Comparison of central venous and inferior vena caval pressures.

Inferior vena caval pressures were measured in 60 patients undergoing cardiac catheterization and compared with central venous pressure from within the right atrium. Mean pressures within the abdominal inferior vena cava were essentially the same as mean right atrial pressure, suggesting that the inferior vena cava provides a useful safe alternative for measuring central venous pressure.

Can compliance with nonpharmacologic treatments for cardiovascular disease be improved?

OBJECTIVE: To critically review the literature regarding the effectiveness of interventions aimed at improving cardiovascular patient compliance with nonpharmacologic treatments. METHODS: We searched Medline, Healthplan, and Psychlit from 1985 to 1996; searched the bibliographies of located studies; contacted Australian government departments and nongovernment organizations; and two experts examined the resulting study list. We selected 27 studies, which randomly allocated patients to groups and were published in English, and we evaluated interventions aimed at increasing compliance with nonpharmacologic treatments for cardiovascular disease. These trials were critically appraised against eight methodologic criteria and, subsequently, classified as of good, fair, or poor quality. Information about target groups, samples, trial intervention strategies and their effectiveness were extracted from the 18 good- and fair-quality trials. Interrater reliability was high on the 20% of references that were double-coded. The 18 studies reviewed described the effectiveness of 27 intervention strategies at improving compliance with dietary, smoking-cessation, exercise, weight-loss, stress-reduction, general lifestyle, relaxation, and blood pressure screening programs. RESULTS: Tentative recommendations were made for or against most trial strategies: partner-focused and structural strategies showed the most consistent benefits, physician-focused strategies were unanimously unsuccessful, and patient-focused strategies were of mixed benefit. CONCLUSIONS: The methodologic quality of many of the located trials was less than optimal. Therefore, further good-quality, randomized trials are necessary to clarify the effectiveness of those strategies identified as potentially useful in this review.

A critical review of interventions to increase compliance with medication-taking, obtaining medication refills, and appointment-keeping in the treatment of cardiovascular disease.

BACKGROUND: The aim of this study was to critically review the literature regarding interventions to improve cardiovascular patients' compliance with medication-taking, obtaining medication refills, or appointment keeping. METHODS: The search for relevant randomized trials involved searching the Medline, Healthplan, and Psychlit databases from 1985 to 1996; searching the bibliographies of located studies; contacting Australian government departments, non-government organizations, and pharmaceutical companies; and ultimate review of the resulting list by two field experts. The 33 located trials were critically appraised and classified as being of good, fair, or poor methodological quality. Descriptive and effectiveness data were then extracted from the 20 good and fair quality trials. Interrater reliability was high on the 20% of references double-coded. RESULTS: The 20 studies reviewed evaluated the effectiveness of 18 intervention strategies. Tentative recommendations were made for many patient-focused and structural strategies across all three target behaviors. Physician-focused strategies, tested only for appointment keeping, were all tentatively recommended against. CONCLUSIONS: The methodological quality of many of the located trials was less than optimal, prohibiting strong recommendations. Therefore, further good-quality, randomized trials are necessary in order to clarify the effectiveness of those strategies identified as potentially useful in this review.

The accuracy of self-reported health behaviors and risk factors relating to cancer and cardiovascular disease in the general population: a critical review.

OBJECTIVE: To critically review the literature concerning the accuracy of self-reported health behaviors and risk factors relating to cancer and cardiovascular disease among the general population. METHOD: A literature search was conducted on three major health research databases: MEDLINE, HealthPLAN, and PsychLit. The bibliographies of located articles were also checked for additional relevant references. Studies meeting the following five inclusion criteria were included in the review: They were investigating the accuracy of self-report among the general population, as opposed to among clinical populations. They employed an adequate and appropriate gold standard. At least 70% of respondents consented to validation, where validation imposed minimal demands on the respondent; and 60% consent to validation was considered acceptable where validation imposed a greater burden. They had a sample size capable of estimating sensitivity and specificity rates with 95% confidence intervals of width +/-10%. The time lag between collection of the self-report and validation data for physical measures did not exceed one month. RESULTS: Twenty-four of 66 identified studies met all the inclusion criteria described above. In the vast majority, self-report data consistently underestimated the proportion of individuals considered "at-risk." Similarly, community prevalences of risk factors were considerably higher according to gold standard data sources than they were according to self-report data. CONCLUSIONS: This review casts serious doubts on the wisdom of relying exclusively on self-reported health information. It suggests that caution should be exercised both when trying to identify at-risk individuals and when estimating the prevalence of risk factors among the general population. The review also suggests a number of ways in which the accuracy of individuals' self-reported health information can be maximized.

Ventricular pacemaker upgrade: experience, complications and recommendations.

OBJECTIVE: To assess outcomes of pacemaker upgrade from single chamber ventricular to dual chamber. DESIGN: Retrospective analysis of patients undergoing the procedure. SETTING: Specialist cardiothoracic unit. PATIENTS: 44 patients (15 female, 29 male), mean (SD) age at upgrade 68.2 (12.9) years. INTERVENTIONS: Upgrade of single chamber ventricular to dual chamber pacemaker. MAIN OUTCOME MEASURES: Procedure duration and complications. RESULTS: Principal indications for upgrade were pacemaker syndrome (17), "opportunistic"--that is, at elective generator replacement (8), heart failure (7), non-specific breathlessness/fatigue (7), and neurally mediated syncope (3). Mean (SD) upgrade procedure duration (82.9 (32.6) minutes) significantly exceeded mean VVI implantation duration (42.9 (13.3) minutes) and mean DDD implantation duration (56.6 (22.7) minutes) (both p < 0.01). Complications included pneumothorax (1), ventricular arrhythmia requiring cardioversion (2), protracted procedure (10), atrial lead repositioning within six weeks (8), haematoma evacuation (1), superficial infection (1), and admission to hospital with chest pain (1); 20 patients (45%) suffered one or more complications including four of the eight who underwent opportunistic upgrade. CONCLUSIONS: Pacemaker upgrade takes longer and has a higher complication rate than either single or dual chamber pacemaker implantation. This suggests that the procedure should be performed by an experienced operator, and should be undertaken only if a firm indication exists. Patients with atrial activity should not be offered single chamber ventricular systems in the belief that the unit can be upgraded later if necessary at minimal risk.

Interictal quantitative EEG in epilepsy.

The interictal EEG is often normal in epilepsy patients, particularly with partial seizures of extratemporal origin. Quantitative techniques of EEG analysis may increase the yield of diagnostic abnormality in such patients. Thirty patients with partial seizures of frontal or temporal origin had EEG recorded from left frontal (F7-C3), right frontal (F8-C4), left posterior (T5-O1), and right posterior (T6-O2) derivations. Four-second epochs were used to compute power in the delta (0.25-4.0 Hz), theta (4.25-8.0 Hz), alpha (8.25-13 Hz), and beta (13.25-30 Hz) bands. The ratio of high (8.25-30 Hz) to low (0.25-8 Hz) power on the left and the right was measured, as was the ratio between the left and the right hemisphere total power. The mean frequency deviation in the alpha band between the left and the right hemispheres was also measured, and spectral mobility was determined in the right and the left frontal regions. These values were also calculated in normal subjects and tension headache patients with normal EEGs. Seizure patients with abnormal interictal EEGs had decreased ratios of high to low power, greater asymmetry of total power and alpha frequency, and reduced spectral mobility on the side of their EEG foci. Epileptics with normal interictal EEGs had lower ratios of high to low power, greater alpha frequency asymmetry, and lower spectral mobility than did headache patients or normal controls. Power and frequency measurements, and determination of spectral measures such as mobility, can be done with commercially available digital EEG equipment. They may demonstrate otherwise obscure asymmetries in the interictal EEG and thereby aid in epilepsy diagnosis and classification.

Late complications following permanent pacemaker implantation or elective unit replacement.

OBJECTIVE: To determine the rate of late complications following first implantation or elective unit replacement of a permanent pacemaker system. DESIGN: Analysis of pacemaker data and complications prospectively acquired on a computerised database. Complications were studied over an 11 year period from January 1984 to December 1994. SETTING: Tertiary referral cardiothoracic centre. PATIENTS: Records of 2621 patients were analysed retrospectively. MAIN OUTCOME MEASURES: Complications requiring repeat procedures occurring more than six weeks after pacemaker implantation or elective unit replacement. RESULTS: The overall rate of late complications was significantly lower after first implantation of a permanent pacemaker (34 cases, complication rate 1.4%, 95% confidence interval 0.9% to 1.9%) than after elective unit replacement (16 cases, complication rate 6.5% (3.3% to 9.7%). There were 20 cases of erosion, 18 infections, five electrode problems, and seven miscellaneous problems. Complications were more common with inexperienced operators (18.9% (6.0% to 31.8%)) than with experienced operators (0.9% (0.3% to 1.5%). CONCLUSIONS: The incidence of late complications following pacemaker implantation is low and compares favourably with early complication rates. The majority are caused by erosion and infection. Patients who have undergone elective unit replacement are at particular risk.

Contingent negative variation in epilepsy.

The contingent negative variation (CNV) is a long-latency event-related potential elicited by paired or associated stimuli. We recorded contingent negative variation in 50 patients with complex partial and secondarily generalized seizures and in 20 neurologically and psychiatrically normal unmedicated controls. CNV was recorded from Fz, Cz, and Pz. A 2000 Hz tone was followed after 1.5 s by 1000 microseconds light flash, at which a button press was to be executed. Filter band pass was 0.1-20 Hz, analysis time was 10 s and 10 responses were replicated. Patients with complex partial seizures with and without secondary generalization had lower measurements of area under the CNV curve (AUC) than did controls, and CNV amplitude was significantly reduced. Patients with interictal behavioural symptoms had significantly smaller AUC and lower amplitude. No significant difference was found between depressed and non-depressed seizure patients with respect to AUC, but amplitude was significantly lower in depressed patients. Seizure patients with psychosis had significantly lower AUC but did not differ from non-psychotic patients in CNV amplitude. No differences were found between seizure patients with and without personality disorder with respect to CNV AUC or amplitude. Post-imperative negative variation was significantly more common in seizure patients than in controls and among patients with epilepsy, was significantly increased in those with inter-ictal behaviour disturbance generally and psychosis particularly. No specific effect of anticonvulsant monotherapy on AUC or amplitude was identified. These findings suggest that CNV may differ between partial epilepsy patients and controls, and that inter-ictal behaviour disturbance may particularly affect CNV measures. They also agree with previous evidence for a frontal lobe generator for the CNV, and a possible role for central dopaminergic pathways in the production of PINV.

Auditory evoked potentials in postconcussive syndrome.

The neuropsychiatric sequelae of minor head trauma have been the source of controversy. Most clinical and imaging studies have shown no alteration after concussion, but neuropsychological and neuropathological abnormalities have been reported. Some changes in neurophysiologic diagnostic tests have been described in postconcussive syndrome. We recorded middle latency auditory evoked potentials (MLR) and slow vertex responses (SVR) in 20 individuals with prolonged cognitive difficulties, behavior changes, dizziness, and headache after concussion. MLR is utilized alternating polarity clicks presented monaurally at 70 dB SL at 4 per second, with 40 dB contralateral masking. Five hundred responses were recorded and replicated from Cz-A1 and Cz-A2, with 50 ms. analysis time and 20-1000 Hz filter band pass. SVRs were recorded with the same montage, but used rarefaction clicks, 0.5 Hz stimulus rate, 500 ms. analysis time, and 1-50 Hz filter band pass. Na and Pa MLR components were reduced in amplitude in postconcussion patients. Pa latency was significantly longer in patients than in controls. SVR amplitudes were longer in concussed individuals, but differences in latency and amplitude were not significant. These changes may reflect posttraumatic disturbance in presumed subcortical MLR generators, or in frontal or temporal cortical structures that modulate them. Middle and long-latency auditory evoked potentials may be helpful in the evaluation of postconcussive neuropsychiatric symptoms.

Middle latency auditory evoked potentials in epilepsy.

Middle latency auditory evoked potentials (MLAEPs) have been recorded after cortical lesions and seizure surgery. We recorded interictal MLAEPs in 14 patients with well documented complex partial and secondary generalized seizures. Na and Pa potentials did not differ in latency between patients and controls, although both were longer among seizure patients. Pa and Na were significantly reduced in amplitude in complex partial seizure patients compared to controls. These findings accord with previous suggestions that MLAEPs may be generated subcortically but modulated by temporal lobe structures. MLAEPs may be of value in differentiating temporal and extratemporal epilepsy. They may also help clarify interictal cognitive or behavioral symptoms related to epilepsy or the effects of antiepileptic medication.

EEG frequency analysis in obsessive-compulsive disorder.

The cerebral basis of obsessions and compulsions has attracted increasing attention in neuropsychology and neuropsychiatry. Clinical and imaging studies have suggested frontal lobe dysfunction in some cases of obsessive-compulsive disorder and Tourette syndrome with obsessional symptoms. We compared EEG spectral measures in 20 such patients not taking medications and 12 neurologically intact unmedicated controls. EEG was recorded from O1-A1+A2, O2-A1+A2, Fz-A1+A2, F7-C3, F8-C4, T5-O1 and T6-O2. One-minute epochs of artifact-free EEG were used for compressed spectral array and calculation of time domain descriptors. We measured modal alpha frequency (MAF), maximal alpha frequency (MxAF), spectral edge frequency and spectral mobility in left and right frontal regions (MOLF and MORF). MAF and MxAF were reduced in the frontal regions in patients as compared to controls, and MOLF and MORF were both lower. No significant differences between patients and controls were found in the temporal or occipital areas. These observations support the suggestions of a physiologic basis for obsessions and compulsions, and of frontal lobe disturbance in their pathophysiology.

Early complications after dual chamber versus single chamber pacemaker implantation.

This study was performed to compare the frequency of early complications after single chamber versus dual chamber permanent pacemaker implantation. Early complication was defined as one occurring in the 6-week period following implantation. We prospectively analyzed consecutive pacemaker implantation from January 1987 to June 1993 at our regional center. All complications were also analyzed for the relationship to operator experience, the venous access route, and the presence of temporary pacing wire at the time of implantation of the permanent pacing system. A total of 2019 new pacemaker units were implanted during this period. 1733 patients (85.8%) received a VVI pacemaker and 286 (14.2%) a DDD unit. Wound infection occurred in 11 (0.6%) VVI patients and 6 (2.1%) DDD patients. Lead displacement occurred in 18 (1%) VVI patients and 15 (5.2%) DDD patients (11 [3.8%] atrial and 4 [1.4%] ventricular). There were 10 (0.6%) pneumothoraces, 9 (0.5%) hematomas requiring drainage, 1 (0.06%) chylocele, and 2 (0.1%) deaths in the VVI group. There were 2 (0.7%) pneumothoraces, 2 (0.7%) hematomas, and no deaths in the DDD group. There was no significant increase in complications for experienced infrequent implanters (< 12 systems per year). In both groups the subclavian approach was associated with a risk of pneumothorax when compared to the cephalic approach. The rate of wound infection was higher in patients who had a temporary pacing wire in place. The use of prophylactic antibiotics does not appear to affect the incidence of wound infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Sleep apnea and periodic leg movements in epilepsy.

Sleepiness is a common complaint in the epilepsy clinic, and sleep disturbances are frequently reported by seizure patients. Polysomnography was performed in 6 patients with complex partial seizures, with and without secondary generalization, who had not yet started anticonvulsant treatment or whose medication had been discontinued. Five patients sleep through the night, but 1 slept only 3 hours. Two patients had reduced sleep efficiency and slow wave sleep was reduced or absent in 4 patients. No REM sleep disturbances occurred. Two patients had almost no periodic leg movements of sleep (PLMS), 2 had few or no arousals and PLMS indices of 5 or less, and 2 had markedly elevated PLMS and arousal indices. No apneas or significant hypopneas were recorded, but snoring indices were elevated in 2 patients. These findings suggest that sleep apnea is infrequent in unmedicated seizure patients. Some patients may have exaggerated PLMS with arousals, possibly related to epileptiform discharge and perhaps exacerbated by medications, but apparently not due to nocturnal seizures.

Multiple sleep latency tests in epilepsy.

Seizure patients often complain of sleepiness or disturbed sleep. Although susceptible of medication effect, the multiple sleep latency test (MSLT) may quantify daytime sleepiness and help to establish whether qualitative sleep disturbance accompanies epilepsy. In order to measure daytime sleepiness in epilepsy patients, 30 patients with newly diagnosed or presently untreated complex partial seizures had MSLT after an overnight sleep EEG that showed no sleep deprivation or nocturnal seizures. Four 20-minute naps were undertaken at 09:00, 11:00, 13:00, and 15:00, and sleep latency was recorded along with 8 channels of EEG. Twenty of 30 seizure patients reported subjective sleepiness. Eight patients had average sleep latencies less than 8 minutes, and 3 had latencies less than 5 minutes. No sleep onset REM or respiratory disturbance was noted. Twenty-five patients had EEG abnormalities but none had ictal seizures. Right temporal epileptiform activity correlated with sleepiness. MSLT may quantify sleepiness in epilepsy patients, which is common but may be subjective or psychophysiological. Some patients with partial seizures have persistent daytime sleepiness independent of medication, possibly related to residual medication effects or non-specific effect of their epileptogenic foci.

Contingent negative variation in Gilles de la Tourette syndrome.

The Contingent Negative Variation (CNV) may measure arousal and attention, and is affected by various dopaminergic disorders. We recorded CNVs in 12 patients fulfilling diagnostic criteria of Gilles de la Tourette Syndrome (TS). Ten of 12 patients were male, 10 had attention deficit disorder (ADD), and 3 also had obsessions and compulsions (OCD). Medication had been stopped or TS treatment not yet started. TS patients had higher CNV amplitude and more frequent postimperative negative variation than controls. CNV2 was enhanced in all TS patients, while CNV1 was attenuated in TS patients with ADD or OCD. This suggests that CNV may be increased in TS, mostly because of CNV2 and perhaps due to dopaminergic excess. CNV2, considered to reflect adrenergic arousal mechanisms, may be effected by neurobehavioral concomitants of TS. Neurophysiological categorization of TS patients may be possible and valuable.

Neurophysiologic studies in nightmare sufferers.

Nightmares have long attracted neurologic and psychiatric attention, yet little is known of their pathophysiology. We recorded 17-channel electroencephalograms (EEGs), brainstem auditory evoked potentials (BAEPs), long-latency auditory event-related potentials (AEPs), and overnight cassette sleep EEGs (AEEGs) in 10 individuals with recurrent nightmares. They were all nocturnal sleepers, took no medications, do not abuse alcohol or drugs, and had no known medical or psychiatric illnesses. Five patients were being evaluated for other complaints, 3 reported disturbed nocturnal sleep and daytime sleepiness, and 2 sought attention chiefly for nightmares. All 10 patients had normal EEGs and BAEPs. BAEP latencies did not differ significantly from control subjects. Latencies and amplitudes of AEPs were not significantly different in nightmare sufferers and controls, but the former had higher amplitude N100, P160, and N200. Those patients with sleep complaints had on overnight AEEG, less sleep, decreased slow-wave sleep, and more awakenings than those without sleep complaints, but nightmares did not occur during the AEEG recordings.

Diagnosis of early cardiac transplant rejection by fall in evoked T wave amplitude measured using an externalized QT driven rate responsive pacemaker.

Reliable diagnosis of cardiac allograft rejection is at present only possible using endomyocardial biopsy. We have serially measured epicardial evoked T wave amplitude during ventricular pacing with an externalized QT driven rate responsive pacemaker telemetered to a TP2 analyzer in 13 patients (12 males) followed for 19 (14-26) days after transplantation. A total of 228 records were analyzed. Rejection was defined on endomyocardial biopsy. On 17 of the 31 occasions on which biopsy was performed during the study, specimens showed significant (moderate) rejection. In 11 patients the initial biopsy proven rejection episode was associated with a significant fall in the evoked T wave amplitude from 1.3 (0.7-2.3) mV to 0.6 (0.5-1.8) mV (P less than 0.005), which began 2 (1-4) days earlier. One patient with uncontrolled diabetes mellitus had no change in evoked T wave amplitude during rejection. The evoked T wave amplitude did not fall in the absence of histologic rejection. These results suggest a noninvasive method for detecting cardiac rejection, which appears both sensitive (92%) and specific (100%) in the first rejection episodes.