Citations

Background —Previous studies of atrial flutter have found linear block at the crista terminalis; this was thought to predispose the patient to the arrhythmia. More recent observations, however, have demonstrated crista conduction. We sought to characterize the posterior boundary of atrial flutter. Methods and Results —Patients with counterclockwise flutter (n=20), clockwise flutter (n=3), or both (n=5) were studied using two 20-pole catheters. Biplane fluoroscopy determined catheter positions. During counterclockwise flutter, craniocaudal activation occurred along the entire lateral and posterior right atrial walls. Septal activation proceeded caudocranially. In all patients, a line of block was seen in the posteromedial (sinus venosa) right atrium; this was manifested by the presence of double potentials where the upward and downward activations collided. Anatomic location was confirmed by intracardiac echocardiography in 9 patients. In patients with clockwise flutter, the line of block and double potentials were seen in the same location during counterclockwise flutter, but the activation sequence around the line of block was reversed. Pacing near the site of double potentials during sinus rhythm excluded a fixed line of block, and premature atrial complexes demonstrated functional block with manifest double potentials. In 2 patients, posterior ectopy organized to subsequently initiate isthmus-dependent atrial flutter. Conclusions —(1) A functional line of block is seen at the posteromedial (sinus venosa region) right atrium during counterclockwise and clockwise atrial flutter. (2) All lateral wall right atrial activation can be uniform during flutter, without linear block or double potentials in the region of the crista terminalis. (3) Activation at the site of posteromedial right atrial functional block can organize to subsequently initiate isthmus-dependent atrial flutter.

Background —The clinical spectrum of constrictive pericarditis (CP) has been affected by a change in incidence of etiological factors. We sought to determine the impact of these changes on the outcome of pericardiectomy. Methods and Results —The contemporary spectrum of CP in 135 patients (76% male) evaluated at the Mayo Clinic from 1985 to 1995 was compared with that of a historic cohort. Notable trends were an increasing frequency of CP due to cardiac surgery and mediastinal radiation and presentation in older patients (median age, 61 versus 45 years). Perioperative mortality decreased (6% versus 14%, P =0.011), but late survival was inferior to that of an age- and sex-matched US population (57±8% at 10 years). The long-term outcome was predicted independently by 3 variables in stepwise logistic regression analyses: (1) age, (2) NYHA class, and most powerfully, (3) a postradiation cause. Of 90 late survivors in whom functional class could be determined, functional status had improved markedly (2.6±0.7 at baseline versus 1.5±0.8 at latest follow-up [ P <0.0001]), with 83% being free of clinical symptoms. Conclusions —The evolving profile of CP, with increasingly older patients and those with radiation-induced disease in the past decade, significantly affects postoperative prognosis. Long-term results of pericardiectomy are disappointing for some patient groups, especially those with radiation-induced CP. By contrast, surgery alleviates or improves symptoms in the majority of late survivors.

BACKGROUND Virtually all natural history studies of Wolff-Parkinson-White (WPW) syndrome have been case series and, as such, have been constrained by referral biases, skewed age and sex distributions, or brief follow-up periods. The purpose of our study was to examine the natural history, the development of arrhythmias, and the incidence of sudden death in an entire cohort of pediatric and adult WPW patients from a community-based local population. METHODS AND RESULTS We identified 113 residents of Olmsted County, Minnesota, during the period 1953-1989 using the centralized records-linkage system provided by the Mayo Clinic and the Rochester Epidemiology Program Project. Medical records and ECGs were reviewed to confirm the diagnosis and to establish pathway location by ECG criteria. Follow-up, via record review and telephone interview, was complete in 95% of subjects through 1990. The incidence of newly diagnosed cases was approximately four per 100,000 per year. Preexcitation was not present on the initial ECG of 22% of the cohort. Approximately 50% of the population was asymptomatic at diagnosis, with 30% subsequently having symptoms related to arrhythmia at follow-up. Two sudden cardiac deaths (SCD) occurred over 1,338 patient-years of follow-up, yielding an overall SCD rate of 0.0015 (95% confidence interval, 0.0002-0.0054) per patient-year. No SCD occurred in patients asymptomatic at diagnosis. CONCLUSIONS The incidence of sudden death in a local community-based population is low and suggests that electrophysiological testing should not be performed routinely in asymptomatic patients with WPW syndrome. Nevertheless, young, asymptomatic patients, particularly those < 40 years old, should return for medical follow-up should symptoms develop.

AbstractBackgroundAmpullary and extensive periampullary lesions can be difficult to treat and often require pancreaticoduodenectomy (PD) for complete removal, even if benign. However, PD may be overtreatment for noninvasive lesions, and pancreas‐sparing total duodenectomy (PSTD) is an emerging valid surgical option for selected cases.MethodsWe reviewed patients undergoing PSTD at our institution over 16 months and a comparison group who had undergone PD for benign duodenal disease over the past 15 years. We also reviewed cases in the English‐language literature and performed a meta‐analysis of those patients who had undergone PSTD.ResultsPSTD had been performed in four patients, who had an average hospital length of stay (LOS) of 13 days; two of them experienced complications. None required conversion to PD, experienced a postoperative fistula or endocrine or exocrine insufficiency, or required intensive care. Two of the PSTDs were performed laparoscopically. Open PD for benign duodenal disease was performed in 22 patients, with overall morbidity and pancreas fistula rates of 82 and 27 %, respectively. The meta‐analysis found 128 unique cases of PSTD with morbidity and mortality rates of 46.4 and 2.3 %, respectively. Pancreaticobiliary leak was seen in 20 %, with an average LOS of 17 days.ConclusionsAlthough PSTD can be used to avoid PD and can be performed laparoscopically, it is technically challenging and still associated with morbidity.

Object Glomus tumors are rare skull base neoplasms that frequently involve critical cerebrovascular structures and lower cranial nerves. Complete resection is often difficult and may increase cranial nerve deficits. Stereotactic radiosurgery has gained an increasing role in the management of glomus tumors. The authors of this study examine the outcomes after radiosurgery in a large, multicenter patient population. Methods Under the auspices of the North American Gamma Knife Consortium, 8 Gamma Knife surgery centers that treat glomus tumors combined their outcome data retrospectively. One hundred thirty-four patient procedures were included in the study (134 procedures in 132 patients, with each procedure being analyzed separately). Prior resection was performed in 51 patients, and prior fractionated external beam radiotherapy was performed in 6 patients. The patients' median age at the time of radiosurgery was 59 years. Forty percent had pulsatile tinnitus at the time of radiosurgery. The median dose to the tumor margin was 15 Gy. The median duration of follow-up was 50.5 months (range 5–220 months). Results Overall tumor control was achieved in 93% of patients at last follow-up; actuarial tumor control was 88% at 5 years postradiosurgery. Absence of trigeminal nerve dysfunction at the time of radiosurgery (p = 0.001) and higher number of isocenters (p = 0.005) were statistically associated with tumor progression–free tumor survival. Patients demonstrating new or progressive cranial nerve deficits were also likely to demonstrate tumor progression (p = 0.002). Pulsatile tinnitus improved in 49% of patients who reported it at presentation. New or progressive cranial nerve deficits were noted in 15% of patients; improvement in preexisting cranial nerve deficits was observed in 11% of patients. No patient died as a result of tumor progression. Conclusions Gamma Knife surgery was a well-tolerated management strategy that provided a high rate of long-term glomus tumor control. Symptomatic tinnitus improved in almost one-half of the patients. Overall neurological status and cranial nerve function were preserved or improved in the vast majority of patients after radiosurgery.

AbstractContext:Both training and normal body mass index are associated with high insulin sensitivity, but the mechanism may be different.Objective:The aim of the study was to examine whether lean trained humans may be protected from acute free fatty acid (FFA)-induced insulin resistance compared with lean sedentary humans.Design and Setting:We conducted an interventional trial using either a 6-h lipid (20% Intralipid at 90 ml/h) or glycerol (2.25 g/100 ml at 90 ml/h) infusion along with a concurrent hyperinsulinemic-euglycemic clamp and serial muscle biopsies (0, 120, 360 min) at a clinical research unit at the University of Minnesota.Patients or Participants:The study included lean endurance-trained (n = 14) and sedentary (n = 14) individuals matched for age, gender, and body mass index.Main Outcome Measures:We measured the decline in glucose infusion rate (GIR) during the hyperinsulinemic-euglycemic clamp.Results:The trained group had higher baseline mitochondrial DNA copy number, mRNA of cytochrome C oxidase subunit 3, and insulin sensitivity (as measured by GIR) compared with the sedentary group. When FFA was acutely elevated to the upper physiological range (0.6–0.7 mEq/liter) by lipid infusion, the GIR in both activity groups declined similarly compared with their respective glycerol controls, although insulin signaling, as measured by Ser 473 pAKT/AKT, remained comparable. Specific to the trained group, the stimulatory effect of hyperinsulinemia on mitochondrial mRNA levels during the glycerol infusion was absent during the lipid infusion.Conclusions:Elevated FFA had similar effects in reducing insulin sensitivity in trained and sedentary humans. In trained participants, this decline was associated with alterations in the skeletal muscle mitochondrial mRNA response to hyperinsulinemia.

Background Reported incidence of extravertebral cement leakage after vertebroplasty varies widely across studies. Purpose To retrospectively compare the relative detection rates of extravertebral leakage noted under intra-procedural fluoroscopic surveillance, postprocedure plain radiographs, and postprocedure computed tomography (CT) in a cohort of patients undergoing vertebroplasty. Material and Methods With IRB approval, we retrospectively identified 181 patients with 277 levels treated with percutaneous vertebroplasty among a total of 1255 patients undergoing vertebroplasty between 1999 and 2010 who had subsequently undergone a CT examination that included the treated level(s). Categories of leakage were paravertebral, end plate, epidural, and prevertebral venous leakage. CT-detected leak rates were then compared to those noted on the vertebroplasty procedure reports and the archived fluoroscopic images for this same cohort using Pearson's χ 2 test. Results One hundred and forty-nine (82%, 95% CI 76–87%) of 181 patients demonstrated evidence of some type of leakage on CT at one or more treated levels. Sixty-two (34%, 95% CI 28–42%) and seventy-seven (50%, 95% CI 43–57%) of 149 CT-detected leaks were reported in the procedural dictation or detected on plain radiography ( P = 0.01 and 0.006, respectively). The most common type of leakage noted on CT was end plate ( n = 81, 45%, 95% CI 38–52%), followed by paravertebral ( n = 64, 35%, 95% CI 29–43%), epidural ( n = 36, 20%, 95% CI 15–26%), and prevertebral venous ( n = 32, 18%, 95% CI 13–24%). Conclusion Cement leakage after vertebroplasty is common and is often not reported by operators in procedural dictations. CT detects substantially more leaks than plain radiography.

Background— Measurement of hospital quality has traditionally focused on processes of care and postprocedure outcomes. Appropriateness measures for percutaneous coronary intervention (PCI) assess quality as it relates to patient selection and the decision to perform PCI. The association between patient selection for PCI and processes of care and postprocedural outcomes is unknown. Methods and Results— We included 203 531 patients undergoing nonacute (elective) PCI from 779 hospitals participating in the National Cardiovascular Data Registry (NCDR) CathPCI Registry between July 2009 and April 2011. We examined the association between a hospital's proportion of nonacute PCIs categorized as inappropriate by the 2009 Appropriate Use Criteria (AUC) for Coronary Revascularization and in-hospital mortality, bleeding complications, and use of optimal guideline-directed medical therapy at discharge (ie, aspirin, thienopyridines, and statins). When categorized as hospital tertiles, the range of inappropriate PCI was 0.0% to 8.1% in the lowest tertile, 8.1% to 15.2% in the middle tertile, and 15.2% to 58.6% in the highest tertile. Compared with lowest-tertile hospitals, mortality was not significantly different at middle-tertile (adjusted odds ratio [OR], 0.93; 95% confidence interval [CI], 0.73–1.19) or highest-tertile hospitals (OR, 1.12; 95% CI, 0.88–1.43; P =0.35 for differences between tertiles). Similarly, risk-adjusted bleeding did not vary significantly (middle-tertile OR, 1.13; 95% CI, 1.02–1.16; highest-tertile OR, 1.02; 95% CI, 0.91–1.16; P =0.07 for differences between tertiles) nor did use of optimal medical therapy at discharge (85.3% versus 85.7% versus 85.2%; P =0.58). Conclusions— In a national cohort of nonacute PCIs, a hospital's proportion of inappropriate PCIs was not associated with in-hospital mortality, bleeding, or medical therapy at discharge. This suggests PCI appropriateness measures aspects of hospital PCI quality that are independent of how well the procedure is performed. Therefore, PCI appropriateness and postprocedural outcomes are both important metrics to inform PCI quality.