Bariatric surgeries can correct abnormal R wave progression and resolve QT dispersion in morbidly obese patients, according to researchers led by a team from the Mother and Child Hospital in Shiraz, Iran. The investigators said that given the positive impact on the cardiovascular system, bariatric surgery could be a practical and beneficial choice for this group of patients who are struggling with cardiac complications.
It has been well documented that excess visceral adipocytes trigger the secretion of “adipokines”, which can lead to myocardial hypertrophy. Moreover, hypertension secondary to obesity can also promote left ventricle hypertrophy (LVH) and cardiac morphologic changes can result in electrocardiographic alterations such as QTc dispersion, P-wave and QTc prolongation, associated with fatal arrhythmias and sudden cardiac death. Previous research has shown that bariatric surgery can lead to significant improvements in heart failure, coronary artery disease, and resolve cardiac rhythm abnormalities.
Therefore, the researchers sought to evaluate the impact of bariatric surgery on electrocardiography and to determine whether surgical weight loss methods are beneficial for correcting obesity-related problems.
The study included 200 patients (166 (83%) female, mean age of the population was 44.6±8.6 years) the majority of whom had severe obesity (BMI>40 kg/m2), and the mean BMI among the patients was 43.8±5.5 kg/m2. They collected demographic information, past medical histories, and intraoperative and postoperative data from the patients' medical records using a prepared checklist. The patients were then divided into two groups based on the type of bariatric surgery they received: sleeve gastrectomy and classic bypass. An electrocardiogram was obtained before the surgery and six months postoperatively. An expert cardiologist blindly interpreted and compared the ECGs before and after surgery.
They evaluate the effects of bariatric surgery on ECG alterations during a 6-month follow-up period. The most common preoperative abnormality was QTc dispersion in 69.5% of participants, followed by RVH and abnormal R wave progression in 31.5% and 30% of the participants, respectively.
They found that bariatric procedures significantly improved R wave progression (60 versus 27, p<0.001), corrected RVH (63 versus 18, p<0.001), reduced QTc dispersion (139 versus 35, p<0.001), shortened the QTc interval (443.9 versus 409.7, p<0.001) and increased the Sokolow-Lyon score (15 versus 17.17, p<0.001). The findings suggest that weight loss achieved through bariatric surgery significantly shortened the QTc duration, improved QTc dispersion and RVH and corrected R wave progression.
The Sokolow-Lyon criteria indicate LVH if the score exceeds 35. As the score significantly increased after the surgery this could be because after surgery, patients experienced weight loss, leading to less subcutaneous fat, better positioning of the heart in the thorax, and lower afterload pressure in the left ventricle, which can result in improved left ventricle function.
A regression analysis was conducted to predict ECG improvements based on sex, age, BMI, and type of surgery, none of these variables had any statistically significant impact on the ECG. However, a statistically meaningful relationship was found between the type of surgery and abnormal R wave progression.
Regression analysis revealed that sleeve gastrectomy was less effective than classic bypass in correcting abnormal R wave progression (OR:0.434, p=0.025). The binomial logistic regression model was statistically significant (χ2(4):10.619; p=0.031). The researchers hypothesised that the reason for these improvements lies in the hormonal and autonomic consequences of bariatric surgeries. Previous studies have shown that insulin resistance (IR) is one of the leading causes of prolonged QTc and QT dispersion.
The findings were reported in the paper, ‘Bariatric surgery mitigated electrocardiographic abnormalities in patients with morbid obesity’, published in Scientific Reports. To access this paper, please click here