ECG and Acute Heart Failure, ECG,HF.

ECG, ECG Changes in Acute Heart Failure.

1. Presenter: Dr Hasan Mahmud Iqbal MD Cardiology Thesis Part Student. NHFH&RI

2. Presenter: Dr Hasan Mahmud Iqbal

3. Abstracts: Patients presenting to the emergency department (ED) with acute heart failure (AHF) are at an increased risk of morbidity and mortality . The electrocardiogram (ECG) is a routine investigation in patients with AHF used to identify potential causes and/or complications. It is unclear whether 12-lead ECG characteristics can serve as a prognostic indicator in this population.

4. Methods & Result: Patients with AHF from four hospital EDs were prospectively enrolled into the AHF – Emergency Management results cohort. In addition to baseline data collection, the first available ECG was read in a core laboratory. Clinical outcomes (all-cause mortality and readmission) were recorded and risk models were developed. Of 937 enrolled patients, 816 had a diagnosis of AHF and an available ECG. Median age of the population was 77. 47% were female and median ejection fraction was 45% .

5. Methods & Result: Abnormalities were common, with only 7.5% of patients having a normal ECG. During the median follow-up of 25.7 months, there were 379 (46%) all-cause deaths and 328 (40%) hospital readmissions. Sinus rhythm was associated with better outcomes [hazard ratio (HR) 0.76; 95% confidence interval (CI) 0.62, 0.94], while paced rhythms (HR 1.51, 95% CI 1.11, 2.05), a wide QRS (HR 1.29, 95% CI 1.04, 1.59) and an ECG with any abnormality (HR 1.57, 95% CI 1.01, 2.44) was associated with poorer outcomes. Other individual ECG characteristics were not related to clinical outcomes after risk adjustment.

6. Conclusion: Certain ECG abnormalities are common in patients with AHF and associated with poor outcomes. Used in conjunction with other clinical variables, the ECG may be a useful tool in long-term risk stratifying patients.

7. Baseline Characteristics …

8. Baseline Characteristics:

9. Introduction: Heart failure (HF) is a life-threatening condition with an estimated prevalence of 2% in the adult population. Patients with HF have an increased risk of morbidity and mortality and commonly present to the emergency department (ED) with acute heart failure (AHF). During the initial care of patients with AHF, clinicians must rapidly diagnose and institute appropriate management for these patients. During the ED evaluation, commonly available laboratory and radiographic studies are recommended by most guidelines, in addition to reviewing a 12-lead electrocardiogram (ECG) for ischemia, arrhythmias and other features that could indicate the aetiology or precipitant of the current episode of AHF.

10. Introduction … Although several descriptive studies of individual ECG characteristics have been conducted in the chronic HF patient population few studies have evaluated ECG characteristics in patients with AHF. Studies involving chronic HF patients have identified that a widened QRS, left bundle branch block(LBBB), prolonged PR interval, and an increased heart rate are all associated with poorer long-term outcomes. Despite their prognostic significance, these ECG characteristics are not employed by clinicians and have not been evaluated in clinical risk stratification tools.

11. Introduction: Previous studies in the AHF population have principally relied on clinically reported ECG findings, focused on short-term outcomes, employed retrospective analysis, limited to patients in sinus rhythm, excluded patients with pacemakers, and/or failed to include all clinically relevant data . In addition, to our knowledge, no studies have specifically targeted the first available ECGs, including those collected at the scene of first contact by emergency medical services (EMS).

12. Introduction: Thus, the relationship between ECG findings and clinically important outcomes remains unclear in patients with AHF. The objective of this study was to describe the ECG findings in patients with AHF and determine which features are related to clinical outcomes after adjustment for other key variables.

13. Methods: From June 2009 to November 2012, 937 patients with suspected decompensated AHF and de novo AHF were prospectively enrolled at four Canadian hospital EDs into the Acute Heart Failure—Emergency Management (AHF-EM) cohort. Details of this protocol have been published previously. Briefly, patients with a diagnosis of AHF were approached and provided written informed consent. Baseline data and ED chart review were completed by trained research nurses and reviewed for completeness by a nurse coordinator.

14. Method … Inclusion criteria were broad, and patients were eligible if the physician in the ED suspected that AHF was the cause for their current ED visit. Patients were excluded from the study if they had severe dementia, if they were haemodialysis dependent, or if they were being treated for an acute coronary syndrome. Each case of suspected AHF was reviewed by an investigator and scored according to the modified Boston Criteria as AHF …… ..highly likely, …… ..possible, or …… ..unlikely. © 2016 The Authors European Journal of Heart Failure © 2016 European Society of Cardiology charts were independently adjudicated to confirm the diagnosis of AHF. Patients were excluded from this analysis if the likelihood of AHF was scored by the independent adjudicator as unlikely (n = 95) or who were missing ECGs (n = 26; Figure 1).

15. Modified Boston criteria:

16. All patients charts were independently adjudicated to confirm the diagnosis of AHF. Patients were excluded from this analysis if the likelihood of AHF was scored by the independent adjudicator as unlikely (n = 95) or who were missing ECGs. All ECGs were transferred to the Canadian VIGOUR Centre (Edmonton, Canada) for core laboratory reading. An investigator who was blinded to clinical outcomes and baseline data reviewed the first available ECG for each participant and coded the results according to international definitions.

17. The investigator underwent training to read ECGs at a core laboratory standard. In addition, a second core laboratory member completely reinterpreted 1% ohf ECGs for quality assurance using a random number generator for study participant identifiers. No discrepancies were identified.

18. Method … . All ECG criteria were adapted from the Minnesota Code Manual of ECG Case definitions. The PR interval was designated prolonged if it exceeded 200 ms. The QTc interval was measured using Bazett’s formula and was designated prolonged if it exceeded 450 ms. The QRS was designated prolonged if it exceeded 120 ms in the absence of paced rhythm. Paced rhythms were identified by the presence of pacing spikes preceding the QRS complex.

19. Method … Atrial fibrillation was identified by an absolutely irregular RR interval with no distinct P-waves. T-wave inversion was identified by a drop of more than 0.1 mV in amplitude below the baseline in the absence of LBBB and paced rhythms. Left ventricular hypertrophy was defined using both the Cornell and Sokolow-Lyons criteria in the absence of LBBB and paced rhythms. Right ventricular hypertrophy was identified by a positive QRS in lead aVR and a negative QRS in lead aVL with an R/S ratio of less than 1 in leads I, II, III, V5, and V6.

20. Method … Left atrial enlargement was identified by a P-wave duration greater than 120 ms in lead II and an amplitude of 100 mV or greater in V1. Right atrial enlargement was identified by a P-wave of greater than 250 mV in lead II. Left bundle branch block was identified by a QRS >120 ms and a R2 peak in leads V5, V6, I, II, or aVL. Right bundle branch block (RBBB) was identified by a QRS >120 ms and R2 peak in leads V1 or V2. Q-waves were identified as pathological if they were greater than 40 ms in duration and deeper than one-fourth

21. Q-waves were identified as pathological if they were greater than 40 ms in duration and deeper than one-fourth of the following R-wave in voltage. The ST elevation and depression was measured at 40 ms following the J-point and was a minimum of ±0.1 mV in amplitude in the absence of LBBB, paced rhythms and left ventricular hypertrophy (LVH). All paced rhythms (atrial, ventricular or dual paced) were coded as paced. Ejection fraction was extrapolated from the last available echocardiogram

22. Method … Data from the AHS was collected when either the primary or secondary coding field indicated a diagnosis of HF using the International Classification of Disease (ICD) 10th coding (I50.x). The ICD codes were derived from the Ambulatory Care Classification system, which collects information on patients who visit an ED or hospital-based outpatient clinic in the province of Alberta, and the Discharge Abstract Database, which collects information on patients admitted to a hospital in Alberta. This approach to collecting administrative data has been shown to have a positive predictive value of 99%, sensitivity of 74%, and specificity of 53% when compared with the gold standard of clinical adjudication.

23. Method … Unless otherwise stated, SAS version 9.4 (SAS Institute Inc., NC, USA) was used for all analyses. Baseline characteristics were summarized using median [interquartile range (IQR)] for continuous variables and frequency (percent) for categorical variables. Percentages were calculated using the number of non-missing as the denominator. For the continuous covariates QRS, QTc and PR interval, they tested for non-linearity by including a quadratic term. The P-values to assess the degree of imbalance between groups of interest with respect to baseline characteristics were provided by the Wilcoxon rank-sum test (non-parametric continuous variables) and Fisher’s exact test (categorical variables).

24. Method … The primary outcome variable was time from presentation to ED to death (all-cause mortality). Up to 5-year survival data were available; surviving patients had their survival time censored at the time of analysis. Hypotheses of interest were the comparison of survival rates between groups defined by the ECG parameters. Cox’s proportional hazards models were used to adjust for those factors deemed clinically important and a priori from published risk models, namely: age, sex, respiratory rate, heart rate, systolic blood pressure, sodium, chronic obstructive pulmonary disease (COPD), diabetes and creatinine.

25. Method … The proportional hazards assumption was evaluated using a formal statistical test and visual inspection of the log-cumulative hazard plot. For the analysis of HF-related hospital readmissions,they estimated the cause specific hazard by including deaths as censored survival times. As recommended by Wolbers et al., the cumulative incidence function using the Fine & Gray approach in a supplementary analysis was also modelled.There was no imputation of missing data or adjustment for multiple testing given the hypothesis-generating nature of the analysis. A significance level of 0.05 was adopted as a guide for discerning differences between groups. The Health Research Ethics Board at the University of Alberta approved the study and all patients provided informed written informed consent.

26. Result.. Of 937 enrolled patients, 95 were excluded because the inde - pendent adjudicator deemed AHF unlikely and 26 were excluded because of missing ECGs leaving 816 (87%) patients with a confirmed diagnosis of AHF and an available ECG. The 26 patients without ECG data were similar in age, sex, and other key clinical variables to the 816 patients included. Of this cohort, 80 (9.8%) were managed solely in the ED, 713 (87.4%) were seen initially in the ED then admitted, and 23 (2.8%) were directly admitted to a hospital ward. Median follow-up time for all patients was 25.7 months (95% CI 24.8–27.3).

27. Result … Data from the initial assessment and investigations in the ED recorded a median age of 77 years, 46% were female, 52% had a history of atrial fibrillation and the median ejection fraction was 45% ,Median heart rate was 85 b.p.m.median systolic blood pressure was 134 mmHg,median BNP levels were 1081 pg/mL median creatinine was 108 μmol/L and median haemoglobin was 120 g/L.

28. Result … Based on core laboratory read ECG, 53% of patients were in sinus rhythm, 36% in atrial fibrillation and 10% were paced. A completely normal ECG was uncommon (7.5%), with other common abnormalities being ST-segment deviation ≥1 mm (21%), LVH (17%), bundle branch block (LBBB 13%; RBBB 8%) and the presence of Q-waves (12%). Median PR interval was 176 ms, median QRS duration was 106 ms and median QTc interval was 471 ms (IQR 444–500). Table demonstrates baseline characteristics of patients based on the presence or absence of a normal ECG at presentation.

29. For 185 (20%) patients the first available ECG was conducted by EMS and recorded electronically. A total of 687 (75%) were conducted in the ED and 46 (5%) following admission. Overall, there were few differences between ECGs collected from different sources. From ECGs collected from EMS sources, there was an increased prevalence of ECGs that met voltage criteria for LVH and a decreased prevalence of prolonged QTc. During the median follow-up of 25.7 months, there were 379 (46%) all-cause deaths and 328 (40%) hospital readmissions. When adjusting for age, sex, respiratory rate, heart rate, systolic blood pressure, history of COPD, diabetes, sodium and creatinine levels, the presence of sinus rhythm was associated with improved odds of survival.An abnormal ECG (HR 1.57, 95% CI 1.01, 2.44; Figure 2), a paced rhythm (HR 1.51, 95% CI 1.11, 2.05; and a prolonged QRS interval (HR 1.29, 95% CI 1.04, 1.59; ) were associated with decreased survival.

30. Result … . During the median follow-up of 25.7 months, there were 379 (46%) all-cause deaths and 328 (40%) hospital readmissions. When adjusting for age, sex, respiratory rate, heart rate, systolic blood pressure, history of COPD, diabetes, sodium and creatinine levels, the presence of sinus rhythm was associated with improved odds of survival. An abnormal ECG (HR 1.57, 95% CI 1.01, 2.44;), a paced rhythm (HR 1.51, 95% CI 1.11, 2.05; and a prolonged QRS interval (HR 1.29, 95% CI 1.04, 1.59; ) were associated with decreased survival.

31. Readmission rates were higher in the presence of paced rhythms (HR 1.54, 95% CI 1.10, 2.15), atrial fibrillation or flutter (HR 1.40, 95% CI 1.11, 1.77) and a prolonged QRS interval (HR 1.44, 95% CI 1.15, 1.81). In comparison, readmission rates were decreased among patients in sinus rhythm at the time of AHF presentation (HR 0.63, 95% CI 0.50, 0.78).

32. Discussion: The ECG is a routine investigation that is recommended in all patients with suspected AHF.Owing to its broad availability and speed by which results may be analyzed, the ECG is a diagnostic tool that physicians may use to risk stratify patients with suspected AHF. The present study supports and adds to previous studies with three key findings. -First, the study demonstrates that a normal ECG in patients with AHF is uncommon and is associated with better outcomes, consistent with previous studies in both acute and chronic HF populations.

33. Discussion … . Second, and divergent from studies of chronic HF, a wider QRS width was associated with worse outcomes while bundle branch block did not appear to be associated with worse outcomes. The reasons for this are unclear; however, the observation may result from the unique features of sample, such as the broad inclusion and generalizable population, detailed core laboratory reading, or unknown factors.

34. Discussion … Finally, the presence of atrial fibrillation on ECG does not appear to be an independent predictor of poor outcomes, which supports previous studies and the importance of the relative weight of atrial fibrillation in the context of other more powerful predictors of clinical outcomes.

35. In this prospective cohort, they found that there is a high prevalence of ECG abnormalities, with a normal ECG seen only in 7.5% of patients. This is higher than previously reported in studies of AHF, which report a normal ECG prevalence of 2%. Discrepancies between previous studies and the present study can be partly explained by the timing of the ECG capture. While the present study used the first available ECG, with the majority captured from EMS or the ED, previous studies have relied on the latest ECG before to the patient’s death or ECGs collected up to 15 days following admission.

36. Discussion … Subtle ECG changes may occur as a patient improves or deteriorates and this may alter the relationshipbetween an ECG and outcomes. A last ECG before death may also identify ECG changes unrelated to a patient’s initial presentation such as terminal arrhythmias or while advanced medical therapy is instituted.

37. Discussion … Previous studies have demonstrated that ECGs may have a role in predicting both short and long term outcomes. A combination of a prolonged QRS and a prolonged PR interval has been shown to be associated with an increased risk of in-hospital and post-discharge death, especially in patients with reduced ejection fractions. While other studies have identified that prolonged QRS is associated with both long and short-term outcomes, many studies suggest that both a wide QRS and LBBB are associated with only long-term outcomes and are not a predictor of short-term outcomes

38. . The present study adds to the evidence that sinus rhythm appears to be protective in both the short and long-term in patients with AHF, and consistent with studies of chronic HF. Our findings suggest that patients with HF who exhibit a widened QRS are at a higher risk of death or readmission. Patients with a broad QRS have been observed to have a higher rate of left ventricular dyssynchrony and a reduced left ventricular ejection fraction, and a higher rate of morbidity and mortality.

39. In the EHFS II (EuroHeart Failure Survey II) study, a statistically significant shorter QRS duration was observed among survivors at 1 year (100 ms ) compared with non-survivors (110 ms ) This is supported by the findings of AHEAD (Acute Heart Failure Database) registry, which found that an increased QRS duration was independently associated with increased inhospital mortality and long-term mortality. This is also seen in data from the KorHF (Korean Heart Failure) registry, where the presence of both a widened QRS (>120 ms) and a prolonged PR interval (>200 ms) was independently associated with in-hospital death, post-discharge death and rehospitalization .

40. Discussion Cont … .. The prevalence and effect of bundle branch blocks on morbidity and mortality is inconsistent in the AHF setting. The prevalence of LBBB among patients with HF has been reported as ranging from 8% to 31%, with variable effects of mortality. Prevalence of RBBB is more consistently reported as ranging from 7% to 14%, also with variable effects on mortality. While univariate analysis demonstrated a statistically significant association between the presence of RBBB and poor outcomes, when entered into a multivariate regression model it was found not to be an independent predictor of mortality.

41. Data from the present study would suggest that the presence of LBBB or RBBB should not be used as a prognostic marker. Mueller et al. while the presence of a LBBB may indicate left ventricular disease, it does not add any additional prognostic information because the majority of patients with AHF already have advanced left ventricular dysfunction. This would lead us to believe that the prognostic ability of ECG characteristics may be influenced by left ventricular ejection fraction. This is supported by the study of Lund et al., which demonstrates that a widened QRS was only predictive of mortality in subgroups of higher ejection fractions.

42. Discussion Contd … . The prevalence of atrial fibrillation in the present study was 36%, which is comparable to other studies that report a prevalence ranging between 22% and 37%. The present study suggests that while atrial fibrillation is associated with rehospitalization , it is not an independent predictor of mortality. In the chronic HF population a meta-analysis of 53 969 patients demonstrated that the presence of atrial fibrillation was associated with increased mortality in both observational studies and clinical trials, which is supported by data from the large CHARM ( Candesartan in Heart failure - Assessment of moRtality and Morbidity) study.

43. Summery: The present study demonstrates that the presence of a normal ECG and sinus rhythm in patients with HF is associated with increased survival, while the presence of a widened QRS, and paced rhythm are associated with decreased survival. When used in conjunction with data from a clinical examination and laboratory results, identification of these characteristics may allow clinicians to risk stratify patients with HF and appropriately adjust their management.

44. When used in conjunction with data from a clinical examination and laboratory results, identification of these characteristics may allow clinicians to risk stratify patients with HF and appropriately adjust their management. Further studies are needed to determine if the addition of these variables can improve the prognostic ability of HF risk models.

45. Thank You All