Unruptured Left Ventricular Pseudoaneurysm After Silent Myocardial Infarction with Mitral Valve Regurgitation

Acquired left ventricular pseudoaneurysm is a rare disorder that occurs after acute myocardial infarction. We present a 55 year-old male patient with a nonruptured pseudoaneurysm after acute MI presenting with severe mitral regurgitation. After resection of sac-like lesion, the defect was 5 cm diameter posterolaterally left ventricular. The aneursym was repaired with pericardium patch to maintain cardiac geometry that diminishes mitral regurgitation without intervention to mitral valve.

SILENT MYOCARDIAL INFARCTION

The aim of the study was to analyze the available publications on silent myocardial infarction.

Abstract 58: Silent Myocardial Infarction and Subsequent Ischemic Stroke in the Cardiovascular Health Study

Background: Whether silent myocardial infarction (MI) is a risk factor for ischemic stroke remains uncertain. Hypothesis: Silent MI is associated with incident ischemic stroke. Methods: The Cardiovascular Health Study prospectively enrolled community-dwelling individuals ≥65 years of age with follow-up through June 30, 2015. For this study, we included participants from the first study cohort (enrolled in 1989-1990) without prevalent stroke or baseline electrocardiographic (ECG) evidence of MI. Our exposures were silent and clinically apparent MI. Silent MI was defined as new evidence of Q-wave MI, without clinical symptoms of MI, on ECGs performed during annual study visits from 1989-1999. Clinically apparent (overt) MI was adjudicated on the basis of information about chest pain, ECG changes, and cardiac enzymes. The primary outcome was incident ischemic stroke. Secondary outcomes were ischemic stroke subtypes: non-lacunar, lacunar, and other/unknown. Cox proportional hazards analysis was used to model the association between time-varying MI status (silent, overt, or no MI) and stroke after adjustment for baseline demographics and vascular risk factors. Due to a violation of the proportional hazards assumption, the association between overt MI and stroke was modeled separately for short-term (within 30 days) and long-term (beyond 30 days) risk. Results: Among 4,224 participants included in this analysis, 362 (8.6%) had an incident silent MI, 421 (10.0%) an incident overt MI, and 377 (8.9%) an incident ischemic stroke during a median follow-up of 9.8 years. After adjustment for demographics and comorbidities, silent MI was independently associated with subsequent ischemic stroke (HR, 1.47; 95% CI, 1.01-2.16). Overt MI was associated with ischemic stroke both in the short term (HR, 80; 95% CI, 53-119) and long term (HR, 1.60; 95% CI, 1.04-2.44). In secondary analyses, the association between silent MI and stroke was limited to non-lacunar ischemic stroke (HR 2.18; 95% CI, 1.24-3.83). Conclusions: In a community-based sample, we found an association between silent MI and ischemic stroke, specifically non-lacunar stroke. These findings suggest that silent MI may be a novel risk factor for ischemic stroke.

Association Between Silent Myocardial Infarction and Long‐Term Risk of Sudden Cardiac Death

Background Although silent myocardial infarction (SMI) is prognostically important, the risk of sudden cardiac death (SCD) among patients with incident SMI is not well established. Methods and Results We examined 2 community‐based cohorts: the ARIC (Atherosclerosis Risk in Communities) study (n=13 725) and the CHS (Cardiovascular Health Study) (n=5207). Incident SMI was defined as electrocardiographic evidence of new myocardial infarction during follow‐up visits that was not present at the baseline. The primary study end point was physician‐adjudicated SCD. In the ARIC study, 513 SMIs, 441 clinically recognized myocardial infarctions (CMIs), and 527 SCD events occurred during a median follow‐up of 25.4 years. The multivariable hazard ratios of SMI and CMI for SCD were 5.20 (95% CI, 3.81–7.10) and 3.80 (95% CI, 2.76–5.23), respectively. In the CHS, 1070 SMIs, 632 CMIs, and 526 SCD events occurred during a median follow‐up of 12.1 years. The multivariable hazard ratios of SMI and CMI for SCD were 1.70 (95% CI, 1.32–2.19) and 4.08 (95% CI, 3.29–5.06), respectively. The pooled hazard ratios of SMI and CMI for SCD were 2.65 (2.18–3.23) and 3.99 (3.34–4.77), respectively. The risk of SCD associated with SMI is stronger with White individuals, men, and younger age. The population‐attributable fraction of SCD was 11.1% for SMI, and SMI was associated with an absolute risk increase of 8.9 SCDs per 1000 person‐years. Addition of SMI significantly improved the predictive power for both SCD and non‐SCD. Conclusions Incident SMI is independently associated with an increased risk of SCD in the general population. Additional research should address screening for SMI and the role of standard post–myocardial infarction therapy.

Abstract 13196: The Utility of Silent Myocardial Infarction on Electrocardiogram as an ASCVD Risk Enhancer for Primary Prevention: The Multi-Ethnic Study of Atherosclerosis

Introduction: The 2018 AHA/ACC cholesterol guidelines introduced a new list of markers called “risk enhancers” that, if present, confer an increased risk of atherosclerotic cardiovascular disease (ASCVD). Notably absent is silent myocardial infarction (SMI) on electrocardiogram (ECG), even though SMI has been shown to be associated with future ASCVD. Hypothesis: Adding SMI to the pooled cohort equation (PCE) will improve risk discrimination and classification in those with intermediate ASCVD risk (5 - 20% 10-year risk). Methods: SMI was defined as a major Q-wave abnormality or minor Q/QS waves in the setting of major ST-T abnormalities in the absence of history of clinical cardiovascular disease. Incident ASCVD events included myocardial infarction, coronary heart disease death, and fatal and non-fatal stroke. Results: Among 2,278 intermediate-risk MESA participants, 48 (2.1%) had SMI at baseline. Over 32,150 person-years (median 15.8), incident ASCVD events occurred in 297/2,230 (13%) of those without SMI and 13/48 (27%) of those with SMI. In a Cox proportional hazards model that was adjusted for calculated 10-year ASCVD risk based on the PCE, SMI was associated with increased risk of ASCVD (HR 2.22, 95% CI 1.27 - 3.87, p = 0.005). Adding SMI to the PCE did not improve discrimination, with areas under the receiver operating characteristic curves for models without and with SMI of 0.5812 and 0.5874, respectively (p-value for difference 0.22; Figure 1a). The net reclassification improvement for adding SMI as a risk enhancer to reclassify participants from intermediate-risk to high-risk was 0.0242 (95% CI 0.0011 - 0.0472, p = 0.04; Figure 1b). Conclusions: Our findings suggest that the prevalence of SMI is 2.1% among those without known clinical cardiovascular disease considered intermediate-risk by the pooled cohort equation. In our analysis, SMI only modestly improved classification of risk, suggesting that it may not be very useful as an ASCVD risk enhancer.