Clinical paperOutcomes for patients with anterior myocardial infarction and prior cardiac arrest in the home automated external defibrillator trial (HAT)
Introduction
There are conflicting data on the risk of mortality in patients with a history of sudden cardiac arrest (SCA) due to an arrhythmic event during the acute phase of a myocardial infarction (MI).1., 2., 3. Analyses of most ACS trials of primary PCI have focused on sustained VT/VF occurring around the time of PCI and have mostly ffound similar or reduced survival compared MI patients without arrhythmia.1., 3., 4. A few single center studies have examined long-term outcomes of OHCA and MI, but mostly in comparison with OHCA due to other causes. 5., 18. Limited data from prospective multicenter clinical trials describe long-term outcomes and subsequent need for ICD therapy in MI populations with prior concurrent SCA (MI-SCA) compared with MI patients without SCA (MI-no SCA).
Accordingly, we analyzed the Home Automated External Defibrillator Trial (HAT) data to: 1) examine baseline characteristics for MI-SCA and MI-no SCA patients, 2) compare the long-term outcomes between the two groups and 3) evaluate whether prior MI-SCA increased mortality and SCD risk after subsequent events.3 The HAT study tested whether an automated external defibrillator (AED) in the home of patients at intermediate risk of sudden cardiac arrest could improve survival. HAT was ideal for this analysis given enrollment of anterior MI patients and 10% of the enrolled cohort had an index sudden cardiac arrest in the setting of their anterior MI before trial enrollment. This study examined outcomes of 1) all-cause mortality, 2) sudden cardiac death, 3) sudden cardiac arrest after trial enrollment and examined the impact of myocardial infarction, repeat revascularization, syncope and ICD implantation after trial enrollment on the study outcomes.
Section snippets
Study population
The design and primary results of the HAT trial have been published previously.6 Briefly, the HAT trial enrolled 7001 patients with anterior wall Q-wave or non Q-wave myocardial infarction (MI), due to presumed increased risk for SCA, between 2003 and 2005. The qualifying MI could have occurred at any point before trial enrollment; the median from MI to enrollment was 22 months. Myocardial infarction with concurrent SCA was defined as development of ventricular fibrillation or cardiac arrest
Patient characteristics
Baseline characteristics of patients with anterior myocardial infarction and concurrent sudden cardiac arrest vs. no sudden cardiac arrest is shown in Table 1, Table 2, Table 3. Patients with MI-SCA prior to HAT trial enrollment were younger (59% vs. 62%, p < 0.0001), more frequently white (91% vs. 88%, p = 0.02), more likely to have Q wave MI (73% vs. 64%, p < 0.0001), and had a higher rate of PCI (61% vs. 53%, p < 0.0001) compared with MI-no SCA. Patients with prior MI-SCA were also less
Discussion
In this retrospective analysis of HAT data, we observed a lower unadjusted risk of death for MI-SCA compared with MI-no SCA patients at each follow-up period; however, no difference in all-cause mortality was observed after adjustment. There was a higher unadjusted risk of SCD in the first two years after trial enrollment; however, there were no differences in unadjusted and adjusted outcomes at 4 years of follow-up. Though event numbers were small, patients with MI-SCA appeared to experience a
Limitations
First, our analysis is observational in nature and cannot prove causation. Second, our original question for this analysis centered around whether long-prognosis is worsened for patients who have SCA around the time of their MI and survive the index event. While we believe the HAT dataset analysis remains the most ideal database to explore this question, one major inherent limitation of HAT is the timing of enrollment in the trial- >50% of enrolled patients were more than 1 year from their
Conclusion
In conclusion, we found that MI-SCA patients had lower risk of unadjusted all-cause mortality at 4 years of follow-up compared with MI no-SCA but no risk difference after adjustment. Within the first two years, MI-SCA patients had higher unadjusted risk of recurrent SCA and SCD, but the risk equalized between the two groups at 4 years. After syncope, recurrent MI, or revascularization, MI-SCA and MI-no SCA patients had similar mortality risk. After ICD implantation, MI-SCA patients may be at
CRediT authorship contribution statement
Monique Anderson Starks: Conceptualization, Methodology, Writing – original draft, Visualization, Funding acquisition. Larry R. Jackson: Conceptualization, Writing – original draft, Visualization. Anne Hellkamp: Conceptualization, Methodology, Validation, Formal analysis, Software, Writing – review & editing, Data curation. Sana M. Al-Khatib: Conceptualization, Writing – review & editing. Daniel Mark: Conceptualization, Writing – review & editing, Methodology, Supervision. Kevin L. Thomas:
Acknowledgments
Our study team would like to thank Dr. Eric Peterson for initially assisting with the design on our manuscript analysis and in part, funding our analysis.
Sources of Funding
The HAT trial was supported by a grant (U01-HL067972) from the National Heart, Lung, and Blood Institute. This analysis was internally funded at the Duke Clinical Research Institute.
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Cited by (1)
Resuscitation highlights in 2021
2022, ResuscitationCitation Excerpt :Patients with sudden cardiac arrest in the acute phase of myocardial infarction (MI-SCA) are believed to be at similar risk of death after revascularization compared with MI patients without SCA (MI-no SCA). In an analysis of the home automated external defibrillator trial (HAT), outcomes of patients with anterior MI and prior cardiac arrest were examined to determine whether they were at greater risk of all-cause mortality or sudden cardiac death (SCD) than MI-no SCA patients.15 Of 6,849 patients, 650 (9.5%) had MI-SCA before trial enrolment.