Incidence and risk factors of ventricular fibrillation before primary angioplasty in patients with first ST-elevation myocardial infarction: a nationwide study in Denmark

[Patients hospitalized in the ICU for acute coronary syndrome from 2012 to 2021: A single-center retrospective study]

INTRODUCTION

Acute Coronary Syndrome (ACS) are one of the main causes of mortality in France. Patients presenting with ACS are typically hospitalized in a specialized cardiology ward. The main objective of this study was to describe, characterize and evaluate the outcome of patients hospitalized for ACS in a generalist intensive care unit (rather than a cardiac care unit).

METHODS

This was a retrospective study. Our population consisted of ACS patients admitted to an intensive care unit in a hospital center (Centre Hospitalier de Troyes) between 2012 and 2021. All patients admitted for ACS to the intensive care unit and who underwent coronary angiography were included.

RESULTS

In 10 years, 104 patients, or 3.8% of ACS patients who underwent coronary angiography were admitted to intensive care. The majority were admitted after recovered cardiac arrest (72%) and were in cardiogenic shock (68%), accounting for a high in-hospital mortality (45.2%). In-hospital mortality was 45.2%. In multivariate analysis, the GRACE score was associated with in-hospital mortality (OR for each additional point = 1.024, 95% confidence interval 1.006-1.045, p = 0.01). Among the survivors, 88% had good neurological function when leaving the hospital.

DISCUSSION

Mortality of ACS patients in intensive care was close to 50%. However, the neurological prognosis of the surviving patients was good. This population is rarely mentioned in the literature, and deserves to be evaluated by multicenter, prospective registries, with a view to improving management and prognosis.

Alcohol is neither a risk factor nor a protective factor for sudden cardiac death and/or fatal ventricular arrhythmia: A population-based study with genetic traits and alcohol consumption in the UK Biobank

BACKGROUND

The association between alcohol consumption and the risk of sudden cardiac death and/or fatal ventricular arrhythmia remains controversial.

OBJECTIVE

We analyzed the association between alcohol consumption, genetic traits for alcohol metabolism, and the risk of sudden cardiac death and/or fatal ventricular arrhythmia.

METHODS

We identified 397,164 individuals enrolled between 2006 and 2010 from the UK Biobank database and followed them until 2021. Alcohol consumption was categorized as current nondrinkers (nondrinkers and ex-drinkers), mild drinkers, moderate drinkers, or heavy drinkers. Genetic traits of alcohol metabolism were stratified according to the polygenic risk score tertiles. The primary and secondary outcomes were a composite of sudden cardiac death and fatal ventricular arrhythmia as well as their individual components.

RESULTS

During follow-up (median 12.5 years), 3543 cases (0.89%) of clinical outcomes occurred. Although mild, moderate, and heavy drinkers showed deceased risks of outcomes compared with current nondrinkers, there was no prognostic difference among nondrinkers, mild drinkers, moderate drinkers, and heavy drinkers. Ex-drinkers showed an increased risk in univariate analysis, but the significance was attenuated after adjusting covariates (hazard ratio 1.19; 95% confidence interval 0.94-1.50). As a continuous variable, alcohol consumption was not associated with clinical outcomes (hazard ratio 1.01; 95% confidence interval 0.99-1.02). Consistent with these findings, there was no association between genetic traits for alcohol metabolism and the risk of clinical outcomes.

CONCLUSION

Alcohol consumption was neither a protective factor nor a risk factor for sudden cardiac death or fatal ventricular arrhythmia. Genetic traits of alcohol metabolism were not associated with the clinical prognosis.

Discovery of plasma proteins associated with ventricular fibrillation during first ST-elevation myocardial infarction via proteomics

AIMS

The underlying biological mechanisms of ventricular fibrillation (VF) during acute myocardial infarction are largely unknown. To our knowledge, this is the first proteomic study for this trait, with the aim to identify and characterize proteins that are associated with VF during first ST-elevation myocardial infarction (STEMI).

METHODS AND RESULTS

We included 230 participants from a Danish ongoing case-control study on patients with first STEMI with VF (case, n = 110) and without VF (control, n = 120) before guided catheter insertion for primary percutaneous coronary intervention. The plasma proteome was investigated using mass spectrometry-based proteomics on plasma samples collected within 24 h of symptom onset, and one patient was excluded in quality control. In 229 STEMI patients {72% men, median age 62 years [interquartile range (IQR): 54-70]}, a median of 257 proteins (IQR: 244-281) were quantified per patient. A total of 26 proteins were associated with VF; these proteins were involved in several biological processes including blood coagulation, haemostasis, and immunity. After correcting for multiple testing, two up-regulated proteins remained significantly associated with VF, actin beta-like 2 [ACTBL2, fold change (FC) 2.25, P < 0.001, q = 0.023], and coagulation factor XIII-A (F13A1, FC 1.48, P < 0.001, q = 0.023). None of the proteins were correlated with anterior infarct location.

CONCLUSION

Ventricular fibrillation due to first STEMI was significantly associated with two up-regulated proteins (ACTBL2 and F13A1), suggesting that they may represent novel underlying molecular VF mechanisms. Further research is needed to determine whether these proteins are predictive biomarkers or acute phase response proteins to VF during acute ischaemia.

Role of low-density lipoprotein electronegativity and sexual dimorphism in contributing early ventricular tachyarrhythmias following ST-elevation myocardial infarction

Background

Early ventricular tachycardia/fibrillation (VT/VF) in patients with ST-elevation myocardial infarction (STEMI) has higher morbidity and mortality. This study examines gender-differentiated risk factors and underlying mechanisms for early onset VT/VF in STEMI.

Methods

We analyzed data from 2,964 consecutive STEMI patients between January 1, 2008 and December 31, 2021. Early VT/VF was defined as occurrence of spontaneous VT/VF of ≥30 s or requirement of immediate cardioversion/defibrillation within the first 48 h after symptoms. An ex vivo ischemic-reperfusion experiments were conducted in 8-week-old ApoE-/- mice fed a high-fat diet to explore the underlying mechanisms of early VT/VF.

Results

In 255 of out 2,964 STEMI patients who experienced early VT/VF, the age was younger (58.6 ± 13.8 vs. 61.0 ± 13.0 years old, P = 0.008) with a male predominance. The plasma levels of L5, the most electronegative subclass of low-density lipoprotein, was higher in early VT/VF patients compared to those without early VT/VF (n = 21, L5: 14.1 ± 22.6% vs. n = 46, L5: 4.3 ± 9.9%, P = 0.016). In the experimental setup, all male mice (n = 4) developed VT/VF post sham operation, whereas no such incidence was observed in the female mice (n = 3). Significantly, male mice exhibited considerably slower cardiac conduction velocity as compared to their female counterparts in whole heart preparations (25.01 ± 0.93 cm/s vs.42.32 ± 5.70 cm/s, P < 0.001), despite analogous action potential durations. Furthermore, isolated ventricular myocytes from male mice showed a distinctly lower sodium current density (-29.20 ± 3.04 pA/pF, n = 6) in comparison to female mice (-114.05 ± 6.41 pA/pF, n = 6, P < 0.001). This decreased sodium current density was paralleled by a reduced membrane expression of Nav1.5 protein (0.38 ± 0.06 vs. 0.89 ± 0.09 A.U., P < 0.001) and increased cytosolic Nav1.5 levels (0.59 ± 0.06 vs. 0.29 ± 0.04 A.U., P = 0.001) in male mice. Furthermore, it was observed that the overall expressions of sorting nexin 27 (SNX27) and vacuolar protein sorting 26 (VPS26) were significantly diminished in male mice as compared to female littermates (0.91 ± 0.15 vs. 1.70 ± 0.28, P = 0.02 and 0.74 ± 0.09 vs. 1.57 ± 0.13, P < 0.01, respectively).

Conclusions

Our findings reveal that male STEMI patients with early VT/VF are associated with elevated L5 levels. The gender-based discrepancy in early VT/VF predisposition might be due to compromised sodium channel trafficking, possibly linked with increased LDL electronegativity.

Clinical and angiographic characteristics of out-of-hospital cardiac arrest among patients with ST-segment elevation myocardial infarction

BACKGROUND

Out-of-hospital cardiac arrest (OHCA) is the most severe complication of ST-segment elevation myocardial infarction (STEMI). Nevertheless, clinical and angiographic characteristics associated with OHCA among patients with STEMI have not been studied extensively.

AIM

To evaluate the clinical and angiographic characteristics of consecutive patients who presented with STEMI associated or not with OHCA.

METHODS

This was an observational study including consecutive patients treated for STEMI associated or not with OHCA. Baseline clinical and angiographic characteristics, biological characteristics and mortality were compared between patients with STEMI who experienced OHCA and patients with STEMI who did not.

RESULTS

Among the 686 included patients with STEMI, 148 (21.6%) presented with concomitant OHCA. Multivariable analysis revealed that culprit lesion localized on the left system (odds ratio [OR] 1.94, 95% confidence interval [CI] 1.24-3.13; P<0.01), culprit lesion at the level of a bifurcation lesion (OR 1.87, 95% CI 1.21-2.88; P<0.01) and the presence of chronic total occlusion on another artery (OR 3.39, 95% CI 1.93-5.99; P<0.001) were associated with the occurrence of OHCA, whereas dyslipidaemia, familial history of coronary artery disease and hypertension were found to be negatively associated with the occurrence of OHCA in patients with STEMI: OR 0.47, 95% CI 0.29-0.75 (P<0.01); OR 0.09, 95% CI 0.02-0.25 (P<0.001); and OR 0.60, 95% CI 0.38-0.93 (P=0.02), respectively.

CONCLUSION

In this study of consecutive patients with STEMI, culprit lesion localized on the left system, culprit lesion at the level of a bifurcation lesion and the presence of chronic total occlusion on a non-culprit artery were associated with OHCA.

Pre-hospital pulse glucocorticoid therapy in patients with ST-segment elevation myocardial infarction transferred for primary percutaneous coronary intervention: a randomized controlled trial (PULSE-MI)

BACKGROUND

Inflammation in ST-segment elevation myocardial infarction (STEMI) is an important contributor to both acute myocardial ischemia and reperfusion injury after primary percutaneous coronary intervention (PCI). Methylprednisolone is a glucocorticoid with potent anti-inflammatory properties with an acute effect and is used as an effective and safe treatment of a wide range of acute diseases. The trial aims to investigate the cardioprotective effects of pulse-dose methylprednisolone administered in the pre-hospital setting in patients with STEMI transferred for primary PCI.

METHODS

This trial is a randomized, blinded, placebo-controlled prospective clinical phase II trial. Inclusion will continue until 378 patients with STEMI have been evaluated for the primary endpoint. Patients will be randomized 1:1 to a bolus of 250 mg methylprednisolone intravenous or matching placebo over a period of 5 min in the pre-hospital setting. All patients with STEMI transferred for primary PCI at Rigshospitalet, Copenhagen University Hospital, Denmark, will be screened for eligibility. The main eligibility criteria are age ≥ 18 years, acute onset of chest pain with < 12 h duration, STEMI on electrocardiogram, no known allergy to glucocorticoids or no previous coronary artery bypass grafting, previous acute myocardial infarction in assumed culprit, or a history with previous maniac/psychotic episodes. Primary outcome is final infarct size measured by late gadolinium enhancement on cardiac magnetic resonance (CMR) 3 months after STEMI. Secondary outcomes comprise key CMR efficacy parameters, clinical endpoints at 3 months, the peak of cardiac biomarkers, and safety.

DISCUSSION

We hypothesize that pulse-dose methylprednisolone administrated in the pre-hospital setting decreases inflammation and thus reduces final infarct size in patients with STEMI treated with primary PCI.

TRIAL REGISTRATION

EU-CT number: 2022-500762-10-00; Submitted May 5, 2022.

CLINICALTRIALS

gov Identifier: NCT05462730; Submitted July 7, 2022, first posted July 18, 2022.

Episode of ventricular fibrillation in patient with coronary artery ectasia during coronary angiography

There was an 83-year-old man having coronary artery disease associated with coronary artery ectasia who occurred ventricular fibrillation suddenly during coronary artery angiography. As Kawasaki disease was suspected to the most likely reason which led to coronary artery lesion.

Early prediction of ventricular fibrillation using electrocardiographic characteristics in prehospital suspected ST-segment elevation myocardial infarction: a case-control study

PURPOSE

Our objective was to determine characteristics of electrocardiograms (ECG) that predict ventricular fibrillation (VF) among prehospital patients with suspected ST-segment elevation myocardial infarction (STEMI) in Québec.

METHODS

We performed a matched case-control study of prehospital adult suspected with STEMI. Patients in case group (STEMI/VF+) were matched with controls (STEMI/VF-) for age and sex and then compared for ECG characteristics, including ST-segment elevations (STE) and depressions (STD), duration of interval complexes, general characteristics, and several calculated variables. Logistic regression was used to measure the association between ECG characteristics and VF development.

RESULTS

Overall, 310 prehospital patients with suspected STEMI were included in the analysis (case group, n = 155; control group, n = 155). We confirmed that the presence of TW-pattern complex (OR 7.0, 95% CI 1.55-31.58), premature ventricular contraction (PVC) (OR 5.5, 95% CI 2.04-14.82), and STE in V2-V6 (OR 3.8, 95% CI 1.21-11.74) were electrocardiographic predictors of VF. We also observed that STD in V3-V5 (OR 6.5, 95% CI 1.42-29.39), atrial fibrillation (AF) ≥ 100 beats per minute (bpm) (OR 6.3, 95% CI 1.80-21.90), the combination of STE in V4 and V5, and STD in II, III and aVF (OR 4.8, 95% CI 1.01-22.35), and the presence of STD in ≥ 6 leads (OR 4.2, 95% CI 1.33-13.13) were also associated with VF development. Finally, simultaneous association of 2 (OR 2.3, 95% CI 1.13-4.06) and 3 (OR 11.6, 95% CI 3.22-41.66) predictors showed significant association with VF.

CONCLUSIONS

In addition to some already known predictors, we have identified several ECG findings associated with the development of VF in patients with suspected STEMI. Early identification of patients with STEMI at increased risk of VF should help EMS providers anticipate adverse events and encourage use of defibrillation pads.

Risk stratification of sudden cardiac death: a review

Sudden cardiac death (SCD) is responsible for several millions of deaths every year and remains a major health problem. To reduce this burden, diagnosing and identification of high-risk individuals and disease-specific risk stratification are essential. Treatment strategies include treatment of the underlying disease with lifestyle advice and drugs and decisions to implant a primary prevention implantable cardioverter-defibrillator (ICD) and perform ablation of the ventricles and novel treatment modalities such as left cardiac sympathetic denervation in rare specific primary electric diseases such as long QT syndrome and catecholaminergic polymorphic ventricular tachycardia. This review summarizes the current knowledge on SCD risk according to underlying heart disease and discusses the future of SCD prevention.

Development and Validation of Nomogram for the Prediction of Malignant Ventricular Arrhythmia Including Circulating Inflammatory Cells in Patients with Acute ST-Segment Elevation Myocardial Infarction

Background

Malignant ventricular arrhythmia (MVA) can seriously affect the hemodynamic changes of the body. In this study, we developed and validated a nomogram to predict the in-hospital MVA risk in patients with STEMI after emergency PCI.

Methods

The multivariable logistic regression analysis included variables with a P<0.05 in the univariate logistic regression analysis and investigated the independent predictors affecting in-hospital MVA after PCI in patients with STEMI in the training cohort. The construction of a nomogram model used independent predictors to predict the risk of in-hospital MVA, and C-index, Hosmer-Lemeshow (HL) test, calibration curves, decision curve analysis (DCA), and receiver operating characteristic (ROC) were used to validate the nomogram.

Results

Killip class [OR=5.034 (95% CI: 1.596-15.809), P=0.005], CK-MB [OR=1.002 (95% CI: 1.001-1.004), P=0.022], serum potassium [OR=0.618 (95% CI: 0.406-0.918), P=0.020], NLR [OR=1.073 (95% CI: 1.034-1.115), P<0.001], and monocyte [OR=1.974 (95% CI: 1.376-2.925), P<0.001] were the independent predictors of in-hospital MVA after PCI in patients with STEMI. A nomogram including the 5 independent predictors was developed to predict the risk of in-hospital MVA. The C-index, equivalent to the area under the ROC curve (AUC), was 0.803 (95% confidence interval [CI]: 0.738-0.868) in the training cohort, and 0.801 (95% CI:0.692-0.911) in the validation cohort, showing that the nomogram had a good discrimination. The HL test (χ²=8.439, P=0.392 in the training cohort; χ²=9.730, P=0.285 in the validation cohort) revealed a good calibration. The DCA suggested an obvious clinical net benefit.

Conclusion

Killip class, CK-MB, serum potassium, NLR, and monocyte were independent factors for in-hospital MVA after PCI in patients with STEMI. The nomogram model constructed based on the above factors to predict the risk of in-hospital MVA had satisfactory discrimination, calibration, and clinical effectiveness, and was an excellent tool for early prediction of the risk of in-hospital MVA after PCI in patients with STEMI.

Characteristics and predictors of out-of-hospital cardiac arrest in young adults hospitalized with acute coronary syndrome: A retrospective cohort study of 30,000 patients in the Gulf region

INTRODUCTION

The characteristics of young adults with out-of-hospital cardiac arrest (OHCA) due to acute coronary syndrome (ACS) has not been well described. The mean age of gulf citizens in ACS registries is 10-15 years younger than their western counterparts, which provided us with a unique opportunity to investigate the characteristics and predictors of OHCA in young adults presenting with ACS.

METHODOLOGY

This was a retrospective cohort study using data from 7 prospective ACS registries in the Gulf region. In brief, all registries included consecutive adults who were admitted with ACS. OHCA was defined as cardiac arrest upon presentation (i.e., before admission to the hospital). We described the characteristics of young adults (< 50 years) who had OHCA and performed multivariate logistic regression analysis to assess independent predictors of OHCA.

RESULTS

A total of 31,620 ACS patients were included in the study. There were 611 (1.93%) OHCA cases in the whole cohort [188/10,848 (1.73%) in young adults vs 423/20,772 (2.04%) in older adults, p = 0.06]. Young adults were predominantly males presenting with ST-elevation myocardial infarction (STEMI) [182/188 (96.8%) and 172/188 (91.49%), respectively]. OHCA was the sentinel event of coronary artery disease (CAD) in 70% of young adults. STEMI, male sex, and non-smoking status were found to be independent predictors of OHCA [OR = 5.862 (95% CI 2.623-13.096), OR: 4.515 (95% CI 1.085-18.786), and OR = 2.27 (95% CI 1.335-3.86), respectively].

CONCLUSION

We observed a lower prevalence of OHCA in ACS patients in our region as compared to previous literature from other regions. Moreover, OHCA was the sentinel event of CAD in the majority of young adults, who were predominantly males with STEMIs. These findings should help risk-stratify patients with ACS and inform further research into the characteristics of OHCA in young adults.

Pre-percutaneous coronary intervention sudden cardiac arrest in ST-elevation myocardial infarction: Incidence, predictors, and related outcomes

Background

ST-segment elevation myocardial infarction (STEMI) is a frequent cause of sudden cardiac arrest (SCA) and early percutaneous coronary intervention (PCI) is associated with increased survival. Despite constant improvements in SCA management, survival remains poor. We aimed to assess pre-PCI SCA incidence and related outcomes in patients admitted with STEMI.

Methods

This was a prospective cohort study of patients admitted with STEMI in a tertiary university hospital over 11  years. All patients were submitted to emergency coronary angiography. Baseline characteristics, details of the procedure, reperfusion strategies, and adverse outcomes were assessed. The primary outcome was in-hospital mortality. The secondary outcome was 1-year mortality after hospital discharge. Predictors of pre-PCI SCA was also assessed.

Results

During the study period 1,493 patients were included; the mean age was 61.1 years (±12), and 65.3% were male. Pre-PCI SCA was present in 133 (8.9%) patients. In-hospital mortality was higher in the pre-PCI SCA group (36.8% vs. 8.8%, p < 0.0001). In multivariate analysis, anterior MI, cardiogenic shock, age, pre-PCI SCA and lower ejection fraction remained significantly associated with in-hospital mortality. When we analyzed the interaction between pre-PCI SCA and cardiogenic shock upon admission there is a further increase in mortality risk when both conditions are present. For predictors of pre-PCI SCA, only younger age and cardiogenic shock remained significantly associated after multivariate analysis. Overall 1-year mortality rates were similar between pre-PCI SCA survivors and non-pre-PCI SCA group.

Conclusion

In a cohort of consecutive patients admitted with STEMI, pre-PCI SCA was associated with higher in-hospital mortality, and its association with cardiogenic shock further increases mortality risk. However, long-term mortality among pre-PCI SCA survivors was similar to non-SCA patients. Understanding characteristics associated with pre-PCI SCA may help to prevent and improve the management of STEMI patients.

Clinical validation of a 13-lead electrocardiogram derived from a self-applicable 3-lead recording for diagnosis of myocardial supply ischaemia and common non-ischaemic electrocardiogram abnormalities at rest

Aims

In this study, we compare the diagnostic accuracy of a standard 12-lead electrocardiogram (ECG) with a novel 13-lead ECG derived from a self-applicable 3-lead ECG recorded with the right exploratory left foot (RELF) device. The 13th lead is a novel age and sex orthonormalized computed ST (ASO-ST) lead to increase the sensitivity for detecting ischaemia during acute coronary artery occlusion.

Methods and results

A database of simultaneously recorded 12-lead ECGs and RELF recordings from 110 patients undergoing coronary angioplasty and 30 healthy subjects was used. Five cardiologists scored the learning data set and five other cardiologists scored the validation data set. In addition, the presence of non-ischaemic ECG abnormalities was compared. The accuracy for detection of myocardial supply ischaemia with the derived 12 leads was comparable with that of the standard 12-lead ECG (P = 0.126). By adding the ASO-ST lead, the accuracy increased to 77.4% [95% confidence interval (CI): 72.4-82.3; P < 0.001], which was attributed to a higher sensitivity of 81.9% (95% CI: 74.8-89.1) for the RELF 13-lead ECG compared with a sensitivity of 76.8% (95% CI: 71.9-81.7; P < 0.001) for the 12-lead ECG. There was no significant difference in the diagnosis of non-ischaemic ECG abnormalities, except for Q-waves that were more frequently detected on the standard ECG compared with the derived ECG (25.9 vs. 13.8%; P < 0.001).

Conclusion

A self-applicable and easy-to-use 3-lead RELF device can compute a 12-lead ECG plus an ischaemia-specific 13th lead that is, compared with the standard 12-lead ECG, more accurate for the visual diagnosis of myocardial supply ischaemia by cardiologists.

Incidence, Characteristics, and Outcomes of Ventricular Fibrillation Complicating Acute Myocardial Infarction in Women Admitted Alive in the Hospital

Background

Little data are available in women presenting with ventricular fibrillation (VF) in the setting of acute myocardial infarction (AMI). We assessed frequency, predictors of VF, and outcomes, with a special focus on women compared with men.

Methods and Results

Data were analyzed from the FAST‐MI (French Registry of Acute ST‐Elevation or Non‐ST‐Elevation Myocardial Infarction) program, which prospectively included 14 406 patients admitted to French cardiac intensive care units ≤48 hours from AMI onset between 1995 and 2015 (mean age, 66±14 years; 72% men; mean left ventricular ejection fraction, 52±12%; 59% with ST‐segment–elevation myocardial infarction). A total of 359 patients developed VF during AMI, including 81 women (2.0% of 4091 women) and 278 men (2.7% of 10 315 men, P=0.02). ST‐segment–elevation myocardial infarction (odds ratio [OR], 2.29 [95% CI, 1.75–2.99]; P<0.001) was independently associated with the onset of VF during AMI. In contrast, female sex (OR, 0.73 [95% CI, 0.56–0.95]; P=0.02), hypertension (OR, 0.75 [95% CI, 0.60–0.94]; P=0.01), and prior myocardial infarction (OR, 0.69 [95% CI, 0.50–0.96]; P=0.03) were protective factors. Women were less likely to have cardiac intervention than men (percutaneous coronary intervention during hospitalization 48.1% versus 66.9%, respectively; P=0.04) with a higher 1‐year mortality in women compared with men (50.6% versus 37.4%, respectively; P=0.03), including increased in‐hospital mortality (42.0% versus 32.7%, respectively; P=0.12). After adjustment, female sex was no longer associated with a worse 1‐year mortality (adjusted hazard ratio, 1.10 [95% CI, 0.75–1.61]; P=0.63).

Conclusions

Women have lower risk of developing VF during AMI compared with men. However, they are less likely to receive cardiac interventions than men, possibly contributing to missed opportunities of improved outcomes.

Current and investigational therapies for the treatment of refractory ventricular fibrillation

DISCLAIMER

In an effort to expedite the publication of articles related to the COVID-19 pandemic, AJHP is posting these manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.

PURPOSE

Esmolol, dual sequential defibrillation, vector change defibrillation, and left stellate ganglion block are presented and reviewed for the treatment of refractory ventricular fibrillation.

SUMMARY

Although no formal definition has been established for refractory ventricular fibrillation, the literature describes it as a pulseless ventricular arrhythmia that persists despite 3 standard defibrillation attempts, administration of amiodarone 300 mg intravenously, and provision of three 1-mg intravenous doses of epinephrine. Evolving literature surrounding resuscitation in this particular subset of cardiac arrest challenges the efficacy of traditional therapies, such as epinephrine, and suggests that other treatment modalities may improve outcomes. Case reports, case series, and small retrospective studies have pointed to benefit when utilizing a variety of therapies, namely, esmolol, dual sequential defibrillation, vector change defibrillation, or left stellate ganglion block, in patients with refractory ventricular fibrillation arrest.

CONCLUSION

A mounting, although limited, body of evidence suggests that esmolol, dual sequential defibrillation, vector change defibrillation, or left stellate ganglion block may be effective at terminating refractory ventricular fibrillation and improving patient outcomes. Further evidence is required before these therapies can be adopted as standard practice; however, as key members of the code response team, it is imperative for pharmacists to be familiar with the supporting evidence, safety considerations, and logistical challenges of utilizing these treatments during arrest.

Electrocardiographic Predictors of Primary Ventricular Fibrillation and 30-Day Mortality in Patients Presenting with ST-Segment Elevation Myocardial Infarction

Primary ventricular fibrillation (PVF) may occur in the early phase of ST-elevation myocardial infarction (STEMI) prior to primary percutaneous coronary intervention (PCI). Multiple electrocardiographic STEMI patterns are associated with PVF and short-term mortality including the tombstone, Lambda, and triangular QRS-ST-T waveform (TW). We aimed to compare the predictive value of different electrocardiographic STEMI patterns for PVF and 30-day mortality. We included a consecutive cohort of 407 STEMI patients (75% males, median age 66 years) presenting within 12 h of symptoms onset. At first medical contact, 14 (3%) showed the TW or Lambda ECG patterns, which were combined in a single group (TW-Lambda pattern) characterized by giant R-wave and downsloping ST-segment. PVF prior to primary PCI occurred in 39 (10%) patients, significantly more often in patients with the TW-Lambda pattern than those without (50% vs. 8%, p < 0.001). For the multivariable analysis, Killip class ≥3 (OR 6.19, 95% CI 2.37–16.1, p < 0.001) and TW-Lambda pattern (OR 9.64, 95% CI 2.99–31.0, p < 0.001) remained as independent predictors of PVF. Thirty-day mortality was also higher in patients with the TW-Lambda pattern than in those without (43% vs. 6%, p < 0.001). However, only LVEF (OR 0.86, 95% CI 0.82–0.90, p < 0.001) and PVF (OR 4.61, 95% CI 1.49–14.3, p = 0.042) remained independent predictors of mortality. A mediation analysis showed that the effect of TW-Lambda pattern on mortality was mediated mainly via the reduced LVEF. In conclusion, among patients presenting with STEMI, the electrocardiographic TW-Lambda pattern was associated with both PVF before PCI and 30-day mortality. Therefore, this ECG pattern may be useful for early risk stratification of STEMI.

Combined In-silico and Machine Learning Approaches Toward Predicting Arrhythmic Risk in Post-infarction Patients

Background: Remodeling due to myocardial infarction (MI) significantly increases patient arrhythmic risk. Simulations using patient-specific models have shown promise in predicting personalized risk for arrhythmia. However, these are computationally- and time- intensive, hindering translation to clinical practice. Classical machine learning (ML) algorithms (such as K-nearest neighbors, Gaussian support vector machines, and decision trees) as well as neural network techniques, shown to increase prediction accuracy, can be used to predict occurrence of arrhythmia as predicted by simulations based solely on infarct and ventricular geometry. We present an initial combined image-based patient-specific in silico and machine learning methodology to assess risk for dangerous arrhythmia in post-infarct patients. Furthermore, we aim to demonstrate that simulation-supported data augmentation improves prediction models, combining patient data, computational simulation, and advanced statistical modeling, improving overall accuracy for arrhythmia risk assessment.

Methods: MRI-based computational models were constructed from 30 patients 5 days post-MI (the “baseline” population). In order to assess the utility biophysical model-supported data augmentation for improving arrhythmia prediction, we augmented the virtual baseline patient population. Each patient ventricular and ischemic geometry in the baseline population was used to create a subfamily of geometric models, resulting in an expanded set of patient models (the “augmented” population). Arrhythmia induction was attempted via programmed stimulation at 17 sites for each virtual patient corresponding to AHA LV segments and simulation outcome, “arrhythmia,” or “no-arrhythmia,” were used as ground truth for subsequent statistical prediction (machine learning, ML) models. For each patient geometric model, we measured and used choice data features: the myocardial volume and ischemic volume, as well as the segment-specific myocardial volume and ischemia percentage, as input to ML algorithms. For classical ML techniques (ML), we trained k-nearest neighbors, support vector machine, logistic regression, xgboost, and decision tree models to predict the simulation outcome from these geometric features alone. To explore neural network ML techniques, we trained both a three - and a four-hidden layer multilayer perceptron feed forward neural networks (NN), again predicting simulation outcomes from these geometric features alone. ML and NN models were trained on 70% of randomly selected segments and the remaining 30% was used for validation for both baseline and augmented populations.

Results: Stimulation in the baseline population (30 patient models) resulted in reentry in 21.8% of sites tested; in the augmented population (129 total patient models) reentry occurred in 13.0% of sites tested. ML and NN models ranged in mean accuracy from 0.83 to 0.86 for the baseline population, improving to 0.88 to 0.89 in all cases.

Conclusion: Machine learning techniques, combined with patient-specific, image-based computational simulations, can provide key clinical insights with high accuracy rapidly and efficiently. In the case of sparse or missing patient data, simulation-supported data augmentation can be employed to further improve predictive results for patient benefit. This work paves the way for using data-driven simulations for prediction of dangerous arrhythmia in MI patients.

Application of machine learning to predict the occurrence of arrhythmia after acute myocardial infarction

Background

Early identification of the occurrence of arrhythmia in patients with acute myocardial infarction plays an essential role in clinical decision-making. The present study attempted to use machine learning (ML) methods to build predictive models of arrhythmia after acute myocardial infarction (AMI).

Methods

A total of 2084 patients with acute myocardial infarction were enrolled in this study. (All data is available on Github: https://github.com/wangsuhuai/AMI-database1.git). The primary outcome is whether tachyarrhythmia occurred during admission containing atrial arrhythmia, ventricular arrhythmia, and supraventricular tachycardia. All data is randomly divided into a training set (80%) and an internal testing set (20%). Apply three machine learning algorithms: decision tree, random forest (RF), and artificial neural network (ANN) to learn the training set to build a model, then use the testing set to evaluate the prediction performance, and compare it with the model built by the Global Registry of Acute Coronary Events (GRACE) risk variable set.

Results

Three ML models predict the occurrence of tachyarrhythmias after AMI. After variable selection, the artificial neural network (ANN) model has reached the highest accuracy rate, which is better than the model constructed using the Grace variable set. After applying SHapley Additive exPlanations (SHAP) to make the model interpretable, the most important features are abnormal wall motion, lesion location, bundle branch block, age, and heart rate. Among them, RBBB (odds ratio [OR]: 4.21; 95% confidence interval [CI]: 2.42–7.02), ≥ 2 ventricular walls motion abnormal (OR: 3.26; 95% CI: 2.01–4.36) and right coronary artery occlusion (OR: 3.00; 95% CI: 1.98–4.56) are significant factors related to arrhythmia after AMI.

Conclusions

We used advanced machine learning methods to build prediction models for tachyarrhythmia after AMI for the first time (especially the ANN model that has the best performance). The current study can supplement the current AMI risk score, provide a reliable evaluation method for the clinic, and broaden the new horizons of ML and clinical research.

Trial registration Clinical Trial Registry No.: ChiCTR2100041960.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12911-021-01667-8.

Polymorphic ventricular tachycardia, ischaemic ventricular fibrillation, and torsade de pointes: importance of the QT and the coupling interval in the differential diagnosis

AIMS

Distinctive types of polymorphic ventricular tachycardia (VT) respond differently to different forms of therapy. We therefore performed the present study to define the electrocardiographic characteristics of different forms of polymorphic VT.

METHODS AND RESULTS

We studied 190 patients for whom the onset of 305 polymorphic VT events was available. The study group included 87 patients with coronary artery disease who had spontaneous polymorphic VT triggered by short-coupled extrasystoles in the absence of myocardial ischaemia. This group included 32 patients who had a long QT interval but nevertheless had their polymorphic VT triggered by ectopic beats with short coupling interval, a subcategory termed 'pseudo-torsade de pointes] (TdP). For comparison, we included 50 patients who had ventricular fibrillation (VF) during acute myocardial infarction ('ischaemic VF' group) and 53 patients with drug-induced TdP ('true TdP' group). The QT of patients with pseudo-TdP was (by definition) longer than that of patients with polymorphic VT and normal QT (QTc 491.4 ± 25.2 ms vs. 447.3 ± 55.6 ms, P < 0.001). However, their QT was significantly shorter than that of patients with true TdP (QTc 564.6 ± 75.6 ms, P < 0.001). Importantly, the coupling interval of the ectopic beat triggering the arrhythmia was just as short during pseudo-TdP as during polymorphic VT with normal QT (359.1 ± 38.1 ms vs. 356.6 ± 39.4 ms, P = 0.467) but was much shorter than during true TdP (581.2 ± 95.3 ms, P < 0.001).

CONCLUSIONS

The coupling interval helps discriminate between polymorphic VT that occurs despite a long QT interval (pseudo-TdP) and polymorphic arrhythmias striking because of a long QT (true TdP).

Genome-wide association studies of cardiac electrical phenotypes

The genetic basis of cardiac electrical phenotypes has in the last 25 years been the subject of intense investigation. While in the first years, such efforts were dominated by the study of familial arrhythmia syndromes, in recent years, large consortia of investigators have successfully pursued genome-wide association studies (GWAS) for the identification of single-nucleotide polymorphisms that govern inter-individual variability in electrocardiographic parameters in the general population. We here provide a review of GWAS conducted on cardiac electrical phenotypes in the last 14 years and discuss the implications of these discoveries for our understanding of the genetic basis of disease susceptibility and variability in disease severity. Furthermore, we review functional follow-up studies that have been conducted on GWAS loci associated with cardiac electrical phenotypes and highlight the challenges and opportunities offered by such studies.

Sex Disparities in Sudden Cardiac Death

The overall incidence of sudden cardiac death is considerably lower among women than men, reflecting significant and often under-recognized sex differences. Women are older at time of sudden cardiac death, less likely to have a prior cardiac diagnosis, and less likely to have coronary artery disease identified on postmortem examination. They are more likely to experience their death at home, during sleep, and less likely witnessed. Women are also more likely to present in pulseless electrical activity or systole rather than ventricular fibrillation or ventricular tachycardia. Conversely, women are less likely to receive bystander cardiopulmonary resuscitation or receive cardiac intervention post-arrest. Underpinning sex disparities in sudden cardiac death is a paucity of women recruited to clinical trials, coupled with an overall lack of prespecified sex-disaggregated evidence. Thus, predominantly male-derived data form the basis of clinical guidelines. This review outlines the critical sex differences concerning epidemiology, cause, risk factors, prevention, and outcomes. We propose 4 broad areas of importance to consider: physiological, personal, community, and professional factors.

Long-term prognostic outcomes and implication of oral anticoagulants in patients with new-onset atrial fibrillation following st-segment elevation myocardial infarction

BACKGROUND

New-onset atrial fibrillation (NEW-AF) following ST-segment elevation myocardial infarction (STEMI) is a common complication, but the true prognostic impact of NEW-AF is unknown. Additionally, the optimal treatment of NEW-AF among patients with STEMI is warranted.

METHODS

A large cohort of consecutive patients with STEMI treated with percutaneous coronary intervention were identified using the Eastern Danish Heart Registry from 1999-2016. Medication and end points were retrieved from Danish nationwide registries. NEW-AF was defined as a diagnosis of AF within 30 days following STEMI. Patients without a history of AF and alive after 30 days after discharge were included. Incidence rates were calculated and multivariate analyses performed to determine the association between NEW-AF and long-term mortality, incidence of ischemic stroke, re-MI, and bleeding leading to hospitalization, and the comparative effectiveness of OAC therapy on these outcomes.

RESULTS

Of 7944 patients with STEMI, 296 (3.7%) developed NEW-AF. NEW-AF was associated with increased long-term mortality (adjusted HR 1.48, 95% CI 1.20-1.82, P<.001) and risk of bleeding leading to hospitalization (adjusted HR 1.36, 95% CI 1.00-1.85, P=.050), and non-significant increased risk of ischemic stroke (adjusted HR 1.45, 95% CI 0.96-2.19, P=.08) and re-MI (adjusted HR 1.14, 95% CI 0.86-1.52, P=.35) with a median follow-up of 5.8 years. In NEW-AF patients, 38% received OAC therapy, which was associated with reduced long-term mortality (adjusted HR 0.69, 95% CI 0.47-1.00, P=.049).

CONCLUSIONS

NEW-AF following STEMI is associated with increased long-term mortality. Treatment with OAC therapy in NEW-AF patients is associated with reduced long-term mortality.

Electroimmunology and cardiac arrhythmia

Conduction disorders and arrhythmias remain difficult to treat and are increasingly prevalent owing to the increasing age and body mass of the general population, because both are risk factors for arrhythmia. Many of the underlying conditions that give rise to arrhythmia - including atrial fibrillation and ventricular arrhythmia, which frequently occur in patients with acute myocardial ischaemia or heart failure - can have an inflammatory component. In the past, inflammation was viewed mostly as an epiphenomenon associated with arrhythmia; however, the recently discovered inflammatory and non-canonical functions of cardiac immune cells indicate that leukocytes can be arrhythmogenic either by altering tissue composition or by interacting with cardiomyocytes; for example, by changing their phenotype or perhaps even by directly interfering with conduction. In this Review, we discuss the electrophysiological properties of leukocytes and how these cells relate to conduction in the heart. Given the thematic parallels, we also summarize the interactions between immune cells and neural systems that influence information transfer, extrapolating findings from the field of neuroscience to the heart and defining common themes. We aim to bridge the knowledge gap between electrophysiology and immunology, to promote conceptual connections between these two fields and to explore promising opportunities for future research.

Pulseless Electrical Activity as the Initial Cardiac Arrest Rhythm: Importance of Preexisting Left Ventricular Function

Background Pulseless electrical activity (PEA) is a common initial rhythm in cardiac arrest. A substantial number of PEA arrests are caused by coronary ischemia in the setting of acute coronary occlusion, but the underlying mechanism is not well understood. We hypothesized that the initial rhythm in patients with acute coronary occlusion is more likely to be PEA than ventricular fibrillation in those with prearrest severe left ventricular dysfunction. Methods and Results We studied the initial cardiac arrest rhythm induced by acute left anterior descending coronary occlusion in swine without and with preexisting severe left ventricular dysfunction induced by prior infarcts in non-left anterior descending coronary territories. Balloon occlusion resulted in ventricular fibrillation in 18 of 34 naïve animals, occurring 23.5±9.0 minutes following occlusion, and PEA in 1 animal. However, all 18 animals with severe prearrest left ventricular dysfunction (ejection fraction 15±5%) developed PEA 1.7±1.1 minutes after occlusion. Conclusions Acute coronary ischemia in the setting of severe left ventricular dysfunction produces PEA because of acute pump failure, which occurs almost immediately after coronary occlusion. After the onset of coronary ischemia, PEA occurred significantly earlier than ventricular fibrillation (<2 minutes versus 20 minutes). These findings support the notion that patients with baseline left ventricular dysfunction and suspected coronary disease who develop PEA should be evaluated for acute coronary occlusion.

Prognosis of the non-ST elevation myocardial infarction complicated with early ventricular fibrillation at higher age

Early ventricular fibrillation (EVF) predicts mortality in ST-segment elevation myocardial infarction (STEMI) patients. Data are lacking about prognosis and management of non-ST-segment elevation myocardial infarction (NSTEMI) EMI with EVF, especially at higher age. In the daily clinical practice, there is no clear prognosis of patients surviving EVF. The present study aimed to investigate the risk factors and factors influencing the prognosis of NSTEMI patients surviving EVF, especially at higher age. Clinical data, including 30-day and 1-year mortality of 6179 NSTEMI patients, were examined; 2.44% (n=151) survived EVF and were further analyzed using chi-square test and uni- and multivariate analyses. Patients were divided into two age groups below and above the age of 70 years. Survival time was compared with Kaplan-Meier analysis. EVF was an independent risk factor for mortality in NSTEMI patients below (HR: 2.4) and above the age of 70 (HR: 2.1). Mortality rates between the two age groups of NSTEMI patients with EVF did not differ significantly: 30-day mortality was 24% vs 40% (p=0.2709) and 1-year mortality was 39% vs 55% (p=0.2085). Additional mortality after 30 days to 1 year was 15% vs 14.6% (p=0.9728). Clinical characteristics of patients with EVF differed significantly from those without in both age groups. EVF after revascularization—within 48 h—had 11.2 OR for 30-day mortality above the age of 70. EVF in NSTEMI was an independent risk factor for mortality in both age groups. Invasive management and revascularization of NSTEMI patients with EVF is highly recommended. Closer follow-up and selection of patients (independent of age) for ICD implantation in the critical first month is essential.

Prognostic value of admission serum magnesium in acute myocardial infarction complicated by malignant ventricular arrhythmias

OBJECTIVES

Although electrolyte abnormalities are related to worse clinical outcomes in patients with acute myocardial infarction (AMI), little is known about the association between admission serum magnesium level and adverse events in AMI patients complicated by out-of-hospital cardiac arrest presenting with malignant ventricular arrhythmias (OHCA-MVA). We investigated the prognostic value of serum magnesium level on admission in these patients.

METHODS

We retrospectively analyzed the data of 165 consecutive reperfused AMI patients complicated with OHCA-MVA between April 2007 and February 2020 in our university hospital. Serum magnesium concentration was measured on admission. The primary outcome was in-hospital death.

RESULTS

Fifty-four patients (33%) died during hospitalization. Higher serum magnesium level was significantly related to in-hospital death (Fine & Gray's test; p < 0.001). In multivariable logistic regression analyses, serum magnesium level on admission was independently associated with in-hospital death (hazard ratio 2.68, 95% confidence interval 1.24-5.80) even after adjustment for covariates. Furthermore, the incidences of cardiogenic shock necessitating an intra-aortic balloon pump (p = 0.005) or extracorporeal membrane oxygenation (p < 0.001), tracheal intubation (p < 0.001) and persistent vegetative state (p = 0.002) were significantly higher in patients with higher serum magnesium level than in those with lower serum magnesium level.

CONCLUSIONS

In reperfused AMI patients complicated by OHCA-MVA, admission serum magnesium level might be a potential surrogate marker for predicting in-hospital death.

Correlation of Prolonged Corrected QT Interval With Ventricular Arrhythmias and In-Hospital Mortality Among ST-Elevation Myocardial Infarction Patients: A Mystique or Lucidity?

Background Ventricular arrhythmias (VAs) are a frequent cause of cardiovascular mortality, especially in developing countries. Prolongation of corrected QT (QTc) interval predisposes patients to life-threatening VAs. Our study aims to assess the correlation of prolonged QTc interval with VAs and in-hospital mortality among ST-elevation myocardial infarction (STEMI) patients.  Methods This cross-sectional study analyzed the data from 40 patients with a confirmed diagnosis of STEMI and prolonged QTc interval. The patients were evaluated for several characteristics including their electrocardiography (ECG) findings. The frequency of in-hospital mortality and VAs developed after admission were recorded. Spearman correlation was used to assess the correlation of prolonged QTc interval with VAs and in-hospital mortality. Results Out of 40 cases, 30 patients were males and 10 were females with a mean age hovering at 52.95 ± 10.65 years. The mean QTc interval of our patients was 512.02 ± 49.74 milliseconds (ms). A total of 11 (27.5%) patients developed VAs while 14 (35%) of the patients succumbed to the disease complications. Spearman correlation showed a strong significant positive correlation of QTc interval with VAs (rho = 0.658, p < 0.001) and in-hospital mortality (rho = 0.314, p = 0.04). Conclusion Prolonged QTc interval is positively correlated with VAs and in-hospital mortality among STEMI patients. These patients should be regularly monitored and must be managed with caution as they have increased chances to develop VAs and in-hospital mortality. There is an utmost need for curation of guidelines that aid in risk stratification and appropriate management of such patients.

Life-threatening arrhythmias in anterior ST-segment elevation myocardial infarction patients treated by percutaneous coronary intervention: adverse impact of morphine

AIMS

Important controversies remain concerning the determinants of life-threatening arrhythmias during ST-segment elevation myocardial infarction (STEMI) and their impact on late adverse events. This study sought to investigate which factors might facilitate ventricular tachycardia (VT) and ventricular fibrillation (VF), in a homogeneous population of anterior STEMI patients defined by abrupt left anterior descending coronary artery (LAD) occlusion and no collateral flow.

METHODS AND RESULTS

The 967 patients, who entered into the CIRCUS (Does Cyclosporine ImpRove Clinical oUtcome in ST elevation myocardial infarction patients) study, were assessed for further analysis. Acute VT/VF was defined as VT (run of tachycardia >30 s either self-terminated or requiring electrical/pharmacological cardioversion) or VF documented by electrocardiogram or cardiac monitoring, during transportation to the cathlab or initial hospitalization. VT/VF was documented in 136 patients (14.1%). Patients with VT/VF were younger and had shorter time from symptom onset to hospital arrival. Site of LAD occlusion, thrombus burden, area at risk, pre-percutaneous coronary intervention Thrombolysis in Myocardial Infarction flow, and ST-segment resolution were similar to that of patients without VT/VF. There was no impact of VT/VF on left ventricular remodelling or clinical outcomes. By multivariate analysis, the use of morphine (odds ratio 1.71; 95% confidence interval (1.13-2.60); P = 0.012) was the sole independent predictor of VT/VF occurrence.

CONCLUSIONS

In STEMI patients with LAD occlusion, our findings support the view that morphine could favour severe ventricular arrhythmias.

Short- and long-term outcomes of out-of-hospital cardiac arrest following ST-elevation myocardial infarction managed with percutaneous coronary intervention

AIM

Out-of-hospital cardiac arrest (OHCA) is frequently associated with ST-elevation myocardial infarction (STEMI) and has a high mortality. We aimed to identify differences in characteristics and very long-term outcomes for STEMI patients with and without OHCA managed with percutaneous coronary intervention (PCI).

METHODS

We analysed data from 12,637 PCI patient procedures for STEMI in the multi-centre Melbourne Interventional Group registry between January 2005 and December 2018. Multivariable models examined associations with OHCA presentation and 30-day mortality. Long-term outcomes were assessed through linkage with the Australian National Death Index.

RESULTS

Compared with patients without OHCA (N = 11,580), patients with OHCA (N = 1057) were younger, more often male, had less cardiovascular risk factors, and more often presented with cardiogenic shock. OHCA preceded an increasing proportion of STEMI PCI cases from 2005 to 2018 (2.4% vs. 9.2%). Factors independently associated with OHCA presentation were younger age, male gender, prior valve surgery, multi-vessel disease, LAD culprit, small vessel diameter, and renal impairment on presentation. Patients with OHCA had lower procedural success, higher rates of bleeding and stroke, larger infarct size (measured by peak CK), and higher 30-day mortality (37% vs. 5%; all p < 0.05). Cardiogenic shock, renal impairment and lower ejection fraction were independently associated with 30-day mortality. Long-term mortality was 44% vs. 20% (median follow-up 4.6 years), with Cox regression analysis demonstrating no difference in survival if patients survived beyond 30 days (HR 1.18, 95% CI 0.95-1.47).

CONCLUSIONS

OHCA has a high short-term mortality and precedes an increasing proportion of STEMI PCI cases. Thirty-day survivors have an excellent long-term prognosis.

Effect of the antipsychotic drug haloperidol on arrhythmias during acute myocardial infarction in a porcine model

Patients receiving psychiatric medication, like the antipsychotic drug haloperidol, are at an increased risk of sudden cardiac death (SCD). Haloperidol blocks the cardiac rapidly-activating delayed rectifier potassium current, thereby increasing electrical dispersion of repolarization which can potentially lead to arrhythmias. Whether these patients are also at a higher risk to develop SCD during an acute myocardial infarction (AMI) is unknown. AMI locally shortens action potential duration, which might further increase repolarization dispersion and increase the risk of arrhythmia in the presence of haloperidol compared to without. Our aim was to test whether treatment with haloperidol implies an increased risk of SCD when eventually experiencing AMI. Twenty-eight female Danish Landrace pigs were randomized into three groups: low dose haloperidol (0.1 mg/kg), high dose (1.0 mg/kg) or vehicle-control group. One hour after haloperidol/vehicle infusion, AMI was induced by balloon-occlusion of the mid-left anterior descending coronary artery and maintained for 120 min, followed by 60 min of reperfusion. VF occurred during occlusion in 7/11 pigs in the control group, 3/11 in the low dose (p = 0.198) and 2/6 in the high dose group (p = 0.335). High dose haloperidol significantly prolonged QT, and reduced heart rate, vascular resistance and blood pressure before and during AMI. Premature ventricular contractions in phase 1b during AMI were reduced with high dose haloperidol. AMI-induced arrhythmia was not aggravated in pigs with haloperidol treatment. Our results do not suggest that AMI is contributing to the excess mortality in patients treated with antipsychotic drugs seen in epidemiological studies.

Seasonality of ventricular fibrillation at first myocardial infarction and association with viral exposure

AIMS

To investigate seasonality and association of increased enterovirus and influenza activity in the community with ventricular fibrillation (VF) risk during first ST-elevation myocardial infarction (STEMI).

METHODS

This study comprised all consecutive patients with first STEMI (n = 4,659; aged 18-80 years) admitted to the invasive catheterization laboratory between 2010-2016, at Copenhagen University Hospital, Rigshospitalet, covering eastern Denmark (2.6 million inhabitants, 45% of the Danish population). Hospital admission, prescription, and vital status data were assessed using Danish nationwide registries. We utilized monthly/weekly surveillance data for enterovirus and influenza from the Danish National Microbiology Database (2010-2016) that receives copies of laboratory tests from all Danish departments of clinical microbiology.

RESULTS

Of the 4,659 consecutively enrolled STEMI patients, 581 (12%) had VF before primary percutaneous coronary intervention. In a subset (n = 807), we found that VF patients experienced more generalized fatigue and flu-like symptoms within 7 days before STEMI compared with the patients without VF (OR 3.39, 95% CI 1.76-6.54). During the study period, 2,704 individuals were diagnosed with enterovirus and 19,742 with influenza. No significant association between enterovirus and VF (OR 1.00, 95% CI 0.99-1.02), influenza and VF (OR 1.00, 95% CI 1.00-1.00), or week number and VF (p-value 0.94 for enterovirus and 0.89 for influenza) was found.

CONCLUSION

We found no clear seasonality of VF during first STEMI. Even though VF patients had experienced more generalized fatigue and flu-like symptoms within 7 days before STEMI compared with patients without VF, no relationship was found between enterovirus or influenza exposure and occurrence of VF.

Potassium Disturbances and Risk of Ventricular Fibrillation Among Patients With ST-Segment-Elevation Myocardial Infarction

Background Potassium disturbances per se increase the risk of ventricular fibrillation (VF). Whether potassium disturbances in the acute phase of ST-segment-elevation myocardial infarction (STEMI) are associated with VF before primary percutaneous coronary intervention (PPCI) is uncertain. Methods and Results All consecutive STEMI patients were identified in the Eastern Danish Heart Registry from 1999 to 2016. Comorbidities and medication use were assessed from Danish nationwide registries. Potassium levels were collected immediately before PPCI start. Multivariate logistic models were performed to determine the association between potassium and VF. The main analysis included 8624 STEMI patients of whom 822 (9.5%) had VF before PPCI. Compared with 6693 (77.6%) patients with normokalemia (3.5-5.0 mmol/L), 1797 (20.8%) patients with hypokalemia (<3.5 mmol/L) were often women with fewer comorbidities, whereas 134 (1.6%) patients with hyperkalemia (>5.0 mmol/L) were older with more comorbidities. After adjustment, patients with hypokalemia and hyperkalemia had a higher risk of VF before PPCI (odds ratio 1.90, 95% CI 1.57-2.30, P<0.001) and (odds ratio 3.36, 95% CI 1.95-5.77, P<0.001) compared with normokalemia, respectively. Since the association may reflect a post-resuscitation phenomenon, a sensitivity analysis was performed including 7929 STEMI patients without VF before PPCI of whom 127 (1.6%) had VF during PPCI. Compared with normokalemia, patients with hypokalemia had a significant association with VF during PPCI (odds ratio 1.68, 95% CI 1.01-2.77, P=0.045) after adjustment. Conclusions Hypokalemia and hyperkalemia are associated with increased risk of VF before PPCI during STEMI. For hypokalemia, the association may be independent of the measurement of potassium before or after VF.

Ventricular Arrhythmias in First Acute Myocardial Infarction: Epidemiology, Mechanisms, and Interventions in Large Animal Models

Ventricular arrhythmia and subsequent sudden cardiac death (SCD) due to acute myocardial infarction (AMI) is one of the most frequent causes of death in humans. Lethal ventricular arrhythmias like ventricular fibrillation (VF) prior to hospitalization have been reported to occur in more than 10% of all AMI cases and survival in these patients is poor. Identification of risk factors and mechanisms for VF following AMI as well as implementing new risk stratification models and therapeutic approaches is therefore an important step to reduce mortality in people with high cardiovascular risk. Studying spontaneous VF following AMI in humans is challenging as it often occurs unexpectedly in a low risk subgroup. Large animal models of AMI can help to bridge this knowledge gap and are utilized to investigate occurrence of arrhythmias, involved mechanisms and therapeutic options. Comparable anatomy and physiology allow for this translational approach. Through experimental focus, using state-of-the-art technologies, including refined electrical mapping equipment and novel pharmacological investigations, valuable insights into arrhythmia mechanisms and possible interventions for arrhythmia-induced SCD during the early phase of AMI are now beginning to emerge. This review describes large experimental animal models of AMI with focus on first AMI-associated ventricular arrhythmias. In this context, epidemiology of first AMI, arrhythmogenic mechanisms and various potential therapeutic pharmacological targets will be discussed.

Risk stratification for complex ventricular arrhythmia complicating ST-segment elevation myocardial infarction

OBJECTIVES

The primary aim of the study was to evaluate risk factors for ventricular fibrillation/sustained ventricular tachycardia (VF/VT) and to develop the risk score for prediction of VF/VT in patients with ST-segment elevation myocardial infarction (STEMI) treated invasively. The secondary aim was to assess the effect of VF/VT on mortality depending on timing of arrhythmia.

PATIENTS AND METHODS

We analyzed 4363 consecutive patients with STEMI treated invasively. Among them, 163 patients with pre-reperfusion arrhythmia were excluded from the study. Group ventricular arrhythmias (VA) encompassed patients with VF/VT - those with reperfusion-induced arrhythmia were included into group VA1, whereas group VA2 consisted of patients with postreperfusion arrhythmia. The control group comprised patients free of VF/VT.

RESULTS

VF or VT occurred in 313 (7.45%) patients - group VA1 encompassed 103 (32.9%) and group AV2 210 (67.1%) patients. Cardiogenic shock on admission [hazard ratio (HR) 3.5], new-onset atrial fibrillation (HR 2.1), incomplete revascularization (HR 1.7), prior myocardial infarction (HR 1.6) and symptom-to-balloon time more than 3 h (HR 1.3) were the independent predictors of VF/VT occurrence. In group VA2, the in-hospital and long-term mortality were 4- and 1.5-fold higher than in the arrhythmia-free population (20.5 vs. 4.5% and 36.2 vs. 22.6%, respectively; P<0.001). On the contrary, in group VA1, the long-term mortality was not significantly higher compared with the control group (26.2 vs. 22.6%; P=NS), whereas in-hospital mortality was almost three-fold increased (12.5 vs. 4.5%, respectively; P<0.001).

CONCLUSION

The risk score based on simple clinical parameters might be useful for risk stratification for VF/VT in patients with STEMI. The predictive value of VF/VT was strongly dependent on timing of arrhythmia.

Characteristics of subjects with alcoholic cardiomyopathy and sudden cardiac death

OBJECTIVE

To study social and clinical characteristics of victims of sudden cardiac death (SCD) due to alcoholic cardiomyopathy (ACM).

METHODS

The study population comprised a subset of Fingesture cohort. All subjects were verified SCD victims determined to have ACM as cause of death in medico-legal autopsy between 1998 and 2017 in Northern Finland. The Finnish Population Register Centre provided SCD victims' last place of residence. Population data of residential area were obtained from Statistics Finland.

RESULTS

From a total of 5869 SCD victims in Fingesture cohort, in 290 victims the cause of SCD was ACM (4.9%; median age 56 (50-62) years; 83% males). In 64 (22.1%) victims, the diagnosis of cardiac disease was made prior to death and in 226 (77.9%) at autopsy. There were no significant differences in autopsy findings between victims with or without known cardiac diagnosis, but steatohepatitis (94.5%) and liver cirrhosis (64,5%) were common in both groups. Alcoholism was more often recorded in the known cardiac disease group (64.1% vs 47.3%, p=0.023). Majority were included in the working age population (ie, under 65 years) (54.8% and 53.1%, p=0.810). In high-income communities, 28.8% of ACM SCD victims had previously diagnosed cardiac disease, the proportion in the middle-income and low-income communities was 18.6% (p=0.05).

CONCLUSIONS

Majority of SCD victims due to ACM did not have previously diagnosed cardiac disease, but documented risk consumption of alcohol was common. This emphasises the importance of routine screening of alcohol consumption and signs of cardiomyopathy in heavy alcohol users in primary healthcare.

Vulnerability to cardiac arrest in patients with ST elevation myocardial infarction: Is it time or patient dependent? Results from a nationwide observational study

AIM

Cardiac arrest is a common complication of ST elevation myocardial infarction and is associated with high mortality. We evaluated whether vulnerability to cardiac arrest follows a circadian rhythm and whether it is related to specific patient characteristics.

METHODS

A total of 24,164 ST elevation myocardial infarction patients who were admitted to 60 Belgian hospitals between 2008-2017 were analysed. The proportion of patients with cardiac arrest before initiation of reperfusion therapy was calculated for different time periods (hour of the day, months, seasons) and related to patient characteristics using stepwise logistic regression analysis.

RESULTS

Cardiac arrest occurred in 10.8% of the ST elevation myocardial infarction patients at a median of 65 min (interquartile range 33-138 min) after onset of pain. ST elevation myocardial infarction patients with cardiac arrest showed a biphasic pattern with one peak in the morning and one peak in the late afternoon. Multivariate analysis identified the following independent factors associated with cardiac arrest: cardiogenic shock (odds ratio=28), left bundle branch block (odds ratio=3.7), short (<180 min) ischaemic period (odds ratio=2.2), post-meridiem daytime presentation (odds ratio=1.4), anterior infarction (odds ratio=1.3). Overall in-hospital mortality was 30% for cardiac arrest patients versus 3.7% for non-cardiac arrest patients (p<0.0001).

CONCLUSION

In the present study population, cardiac arrest in ST elevation myocardial infarction showed an atypical circadian rhythm with not only a morning peak but also a second peak in the late afternoon, suggesting that cardiac arrest and ST elevation myocardial infarction triggers are, at least partially, different. In addition, specific patient characteristics, such as short ischaemic period, cardiogenic shock and left bundle branch block, increase the vulnerability to cardiac arrest.

Physical activity and risk of instant and 28-day case-fatality in myocardial infarction

BACKGROUND

While physical activity reduces risk of developing myocardial infarction (MI), it is unknown whether a history of physical activity is also protective of fatal arrhythmia and case-fatality in patients who have suffered an acute MI.

METHODS

104,801 individuals included in 2003-2014 in the Copenhagen General Population Study (CGPS), a prospective population-based study with self-reported leisure time physical activity (LTPA) in three categories measured at baseline, were followed until 2014 through national registries. The 1,517 individuals who suffered a first time MI during follow-up constituted the study population. Outcomes were fatal MI, defined as date of death same as date of MI (including out-of-hospital deaths) and 28-day fatality. Through multivariable analyses the association between baseline LTPA and outcomes were assessed adjusted for CVD risk factors.

RESULTS

Of 1,517 MI events, 117 (7.7%) were fatal and another 79 (5.6%) lead to death within 28 days. Median time from baseline to MI was 3.6 years (IQR 1.7-5.8). LTPA was associated with lower risk of fatal MI with odds ratios of 0.40 (95% CI: 0.22-0.73) for light and 0.41 (0.22-0.76) for moderate/high LTPA after multivariable adjustment with sedentary LTPA as reference. Age, alcohol-intake, education and smoking were identified as other predictors for fatal MI. We found no association between LTPA and 28-day case fatality.

CONCLUSIONS

Among individuals with MI, those that have engaged in any light or moderate physical activity were more likely to survive their MI. Results are consistent with effect of exercise preconditioning on risk of fatal arrhythmia.

Feasibility and performance of a device for automatic self-detection of symptomatic acute coronary artery occlusion in outpatients with coronary artery disease: a multicentre observational study

BACKGROUND

Time delay between onset of symptoms and seeking medical attention is a major determinant of mortality and morbidity in patients with acute coronary artery occlusion. Response time might be reduced by reliable self-detection. We aimed to formally assess the proof-of-concept and accuracy of self-detection of acute coronary artery occlusion by patients during daily life situations and during the very early stages of acute coronary artery occlusion.

METHODS

In this multicentre, observational study, we tested the operational feasibility, specificity, and sensitivity of our RELF method, a three-lead detection system with an automatic algorithm built into a mobile handheld device, for detection of acute coronary artery occlusion. Patients were recruited continuously by physician referrals from three Belgian hospitals until the desired sample size was achieved, had been discharged with planned elective percutaneous coronary intervention, and were able to use a smartphone; they were asked to perform random ambulatory self-recordings for at least 1 week. A similar self-recording was made before percutaneous coronary intervention and at 60 s of balloon occlusion. Patients were clinically followed up until 1 month after discharge. We quantitatively assessed the operational feasibility with an automated dichotomous quality check of self-recordings. Performance was assessed by analysing the receiver operator characteristics of the ST difference vector magnitude. This trial is registered with ClinicalTrials.gov, number NCT02983396.

FINDINGS

From Nov 18, 2016, to April 25, 2018, we enrolled 64 patients into the study, of whom 59 (92%) were eligible for self-applications. 58 (91%) of 64 (95% CI 81·0-95·6) patients were able to perform ambulatory self-recordings. Of all 5011 self-recordings, 4567 (91%) were automatically classified as successful within 1 min. In 65 balloon occlusions, 63 index tests at 60 s of occlusion in 55 patients were available. The mean specificity of daily life recordings was 0·96 (0·95-0·97). The mean false positive rate during daily life conditions was 4·19% (95% CI 3·29-5·10). The sensitivity for the target conditions was 0·87 (55 of 63; 95% CI 0·77-0·93) for acute coronary artery occlusion, 0·95 (54 of 57; 0·86-0·98) for acute coronary artery occlusion with electrocardiogram (ECG) changes, and 1·00 (35 of 35) for acute coronary artery occlusion with ECG changes and ST-segment elevation myocardial infarction criteria (STEMI). The index test was more sensitive to detect a 60 s balloon occlusion than the STEMI criteria on 12-lead ECG (87% vs 56%; p<0·0001). The proportion of total variation in study estimates due to heterogeneity between patients (I²) was low (12·6%). The area under the receiver operator characteristics curve was 0·973 (95% CI 0·956-0·990) for acute coronary artery occlusion at different cutoff values of the magnitude of the ST difference vector. No patients died during the study.

INTERPRETATION

Self-recording with our RELF device is feasible for most patients with coronary artery disease. The sensitivity and specificity for automatic detection of the earliest phase of acute coronary artery occlusion support the concept of our RELF device for patient empowerment to reduce delay and increase Survival without overloading emergency services.

FUNDING

Ghent University, Industrial Research Fund.

Serum of patients with acute myocardial infarction prevents inflammation in iPSC-cardiomyocytes

Acute myocardial infarction (MI) evokes a systemic inflammatory response and locally the degradation of the necrotic tissue, followed by scar formation. The mechanisms for containment of the infarct zone are not studied well. The study aimed to examine the response of healthy cardiomyocytes to serum of patients with myocardial infarction. Human iPSC-cardiomyocytes (iPSC-CM) generated from two healthy donors were incubated with serum of patients with MI with and without ventricular fibrillation (VF) or of healthy controls. Different cell adhesion molecules were studied by flow cytometry and immunostaining. Cellular electrophysiology was studied by patch clamp. The cell adhesion molecules CD54/ICAM-1, CD58/LFA-3 and CD321/JAM-A were expressed on iPSC-CM within the plasma membrane. Incubation with serum of MI patients reduced the levels of expression of CD54/ICAM-1 and CD321/JAM-A by 15–20%. VF serum was less effective than serum of MI patients without VF. MI serum or VF serum did not affect resting potential, action potential duration or maximum depolarization velocity. Myocardial infarction serum exerts anti-inflammatory effects on healthy cardiomyocytes without affecting their electrical activity, thus helping to contain the infarct zone and to protect healthy tissue. Ventricular fibrillation during MI drives healthy cardiomyocytes towards a pro-inflammatory phenotype.

Post-mortem toxicology in young sudden cardiac death victims: a nationwide cohort study

Aims

Several drugs increase the risk of ventricular fibrillation and sudden cardiac death (SCD). We aimed to investigate in detail the toxicological findings of all young SCD throughout Denmark.

Methods and results

Deaths in persons aged 1-49 years were included over a 10-year period. Death certificates and autopsy reports were retrieved and read to identify cases of sudden death and establish cause of death. All medico-legal autopsied SCD were included and toxicological reports collected. Positive toxicology was defined as the presence of any substance (licit and/or illicit). All toxicological findings had previously been evaluated not to have caused the death (i.e. lethal concentrations were excluded). We identified 620 medico-legal autopsied cases of SCD, of which 77% (n = 477) were toxicologically investigated post-mortem, and 57% (n = 270) had a positive toxicology profile. Sudden cardiac death with positive toxicology had higher rates of sudden arrhythmic death syndrome (SADS), compared with SCD with negative toxicology (56% vs. 42%, P < 0.01). In total, 752 agents were detected, and polypharmacy (defined as the presence of more than one drug) was present in 61% (n = 164), all substances combined. Psychotropic drugs were the most frequent (62%, n = 467), and 82% (n = 385) were in pharmacological or subpharmacological levels.

Conclusion

We found that more than half of all toxicologically investigated SCD victims have positive post-mortem toxicological findings, and polypharmacy is displayed in a considerable proportion. SCD with positive toxicology had higher rate of SADS, suggesting that the compounds may play a proarrhythmic role in these cases.

Amiodarone Treatment in the Early Phase of Acute Myocardial Infarction Protects Against Ventricular Fibrillation in a Porcine Model

Ventricular fibrillation (VF) occurring in the first minutes to hours of acute myocardial infarction (AMI) is a frequent cause of death and treatment options are limited. The aim was to test whether early infusion of amiodarone 10 min after onset of AMI reduced the incidence of VF in a porcine model. Eighteen female Danish landrace pigs were randomized to a control and an amiodarone group. AMI was induced by ligation of the mid-left anterior descending artery for 120 min followed by 60 min of reperfusion. VF occurred in 0/8 pigs treated with amiodarone compared to 7/10 controls (P < 0.01). Amiodarone treatment prolonged RR intervals, reduced dispersion of action potential duration in the infarcted area and mean number of ectopic beats. No negative effects on cardiac output and blood pressure were observed with amiodarone. Amiodarone qualifies as a potential drug candidate to prevent VF in the first minutes to hours of AMI.

Risk assessment model for predicting ventricular tachycardia or ventricular fibrillation in ST-segment elevation myocardial infarction patients who received primary percutaneous coronary intervention

Ventricular tachycardia/ventricular fibrillation (VT/VF) is a kind of malignant arrhythmia in ST-segment elevation myocardial infarction (STEMI) patients who received primary percutaneous coronary intervention (PPCI). However, there are no risk assessment tools to anticipate the occurrence of VT/VF.This study is to build a risk assessment model to predict the possibility of VT/VF onset in STEMI patients undergoing PPCI.A retrospective study was conducted to analyze the patients who underwent PPCI from January 2006 to May 2015. Subjects were divided into VT/VF group and no VT/VF group based on whether VT/VF had occurred or not. In addition, the VT/VF group was further separated into early-onset group (from the time that symptoms began to before the end of PPCI) and late-onset group (after the end of PPCI) based on the timing of when VT/VF happened. Multivariate regression analysis was carried out to distinguish the independent risk factors of VT/VF and an additional statistical method was executed to build the risk assessment model.A total of 607 patients were enrolled in this study. Of these patients, 67 cases (11%) experienced VT/VF. In addition, 91% (61) of patients experienced VT/VF within 48 h from the time that the symptoms emerged. Independent risk factors include: age, diabetes mellitus, heart rate, ST-segment maximum elevation, ST-segment total elevation, serum potassium, left ventricular ejection fraction (LVEF), culprit artery was right coronary artery, left main (LM) stenosis, Killip class > I class, and pre-procedure thrombolysis in myocardial infarction (TIMI) flow zero grade. Risk score model and risk rank model have been established to evaluate the possibility of VT/VF. Class I: ≤ 4 points; Class II: > 4 points, ≤ 5.5 points; Class III: > 5.5 points, < 6.5 points; and Class IV ≥ 6.5 points. The higher the class, the higher the risk.The incidence of VT/VF in STEMI patients undergoing PPCI is 11% and it occurs more frequently from the time that symptoms begin to before the end of PPCI, which, in most cases, occurs within 48 h of the event. Our risk assessment model could predict the possible occurrence of VT/VF.

Mechanisms of cardiac ethanol toxicity and novel treatment options

Ethanol can acutely and chronically alter cardiomyocyte and whole-organ function in the heart. Importantly, ethanol acutely and chronically predisposes to arrhythmias, while chronic abuse can induce heart failure. However, the molecular mechanisms of ethanol toxicity in the heart are incompletely understood. In this review, we summarize the current mechanistic knowledge on cardiac ethanol toxicity, with a focus on druggable pathways. Ethanol effects on excitation-contraction coupling, oxidative stress, apoptosis, and cardiac metabolism, as well as effects of ethanol metabolites will be discussed. Important recent findings have been gained by investigation of acute ethanol effects. These include a renewed focus on reactive oxygen species (ROS) and induction of SR Ca²⁺ leak by CaMKII-mediated pathways downstream of ROS. Furthermore, a clinical outlook into potential novel treatment options is provided.

Modifier genes for sudden cardiac death

Genetic conditions, even those associated with identical gene mutations, can present with variable clinical manifestations. One widely accepted explanation for this phenomenon is the existence of genetic factors capable of modifying the consequences of disease-causing mutations (modifier genes). Here, we address the concepts and principles by which genetic factors may be involved in modifying risk for cardiac arrhythmia, then discuss the current knowledge and interpretation of their contribution to clinical heterogeneity. We illustrate these concepts in the context of two important clinical conditions associated with risk for sudden cardiac death including a monogenic disorder (congenital long QT syndrome) in which the impact of modifier genes has been established, and a complex trait (life-threatening arrhythmias in acute myocardial infarction) for which the search for genetic modifiers of arrhythmic risk is more challenging. Advances in understanding the contribution of modifier genes to a higher or lower propensity towards sudden death should improve patient-specific risk stratification and be a major step towards precision medicine.