Background Abnormal cardiac repolarization, indicated by a prolongation of the QT-interval, increases the risk for torsade de pointes, a potentially life-threatening arrhythmia. Many perioperatively administered drugs and conditions prolong the QT-interval. Despite several reports of perioperative torsade de pointes, systematic evidence regarding perioperative QT-interval prolongation is limited. Methods Serial postoperative 12-lead electrocardiograms were obtained from 469 adult patients undergoing major non-cardiac surgery under general anesthesia. Heart-rate corrected QT-interval duration (Fridericia’s formula) was the primary outcome. All perioperatively administered drugs were recorded. Emphasis was placed on absolute QTc prolongation >500ms and relative increases of 30 and 60ms. Results At the end of surgery, 80% of the patients (345/429) experienced a significant QTc interval prolongation (ΔQTc 23 ± 26ms (mean and SD), 95% CI 20 to 25ms, p<0.0001). Approximately 51% (219/429) had a QTc >440 ms, and 4% (16/429) a QTc >500ms. In 39% (166/429), the ΔQTc was >30ms, in 8% (34/429) >60ms, and in 0.5% (2/429) >100ms. No changes in ΔQTc occurred at subsequent time points. One patient developed torsade de pointes with a ΔQTc: 29ms (0.4% incidence rate). Several drugs had a large effect on ΔQTc: isoflurane; methadone; ketorolac; cefoxitin; zosyn; unasyn; epinephrine; ephedrine and calcium. Postoperative body temperature had a weak negative correlation with ΔQTc (r= −0.15, p=0.02); serum magnesium, potassium and calcium concentrations were not correlated. Conclusions Postoperative QT-interval prolongation is common. Several perioperatively administered drugs are associated with a substantial QT-interval prolongation. The exact cause and its clinical relevance are, however, unclear. Nevertheless, an association between postoperative QT-prolongation and risk for torsade de pointes is likely.
Background-Abnormal cardiac repolarization, indicated by a prolongation of the QT-interval, increases the risk for torsade de pointes, a potentially life-threatening arrhythmia. Many perioperatively administered drugs and conditions prolong the QT-interval. Despite several reports of perioperative torsade de pointes, systematic evidence regarding perioperative QT-interval prolongation is limited.
Background: The accumulation of subconcussive impacts has been implicated in permanent neurological impairment. A gap in understanding the relationship between head impacts and neurological function is the lack of precise characterization and quantification of forces that individuals experience during sports training and competition. Purpose: To characterize impact exposure during training and competition among male and female athletes participating in boxing and mixed martial arts (MMA) via an instrumented custom-fit Impact Monitoring Mouthguard (IMM). Study Design: Cross-sectional study; Level of evidence, 3. Methods: Twenty-three athletes (n = 4 women) were provided a custom-fit IMM. The IMM monitored impacts during sparring and competition. All training and competition sessions were videotaped. Video and IMM data were synchronized for post hoc data verification of true positives and substantiation of impact location. IMM data were collected from boxing and MMA athletes at a collaborating site. For each true-positive impact, peak linear acceleration and peak angular acceleration were calculated. Wilcoxon rank sum tests were used to evaluate potential differences in sport, activity type, and sex with respect to each outcome. Differences in impact location were assessed via Kruskal-Wallis tests. Results: IMM data were collected from 53 amateur training sessions and 6 competitions (session range, 5-20 minutes). A total of 896 head impacts (men, n = 786; women, n = 110) were identified using IMM data and video verification: 827 in practice and 69 during competition. MMA and boxers experienced a comparable number of impacts per practice session or competition. In general, MMA impacts produced significantly higher peak angular acceleration than did boxing impacts ( P < .001) and were more varied in impact location on the head during competitions. In terms of sex, men experienced a greater number of impacts than women per practice session. However, there was no significant difference between men and women in terms of impact magnitude. Conclusion: Characteristic profiles of head impact exposure differed between boxing and MMA athletes; however, the impact magnitudes were not significantly different for male and female athletes.
Background Torsade de pointes is a rare, but potentially fatal arrhythmia. More than 40 cases of perioperative torsade de pointes have been reported in the literature; however, the current evidence regarding this complication is very limited. To improve our understanding we performed a systematic review and meta-analysis of all published case reports of perioperative torsade de pointes. Methods MEDLINE was systematically searched for cases of perioperative torsade de pointes. We included patients of all age groups, and cases that occurred from the immediate preoperative period to the third postoperative day. Patient and case characteristics as well as QT interval data were extracted. Results Forty-six cases of perioperative torsade de pointes were identified; 29 occurred in women (67%) and two episodes were fatal (case fatality rate: 4%). Craniotomies and cardiac surgery accounted for 40% of all cases. Preceding events identified by the authors were hypokalemia (12/46, 26%; 99%CI 9% – 43%) and bradycardia (7/46, 15%; 99%CI 2% – 28%). Drugs were implicated in approximately one-third of the events (14/46, 30%; 99% CI 13% – 48%). The mean QTc at baseline was 457 ± 67ms (min. 320ms; max. 647ms; data available in 27/46 patients). At the time of the event, the mean QTc increased to 575 ± 77ms (min. 413ms; max. 766ms; data available in 33/46 patients). On average, QTc increased by +118ms (99% CI 70 – 166 ms; p< 0.001) between baseline and after the torsade de pointes event. All patients, except for two, had a substantial prolongation of their QTc interval at the time of the event. Conclusions This systematic review identified several common risk factors for perioperative torsade de pointes. Given the nearly uniform presence of a substantial QTc interval prolongation at the time of a torsade de pointes episode, increased vigilance for perioperative QTc interval prolongation may be warranted.
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