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ShouldWeAchievetheTargetDosesofBeta-blockersinChronicHeartFailurePatientswithAdequateHeartRateControl?KritLeemasawat,MD;ArintayaPhrommintikul,MD;RungsritKanjanavanit,MD;WanwarangWongcharoen,MD;KanOkonogi,MD;LalitaYongsmith,MD;SirilakYooprasert,MD;andApichardSukonthasarn,MDFacultyofMedicine,ChiangMaiUniversity,ThailandPurposeRecentstudiesindicatedthatheartratewasanimportanttargetforchronicheartfailuretreatment,whereastheimportanceofdosesofbeta-blockerswasstilluncertain.Weconductedaretrospectivestudytodeterminethesurvivalprognosisofachievingthetargetdosesofbeta-blockersinchronicheartfailurepatientswithadequateheartratecontrolMethodsWescreenedforsymptomaticchronicheartfailurepatientswithreducedleftventricularejectionfraction(0.40)(HFrEF)andnewlyinitiatedbeta-blockertreatment(bisoprolol,carvedilol,metoprololtartrate,ornebivolol)withatleast1yearfollow-upinMaharajNakornChiangMaiHospitalbetweentheyear2000and2010.Among3,754HFrEFpatients,325patientswereeligibleandwereclassifiedinto4groups,accordingtoheartratecontrol(70vs.≥70beatsperminute)andtargetbeta-blockerdose(achievedvs.notachieved)(Figure1).Theendpointofthestudywasall-causemortality.ResultsBaselineheartratewassimilarinallgroups.Thepatientsingroupwhichthetargetbeta-blockerdosewasnotachievedwereolder(63.0vs.58.3years,P=0.004),hadmorefrequenthistoryofmyocardialinfarction(59.8%vs.43.0%,p=0.007),hadlowerprevalenceofhypertension(40.6%vs.62.5%,p0.001),andhadlowerbaselinebloodpressure(systolicBP119.4vs.126.3mmHg,P=0.005anddiastolicBP68.3vs.74.5mmHg,P0.001).ThebaselineLVejectionfraction,NYHAfunctionalclass,andconcomitantmedicationwerenotdifferentamonggroups.Themedianfollow-upwas49.4months(IQR29.1-71.2).Theannualall-causemortalitywassignificantlylowerinthegroup(I)thanintheothergroups(Figure1).Afteradjustingforpossibleconfoundingfactors,thedifferenceamonggroupsremainedsignificant(p=0.028).Incidenceofsymptomaticbradycardiaandheartblockwashigherintheadequateheartratecontrolgroup(10.5%vs.2.8%,p=0.008).ConclusionsThegreatestsurvivalprognosiswasobservedinHFrEFpatientswhobothhadadequateheartratecontrolandachievedthetargetdosesofbeta-blockers.Bothheartrateandbeta-blockerdosewereimportanttargetsforchronicheartfailuretreatment.SupportedbytheFacultyofMedicineFundformedicalresearch,FacultyofMedicine,ChiangMaiUniversity