Background— The risk of syncope occurring while driving has obvious implications for personal and public safety. We aimed to define the clinical characteristics, causes, and prognosis of syncope while driving. Methods and Results— In this case-control study of consecutive patients evaluated for syncope from 1996 through 1998 at an academic medical center, we documented causes, clinical characteristics, and recurrence of syncope while driving. Of 3877 patients identified, 381 (9.8%) had syncope while driving (driving group). Compared with the 3496 patients (90.2%) who did not have syncope while driving, the driving group was younger ( P =0.01) and had higher percentages of male patients ( P <0.001) and patients with a history of any cardiovascular disease ( P =0.01) and stroke ( P =0.02). Syncope while driving was commonly caused by neurally mediated syncope (37.3%) and cardiac arrhythmias (11.8%). Long-term survival in the driving group was comparable to that of an age- and sex-matched cohort from the Minnesota population ( P =0.15). Among the driving group, syncope recurred in 72 patients, 35 of whom (48.6%) had recurrence >6 months after the initial evaluation. Recurrences during driving happened in 10 patients in the driving group, 7 of which (70%) were >12 months after the initial evaluation. Conclusions— In our study, neurally mediated syncope was the most common type of syncope while driving. The causes of syncope, the late recurrences of syncope (during ≥6 months of follow-up), and the overall low incidence of recurrent syncope while driving provide useful information to supplement current recommendations on driving for these patients.

Background Data derived from stress myocardial perfusion imaging (MPI) carry prognostic significance in young patients with hypertrophic cardiomyopathy (HCM), but there are limited data on the utility of stress MPI in patients with HCM who are older. This study examined the prognostic significance of stress MPI in an adult population of patients with HCM.Methods We examined 158 patients with HCM (aged 60 +/- 16 years, 61% men) who underwent exercise or pharmacologic stress MPI. Summed stress score (SSS, normal = 56) and summed reversibility scores were calculated for each patient. Follow-up was complete in 157 (99%) patients at a median duration of 5.2 years.Results Normal single-photon emission computed tomography (SPECT) images were present in 38% of the population. Summed stress score (P =.01) and summed reversibility score (P =.03) were both significantly associated with cardiovascular death. Survival at 10 years was significantly better in those with normal versus abnormal SPECT (89% vs 67%, P =.04). Ten-year survival also was better in those without versus those with ischemia (90% vs 64%, P =.02). Five-year survival could be stratified by SSS risk categories: low risk (SSS >= 53), 97%; intermediate risk (SSS = 48-52), 94%; and high risk (SSS <= 47), 79% (P =.04). Bivariate models of SSS and other significant covariates supported an independent relation of SSS to cardiovascular death..Conclusions In an older population of. patients with HCM referred for SPECT imaging, abnormal stress MPI identifies those at increased risk of cardiovascular death.

OBJECTIVE:To evaluate the long-term outcome of a community-based patient population with incidentally discovered asymptomatic and uncomplicated bundle branch block (BBB).PATIENTS AND METHODS:A retrospective observational cohort study was undertaken of patients in Olmsted County, Minnesota, who were evaluated between 1975 and 1999 and were incidentally diagnosed as having BBB. We performed Kaplan-Meier analyses of all-cause mortality and development of first cardiac morbidity after the diagnosis of BBB, along with matched control group comparisons.RESULTS:A total of 723 patients with left BBB (LBBB) (58.1%) and right BBB (41.9%) met criteria. Mortality was higher in patients with BBB compared with controls (absolute difference of approximately 10% over 20 years; hazard ratio = 1.27; confidence interval, 1.02-1.58; P=.03) as was the development of first cardiac-related morbidity (hazard ratio = 1.32; confidence interval, 1.14-1.54; P<.001). Patients with BBB and without the risk factors of diabetes, hypertension, and/or hypercholesterolemia showed increased long-term mortality compared with matched controls (no BBB) also without risk factors (P=.02). However, comparable mortality was shown between patients with BBB who did not have these risk factors and matched control patients who had these risk factors. The risk of developing cardiac-related morbidity also was increased in the presence of BBB, particularly LBBB.CONCLUSIONS:Uncomplicated asymptomatic BBB (notably LBBB) with normal left ventricular ejection fraction is not benign. Our findings indicate that the presence of isolated BBB denotes a high-risk patient subgroup that has a compromised long-term outcome comparable to patients with conventional cardiovascular risk factors.

Purpose: To measure subbasal nerve density and orientation in normal human corneas across a broad age range. Methods: Sixty-five normal corneas of 65 subjects were examined by using tandem scanning confocal microscopy. Ages of subjects ranged from 15 to 79 years (mean 46 ± 19 years), with 5 subjects from each hemidecade. Subbasal nerve fiber bundles appeared as bright, well-defined linear structures in confocal images of the central cornea. Images from 3 to 8 scans per eye (mean 4.6 ± 1.8 scans) were randomly presented to a masked observer for analysis. The mean subbasal nerve density (total nerve length [μm] within a confocal image [area = 0.166 mm2]), the mean nerve number per confocal scan, and the mean nerve orientation were determined by using a custom software program. Correlations between age and nerve density and age and nerve orientation were assessed by using Pearson correlation coefficients. Results: The subbasal nerve plexus was visible in the central cornea of all subjects. The mean subbasal nerve density was 8404 ± 2012 μm/mm2 (range 4735 to 14,018 μm/mm2). The mean subbasal nerve number was 4.6 ± 1.6 nerves (range 1 to 8 nerves). The mean subbasal nerve orientation was 94 ± 16 degrees (range 58 to 146 degrees). There was no correlation between age and subbasal nerve density (r = 0.21, P = 0.09) or between age and subbasal nerve orientation (r = −0.19, P = 0.12). Conclusion: The density and orientation of the subbasal nerve plexus in the central human cornea does not change with age.

Background: Atrial remodeling secondary to atrial fibrillation (AF) may be important in the arrhythmogenic process. Unfortunately, the study of electrophysiologic remodeling in humans has been limited by the invasive nature of most tests of electrophysiologic characteristics. We sought to determine whether changes in atrial electrophysiology occur acutely (within the first hour) after cardioversion and whether these changes could be detected noninvasively by measuring the signal‐averaged P‐wave. Methods: The filtered P‐wave duration (FPD) was measured by signal‐averaged electrocardiography (ECG) at 20 and 60 minutes after cardioversion in 46 patients with AF, and the difference between the two values was calculated. The root‐mean‐square voltage of the terminal 40 ms of the signal‐averaged P‐wave at 20 and 60 minutes and the difference between them were also determined. Results: The FPD at 20 minutes was significantly different from that at 60 minutes (153.0 ± 19.1 vs 159.7 ± 24.8 ms; P = 0.02). In a univariate linear regression model, none of the clinical variables studied was significantly associated with the change in FPD. The root‐mean‐square voltage at 20 minutes was not significantly different from that at 60 minutes (5.8 ± 3.0 vs 5.5 ± 2.7; P = 0.14). Conclusions: We conclude that significant changes in atrial electrophysiology occur within the first hour after cardioversion of AF. These changes can be detected by measuring the FPD.

Background—In a recent study, we reported that the Duke treadmill score was unable to effectively stratify elderly patients according to risk. The purpose of this study was to evaluate the prognostic value of exercise single-photon emission computed tomography (SPECT) in this same population and to examine results by gender. Methods and Results—A cohort of 247 elderly (age ≥75 years) patients (108 women, 139 men, age 77±3 years) who underwent exercise thallium-201 SPECT were followed up for a median duration of 6.4 years. SPECT variables were significantly associated with cardiac death: summed stress score (SSS) &khgr;2=19.5, P<0.001; summed difference score &khgr;2=12.3, P<0.001; increased lung uptake &khgr;2=9.6, P=0.002; and left ventricular enlargement &khgr;2=8.3, P=0.004. The Duke score was not significantly associated with cardiac death (&khgr;2<1, P=NS). The SSS classified most patients as low risk (49%) or high risk (35%); the Duke score classified the majority (68%) as intermediate risk. Annual cardiac mortality rates for patients categorized by SSS as low risk and high risk were 0.8% and 5.8%, respectively. Cardiac survival rates according to SSS risk categories were significantly different for both women (P=0.012) and men (P=0.003). Conclusions—SPECT classified most elderly patients into clinically useful low- and high-risk categories and accurately predicted outcomes in both genders. If these results can be validated in future studies, exercise SPECT rather than standard treadmill testing may emerge as the initial noninvasive testing strategy in elderly patients who are able to exercise.

Background— The Bypass Angioplasty Revascularization Investigation trial demonstrated that symptomatic diabetics with multivessel coronary artery disease had a survival advantage with initial coronary artery bypass grafting (CABG) versus percutaneous coronary intervention (PCI). No published study has examined different treatments and outcome in asymptomatic diabetics. Methods and Results— This study group consisted of 826 asymptomatic diabetics (age 62±12 years; 76% men) without known coronary artery disease who had abnormal myocardial perfusion during stress single photon emission computed tomography (SPECT). SPECT images were classified as low-, intermediate-, and high-risk. Early revascularization (CABG or PCI ≤4 months after SPECT) was performed in 76 patients. Survival (follow-up, 5.3±3.3 years) was compared in patients treated with CABG, PCI, or medical therapy. Revascularization (CABG or PCI) was performed in 54 of 261 patients with high-risk scans and was independently associated with improved survival (χ 2 =4.55; P =0.03 after multivariate adjustment). Subset analysis demonstrated that the survival advantage was confined to patients treated with CABG (n =39), with a 5-year survival CABG at 85%, PCI at 72%, and medical therapy at 67% ( P =0.02 for 3 groups). Although CABG was associated with better survival, mortality remained high (3% per year). There was no survival advantage by treatment for patients with less-severe SPECT abnormalities. Conclusions— These nonrandomized data suggest that CABG improves survival in asymptomatic diabetic patients with high-risk SPECT, although revascularization was performed infrequently in these patients. These results parallel those of the Bypass Angioplasty Revascularization Investigation trial in symptomatic diabetic patients.

PURPOSE OF REVIEW:In the absence of an established critical pathway to evaluate patients with syncope presenting to the emergency department, this review is timely because of new clinical evidences supporting a specialized syncope management unit in the emergency department, and it is relevant because of the potential impact on a very large and heterogeneous population.RECENT FINDINGS:Three observational syncope studies from Italy showed a high degree of variability in practice patterns, diagnostic yields, and lengths of hospital stay. An appropriate and efficacious syncope management pathway in the emergency department remains far from established. In a randomized trial from a tertiary care hospital in the US, the SEEDS study demonstrated that a designated 'syncope unit' in the emergency department, with a multidisciplinary effort and appropriate resources, significantly improved diagnostic yield, reduced hospital admission and total length of hospital stay in intermediate-risk patients. Long-term follow-up showed that reduced hospital stay did not negatively affect survival and recurrent syncope.SUMMARY:Limited randomized trial data suggest a designated syncope unit in the emergency department holds promise to provide specialized and efficient care for patients with syncope. Additional data are needed to assess the general applicability of this critical pathway in community-based hospitals.

PURPOSE: To measure and compare the return of corneal innervation up to 5 years after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK).DESIGN: Prospective, nonrandomized clinical trial.METHODS: Eighteen eyes of 12 patients received PRK to correct a mean refractive error of -3.73 +/- 1.30 diopters, and 16 eyes of 11 patients received LASIK to correct a mean refractive error of -6.56 +/- 2.44 diopters. Corneas were examined by confocal microscopy before and at 1, 2, 3, and 5 years after the procedures. Subbasal nerve fiber bundles were measured to determine density (visible length of nerve/frame area) and expressed as micrometers per square millimeters. Differences were compared by Friedman's test and adjusted for multiple comparisons by the Student-Newman-Keuls procedure.RESULTS: After PRK, mean subbasal nerve density was reduced by 59% at 1 year (2764 +/- 1321 mu m/mm(2) [+/- SD]) when compared with preoperative (6786 +/- 1948 mu m/ mm(2); P <.001). By 2 years, subbasal nerve density (6242 +/- 1763 mu m/mm(2)) was not significantly different from density before PRK and remained unchanged to 5 years (5903 3086 ILm/mm 2). After LASIK, subbasal nerve density was reduced by 51%, 35%, and 34% at 1, 2, and 3 years, respectively (P <.001). By 5 years, subbasal nerves had returned to densities (4441 +/- 2819 mu m/mm(2)) that were not significantly different from densities before LASIK (5589 +/- 2436 mu m/mm(2)).CONCLUSION: Corneal subbasal nerve density does not recover to near preoperative densities until 5 years after LASIK, as compared with 2 years after PRK.

Purpose: Diabetes mellitus and systemic hypertension are frequently reported as ischemic causes of nerve palsy/paresis, but there are few rigorous studies to support these associations. We conducted a lation-based case-control study to determine the presence and magnitude of any association of diabetes mellitus and systemic hypertension with isolated sixth nerve palsy.Design: Retrospective population-based case-control study.Participants and Controls: Participants were patients with new onset of neurologically isolated sixth palsy or paresis (n = 76) in Olmsted County, Minnesota, from January 1, 1978, to December 31, 1992. (n = 76) were selected from the same general population and were matched for age, gender, and length medical follow-up.Methods: Using the Rochester Epidemiology Project medical records linkage system, which virtually all medical care provided to residents of Olmsted County, Minnesota, we identified all incident cases neurologically isolated sixth nerve palsy/paresis (n = 76) among county residents between the given dates. equal number (n = 76) of controls were randomly selected from the general population. We reviewed the medical record of each case and control, using stringent predetermined criteria to define the presence diabetes mellitus and systemic hypertension. We compared the prevalence of diabetes and systemic sion between cases and controls by use of chi-square tests, and we calculated odds ratios (OR) with confidence intervals (SI).Main Outcome Measures: Presence or absence of diabetes mellitus and systemic hypertension.Results: Diabetes mellitus occurred more frequently in cases (23.7%) than in controls (5.3%; P = 0.001; 5.59; 95% CI, 1.79-17.42). Systemic hypertension occurred with similar frequency in cases (51.3%) and (39.5%; P = 0.14; OR, 1.62; 95% CI, 0.85-3.08). Coexistent diabetes mellitus and hypertension were common in cases (18.4%) than in controls (2.6%; P = 0.002; OR, 8.36; 95% CI, 1.83-38.18).Conclusions: We conclude that there is a 6-fold increase in odds of having diabetes in cases of sixth palsy over controls, whereas systemic hypertension does not seem to be associated with increased odds. contrast, there is an 8-fold increased odds of having coexistent diabetes and hypertension in cases of sixth palsy over controls. The much-cited association of systemic hypertension alone with sixth nerve palsy may be coincidental. (c) 2005 by the American Academy of Ophthalmology.

The purpose of this study was to quantify and determine predictors of long-term survival and functional outcome in patients with double-inlet left ventricle (DILV) after the Fontan operation. The Fontan operation has become the procedure of choice for DILV. Early survival has improved, but mortality and morbidity persist. Record review and follow-up questionnaires were used to ascertain the status of 225 patients with DILV who had Fontan operations from 1974 to 2001 at the Mayo Clinic. The median age at operation was 9 years. The median follow-up period was 12 years (range 3 months to 25 years). There were 22 deaths (9.3%) <30 days after the operation. Early mortality decreased to 3% (2 of 70 patients) after 1989. Overall late survival was 78% (159 of 203 patients). Actuarial survival for the 203 early operative survivors at 5, 10, 15, and 20 years was 91%, 80%, 73%, and 69%, respectively. Forty-nine percent (99 of 203) had additional surgical procedures after the Fontan operation. Other frequent late events were atrial flutter or fibrillation (57%), protein-losing enteropathy (9%), and thromboembolic events (6%). Current health status was described as good or excellent by 84% of patients, fair by 18%, and poor by 12%. In conclusion, the Fontan operation for DILV is now performed with a low operative mortality rate. Long-term survival has improved, and most patients have good functional status.

The clinical presentation of recurrent atrial fibrillation (AF) has been categorized into 3 general patterns: paroxysmal, persistent, and permanent AF. This community-based cohort study characterized the effect of the AF pattern on survival. Community residents in Olmsted County, Minnesota, with electrocardiographically proven new-onset AF during 1996 and 1997 were retrospectively identified and prospectively followed. Observed survival was estimated using the Kaplan-Meier method and compared with the expected survival. Log-rank tests were used for group comparisons. The association between the baseline variables and mortality was assessed using Cox proportional hazards models. Of 270 patients (mean +/- SD age 73 +/- 14 years; 148 men [55%]), 143 had paroxysmal AF, 40 had persistent AF, and 87 had permanent AF. The cohort's observed survival was significantly worse than expected (p <0.001). The factors associated with increased mortality included older age, concomitant heart failure, and concomitant chronic obstructive pulmonary disease (all p <0.001). Permanent AF was associated with higher mortality than paroxysmal AF (hazard ratio 1.6, 95% confidence interval 1.1 to 2.3). Persistent AF was associated with better survival (hazard ratio 0.3, 95% confidence interval 0.1 to 0.8). In conclusion, survival among patients with persistent AF was significantly better than that among patients with paroxysmal AF or permanent AF. The ability to maintain sinus rhythm may be associated with better survival.

Purpose: We compared endothelial cell density (ECD) from images recorded by the ConfoScan 3 confocal microscope and a noncontact specular microscope.Methods: Endothelial micrographs of 50 normal corneas of 25 subjects were acquired by a Konan Noncon Robo noncontact specular microscope (Konan Medical, Inc., Hyogo, Japan) and a ConfoScan 3 confocal microscope (Nidek Technologies, Inc, Greensboro, NC). ECD was determined in images from both instruments by using the HAI CAS System Corners Method (HAI Labs, Inc., Lexington, MA). Distances in the images from both machines were calibrated from images of an external scale. Images from the ConfoScan 3 were also assessed using the automated endothelial analysis software provided by the manufacturer, with and without manual correction.Results: The ECD was 2634 +/- 186 cells/mm(2) (mean +/- SD) and 2664 +/- 173 cells/mm(2) by the Robo and ConfoScan 3 Corners methods, respectively. Differences between these 2 methods were not significant. When the automated analysis software was used, however significant differences were found (P = 0.001). The uncorrected analysis program provided with the ConfoScan 3 indicated a higher ECD (2742 +/- 284 cells/mm(3)) than the Corners method did with images from the Robo and ConfoScan 3. The ECD from the manually corrected ConfoScan 3 method was 2716 +/- 229 cells/mm(3), not significantly different from the ConfoScan 3 Corners method but significantly different from the Robo Corners method.Conclusions: The ConfoScan 3 can be used interchangeably with the Robo when the Corners method is used to assess ECD and the magnification of both microscopes is calibrated with an external scale. If the proprietary software provided with the ConfoScan 3 is used, it should be manually corrected.

Blood Pressure and AVNRT. Introduction: We aimed to characterize blood pressure (BP) response at the beginning of atrioventricular nodal reentrant tachycardia (AVNRT) and its relationship to orthostatic challenge and variable atrioventricular interval.Methods and Results: In this prospective study of 17 consecutive patients with documented AVNRT, mean BP was analyzed in the supine and upright positions during sinus rhythm, AVNRT, and pacing with atrioventricular delay of 150 msec (AV150) and 0 msec (AV0). Mean BPs were compared at 3-5 seconds, 8-10 seconds, and 28-30 seconds after the onset of AVNRT or pacing. BP decreased immediately after AVNRT initiation, with gradual recovery during the first 30 seconds from 71.9 +/- 16.5 mmHg to 86 +/- 13.8 mmHg, P < 0.01. A similar pattern was observed during AV0, but not during AV150, pacing. While supine, mean BP decrease was more pronounced during AVNRT and AV0 pacing (-26.1% and -32.1%, respectively) than during AV150 pacing (-8%, P = 0.02 and P = 0.07, respectively). This difference subsided 30 seconds after the onset of AVNRT or pacing. When upright, the mean BP time course was similar, but mean BP recovery during AVNRT was slower, and the difference between mean BP during AVNRT and AV150 persisted at 30 seconds.Conclusions: The initial mean BP decrease during AVNRT recovered gradually within 30 seconds. A short atrioventricular interval is associated with a greater mean BP decrease at the onset of tachycardia. These observations may explain clinical symptoms immediately after the onset of AVNRT.