News Article
Bariatric Surgery Leads to Normalization of Abnormal QTc in Obese Men
PHOENIX (EGMN) - Weight loss following bariatric bypass surgery lowered heart rates and resolved most QTc abnormalities in the electrocardiograms of 100 patients in a retrospective study presented at the annual scientific meeting of the Obesity Society.
Dr. Philippe Gilbert reported men and women had significantly slower heart rates at 22 months of follow-up. In men, greater weight loss correlated with reductions in QTc interval. Although women also had shorter QTc intervals as a group after surgery, this did not correlate with weight loss.
Dr. Gilbert, a cardiologist at Hôpital Laval in Quebec City, speculated that the sex difference may have occurred because more QTc abnormalities occurred in men. "When you look at the male population, there is a higher percentage of men with abnormal QTc before surgery," he said.
Bariatric surgery is associated with improvements in comorbidities associated with metabolic syndrome. Dr. Gilbert said he and his coinvestigators decided to look at its impact on electrocardiographic (ECG) abnormalities because obese patients have "a 50%-100% increased risk of death associated with a 1.6-fold increase of sudden death caused by cardiac arrhythmias."
They reviewed 100 consecutive patients who underwent biliopancreatic diversion with a duodenal switch from January 2000 to July 2001, and for whom records of sinus rhythm, 12-lead ECG, and all medications were available. Patients were excluded if no ECG was done during follow-up.
The population comprised 32 men and 68 women, who were on average aged 40 and 43 years, respectively, at baseline. Changes in weight, body mass index, heart rate, and QTc before and after surgery were statistically significant for both genders.
Among the men, body weight went from 173 to 104 kg, BMI from 57 to 34 kg/m², and heart rate from 83 to 62 beats per minute; their QTc fell from 428 to 411 milliseconds. Among the women, body weight was reduced from 131 to 83 kg, BMI from 50 to 32 kg/m², heart rate from 79 to 62 beats per minute, and QTc from 430 to 410 milliseconds.
Dr. Gilbert used graphics to show that the reductions in QTc correlated with the amount of weight loss in men but not in women. In each sex, he noted, only one patient did not have a normal QTc after surgery.
"Ninety percent of our population with an abnormal QTc had corrected QTc after surgery, which is a fairly important and positive finding in our study," he said.
He also reviewed use of medications before and after the procedure. Use of calcium channel blockers, metformin, statins, and glyburide - all associated with metabolic syndrome - declined significantly. Use of antidepressants that might prolong QTc intervals stayed about the same, however.
"Weight loss secondary to bariatric surgery modulates favorably ECG features," he said. "Considering the high rate of sudden death in this population, normalization of QTc through weight loss could prevent fatal arrhythmias."
Dr. Gilbert and his coinvestigators said they have no conflicts of interest.
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