnormalities gradually increased throughout presyncope. During presyncope, theta and delta wave slowing, and background suppression were noted in eight of 14, nine of 14 and one of 14 patients, respectively. During syncope, theta and delta wave slowing, and background suppression were noted in nine of 18, 11 of 18 and six of 18 patients, respectively (not significant versus presyncope). There were strikingly abrupt changes in the EEG rhythm within 15 s of the transition to syncope in 14 of 18 patients. Six patients developed new theta wave slowing, 11 developed new delta wave slowing, and seven developed background suppression. No epileptiform activity was recorded. CONCLUSIONS: Both presyncope and syncope induced by tilt testing are associated with EEG abnormalities, and no single EEG pattern is pathognomonic of either. The transition from presyncope to syncope is marked by abrupt EEG changes.     

Dysaesthetic neck pain with syncope

Neurogenic dysaesthetic pain in the neck following surgery for tumours in the neck is rare. Rarer still is the combination of pain following surgery with syncope. We looked at four patients who had tumours within the neck excised and then went on to develop neurogenic dysaesthetic neck pain associated with syncope. Distinction is made between neurogenic dysaesthetic pain following neck surgery and glossopharyngeal neuralgia which has been previously reported in association with neck surgery and also glossopharyngeal neuralgia with syncope. Spinal cord stimulation was used successfully to treat the dysaesthetic pain and syncope in three of the patients while the fourth patient died from the effects of his tumour. Medical practitioners may wish to consider spinal cord stimulation in relation to treating neurogenic dysaesthetic neck pain with syncope.