RIGTH BUNDLE BRANCH BLOCK AS RISK MARKER OF

RIGTH BUNDLE BRANCH BLOCK AS RISK MARKER OF IN HOSPITAL MORTALITY IN STELEVATION ACUTE MYOCARDIAL INFARCTION. A RENASICA - II SUBSTUDY National Registry of Mexican Society of Cardiology Authors : Úrsulo Juárez MD FACC , Carlos Jerjes-Sanchez MD FACC, Eduardo Chuquiure MD , Carlos Martínez MD FACC On Behalf of RENASICA II and Sociedad Mexicana de Cardiología, México City, México. ESC Congress 2007

BACKGROUND-1 • Bundle branch block (BBB) early during acute myocardial infarction (AMI) is often considered high risk for mortality • In the Fibrinolytic Therapy Trialists’ meta-analysis, patients with BBB at randomization had a 35 -day mortality rate of 24% without and 19% with fibrinolytic therapy. The studies included made no distinction between rigth bundle branch block (RBBB) and left bundle branch block (LBBB) and did not specify whether the BBB was new or old • Different types of BBB occurring during the initial hours of AMI may have different prognostic implications that are independient of another prognostic factors ESC Congress 2007

BACKGROUND-2 • Development of new BBB despite prompt fibrinolytic therapy may signify an extensive and ongoing AMI. Some types of BBB may reflect larger infarct territories, indicating that these patients might benefit from more aggressive reperfusion therapy • Until our knowledgment the prognosis of RBBB in patients with acute coronary syndromes is unclear Reference : European Heart Journal (2006)27, 21 -28 ESC Congress 2007

METHODS-1 The RENASICA II Design overview • Is the largest national registry of ACS recruited 8, 098 patients with final diagnosis of ACS ST elevation (STE) or non-ST elevation (NSTE) secundary to ischaemic heart disease and designed to characterize an unbiased and representative population • The patients were enrrolled in 66 primary and tertiary Mexican Hospitals and for quality control criteria af Alpert were used. The hospitals varied in terms of access to on-site cardiac catheterization, number of acute care beds and the type of practice setting with an aim of stlablishing a representative rather than selective study population ESC Congress 2007

METHODS – 2 : • Patients with ST acute myocardial infarction (AMI) with LBBB or RBBB were compared in terms of in-hospital outcome and major cardiovascular adverse events (MACE) , cardiovascular death, myocardial infarction (MI) and recurrent ischaemia • patients with symptoms precipitated by anemia, hypertension, heart failure, etc were excluded • BBB was defined as de the QRS duration of 0. 12 sec in precence sinus or supraventricular rhythm • Multivariable Analysis was performed to identify in hospital mortality risk among RBBB and LBBB with MACE • Odd ratio (OR) and confidence intervals 95% (CI) ESC Congress 2007

RIGTH BUNDLE BRANCH BLOCK AS RISK MARKER OF IN HOSPITAL MORTALITY IN ST-ELEVATION ACUTE MYOCARDIAL INFARCTION. A RENASICA- II SUBSTUDY Inclusion Criteria INCLUSION (4) 1. lchemic Chest Pain > 20 min 2. ST-E: in BL > 1 mm; Precordial leads > 2 mm 3. QRS duration > 0. 12 seg. 4. Complete Register Form – Signed IC EXCLUTION (1) 1. Non Ischaemic CP precipitated by secundary cause as anemia, heart failure or hypertension 2. Previous BBB 3. Pacemaker rythm ESC Congress 2007

QUALITY To ensure quality control of registry data the following criteria developed by Alpert were applied in RENASICA II: a) Standarizad definitions and all participants were familiarizad b) Careful hospitals selection c) Hospitals approved registry data collection process d) All collected data were reported e) Original data, electronic submissions were centralized f) A professional statistician analyzed the data g) All data and electronic submissions were examined by the central data management h) Principal investigator and steering committee keep administrative order, adjudicated disagreements and encouraged timely submission of documents and data analysis. ESC Congress 2007

RIGTH BUNDLE BRANCH BLOCK AS RISK MARKER OF IN HOSPITAL MORTALITY IN ST-ELEVATION ACUTE MYOCARDIAL INFARCTION. A RENASICA- II SUBSTUDY RESULTS • 4, 555 patients with STE AMI were analyzed in this substudy • Of them 7% had RBBB and 5% LBBB • There were not statistical differences in both groups among aged, gender baseline characteristics, onset symptoms, ischemic time, AMI location, Killip functional class, ventricular dysfunction, and reperfusion strategies. • Patients with inferior or anterior STE AMI with RBBB had highest mortality and association with MACE ( OR 1. 70, CI 1. 19 – 2. 42, p< 0. 003 compared to LBBB. ESC Congress 2007

RIGTH BUNDLE BRANCH BLOCK AS RISK MARKER OF IN HOSPITAL MORTALITY IN ST-ELEVATION ACUTE MYOCARDIAL INFARCTION. A RENASICA- II SUBSTUDY n = 8, 098 Patients with ACS Unspeciphic Chest Pain n = 625 (7%) UA / Non ST AMI* n = 3, 445 (40%) RBBB n= 318 (7%) * UA/Non ST AMI = Unstable Angina No ST elevation acute myocardial infarction ESC Congress 2007 STE AMI** n = 4, 555 (53%) LBBB n= 227 (5%) ** STE AMI = ST elevation acute myocardial infarction

RIGTH BUNDLE BRANCH BLOCK AS RISK MARKER OF IN HOSPITAL MORTALITY IN ST-ELEVATION ACUTE MYOCARDIAL INFARCTION. A RENASICA- II SUBSTUDY ACS-AMI-ST ELEVATION RENASICA – II REGISTRY n = 4, 555 STEMI BBB n = 545 patients RIGTH BUNDLE BRANCH BLOCK N = 318 ( 7% ) LEFT BUNDLE BRANCH BLOCK N = 227 ( 5% ) In Hospital Outcome – Major Cardiovascular Adverse Events – Cardiovascular Death Recurrent ischemia – Re AMI Multivariable Analysis to In Hospital Mortality Risk among RBBB and LBBB with MACE Odd Ratio (OR) and Confidence Intervals 95% ESC Congress 2007

Baseline Characteristics-1 Characteristic RBBB LBBB (n=318) (n=227) Age-years-median 66. 7 Men (%) 76 Hypertension (%) 55 Hyperlipidemia (%) 27 Current/former smoker (%) 63 Diabetes (%) 48 Previous AMI (%) 23 ESC Congress 2007 67. 3 71 59 26 66 47 35 all p = NS

Baseline Characteristics-2 Characteristic AMI location (%) Anterior Inferior K Killip I II IV ESC Congress 2007 (n =) RBBB LBBB (n=318) (n=227) 32 23 23 16 235 54 16 13 168 38 12 9 All p = NS

TREATMENT Medication Reperfusion Strategy Lytic (%) Primary PTCA (%) Clopidogrel (%) ASA (%) Beta Bloq. (%) IECA/ARB (%) Statins (%) ESC Congress 2007 RBBB (n=318) LBBB (n=227) 32 23 23 20 44 88 51 64 14 38 89 51 59 13 all p = NS

Outcomes in Hospital Comparison in both BBB and MACE ESC Congress 2007 30 RBBB LBBB 20 % 10 0 * P value = ns

IN HOSPITAL MORTALITY PREDICTORS IN STEMI A SUBSTUDY OF RENASICA II findings ECG (OR 1. 7, CI 1. 1 – 2. 5) LBBB (OR 1. 7, CI 1. 1 – 2. 4) RBBB (OR 2. 4, 95% CI 1. 9 – 3. 1) 3 rd degree AV block ST Depresion in > 3 ECG leads 0. 5 ESC Congress 2007 1. 0 2. 0 5. 0 10 100 logistic regresion in mortality predictors

Clinical Implications • The higher mortality and higher incidence of RBBB seen in patients with anterior AMI may be axplained by: • Septal ischaemia from a more proximal left descending artery occlusion (before the large septal branch) • The course of the rigth bundle branch traversing the septum towards the apex. Limitations • As in all clinical trials, a selection bias could have occurred in RENASICA II resulting in under-representation of very high risk patients (including those with RBBB accompanying anterior AMI) in the trial cohort. ESC Congress 2007

RIGTH BUNDLE BRANCH BLOCK AS RISK MARKER OF IN HOSPITAL MORTALITY IN ST-ELEVATION ACUTE MYOCARDIAL INFARCTION. A RENASICA- II SUBSTUDY Conclusion The RBBB accompanying anterior or inferior AMI at presentation was an independient predictor of high in hospital mortality. These electrocardiographics features should be considered in risk stratification to identify highrisk patients ESC Congress 2007