UNASSIGNED: Overweight and obesity have been found to exhibit a statistically significant increase in corrected QT interval (QTc), a major contributing factor to sudden death. However, the influence of widely used weight loss strategies including diet, exercise, anti-obesity drugs, and bariatric surgery on QTc remains inconsistent. Therefore, the present systematic review and meta-analysis aim to quantitatively analyse and evaluate the effect of weight loss on QTc in obese patients after diet control with exercise intervention and anti-obesity drugs, as well as bariatric surgery.
UNASSIGNED: Twenty randomised controlled trials (RCT) and observational studies were included in the meta-analysis on the effects of weight loss on QTc. The fixed-effects model was employed in the RCTs, and the random-effects model was employed due to the presence of statistical heterogeneity among observational studies. Subgroup analysis was conducted to understand the differences in distinct weight loss methods and follow-up time.
UNASSIGNED: Overall, the QTc of people with obesity after weight loss was shorter than that before (mean difference (MD) = 21.97 ms, 95% confidence interval (CI) = 12.42, 31.52, p < .0001). Subgroup analysis restricted to seven included studies whose intervention was diet control with exercise showed a decrease of QTc with statistical significance (MD = 9.35 ms, 95%CI = 2.56, 37.54, p = .007). In the remaining 11 studies, bariatric surgery was the weight loss method. The results also showed a shortening of QTc after surgery, and the difference was statistically significant (MD = 29.04 ms, 95%CI = -16.46, 41.62, p < .00001). A statistically significant difference in QTc shortening at 6 months compared to pre-operation values was further observed (MD = -31.01 ms, 95%CI = -2.89, -59.12, p = .03). The shortening of QTc at 12 months of follow-up was also significantly different from that before surgery (MD = 36.47 ms, 95%CI = 14.17, 58.78, p < .00001). Moreover, the differences became more pronounced as the follow-up time extended.
UNASSIGNED: We demonstrate that weight loss links to a shortened QTc, without considering the means of weight loss. Bariatric surgery has been found to result in a greater reduction in QTc.

OBJECTIVE: To analyze the clinical and genetic characteristics of a patient with long QT syndrome type 14 (long QT syndrome-14, LQT14, OMIM # 616247) caused by a de novo CALM1 mutation.
METHODS: The clinical data of the patient were collected, next-generation sequencing technology was used to determine the exome gene sequence of the patient, and the suspected pathogenic locus was verified by Sanger sequencing.
RESULTS: A 5-year and 9-month-old girl was admitted to the hospital due to a syncopal episode. During the attack, the main symptoms were loss of consciousness, cyanosis of the face and lips, and weakness of limbs. The child had multiple seizures in the past, all of which occurred after emotional excitement and activity. She was diagnosed with epilepsy for more than 3 years, but the effect of antiepileptic treatment was not satisfactory. The electrocardiogram was normal in the past. A month ago, convulsions occurred again after exercise, and the electrocardiogram showed QTc 496 ms. The treadmill test showed a significant prolongation of QTc after exercise, and the genetic results suggested a new heterozygous variant of CALM1, c.395A>G; p. (Asp132Gly). Consequently, she was diagnosed with LQT14 and treated with propranolol. During a follow-up of 15 months, there were no seizures or syncope.
CONCLUSIONS: This patient had multiple episodes of convulsions or syncope after emotional stimulation or activity, with intermittent prolongation of the QTc on routine ECG, marked prolongation of the QTc after exercise, and T-wave alternans, which differed from the LQT14 phenotype caused by the previous CALM1 mutation.

The Food and Drug Administration (FDA) warned about lamotrigine\'s arrhythmogenicity based on in vitro data. This systematic review investigates lamotrigine\'s effect on cardiac conduction and risk of sudden cardiac death (SCD) in individuals with and without cardiovascular disease.
We searched Web of Science and PubMed from inception through August 2021. We included studies measuring electrocardiogram (ECG) changes, laboratory abnormalities, or SCD among patients taking lamotrigine. Studies examining sudden unexpected death in epilepsy were excluded for scope. Two reviewers assessed articles and extracted data. We used the Effective Public Healthcare Panacea Project tool to evaluate confidence in evidence.
Eight randomized controlled trials, 9 nonrandomized observational studies, and 24 case reports were identified, with >3054 total participants, >1606 of whom used lamotrigine. One randomized trial of older patients found an average QRS increase of 3.5 +/- 13.1 ms. Fifteen studies reported no changes in ECG parameters. Case reports documented QRS widening (13), Brugada syndrome (6), QTc prolongation (1) and SCD (2), though many ingested toxic quantities of lamotrigine and/or other medications.
Evidence is insufficient to support the breadth of the FDA warning concerning lamotrigine\'s cardiac risk. Lamotrigine at therapeutic doses may be associated with modest, non-dangerous QRS widening.

OBJECTIVE: To evaluate the risk of QT prolongation in patients treated for Cannabis Hyperemesis Syndrome (CHS) in the emergency department.
METHODS: This was a retrospective comprehensive chart review of patients in the University of Colorado Health Emergency Department. Charts were identified by ICD9/10 codes from January 1, 2012 to December 31, 2014 for cannabis use and data were manually abstracted. We performed chi-square and odds ratios, stratified by drug, to determine differences in medication induced QTc prolongation and performed logistic regression to predict prolongation greater than 500 ms. We captured adverse events from medications as a secondary outcome.
RESULTS: We found 282 cases of CHS during the study period. There were no significant differences between the median post-medication QTc value stratified by drug when all medications were analyzed simultaneously. A multiple logistic regression model showed that only a potassium below 3.0 mmol/L predicted QT prolongation greater than 500 msec.
CONCLUSIONS: Anti-emetics used to treat CHS did not result in significant QTC prolongation in this cohort.

β-Blockers are first-line therapy in patients with long QT syndrome (LQTS). However, β-blockers had genotype dependent efficacy (LQT1>LQT2>LQT3). Sodium channel blockers have been recommended as add-on therapy for LQT3 patients. However, the pooled effect of sodium channel blockers in all LQTS patients remains unknown.
We conducted a systematic electronic search of PubMed, Embase, and the Cochrane Library. Fixed effects model was used to assess the effect of sodium channel blockers on QTc, cardiac events (CEs), and the proportion of QTc ≥ 500 ms and QTc ≤ 460 ms in LQTS patients.
Pooled analysis of 14 studies with 213 LQTS (9 LQT1 + 63 LQT2 + 135 LQT3 + 6 others) patients showed that sodium channel blockers significantly shortened QTc by nearly 50 ms (mean difference [MD], -49.43; 95% confidence interval [CI], -57.80 to -41.05, p < .001), reduced the incidence of CEs (risk ratio [RR], 0.23; 95% CI, 0.11-0.47; p < .001) and the proportion of QTc ≥ 500 ms (RR, 0.33; 95% CI, 0.24-0.47; p < .001), and increased the proportion of QTc ≤ 460 ms (RR, 10.33; 95% CI, 4.62-23.09; p < .001). Sodium channel blockers significantly shortened QTc both in LQT3 and LQT2 patients, while the QTc shortening effect in LQT3 was superior to that in LQT2 (57.39 vs. 36.61 ms). Mexiletine, flecainide, and ranolazine all significantly shortened QTc, and the QTc shortening effect by mexiletine was the best (60.70 vs. 49.08 vs. 50.10 ms).
Sodium channel blockers can be useful both in LQT3 and LQT2 patients. Mexiletine, flecainide and ranolazine significantly shortened QTc in LQTS patients, and the QTc shortening effect by mexiletine was the best.

BACKGROUND: Hydroxychloroquine or chloroquine with or without the concomitant use of azithromycin have been widely used to treat patients with SARS-CoV-2 infection, based on early in vitro studies, despite their potential to prolong the QTc interval of patients.
OBJECTIVE: This is a systematic review and metanalysis designed to assess the effect of hydroxychloroquine with or without the addition of azithromycin on the QTc of hospitalized patients with COVID-19.
METHODS: PubMed, Scopus, Cochrane and MedRxiv databases were reviewed. A random effect model meta-analysis was used, and I-square was used to assess the heterogeneity. The prespecified endpoints were ΔQTc, QTc prolongation > 500 ms and ΔQTc > 60 ms.
RESULTS: A total of 18 studies and 7179 patients met the inclusion criteria and were included in this systematic review and meta-analysis. The use of hydroxychloroquine with or without the addition of azithromycin was associated with increased QTc when used as part of the management of patients with SARS-CoV-2 infection. The combination therapy with hydroxychloroquine plus azithromycin was also associated with statistically significant increases in QTc. Moreover, the use of hydroxychloroquine alone, azithromycin alone, or the combination of the two was associated with increased numbers of patients that developed QTc prolongation > 500 ms.
CONCLUSIONS: This systematic review and metanalysis revealed that the use of hydroxychloroquine alone or in conjunction with azithromycin was linked to an increase in the QTc interval of hospitalized patients with SARS-CoV-2 infection that received these agents.

Obesity is known to be a strong predictor of sudden cardiac death. For this reason, concern exists that this association may be related to delayed ventricular repolarization (VR), which has been extensively studied in overweight and obese patients. The corrected QT interval (QTc) and QT or QTc dispersion have been the most commonly-used electrocardiographic methods for assessing VR. Multiple controlled studies demonstrated that QTc and QT or QTc dispersion were significantly longer/greater in overweight and obese subjects than in normal weight controls. The preponderance of evidence indicates that weight loss in overweight and obese patients, whether achieved by diet or bariatric surgery, significantly shortens QTc and decreases QT or QTc dispersion. Several co-morbidities that are commonly associated with obesity may delay VR. These include diabetes mellitus, the metabolic syndrome, systemic hypertension, left ventricular hypertrophy, heart failure, and obstructive sleep apnea. It is unclear whether overweight and obesity are independent predictors of delayed VR. It is also uncertain whether prolongation of QTc in such patients is sufficient to predispose to potentially fatal ventricular arrhythmias.

We performed a systematic review and meta-analysis of the effects of obesity ± overweight and weight loss on the corrected QT interval (QTc) and QT or QTc dispersion (indices of ventricular repolarization). Mean difference for both QTc and QT or QTc dispersion with 95% confidence intervals (CIs) was calculated comparing obese ± overweight subjects and normal weight controls and QTc and QT or QTc dispersion before and after weight loss from diet ± exercise or bariatric surgery. A total of 22 studies fulfilled the selection criteria. Compared with normal weight controls, there was a significantly longer QTc in obese ± overweight subjects (mean difference of 21.74 msec, 95% CI: 18.76 to 22.32) and significantly longer QT or QTc dispersion (mean difference of 15.17 msec, 95% CI: 13.59 to 16.74). Weight loss was associated with a significant decrease in QTc (mean difference -25.77 msec, 95% CI: -28.33-23.21) and QT or QTc dispersion (mean difference of -13.46 msec, 95% CI: -15.60 to -11.32 in obese ± overweight subjects. Thus, obesity ± overweight is associated with significant prolongation of QTc and QT or QTC dispersion. Weight loss in obese ± overweight subjects produces significant decreases in these variables. © 2016 World Obesity.

OBJECTIVE: To evaluate the effect of antipsychotics on the corrected QT (QTc) interval in youth.
METHODS: We searched PubMed (http://www.ncbi.nlm.nih.gov/pubmed) for randomized or open clinical trials of antipsychotics in youth <18 years with QTc data, meta-analyzing the results. Meta-regression analyses evaluated the effect of age, sex, dose, and study duration on QTc. Incidences of study-defined QTc prolongation (>440-470 milliseconds), QTc >500 milliseconds, and QTc change >60 milliseconds were also evaluated.
RESULTS: A total of 55 studies were meta-analyzed, evaluating 108 treatment arms covering 9 antipsychotics and including 5,423 patients with QTc data (mean age = 12.8 ± 3.6 years, female = 32.1%). Treatments included aripiprazole: studies = 14; n = 814; haloperidol: studies = 1; n = 15; molindone: studies = 3; n = 125; olanzapine: studies = 5; n = 212; paliperidone: studies = 3; n = 177; pimozide: studies = 1; n = 25; quetiapine: studies = 5; n = 336; risperidone: studies = 23; n = 2,234; ziprasidone: studies = 10, n = 523; and placebo: studies = 19, n = 962. Within group, from baseline to endpoint, aripiprazole significantly decreased the QTc interval (-1.44 milliseconds, CI = -2.63 to -0.26, p = .017), whereas risperidone (+1.68, CI = +0.67 to +2.70, p = .001) and especially ziprasidone (+8.74, CI = +5.19 to +12.30, p < .001) significantly increased QTc. Compared to pooled placebo arms, aripiprazole decreased QTc (p = .007), whereas ziprasidone increased QTc (p < .001). Compared to placebo, none of the investigated antipsychotics caused a significant increase in the incidence of the 3 studied QTc prolongation measures, but there was significant reporting bias.
CONCLUSIONS: Based on these data, the risk of pathological QTc prolongation seems low during treatment with the 9 studied antipsychotics in otherwise healthy youth. Nevertheless, because individual risk factors interact with medication-related QTc effects, both medication and patient factors need to be considered when choosing antipsychotic treatment.