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J Am Coll Cardiol, 2005; 45:705-711, doi:10.1016/j.jacc.2004.06.080 © 2005 by the American College of Cardiology Foundation |
,*







* Department of Medicine, Glostrup University Hospital, Glostrup, Denmark
Division of Cardiology, Weill Medical College of Cornell University, New York, New York
Department of Medicine, Sahlgrenska University Hospital/Östra, Göteborg, Sweden
Department of Cardiology, Helsinki University Central Hospital, Helsinki, Finland
|| Department of Cardiology, Haukeland University Hospital, Bergen, Norway
¶ Merck Research Laboratories, West Point, Pennsylvania
# Department of Medicine, University of Michigan, Ann Arbor, Michigan
** Department of Preventive Medicine, Umeå University Hospital, Umeå, Sweden

Department of Medicine, Ullevål University Hospital, Oslo, Norway
Manuscript received January 26, 2004; accepted June 9, 2004.
* Reprint requests and correspondence: Dr. Kristian Wachtell, Rigshospitalet, Department of Medicine B2142, 9 Blegdamsvej, DK-2100 Copenhagen, Denmark (Email: kristian{at}wachtell.net).
| Abstract |
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BACKGROUND: Optimal treatment of hypertensive patients with AF to reduce the risk of cardiovascular morbidity and mortality remains unclear.
METHODS: As part of the Losartan Intervention For End point reduction in hypertension (LIFE) study, 342 hypertensive patients with AF and LV hypertrophy were assigned to losartan- or atenolol-based therapy for 1,471 patient-years of follow-up.
RESULTS: The primary composite end point (cardiovascular mortality, stroke, and myocardial infarction) occurred in 36 patients in the losartan group versus 67 in the atenolol group (hazard ratio [HR] = 0.58, 95% confidence interval [CI] 0.39 to 0.88, p = 0.009). Cardiovascular deaths occurred in 20 versus 38 patients in the losartan and atenolol groups, respectively (HR = 0.58, 95% CI 0.33 to 0.99, p = 0.048). Stroke occurred in 18 versus 38 patients (HR = 0.55, 95% CI 0.31 to 0.97, p = 0.039), and myocardial infarction in 11 versus 8 patients (p = NS). Losartan-based treatment led to trends toward lower all-cause mortality (30 vs. 49, HR = 0.67, 95% CI 0.42 to 1.06, p = 0.090) and fewer pacemaker implantations (5 vs. 15, p = 0.065), whereas hospitalization for heart failure took place in 15 versus 26 patients and sudden cardiac death in 9 versus 17, respectively (both p = NS). The benefit of losartan was greater in patients with AF than those with sinus rhythm for the primary composite end point (p = 0.019) and cardiovascular mortality (p = 0.039).
CONCLUSIONS: Losartan is more effective than atenolol-based therapy in reducing the risk of the primary composite end point of cardiovascular morbidity and mortality as well as stroke and cardiovascular death in hypertensive patients with ECG LV hypertrophy and AF.
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| Methods |
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Patients age 55 to 80 years, having previously treated or untreated hypertension and ECG LV hypertrophy by either Cornell voltage-duration or Sokolow-Lyon voltage criteria (9), were randomized to initial therapy with 50 mg/day losartan or atenolol after one to two weeks of placebo if they had a sitting systolic blood pressure of 160 to 200 mm Hg and/or diastolic blood pressure of 95 to 115 mm Hg. In both groups, hydrochlorothiazide was added in the case of insufficient pressure lowering. Thereafter the study drug was increased to 100 mg/day and supplemented with additional antihypertensive therapy in order to reach a target blood pressure of <140/90 mm Hg. Patients were enrolled from June 1995 to May 1997 and were followed for four years or longer. Of 342 LIFE study participants (3.7% of 9,193) who had either electrocardiographically documented AF or a history of AF (n = 324) or atrial flutter (n = 18) reported by the investigator at baseline, 157 were randomized to losartan and 185 to atenolol. Centralized ECG reading confirmed that 135 patients (40%) had persistent or permanent AF documented by electrocardiography. The care of patients' AF was left to the discretion of the physician.
Statistical analysis. All end points were analyzed using the intention-to-treat approach, all randomized patients were included in their randomized treatment group, and all available follow-up data were included from randomization through the study termination date. Only end points confirmed by the Endpoint Committee were included in analyses. Patients with multiple end points were counted as having had an event in all relevant end point analyses; however, only the first event in a specific category counted in any individual analysis. The difference between treatment groups with respect to clinical events was assessed by Cox regression models with the degree of LV hypertrophy (as measured by both Cornell voltage-duration product and Sokolow-Lyon voltage) and the Framingham risk score (10) at baseline and difference in blood pressure during treatment as covariates. This adjusted analysis was chosen a priori primarily to account for any difference in key risk predictors at baseline; additional adjustments based on findings in the present study are described. The risk reduction for losartan versus atenolol was calculated as: 100·(1 relative risk). Event rates over time are presented as Kaplan-Meier curves: the numbers below the curves represent the number of event-free patients remaining in follow-up at the corresponding time point. Differences in baseline characteristics were assessed by Student t test and chi-square for categorical variables. Tests were performed at two-sided 5% significance levels. For further details, see Dahlöf et al. (8).
| Results |
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Patients with a history of AF had a similar high prevalence of use of another antihypertensive therapy (e.g., centrally acting and/or non-dihydropyridine calcium channel blocker) and received similar concomitant treatment with other rate-controlling, antiarrhythmic and lipid-lowering drugs during the study (Table 3). Most patients adhered to the treatment regimen, and crossover treatment occurred mainly in patients who discontinued study medication. Among patients originally assigned to losartan, 27.6% crossed over to beta-blockade, and among those originally assigned to atenolol, 34.9% crossed over to angiotensin-converting enzyme inhibition/angiotensin-II receptor blockade by the study's end. Patients who discontinued losartan were no more likely to receive open-label beta-blockade than patients who discontinued atenolol (27.6% vs. 31.7%, p = NS). Open-label combination therapy of beta-blocker and angiotensin-converting enzyme inhibition/angiotensin-II receptor blockade during the study was seen in 14.6% and 21.6%, respectively, among losartan- and atenolol-assigned patients (p = 0.123).
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Alternative adjustment for differences in the prevalence of peripheral vascular disease, diabetes, and isolated systolic hypertension instead of Framingham Risk Score yielded HRs associated with losartan treatment of 0.61 for the primary composite end point (95% CI 0.41 to 0.92, p = 0.019), 0.64 for cardiovascular mortality (95% CI 0.37 to 1.11, p = 0.114), 0.52 for stroke (95% CI 0.29 to 0. 92, p = 0.024), 1.70 for MI (95% CI 0.68 to 4.28, p = 0.260), and 0.74 for total mortality (95% CI 0.47 to 1.18, p = 0.206). Other secondary end points did not attain statistical significant difference (data not shown).
Among patients with a history of AF but without clinically recognized diabetes or coronary, cerebral, or peripheral vascular disease at enrollment in the LIFE study, the composite end point occurred in 10 of 77 patients in the losartan group versus 22 of 82 in the atenolol group (26.3 vs. 62.8 per 1,000 patient-years; HR = 0.57, 95% CI 0.38 to 0.87, p = 0.008). The secondary end point of stroke occurred in 5 versus 17 patients (13.1 vs. 47.1 per 1,000 patient-years) in the losartan and atenolol groups, respectively (HR = 0.52, 95% CI 0.29 to 0.92, p = 0.025). A parallel albeit non-significant trend was seen for cardiovascular death (12.8 vs. 25.7 deaths per 1,000 patient-years; HR = 0.60, 95% CI 0.35 to 1.03, p = 0.06), but not for MI or other secondary end points (data not shown).
| Discussion |
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Our study did not show reductions of MI and hospitalizations for angina pectoris or HF with losartan in hypertensive patients with a history of AF. However, beta-blockade is a well-documented treatment for ischemic heart disease and has shown substantial effect on morbidity and mortality in patients with angina pectoris, previous MI, and HF. A study of patients with hypertension and HF showed a 50% reduction in sudden death and a 30% reduction in hospitalizations for HF with metoprolol compared with placebo treatment (15) on top of standard treatments, including angiotensin-converting enzyme inhibition. Furthermore, beta-blocker use has been shown to independently reduce the risk of pump failure death in patients with AF (16). That treatment with losartan did as well as atenolol in MI and hospitalization for angina and HF is reassuring because of the high risk of coronary events in hypertensive patients with LV hypertrophy.
Another important observation of this study is the fact that beta-blocker treatment did not seem to reduce the risk of sudden cardiac death compared with losartan treatment. This is surprising, as many regard beta-blocker therapy as a first-line intervention for prevention of sudden cardiac death (17). In the merged European Myocardial Infarct Amiodarone Trial (EMIAT) and Canadian Amiodarone Myocardial Infarction Trial (CAMIAT) databases, concomitant use of beta-blockers and amiodarone provided a survival benefit, especially for arrhythmic cardiac death (18). In our study, even though the difference in sudden cardiac death did not attain statistical significance, there was a 48% risk reduction favoring the losartan-treated patients. Furthermore, beta-blockertreated patients seemed to need increased pacemaker implantation even though patients at baseline had heart rates averaging 75 beats/min. Losartan also reduced heart rate, albeit less than atenolol, with less heart rate difference at the end of study (Fig. 2). This might be due to blockade of sympathetic nervous system activation by renin-angiotensin system blockade by losartan.
Mechanisms. One explanation for the added effects by losartan on cardiovascular morbidity and mortality in this hypertensive population with LV hypertrophy could be the parallel effects of losartan on regression of atrial and ventricular hypertrophy. We have recently shown in the LIFE echocardiography substudy that patients with LV hypertrophy also exhibit increased left atrial size and hypertrophy (19), which have been associated with increased risk of stroke in population of normotensive and hypertensive adults (20). Further analyses from the LIFE echocardiography study will investigate whether left atrial diameter decreases with reduction in LV mass during treatment and whether this is related to a reduction in subsequent events.
Another possible explanation for reduced vascular events with losartan treatment could be greater effects on arterial atherothrombosis or on coagulation system activation in patients with AF. However, the fact that the benefit of losartan was not limited to high-risk patients with either vascular disease or diabetes, but also occurred in patients with hypertension and AF alone, suggests that the benefits of losartan in patients with AF are due to prevention of vascular disease as well as reduced progression of established arterial disease.
Furthermore, our study does not suggest high serum potassium as the cause of increased cardiovascular morbidity and mortality, because our hypertensive patients with AF treated with losartan had a slightly higher serum potassium level than those treated with atenolol.
Study limitations. The participants in the LIFE study were selected for hypertension and ECG LV hypertrophy but also for lack of current need for atenolol, losartan, or angiotensin-converting enzyme inhibitors, or known intolerance to primary study treatment. Furthermore, in view of the relatively low proportion of patients treated with non-dihydropyridine calcium blockers, most patients in the present study could be rate-controlled by digoxin alone or by no antiarrhythmic treatment during the study. However, in view of the large number of hypertensive patients age 55 to 80 years with LV hypertrophy meeting the LIFE study blood pressure criteria, estimated at 3.9 million in the U.S. and 4.8 million in the European Union (21,22), a considerable number of hypertensive patients with AF might have their risk of cardiovascular events and stroke reduced by losartan therapy.
Although the analysis of AF was not pre-specified in the LIFE study analysis plan from 1995, evaluation of treatment effects in the subgroup of patients with AF at baseline was a planned secondary analysis before termination (September 2001) and unblinding. Furthermore, since the sub-study population was recruited for hypertension and ECG LV hypertrophy and not for AF, balanced randomization is not guaranteed.
Because outcomes were analyzed by the intention-to-treat principle and without restriction after study drug discontinuation, open-label use of angiotensin-II receptor blocker/angiotensin-converting enzyme inhibitor/beta-blocker may have diminished the difference between the groups.
Conclusions. Losartan-based antihypertensive therapy was more effective than an atenolol-based regimen in reducing the risk of the primary composite end point of cardiovascular morbidity and cardiovascular mortality as well as the secondary end points of stroke and cardiovascular death in hypertensive patients with ECG LV hypertrophy and a history of AF. Hypertensive patients with AF who do not need beta-blockade for heart rate control seem to benefit more from losartan-based treatment than from conventional antihypertensive and anti-arrhythmic treatment.
| Acknowledgments |
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| Footnotes |
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