Biliopancreatic diversion reduces QT interval and dispersion in severely obese patients

Effects of weight loss on QTc in people with obesity: a systematic review and meta-analysis

BACKGROUND AND AIMS

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Bariatric surgery mitigated electrocardiographic abnormalities in patients with morbid obesity

Obesity can lead to cardiovascular dysfunctions and cause electrocardiographic disruptions. Bariatric surgery plays a significant role in weight loss. To assess its benefits, this study investigated electrocardiographic changes before and after bariatric surgery. The present article describes a retrospective cohort study with a 6-month follow-up period. Electrocardiograms were interpreted and compared before and six months after surgery. The relationships between weight loss, type of surgery, and electrocardiographic alterations were analyzed. A total of 200 patients participated in the study, with 34 (17%) men and 166 (83%) women. The mean age of the participants was 44.6 ± 8.6, and their mean body mass index was 43.8 ± 5.5 kg/m2. The mean of QTc decreased after the surgery, while the Sokolow-Lyon scores increased. The statistical analysis showed that QTc dispersion (> 40) (P < 0.001), right ventricular hypertrophy (P < 0.001), abnormal R wave progression (P < 0.001), QTc (P < 0.001) and Sokolow-Lyon criteria (P < 0.001) significantly changed postoperatively. In conclusion, bariatric surgery can reduce QTc, correct poor R wave progression, and resolve right ventricular hypertrophy (RVH) in patients with morbid obesity.

Ventricular conduction improvement after pericardial fat reduction triggered by rapid weight loss in subjects with obesity undergoing bariatric surgery

BACKGROUND

Obesity is considered a major cardiovascular risk factor. The excess of pericardial fat (PF) in patients with obesity has been associated with a variety of electrocardiographic alterations. In previous studies, we demonstrated that rapid weight loss and bariatric interventions result in decreased PF.

OBJECTIVES

The aim of this study is to report the changes in PF after bariatric surgery and its effect on ventricular conduction.

SETTING

US hospital, academic institution.

METHODS

A linear measurement of PF thickness on computed tomography scans was obtained for 81 patients, as well as a retrospective review of electrocardiographic changes before and after bariatric surgery. We compared the changes in PF thickness and electrocardiographic components before and after procedures. Common demographics and co-morbidities were collected along with lipid profiles preoperative and postoperative.

RESULTS

A total of 81 patients had electrocardiograms done before and 1 year after bariatric surgery. Females comprised 67.9% (n = 55), and the average age for our population was 55.07 ± 14.17 years. Pericardial fat thickness before surgery was 5.6 ± 1.84 and 4.5 ± 1.62 mm after surgery (P = .0001). Ventricular conduction (QT and QT corrected [QTc] intervals) showed a significant improvement from 438.7 + 29 before to 426.8 + 25.3 after bariatric surgery (P = .006). We found a statistically significant association between the decrease in PF and the decrease in QTc intervals (P = .002).

CONCLUSION

Obesity is a risk factor for arrhythmias and sudden cardiac death. Bariatric surgery and its effect on PF produce an improvement in ventricular conduction, which may reduce the ventricular electrical instability in patients with obesity.

Effects of Bariatric Surgery on Heart Rhythm Disorders: a Systematic Review and Meta-Analysis

The aim of this systematic review is to provide an overview of the literature on the effects of bariatric surgery on obesity-associated electrocardiogram (ECG) abnormalities and cardiac arrhythmias. Fourteen studies were included with a methodological quality ranging from poor to good. Majority of the studies showed a significant decrease of QT interval and related measures after bariatric surgery. Seven studies were included in the meta-analysis on effects of bariatric surgery on QTc interval and a significant decrease in QTc interval of - 33.6 ms, 95%CI [- 49.8 to - 17.4] was seen. Bariatric surgery results in significant decrease in QTc interval and P-wave dispersion, i.e., a normalization of initial pathology. The effects on atrial fibrillation are conflicting and not yet fully understood.

Effect of obesity and weight loss on ventricular repolarization: a systematic review and meta-analysis

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.

Lipidomic profiling at the interface of metabolic surgery and cardiovascular disease

Bariatric surgery has helped patients attain not only significant and sustained weight loss but has also proved to be an effective means of mitigating or reversing various obesity-related comorbidities. The impressive rates of remission or resolution of type 2 diabetes mellitus (T2D) following bariatric surgery are well documented and have rightly received great attention. Less understood are the effects of bariatric surgery on cardiovascular disease (CVD) and its underlying risk factors. Thanks to the availability of increasingly sensitive laboratory tools, the emerging science of lipidomics and metagenomics is poised to offer significant contributions to our understanding of metabolically induced vascular diseases. They are set to identify novel mechanisms explaining how the varied approaches of bariatric surgery produce the remarkable improvements in multiple organs observed during patient follow-up. This article reviews recent and novel findings in patients through the lens of lipidomics with an emphasis on CVD.

Relation of left ventricular mass to QTc in normotensive severely obese patients

Prolongation of the corrected QT interval (QTc) has been described in obese subjects. This study assesses the relation of left ventricular (LV) mass to QTc in normotensive severely obese subjects. Fifty normotensive patients whose BMI was ≥40 kg/m(2) (mean age: 38 ± 7 years) were studied. QTc was derived using Bazett's formula. LV mass was calculated using the formula of Devereux et al. and was indexed to height(2.7). Mean QTc was 428.8 ± 19.0 ms and was significantly longer in those with than in those without LV hypertrophy (P < 0.01) QTc correlated positively and significantly with BMI (r = 0.392, P < 0.025), LV mass/height(2.7) (r = 0.793, P < 0.0005), systolic blood pressure (r = 0.742, P < 0.001), LV end - systolic wall stress (r = 0.746, P < 0.001) and LV internal dimension in diastole (r = 0.788, P < 0.0005). Among five variables tested, LV mass/height(2.7) was identified as the sole predictor of QTc by multivariate analysis. In conclusion, LV mass and loading conditions that may affect LV mass are important determinants of QTc in normotensive severely obese subjects.

Effect of weight loss after bariatric surgery on left ventricular mass and ventricular repolarization in normotensive morbidly obese patients

To assess the effect of weight loss on ventricular repolarization in morbidly obese patients, 39 normotensive subjects whose baseline body mass indexes were ≥40 kg/m(2) before weight loss from bariatric surgery were studied. All patients were free of underlying organic heart disease, heart failure, and conditions that might affect ventricular repolarization. Twelve-lead electrocardiography and transthoracic echocardiography were performed just before surgery and at the nadir of postoperative weight loss. The corrected QT interval (QTc) was derived using Bazett's formula. QTc dispersion was calculated by subtracting the minimum from the maximum QTc on the 12-lead electrocardiogram. Echocardiographic left ventricular (LV) mass was indexed to height(2.7). The mean body mass index decreased from 42.8 ± 2.1 to 31.9 ± 2.2 kg/m(2) (p <0.0005). For the entire group, weight loss was associated with significant reductions in mean QTc (from 428.7 ± 18.5 to 410.5 ± 11.9 ms, p <0.0001) and mean QTc dispersion (from 44.1 ± 11.2 to 33.2 ± 3.3 ms, p <0.0005). Mean QTc and QTc dispersion decreased significantly with weight loss in patients with LV hypertrophy but not in subjects without LV hypertrophy. Multivariate analysis identified pre-weight loss LV mass/height(2.7) as the most important predictor of pre-weight loss QTc and QTc dispersion and also identified weight loss-induced change in LV mass/height(2.7) as the most important predictor of weight loss-induced changes in QTc and QTc dispersion. In conclusion, LV hypertrophy is a key determinant of QTc and QTc dispersion in normotensive morbidly obese patients. Regression of LV hypertrophy associated with weight loss decreases QTc and QTc dispersion.

Impact of bariatric surgery on comorbidities

Published data show that bariatric surgery not only leads to significant and sustained weight loss but also resolves or improves multiple comorbidities associated with morbid obesity. Evidence suggests that the earlier the intervention the better the resolution of comorbidities. Patients with metabolic syndrome and comorbidities associated with morbid obesity should be promptly referred for consideration for bariatric surgery earlier in the disease process.

Anesthesia induction with sevoflurane and propofol: evaluation of P-wave dispersion, QT and corrected QT intervals

The present study compared the effects of anesthesia induction with sevoflurane and propofol on hemodynamics, P-wave dispersion (Pwd), QT interval and corrected QT (QTc) interval. A total of 72 adult patients were included in this prospective study. All patients had control electrocardiograms (ECGs) before anesthesia induction. Anesthesia was induced with sevoflurane inhalation or intravenous propofol. Electrocardiography for all patients was performed during the 1(st) and 3(rd) minutes of induction, 3 minutes after administration of muscle relaxant, and at 5 minutes and 10 minutes after intubation. Pwd and QT intervals were measured on all ECGs. QTc intervals were determined using the Bazett formula. There was no significant difference in Pwd and QT and QTc intervals on control ECGs. In the sevoflurane group, except for control ECGs, Pwd and QTc interval on all ECGs were significantly longer than those in the propofol group (p < 0.05). We conclude that propofol should be used for anesthesia induction in patients with a predisposition to preoperative arrhythmias, and in those whose Pwd and QTc durations are prolonged on preoperative ECGs.

The myth of QT shortening by weight loss and physical training in obese subjects with coronary heart disease

This study aims to describe the changes that a period of low-calorie diet and physical training determines in heart rate and in corrected QT (QTc) interval in obese patients with coronary heart disease (CHD) and to verify whether it is effective in shortening the QT interval using three different methods for QT correction. Two hundred and seventy obese white patients (162 males--60%) affected with stable CHD and treated with β-blockers were retrospectively studied in the setting of a program aimed at losing weight through training (aerobic activity + strength exercise) and diet (80% of estimated resting energy expenditure). Age was related to RR interval, QTc was related to left ventricular ejection fraction (EF) while sex exerted no effects. At the end of the study period heart rate decreased by 8.3% and noncorrected QT increased by 3.0%; QT corrected with the Bazett formula decreased by 0.7% (P = 0.007), QT corrected with the Fridericia formula increased by 0.5% (P = 0.023), whereas the modifications were nonsignificant when the Framingham correction was used. In conclusion, contrary to the current views, physical training and diet, which are effective in reducing heart rate, produced no clinically relevant change in the QT interval.

Preoperative abnormal P and QTc dispersion intervals in patients with metabolic syndrome

We evaluated P wave dispersion (Pwd), QT, corrected QT (QTc), QT dispersion, and corrected QT dispersion (QTcd) intervals in patients with metabolic syndrome (MetS). Patients scheduled to undergo elective noncardiac surgery were included in the study. The main diagnoses, anthropometric measurements, waist circumferences, body mass index, electrocardiograms, serum levels of electrolytes, glucose, and lipids were recorded for all patients. QTc, QTcd intervals were determined with the Bazett formula. MetS (group M, n = 36) was diagnosed using the Adult Treatment Panel III. Controls (group C, n = 40) were chosen on the basis of patients with no MetS and matched for age and gender. There were no differences between groups in terms of age, sex, or serum electrolyte levels (P > 0.05). Waist circumferences, body mass index, serum glucose, and triglyceride values in group M were significantly higher than those in group C (P < 0.001). In group M, Pwd, QTc, QT dispersion and QTcd intervals were significantly longer than those in group C (P < 0.001). This finding and our retrospective analysis suggest that these patients may be at greater risk of perioperative arrhythmias.