Predictors of Outcomes in Myocardial Infarction and Cardiogenic Shock

MiR-144-3p Enhances Cardiac Fibrosis After Myocardial Infarction by Targeting PTEN

Myocardial infarction (MI) may cause heart failure and seriously harm human health. During the genesis of cardiac fibrosis after MI, the proliferation and migration of cardiac fibroblasts contribute to secretion and maintenance of extracellular matrix (ECM) components. Many miRNAs have been highly implicated in the processes of cardiac fibrosis after MI. However, the molecular mechanisms for how miRNAs involve in cardiac fibrosis remain largely unexplored. Based on MI model in miniature pigs, the potential miRNAs involved in MI were identified by using small RNA sequencing. Using human cardiac fibroblasts (HCFs) as a cellular model, EdU, Transwell, and the expression of ECM-related proteins were applied to investigate the cell proliferation, migration and collagen synthesis. In this study, using MI model based on miniature pigs, 84 miRNAs were identified as the differentially expressed miRNAs between MI and control group, and miR-144-3p, one of differentially expressed miRNAs, was identified to be higher expressed in infarct area. The cell proliferation, migration activity, and the mRNA and protein levels of the ECM-related genes were significantly increased by miR-144-3p mimic but significantly decreased by miR-144-3p inhibitor in cardiac fibroblasts. Furthermore, miR-144-3p was observed to repress transcription and translation of PTEN, and interfering with the expression of PTEN up-regulated the mRNAs and proteins levels of α-SMA, Col1A1, and Col3A1, and promoted the proliferation and migration of cardiac fibroblasts, which was in line with that of miR-144-3p mimics, but this observation could be reversed by miR-144-3p inhibitor. Collectively, miR-144-3p promotes cell proliferation, migration, and collagen production by targeting PTEN in cardiac fibroblasts, suggesting that miR-144-3p-mediated-PTEN regulation might be a novel therapeutic target for cardiac fibrosis after MI.

Malignant Arrhythmias During Induction of Target Temperature Management After Cardiac Arrest

The aim of this study was to evaluate the incidence and determinants of malignant arrhythmias (MA) in patients with shock following out-of-hospital cardiac arrest (OHCA) treated with targeted temperature management. Risk factors for the development of MA were prospectively analyzed in patients after OHCA. MA were defined as ventricular tachycardia or fibrillation with a duration >30 seconds, which had to be terminated by defibrillation. All patients were treated with therapeutic hypothermia for 24 hours. Demographics, OHCA details, interventions, and intensive care unit (ICU) treatment were recorded. A total of 55 patients were included, 11 (20%) of whom developed MA during the ICU stay. All MA occurred within the first 18 hours after admission. Patients who developed MA showed a stronger decrease in body temperature (Δ -2.4°C ± 0.8°C vs. Δ -1.3°C ± 1.3°C; p = 0.016) and in serum potassium levels (Δ -0.9 ± 1 mmol/L vs. Δ -0.3 ± 0.6 mmol/L; p = 0.037) during the cooling period compared with patients without MA. In the multivariable analysis, fast temperature decline as well as lower potassium levels were associated with MA. In addition, higher number of shocks during resuscitation and higher ICU epinephrine use were independent predictors of MA in patients with OHCA. The use of epinephrine as well as hypokalemia in context with intense cooling may increase the incidence of MA in patients with shock after cardiac arrest. Therefore, these therapeutic strategies should be applied with caution in this vulnerable group of patients.

Clinical characteristics and outcome in patients with a delayed presentation after ST-elevation myocardial infarction and complicated by cardiogenic shock

OBJECTIVE

Delayed presentation after ST-elevation myocardial infarction (STEMI) and complicated by cardiogenic shock (CS-STEMI) is commonly encountered in developing countries and is a challenging scenario because of a delay in revascularization resulting in infarction of a large amount of the myocardium. We aimed to assess the clinical characteristics, angiographic profile, and predictors of outcome in patients with a delayed presentation after CS-STEMI.

METHODS

A total of 147 patients with CS-STEMI with time to appropriate medical care ≥12 h after symptom onset were prospectively recruited at a tertiary referral center.

RESULTS

The median time to appropriate care was 24 h (interquartile range 18-48 h). The mean age was 58.7 ± 11.1 years. Left ventricular pump failure was the leading cause of shock (67.3%), whereas mechanical complications accounted for 14.9% and right ventricular infarction for 13.6% of cases. The overall in-hospital mortality was 42.9%. Acute kidney injury [Odds ratio (OR) 8.04; 95% confidence intervals (CI) 3.08-20.92], ventricular tachycardia (OR 7.04; CI 2.09-23.63), mechanical complications (OR 6.46; CI 1.80-23.13), and anterior infarction (OR 3.18; CI 1.01-9.97) were independently associated with an increased risk of mortality. Coronary angiogram (56.5%) revealed single-vessel disease (45.8%) as the most common finding. Percutaneous coronary intervention was performed in 53 patients (36%), at a median of 36 h (interquartile range 30-72) after symptom onset.

CONCLUSION

Patients with a delayed presentation after CS-STEMI were younger and more likely to have single-vessel disease. We found a high in-hospital mortality of 42.9%. Appropriate randomized studies are required to evaluate the optimal treatment strategies in these patients.