Annie Chou Internal Medicine PGY3 University of British Columbia. Rocky Mountain Internal Medicine Conference November 24, 2011

Transcription

1 Annie Chou Internal Medicine PGY3 University of British Columbia Rocky Mountain Internal Medicine Conference November 24, 2011

2 Role of the ECG in STEMI Diagnosis of myocardial infarction Localization of infarct & early risk stratification Suitability for acute reperfusion Efficacy based on ST-segment resolution after thrombolytic therapy

3 TIMI 0/1 TIMI 2 TIMI 3 TIMI 0/1 Penetration of obstruction by contrast but no distal perfusion TIMI 2 TIMI 3 Perfusion of entire artery but delayed flow Full perfusion, normal flow Mortality at 42 Days TIMI 0/1 TIMI 2 TIMI 3 JACC. 1991;17:275A

4 Can the bedside ECG provide non-invasive assessment of myocardial tissue reperfusion? UBC Ethics Committee Approval # H

5 STEMI database to identify consecutive subjects Retrospective analysis of prospectively collected data Inclusion criteria: All STEMI patients undergoing PCI at SPH & VGH from May 2007 to September 2009 Exclusion criteria: First facility presentation other than SPH or VGH Unsuccessful primary PCI All BBB Post-PCI ECG >24h Unavailable or uninterpretable ECG

6 Paired ECGs Pre-PCI ECG: maximal ST elevation Post-PCI ECG: first available within 90 min Electronic calipers Nearest 0.1mm Averaged over 2 beats Blinded to outcomes

7 Variables Single-lead ST-elevation recovery Summed ST-deviation recovery (ST-elevation and ST-depression) ST Recovery < 50% 50% < 30% 30-69% 70% ST-elevation only vs. ST-elevation and STdepression

8 Primary Outcome Composite of: In-hospital Mortality Recurrent MI Congestive Heart Failure Cardiogenic Shock Secondary Outcomes are individual components of the composite Statistical analysis Univariate associations were made using Chi-square test or Fisher s Exact test

9 Composite In-Hospital Events 45% p= % 35% 30% 25% p=0.032 <50% p=0.039 <30% 30-69% p=0.001 <50% p=0.002 <30% 30-69% ST-E only 20% 15% 50% 70% 50% 70% ST-E+D 10% 5% 0% Single-lead Recovery Summed-leads Recovery ST-Segment Recovery Measures Deviation

10 Cardiogenic Shock Mortality Heart Failure Reinfarction 45% 40% p=0.014 p=0.009 P= % 40% 35% 30% 25% 20% <50% <30% <50% <30% ST-E only 35% 30% 25% 20% p= % 10% 5% 0% 30-69% 30-69% 50% 70% 50% 70% ST-E+D Single-lead Recovery Summed-leads Recovery Deviation ST-Segment Recovery Measures 15% 10% 5% 0% <50% 50% <30% <50% 30-69% 70% 50% <30% Single-lead Recovery Summed-leads Recovery ST-Segment Recovery Measures 30-69% 70% ST-E only ST-E+D Deviation 45% 45% 40% 40% 35% 30% p= % 30% 25% 25% 20% 20% 15% 10% 5% 0% <50% 30-69% <50% 50% <30% 30-69% <30% 70% 50% 70% Single-lead Recovery Summed-leads Recovery ST-Segment Recovery Measures ST-E only Deviation ST-E+D 15% 10% 5% 0% <50% 50% 30-69% 30-69% 70% <50% 50% <30% 70% <30% Single-lead Recovery Summed-leads Recovery ST-Segment Recovery Measures ST-E only ST-E+D Deviation

11 Degree of ST-elevation recovery correlated with outcomes Extent of summated ST-deviation recovery correlated with outcomes Higher rate of events in patients with STelevation only compared with patients with both ST-elevation and depression

12 A simple ECG performed 90 mins post-pci can provide important prognostic information in STEMI patients Patients with poor ST-segment recovery post-pci may be early candidates for therapies shown to improve outcomes, or for other novel therapies ECGs are widely available bedside tests

13 Small population size Anticipate more findings in 2010 cohort Low frequency of pre-specified endpoints Excludes patients who expire during or shortly after angioplasty without an ECG

14 Research Supervisor Dr. Krishnan Ramanathan Biostatistician Ms. Aihua Pu Regional STEMI Co-chair Dr. Graham Wong

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17 Gold standard for assessing reperfusion Assessed on coronary angiography Based on epicardial coronary anatomy Provides inconsistent information at level of myocardial tissue TIMI Flow Grade Definition 0 No flow beyond a coronary occlusion 1 Faint flow, incomplete fill beyond occlusion 2 Delayed flow with complete distal filling 3 Normal flow with complete distal filling Circulation. 1987;76(1):142

18 Assessed on coronary angiogram Uses degree of contrast density in territory of infarctrelated artery Visually derived Not routinely done MBG Definition 0 No opacification of myocardium 1 Blush is not cleared from microvasculature 2 Myocardial blush clears slowly 3 Myocardial blush begins to clear during washout Circulation. 2000;101(2):125

19 Measurement Definitions ST-elevation ST-depression Outcome Definitions In-hospital Mortality Recurrent MI Congestive Heart Failure Cardiogenic Shock

20 Next Steps Increase sample size Adjustment for confounding variables Utility of worst residual lead binary categorization Association with longer-term outcomes Location of infarct on outcome QT prolongation resolution on outcome Correlation with clinical utility Correlation with TIMI flow grade