SMAC-AF: Atrial arrhythmias not reduced with aggressive BP treatment
NEW ORLEANS — Aggressive BP treatment did not reduce atrial arrhythmias after ablation in patients with atrial fibrillation undergoing catheter ablation, according to the results of the SMAC-AF trial, presented at the American Heart Association’s Scientific sessions.
“Radiofrequency catheter ablation for atrial fibrillation has become an important therapy for AF, however recurrence rates remain high,” Ratika Parkash, MD, MS, FHRS, from Queen Elizabeth II Health Sciences Centre, Dalhousie University, Halifax, Nova Scotia, Canada, said in a presentation.
The randomized, parallel-group, open-label clinical trial with blinded endpoint evaluation took place in 13 centers across Canada.
Parkash said patients (n = 184; mean age, 60 years; 26% women) were included in the study if they had a baseline BP > 130 mm Hg systolic/80 mm Hg diastolic in the clinic, if they had symptomatic paroxysmal or persistent AF, were refractory or intolerant of at least one class I or II antiarrhythmic medication and were scheduled to undergo catheter ablation.
Patients receiving aggressive BP treatment were given a five-step treatment consisting of quinapril (20 to 40 mg once daily), hydrochlorothiazide (12.5 mg once daily), atenolol 50 mg once daily), amlodipine (Norvasc, Pfizer; 2.5 to 10 mg once daily) and terazosin (1 mg once daily).
Those receiving standard BP treatment were given therapy as recommended by the Canadian Hypertension Guidelines.
The primary outcome was time to symptomatic AF, atrial tachycardia or atrial flutter lasting over 30 seconds more 3 months after ablation.
At 6 months, systolic BP was significantly lower in the aggressive-treatment group (123.2 mm Hg vs. 135.4 mm Hg; P < .001), Parkash said.
However, there was no significant difference between the groups in the primary outcome (HR = 0.94; 95% CI, 0.65-1.38), she said.
Secondary outcomes including AF-related ED visits, AF-related hospitalizations and recurrent ablation therapy were also not different between the groups, she said.
Aggressive BP treatment was more likely to benefit those aged older than 61 years (P for interaction = .013) and those with baseline systolic BP < 140 mm Hg (P for interaction = .022), according to the researchers.
“Upstream therapy for AF will require further study in randomized clinical trials to better understand its potential benefit in AF prevention,” Parkash said. – by Dave Quaile
Parkash, R. CSSR.04: Hi Impact EP Registries and Clinical Trials. Presented at: American Heart Association Scientific Sessions; Nov. 12-16, 2016; New Orleans.
Disclosure: Parkash reports receiving research grants from Medtronic and St. Jude Medical and honoraria from Pfizer.