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Background: Previous work has demonstrated that treatment of hypertensive patients with the angiotensin-converting enzyme inhibitor lisinopril was associated with a reduced incidence of a composite conduction system disease endpoint and also left bundle branch block (LBBB) compared with either amlodipine or chlorthalidone therapy. The relationship of incident conduction system disease to angiotensin receptor blocker therapy has not been examined.
Methods: Risk of new right (RBBB) or LBBB in relation to losartan- vs atenolol-based treatment was assessed in 8,342 hypertensive patients without baseline RBBB or LBBB. Risk of incident intraventricular conduction delay (IVCD), defined as new QRS duration ≥110 ms was assessed in the 7,710 patient subset who also had baseline QRS duration <110 ms. QRSd and BBB were determined on in-study ECGs done at 6 months, 1 year and then yearly.
Results: During 4.8±1.0 years follow-up, 459 patients developed new LBBB (5.5%), 184 (2.25) new RBBB and 1,173 (15.2%) a new IVCD. In univariate Cox analyses, losartan-based treatment was not associated with a significantly reduced risk of either new LBBB (HR 0.95, 95% CI 0.79-1.14, p=0.583) or RBBB (HR 1.02, 95% CI 0.76-1.36, p=0.903), but resulted in a 15% lower risk of new IVCD (HR 0.85, 95% CI 0.76-0.95, p=0.005). In a multivariable Cox model that adjusted for other statistically significant predictors of incident IVCD in this population (age, sex, race, history of ischemic heart disease, MI, heart failure, diabetes or atrial fibrillation, prior anti-hypertensive treatment, baseline total and HDL cholesterol, serum glucose and creatinine and baseline QRS duration as standard covariates and incident MI and on-treatment systolic and diastolic pressure, body mass index and Cornell voltage as time-dependent covariates), losartan treatment remained associated with a 13% lower risk of new IVCD (HR 0.87, 95% CI 0.77-0.98, p=0.021).
Conclusions: Incident IVCD but not BBB is significantly reduced by losartan-based treatment. Further study is warranted to assess the potential differential impact of this therapy on QRS prolongation vs development of more discrete conduction system block.
Poster Hall, Hall C
Friday, March 17, 2017, 10:00 a.m.-10:45 a.m.
Session Title: Assessing the Clinical Impact of Blood Pressure Lowering Therapies
Abstract Category: 33. Prevention: Hypertension
Presentation Number: 1105-033
- 2017 American College of Cardiology Foundation