Clinical and laboratory indices that enhance the diagnosis of postural tachycardia syndrome

OBJECTIVE: To identify clinical and laboratory indices that improve the diagnosis of the postural tachycardia syndrome (POTS). DESIGN: We assessed associations of orthostatic intolerance by using multivariate regression analysis. MATERIAL AND METHODS: We evaluated autonomic symptoms and autonomic function in 30 patients with POTS, 30 patients with mild orthostatic intolerance, and 19 age- and gender-matched control subjects. Indices of parasympathetic and sympathetic functions were analyzed on the basis of (1) autonomic function tests (head-up tilt), (2) oscillations at respiratory and nonrespiratory frequencies (0.01 to 0.09 Hz) in R-R interval and blood pressure (Wigner distribution), and (3) deterministic component (rescaled range analysis). RESULTS: The four clinical and laboratory indices that independently supported the diagnosis of POTS are as follows: (1) orthostatic heart rate during the first minute of head-up tilt, (2) autonomic deficit (adrenergic autonomic score), (3) loss of spectral powers in R-R interval during head-up tilt at the fifth minute, and (4) severity of orthostatic dizziness, fatigue, palpitations, and shortness of breath. CONCLUSION: Enhancing the sensitivity and specificity of the diagnosis of POTS should be possible by using these four indices. A hyperadrenergic state and distal neuropathy, affecting adrenergic sympathetic cardiovagal fibers, seem to be involved in the pathophysiology of POTS. Certain features suggest brain-stem dysregulation.     

Orthostatic tremor: an electrophysiological analysis

Orthostatic tremor (OT) is a clinically defined syndrome of leg tremor while standing. Controversy surrounds whether OT is a distinct syndrome or is an essential tremor (ET) variant. We report two patients with OT. Electrophysiological testing included polymyography, accelerometry, nerve conduction, and evoked potential studies. The effects of various maneuvers and body positions on the tremor were assessed. The findings included rapid (15-17 Hz) lower-extremity tremor burst frequency evoked by standing but not by walking or swaying; rapid upper-extremity burst pattern synchronous with lower-extremity bursts; and failure of electrical stimulation or mental concentration to "reset" the tremor. Additionally, there was the novel finding of accelerometric recordings in the legs revealing the same rapid frequency (16-17 Hz) as the electromyographic tremor bursts. Some prior reports have suggested that OT is related to ET by emphasizing a considerable disparity and variability between the accelerometric tremor frequency and the electromyographic burst frequency. In our patients, however, the rapid (15-17 Hz) accelerometer-recorded tremor synchronous with the electromyographic bursts, and also the clinical improvement with clonazepam but not beta blockers or mysoline, and the lack of a family history of ET provide support that OT is distinct from ET.     

Orthostatic tremor: clinical and electrophysiologic characteristics

Orthostatic tremor, sometimes known as "shaky legs syndrome," is a disorder of middle-aged or elderly people characterized by feelings of unsteadiness in the legs and a fear of falling when standing. Patients stand on a wide base but walk normally. These symptoms are due to high-frequency (13-18 Hz) burst firing in weight-bearing muscles. They are attenuated by walking and are abolished immediately by sitting. Some authors believe that the disorder is a variant of essential tremor. This study reports the clinical and electrophysiologic features of orthostatic tremor in 30 patients. The findings indicate that orthostatic tremor is distinct from essential tremor, both clinically and electrophysiologically. The major differences are the frequency of electromyographic burst firing, the invariable involvement of lower limb and paraspinal muscles, and the task-specific nature of the tremor in orthostatic tremor. The study shows that the diagnosis can be established rapidly with surface electromyographic recordings.     

Orthostatic hypotension: epidemiology, pathophysiology and management

Orthostatic hypotension is characterized by low upright blood pressure levels and symptoms of cerebral hypoperfusion. Whereas orthostatic hypotension is heterogeneous, correct pathophysiologic diagnosis is important because of therapeutic and prognostic considerations. Although therapy is not usually curative, it can be extraordinarily beneficial if it is individually tailored. Management of the Shy-Drager syndrome (multiple-system atrophy) remains a formidable challenge.     

Junctional tachycardia during radiofrequency ablation of the slow pathway in patients with AV nodal reentrant tachycardia: effects of autonomic blockade

BACKGROUND: Exogenous surfactant treatment of hyaline membrane disease is known to modify the pattern of radiological changes on the chest radiograph. OBJECTIVES: To analyse and attempt to explain the radiological changes observed after exogenous surfactant treatment. Materials and methods. Thirty-nine premature infants with typical hyaline membrane disease. RESULTS: Transient asymmetrical clearing with better aeration of the right lung in the absence of malposition of the tip of the endotracheal tube was observed in nine cases (23 %). This asymmetry was patchy in one case. It was due to a complication of mechanical ventilation in three cases [pneumothorax (n = 2) and pneumomediastinum (n = 1)]. In the other six cases, asymmetrical clearing could be related to the anatomical position of the right main bronchus, which facilitates distribution of surfactant to the right lung. However, the course of these premature infants was similar to that of infants with symmetrical chest radiological findings after treatment. CONCLUSIONS: Asymmetrical clearing of chest radiographs, sometimes patchy, after surfactant treatment requires exclusion of pneumothorax or infection but has no influence on clinical outcome.     

Orthostatic hypotension and low blood pressure in organic dementia: a study of prevalence and related clinical characteristics

OBJECTIVE: To determine the prevalence of orthostatic hypotension (OH), low blood pressure and dizziness, falls and fractures in patients with organic dementia. DESIGN: We prospectively studied 151 patients, assessing the prevalence of OH, hypertension, heart disorders, diabetes mellitus and the use of medication possibly associated with OH. SETTING: The patients were admitted to our psychogeriatric clinic as part of routine clinical investigation of their dementia. PATIENTS: Forty-six patients with Alzheimer's disease (AD), 28 patients with frontotemporal dementia (FTD) and 77 patients with vascular dementia (VaD) were investigated. MAIN OUTCOME MEASURE: Due to the paucity of information about the prevalence of OH in organic dementia, this study is mainly explorative in nature, thus preventing explicit hypothesis formulation. However, clinical impressions indicated a higher prevalence of OH in organic dementia than normally seen in healthy elderly. RESULTS: OH/low blood pressure was present in 39-52% of the patients. The majority reached their maximum systolic decrease within 5 minutes of standing, but in 20-30% the maximum blood pressure drop occurred after 5 minutes or later. In 38%, the systolic blood pressure drop was more than 40 mm Hg. Hypertension and heart disease was found only in AD and VaD, with no difference between those with and without OH/low blood pressure. Falls and fractures were common in orthostatic and hypotensive patients, with an incidence of more than 50% in AD and VaD. CONCLUSIONS: The results support our clinical impressions that OH and low blood pressure is common and an important factor in organic dementia.     

Stereovideographic evaluation of the postural geometry of healthy and scoliotic patients

Idiopathic scoliosis principally characterised by a deformation of the vertebral column can also be associated to postural abnormalities. The validity and reliability of current quantitative postural evaluations has not been thoroughly documented, frequently limited by a two dimensional view of the patient, and do not include the whole posture of the patient. The purpose of this study is to 1) quantify within and between-session reliability of a stereovideographic Postural Geometry (PG) evaluation and 2) to investigate the sensitivity of this technique for the postural evaluation of scoliosis patients. The PG of 14 control subjects and 9 untreated scoliosis patients were evaluated with 5 repeat trials, on two occasions. Postural geometry parameters that describe the position and orientation of the pelvis, trunk, scapular girdle and head were calculated based on the 3-dimensional co-ordinates of anatomical landmarks. The mean between and within-session variability across all parameters were 12.5 mm, 2.8 degrees and 5.4 mm and 1.4 degrees respectively. The patient group was heterogeneous with some noted pathological characteristics. This global stereovideographic postural geometry evaluation appears to demonstrate sufficient reliability and sensitivity to follow-up on the posture of scoliosis patients.     

Radiofrequency catheter ablation of ventricular tachycardia in 26 patients

Electrophysiology study and radiofrequency catheter ablation (RFCA) were performed in 26 patients with refractory sustained ventricular tachycardia (VT). After induction of VT, 12-lead electrocardiogram (ECG) was recorded and QRS morphology and axis of induced VT were studied to identify the origin of VT. The precise site of VT origin were localized by pace mapping and activation mapping carefully. RF energy was delivered through a big-tip deflectable electrode catheter when the earliest site of endocardial activation and a high-frequency and low-amplitude potential of Purkinje fiber, preceding surface QRS by more than 25 ms, were identified and/or a pace map was obtained showing identical QRS complexes in at least 11 of 12 ECG leads. VTs were ablated successfully in 24 of 26 patients (success rate was 92%). For successful ablation, it is essential that the pace map QRS morphology in 12 leads should be identical with that in spontaneous or induced VT as far as possible in performing pace mapping. Pace mapping is safe, simple and has no unfavourable effect hemodynamics although it takes longer time. Activation mapping takes shorter time and has a high success rate. QRS configuration in spontaneous VT can help to localize the site of VT origin. Deliberate mapping at the site suggested to bo the origin of VT by surface ECG can shorten the duration of mapping and increase the success rate of RFCA. RFCA of VT in patients without structural heart disease is effective, safe, and has a high success rate, so it may be considered as an early therapy for these patients.     

Verapamil-sensitive left anterior fascicular ventricular tachycardia: results of radiofrequency ablation in six patients

INTRODUCTION: Verapamil-sensitive left ventricular tachycardia (VT) with a right bundle branch block (RBBB) configuration and left-axis deviation has been demonstrated to arise from the left posterior fascicle, and can be cured by catheter ablation guided by Purkinje potentials. Verapamil-sensitive VT with an RBBB configuration and right-axis deviation is rare, and may originate in the left anterior fascicle. METHODS AND RESULTS: Six patients (five men and one woman, mean age 54+/-15 years) with a history of sustained VT with an RBBB configuration and right-axis deviation underwent electrophysiologic study and radiofrequency (RF) ablation. VT was slowed and terminated by intravenous administration of verapamil in all six patients. Left ventricular endocardial mapping during VT identified the earliest ventricular activation in the anterolateral wall of the left ventricle in all patients. RF current delivered to this site suppressed the VT in three patients (ablation at the VT exit). The fused Purkinje potential was recorded at that site, and preceded the QRS complex by 35, 30, and 20 msec, with pace mapping showing an optimal match between the paced rhythm and the clinical VT. In the remaining three patients, RF catheter ablation at the site of the earliest ventricular activation was unsuccessful. In these three patients, Purkinje potential was recorded in the diastolic phase during VT at the mid-anterior left ventricular septum. The Purkinje potential preceded the QRS during VT by 66, 56, and 63 msec, and catheter ablation at these sites was successful (ablation at the zone of slow conduction). During 19 to 46 months of follow-up (mean 32+/-9 months), one patient in the group of ablation at the VT exit had sustained VT with a left bundle branch block configuration and an inferior axis, and one patient in the group of ablation at the zone of slow conduction experienced typical idiopathic VT with an RBBB configuration and left-axis deviation. CONCLUSION: Verapamil-sensitive VT with an RBBB configuration and right-axis deviation originates close to the anterior fascicle. RF catheter ablation can be performed successfully from the VT exit site or the zone of slow conduction where the Purkinje potential was recorded in the diastolic phase.     

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.     

High frequency catheter ablation in young patients with permanent junctional reentry tachycardia and ectopic atrial tachycardia]

A total of 160 simulated canals of various angles and positions of curvature were prepared by hand using either Mani Flexile Files, Mani SEC-O Files, Maillefer Flexofiles, or Zipperer Flexicut Files. After orifice enlargement, each file type was used to prepare 40 canals employing a balanced force motion and a modified double-flared technique. Pre- and postoperative images of the canals were taken with a videocamera, and stored and manipulated in a computer with image analysis software. The presence of canal aberrations and the amount of material removed as a result of preparation were determined from composite images of superimposed pre- and postoperative views. Significant differences (p < 0.001) in preparation time were observed, with Flexile Files being quickest and SEC-O Files being slowest. Overall, Flexofiles and Flexicut Files deformed significantly more (p < 0.001) than Flexile and SEC-O Files. The incidence of canal blockage was not influenced by instrument type, but the incidence of apical extrusion was significantly greater (p < 0.001) with SEC-O Files. SEC-O Files created significantly fewer (p < 0.001) and significantly narrower (p < 0.001) zips, with significantly less (p < 0.001) removal of material from the outer aspect of the curve and thus significantly less (p < 0.001) transportation. Flexicut Files created the widest canals apically, with the greatest removal of material from the outer aspect of the curve and the most transportation. Flexofiles created significantly more (p < 0.001) perforations. Under the conditions of this study, obvious differences between instruments were highlighted with SEC-O Files preparing canals more safely and with least destruction. The unique rounded tip of the SEC-O Files may have had an influence on the outcome.     

Effects of postural change on aspiration in head and neck surgical patients

This study was designed to define the effects of postural change on liquid aspiration during videofluorographic examination of oropharyngeal swallow in head and neck surgical patients. Thirty-two patients were given two swallows of five different amounts of liquid barium as tolerated. When aspiration occurred, the patient's head and/or body position was changed, new posture being determined by the swallowing disorder identified as the cause of the aspiration. Postural techniques were successful in eliminating aspiration on at least one volume of liquid in 81% of these patients. Patients in all surgical groups were able to use postures with equal success. A variety of positions were used in each type of surgical patient, indicating that these patients exhibited a variety of swallowing problems. Results emphasize the importance of introducing postural techniques during the radiographic study of oropharyngeal swallow to facilitate safe oral intake of liquids.     

Diffuse plane xanthoma: clinicopathologic study of 8 cases

We report a 17-year-old woman who had two synchronous solid and cystic tumors of the pancreas (SCTP) detected by abdominal echography and computed tomography. There was a 6 x 5 cm mass in the pancreatic body and a 3 x 3 cm mass in the tail, with the two lesions being separate. No distal metastases were detected. The resected tumors consisted of solid and cystic components and both were well demarcated with fibrous capsules. The larger tumor was predominantly solid and the smaller one was mostly hemorrhagic. On microscopy, the tumor cells were small, eosinophilic, and arranged, in part, like pseudorosettes. The tumor cells were immunohistochemically positive for alpha-1 antitrypsin, neuron-specific enolase, and synaptophysin. The final diagnosis was SCTP arising synchronously and independently at two sites. As far as we know, only one case of multicentric SCTP has been reported previously. Local recurrence of SCTP suggests the possibility of multicentric occurrence, and we believe that reports of such cases may increase in the future with advances in echography and computed tomography.     

Osteoarthritis, bone density, postural stability, and osteoporotic fractures: a population based study

OBJECTIVE: Osteoarthritis (OA) is associated with an increase in bone density both locally and at distant sites. Prospective data are limited on the relationship between OA and fracture. We studied the possible relationship between self-reported OA, bone density, postural stability measures, and atraumatic fractures as part of a study of men and women over 60 years of age. METHODS: Subjects were part of the Dubbo Osteoporosis Epidemiology Study (a longitudinal population based study of fracture risk factors). Bone density was measured by dual energy x-ray absorptiometry. Postural stability was assessed by the validated measures of quadriceps strength and sway. Medication use and self-reported arthritis were assessed by a structured personal interview. Fractures were ascertained retrospectively by interview and prospectively by viewing radiographic reports for fracture. RESULTS: Among a study population of 1101 women and 720 men (mean age 69) there were 462 subjects (25%) who reported a diagnosis of OA. In both sexes, subjects with OA had higher bone density (adjusted for age and body mass index) at both the femoral neck (men, p = 0.026; women, p = 0.048) and lumbar spine (men, p = 0.0007; women, p = 0.0007). However, in both sexes, those with self-reported OA also had higher body sway and lower quadriceps strength. The combination of these observed differences in fracture risk factors led to no predicted change in fracture risk overall when using established nomograms for this population [men, OR = 1.11 (95% CI 0.83-1.45); women, OR = 1.08 (95% CI 0.83-1.39)]. This paralleled our observational finding that self-reported OA was not associated with a decrease in fracture incidence compared to those not reporting OA in both men (RR 0.64, 95% CI 0.29-1.39) and women (RR 1.00, 95% CI 0.66-1.51). CONCLUSION: Individuals with self-reported OA, despite higher bone density, are not protected against nonvertebral osteoporotic fracture, apparently due to worsened postural stability and thus an increased tendency to fall.     

Radiofrequency catheter ablation therapy in elderly patients with supraventricular tachycardia

In the present study, long-term and short-term rat preparations were used to develop a model for investigating external anal sphincter (EAS) reflexes in intact and spinal cord-injured (SCI) rats. In this model, EAS distension with an external probe elicits reflex contractions of the EAS in intact, unanesthetized animals. At 2 h after spinal cord transection, none of the lesioned animals displayed EAS EMG activity. In fact, once distended, the EAS was incapable of maintaining closure of the anal orifice. Over a period of 4 days, spinalized animals developed a hyperreflexia of the EAS response. By 48 h, the rectified, integrated EAS EMG was significantly elevated in comparison with nonlesioned controls (EAS hyperreflexia). In addition, the duration of the EAS EMG bursts in response to sphincter distension had significantly increased. At 6 weeks after injury, the EAS was significantly hyperreflexic as measured by EMG burst duration and burst area. As with intact animals, posttransection EAS reflexes were highly anesthesia sensitive. These studies indicate that (1) brief distension of the anal orifice is sufficient to evoke a physiologically relevant reflexive activation of the EAS in the rat, (2) the 2- to 24-h postinjury areflexia observed in these experiments may be a suitable model for the study of spinal shock, and (3) the observed EAS hyperreflexia after chronic SCI may represent the permanent effects of removing descending inhibitory circuits and segmental plasticity, making this reflex an appropriate measure of defecatory dysfunction after spinal cord injury.     

Orthostatic hypotension predicts mortality in elderly men: the Honolulu Heart Program

BACKGROUND: Population-based data are unavailable concerning the predictive value of orthostatic hypotension on mortality in ambulatory elderly patients, particularly minority groups. METHODS AND RESULTS: With the use of data from the Honolulu Heart Program's fourth examination (1991 to 1993), orthostatic hypotension was assessed in relation to subsequent 4-year all-cause mortality among a cohort of 3522 Japanese American men 71 to 93 years old. Blood pressure was measured in the supine position and after 3 minutes of standing, with the use of standardized methods. Orthostatic hypotension was defined as a drop in systolic blood pressure (SBP) of >/=20 mm Hg or in diastolic blood pressure of >/=10 mm Hg. Overall prevalence of orthostatic hypotension was 6.9% and increased with age. There was a total of 473 deaths in the cohort over 4 years; of those who died, 52 had orthostatic hypotension. Four-year age-adjusted mortality rates in those with and without orthostatic hypotension were 56.6 and 38.6 per 1000 person-years, respectively. With the use of Cox proportional hazards models, after adjustment for age, smoking, diabetes mellitus, body mass index, physical activity, seated systolic blood pressure, antihypertensive medications, hematocrit, alcohol intake, and prevalent stroke, coronary heart disease and cancer, orthostatic hypotension was a significant independent predictor of 4-year all-cause mortality (relative risk 1.64, 95% CI 1.19 to 2.26). There was a significant linear association between change in systolic blood pressure from supine position to standing and 4-year mortality rates (test for linear trend, P<0.001), suggesting a dose-response relation. CONCLUSIONS: Orthostatic hypotension is relatively uncommon, may be a marker for physical frailty, and is a significant independent predictor of 4-year all-cause mortality in this cohort of elderly ambulatory men.     

Atrioventricular nodal reentrant tachycardia in patients with ventriculo-atrial conduction block

OBJECTIVE: To demonstrate the reversibility of retrograde ventriculo-atrial block by isoproterenol in patients with atrioventricular nodal reentrant tachycardia (AVNRT). DESIGN: Three case reports and their electrophysiological features. PATIENTS: Three patients with documented or suspected paroxysmal supraventricular tachycardia. INTERVENTIONS: At routine electrophysiology study, no supraventricular tachycardia was inducible in the baseline state. Infusion of isoproterenol (1 to 5 micrograms/min) was given and stimulation procedures were repeated. RESULTS: At baseline, all three patients had discontinuous antegrade atrioventricular (AV) nodal conduction, but very poor (two patients) or absent (one patient) ventriculo atrial conduction prevented induction of AVNRT. During infusion of isoproterenol, retrograde conduction was enhanced so that 1:1 retrograde occurred to cycle lengths of 300, 340 and 260 ms. AVNRT was then inducible in all patients, reproducing their clinical symptoms. CONCLUSION: Absent or poor ventriculo-atrial conduction in patients with suspected AV node reentry does not preclude the development of tachycardia with sympathomimetic enhancement. Isoproterenol should be given to attempt reversal of retrograde block in these patients.     

Effects of postural changes on left atrial function in patients with hypertrophic cardiomyopathy

BACKGROUND: We assessed left atrial function in normal subjects and in patients with hypertrophic cardiomyopathy (HCM) by using Doppler echocardiography at the supine position and after sudden standing. METHODS AND RESULTS: Twenty-seven patients with hypertrophic obstructive cardiomyopathy (HOCM), 17 patients with HCM, and 35 normal subjects were studied. From the transmitral Doppler flow velocities, peak early and late (E and A) waves, E/A ratio, and time velocity integrals (Ei and Ai) were calculated. Left atrial active contribution (LAAC) was assessed as the ratio Ei/(Ei + Ai). Furthermore, isovolumetric relaxation time (IVRT) was estimated by means of Doppler echocardiography. In the supine position, the E/A ratio was similar in the 3 groups. Conversely, LAAC was significantly higher in patients with HOCM (24.4 +/- 2.0) and in patients with HCM (23.3 +/- 3.3) compared with normal subjects (20.3 +/- 2.3, P <.001 and P <.05, respectively). After sudden standing, LAAC increased significantly in normal subjects by 11%, in patients with HOCM by 24%, and in patients with HCM by 13% (P <.001). Similarly, IVRT increased significantly in all study groups (P <. 001). By using stepwise forward multiple linear regression analysis, we found that LAAC was associated with age, IVRT, and body mass index in the supine position and with diastolic blood pressure and IVRT in the standing position. CONCLUSIONS: Left atrial contribution to left ventricular filling was increased after sudden changes of posture in normal subjects and in patients with HOCM or HCM.