Variant Angina and Aborted Sudden Cardiac Death

Characterization of global research trends and prospects on sudden coronary death: A literature visualization analysis

Background

Sudden coronary death is a major global public health issue that has a significant impact on both individuals and society. Nowadays, scholars are active in sudden coronary death all over the world. However, no relevant bibliometric studies have been published. Here, we aim to gain a better understanding the current state of research and to explore potential new research directions through bibliometric analysis.

Methods

Articles and reviews on sudden coronary death from 2012 to 2023 were retrieved from the Web of Science Core Collection (WoSCC). The topic search was conducted using the following keywords: ((("sudden cardiac death" OR "sudden death") AND (coronary OR "myocardial infarction")) OR "sudden coronary death"). Knowledge maps of authors, countries, institutions, journals, keywords, and citations were conducted by CiteSpace. Publication dynamics, hotspots, and frontiers were analyzed independently by authors.

Results

A total of 2914 articles were identified from January 1, 2012 to June 20, 2023. The USA (n = 972) contributed the greatest absolute productivity and UK (centrality = 0.13) built a robust global collaboration. Harvard University was the institution with the highest number of publications (n = 143). Huikuri HV and Junttila MJ were the most published authors who devoted to searching for biomarkers of sudden coronary death. American Journal of Cardiology was the journal with the most publications, and Circulation was the most cited journal. Left ventricular ejection fraction, society, inflammation, and fractional flow reserve became novel burst words that lasted until 2023. Research on etiology and pathology, role of early risk factors in risk stratification, potential predictive biomarkers and novel measurement methods for the prevention and management of sudden coronary death were identified as the research hotspots and frontiers.

Conclusion

Our knowledge and understanding of sudden coronary death have significantly improved. Ongoing efforts should focus on the various etiologies and pathologies of sudden coronary death. Furthermore, a novel sudden coronary death risk model, large-scale population studies, and the rational use of multiple indicators to individualize the assessment of sudden coronary death and other risk factors are other emerging research trends.

Coronary vasospasm: A narrative review

Coronary artery vasospasm (CAVS) plays an important role in acute chest pain syndrome caused by transient and partial or complete occlusion of the coronary arteries. Pathophysiology of the disease remains incompletely understood, with autonomic and endothelial dysfunction thought to play an important role. Due to the dynamic nature of the disease, its exact prevalence is not entirely clear but is found to be more prevalent in East Asian and female population. Cigarette smoking remains a prominent risk factor, although CAVS does not follow traditional coronary artery disease risk factors. Many triggers continue to be identified, with recent findings identifying chemotherapeutics, allergens, and inflammatory mediators as playing some role in the exacerbation of CAVS. Provocative testing with direct visualization is currently the gold-standard for diagnosis, but non-invasive tests, including the use of biomarkers, are being increasingly studied to aid in the diagnosis. Treatment of the CAVS is an area of active research. Apart from risk factor modification, calcium channel blockers are currently the first line treatment, with nitrates playing an important adjunct role. High-risk patients with life-threatening complications should be considered for implantable cardioverter defibrillator (ICD), although timing criteria for escalated therapy require further investigation. The role of pharmaceuticals targeting oxidative stress remains incompletely understood.

Coronary vasospasm as an etiology of recurrent ventricular fibrillation in the absence of coronary artery disease: a case report

Background: Vasospastic angina (VA), or Prinzmetal’s angina, is characterized by symptoms of coronary angina caused by coronary vasospasm, usually in the absence of atherosclerotic changes. It typically presents with chest pain, which can be accompanied by transient electrocardiographic changes, if visualized during the attack. It can also rarely present with severe manifestations of acute myocardial angina, ventricular fibrillation, or cardiac arrest.

Case presentation: We present a case of a 50-year-old Caucasian male who initially presented to the hospital with chest pain and was diagnosed with VA. Later, he was brought to the hospital by emergency medical services later with ventricular fibrillation, despite normal coronary anatomy on angiogram. He was managed with placement of an intra–cardiac defibrillator (ICD) for secondary prevention. The patient continued to have recurrent episodes of ventricular fibrillation with associated ICD shocks, and had multiple admissions to the hospital with similar presentations. Symptoms and arrhythmia improved after optimizing antianginal therapy.

Conclusions: Ventricular fibrillation can be an uncommon but severe manifestation during VA crises. In cases with normal coronary vasculature, it is important to recognize VA as a cause of recurrent ventricular fibrillation in order to optimize medical management for prevention of fatal arrhythmias.

SIRT1/SIRT3 Modulates Redox Homeostasis during Ischemia/Reperfusion in the Aging Heart

Ischemia/reperfusion (I/R) injury is the central cause of global death in cardiovascular diseases, which is characterized by disorders such as angina, stroke, and peripheral vascular disease, finally causing severe debilitating diseases and death. The increased rates of morbidity and mortality caused by I/R are parallel with aging. Aging-associated cardiac physiological structural and functional deterioration were found to contribute to abnormal reactive oxygen species (ROS) production during I/R stress. Disturbed redox homeostasis could further trigger the related signaling pathways that lead to cardiac irreversible damages with mitochondria dysfunction and cell death. It is notable that sirtuin proteins are impaired in aged hearts and are critical to maintaining redox homeostasis via regulating substrate metabolism and inflammation and thus preserving cardiac function under stress. This review discussed the cellular and functional alterations upon I/R especially in aging hearts. We propose that mitochondria are the primary source of reactive oxygen species (ROS) that contribute to I/R injury in aged hearts. Then, we highlight the cardiomyocyte protection of the age-related proteins Sirtuin1 (SIRT1) and Sirtuin1 (SIRT3) in response to I/R injury, and we discuss their modulation of cardiac metabolism and the inflammatory reaction that is involved in ROS formation.

Variability in electrophysiological properties and conducting obstacles controls re-entry risk in heterogeneous ischaemic tissue

Ischaemia, in which inadequate blood supply compromises and eventually kills regions of cardiac tissue, can cause many types of arrhythmia, some life-threatening. A significant component of this is the effects of the resulting hypoxia, and concomitant hyperklaemia and acidosis, on the electrophysiological properties of myocytes. Clinical and experimental data have also shown that regions of structural heterogeneity (fibrosis, necrosis, fibro-fatty infiltration) can act as triggers for arrhythmias under acute ischaemic conditions. Mechanistic models have successfully captured these effects in silico. However, the relative significance of these separate facets of the condition, and how sensitive arrhythmic risk is to the extents of each, is far less explored. In this work, we use partitioned Gaussian process emulation and new metrics for source-sink mismatch that rely on simulations of bifurcating cardiac fibres to interrogate a model of heterogeneous ischaemic tissue. Re-entries were most sensitive to the level of hypoxia and the fraction of non-excitable tissue. In addition, our results reveal both protective and pro-arrhythmic effects of hyperklaemia, and present the levels of hyperklaemia, hypoxia and percentage of non-excitable tissue that pose the highest arrhythmic risks. This article is part of the theme issue 'Uncertainty quantification in cardiac and cardiovascular modelling and simulation'.

Vasospastic Arrest

Vasospastic angina is an uncommon cause of cardiac arrest. We describe a patient who presented with sudden cardiac arrest due to severe coronary vasospasm. Telemetry during the event revealed ventricular arrhythmias and asystole followed by spontaneous self-conversion back to normal sinus rhythm. The patient underwent implantable cardioverter-defibrillator therapy. (Level of Difficulty: Beginner.)

Severe Prinzmetal's Angina Inducing Ventricular Fibrillation Cardiac Arrest

Prinzmetal's angina is a vascular spasm of the coronary artery that can mimic acute coronary syndrome. It is rarely responsible for ventricular arrhythmias and cardiac arrest; however, survivors with these complications are at increased risk for recurrent ventricular arrhythmias and sudden cardiac death. This is true despite the presence of normal cardiac function and optimal medical therapy. Thus, this select population should be considered for an implantable cardioverter defibrillator (ICD). In this case vignette, we describe a healthy 48-year-old female with ventricular fibrillation arrest, followed by recurrent ventricular tachyarrhythmias caused by Prinzmetal's angina.

Occurrence and mortality of vasospastic angina pectoris hospitalised patients in Finland: a population-based registry cohort study

OBJECTIVES

The occurrence and mortality of vasospastic angina pectoris (VAP) is largely unknown in western countries. Our objective was to clarify the occurrence, gender-distribution and mortality of VAP in Finland using a population-based hospital registry.

METHODS

We studied consecutive patients aged ≥18 years hospitalized with VAP as the primary cause of admission in Finland during 2004-2014. The data were collected from obligatory nationwide registries. During the study period 1762 admissions were recorded.

RESULTS

Majority of all VAP patients were male (59.7%) and mean age was 65.7±12.0 years. Annual admission rate for VAP was 2.29/100 000 person-years. Men were in higher risk for VAP than women (admission rate 3.00/100 000 vs 1.68/100 000; RR 1.70; p<0.0001). Gender difference was not modified by age. Likelihood of VAP was highest in population aged 70-84 years. Admission rate for VAP decreased notably during the study period. One-year all-cause mortality was 8.0% and 3-year mortality was 15.5% (cardiac mortality 11.1%). Mortality was associated with increasing age, comorbidity burden and lack of detected coronary artery obstruction, but was similar between genders and during the study period.

CONCLUSIONS

Men have higher risk for vasospastic angina caused admissions. Likelihood of vasospastic angina admission was highest in aged population. The 3-year all-cause mortality was 15.5%. Mortality was associated with increasing age, comorbidities and non-obstructive VAP diagnosis but was similar between genders.

Ectopic beats arise from micro-reentries near infarct regions in simulations of a patient-specific heart model

Ectopic beats are known to be involved in the initiation of a variety of cardiac arrhythmias. Although their location may vary, ectopic excitations have been found to originate from infarct areas, regions of micro-fibrosis and other heterogeneous tissues. However, the underlying mechanisms that link ectopic foci to heterogeneous tissues have yet to be fully understood. In this work, we investigate the mechanism of micro-reentry that leads to the generation of ectopic beats near infarct areas using a patient-specific heart model. The patient-specific geometrical model of the heart, including scar and peri-infarct zones, is obtained through magnetic resonance imaging (MRI). The infarct region is composed of ischemic myocytes and non-conducting cells (fibrosis, for instance). Electrophysiology is captured using an established cardiac myocyte model of the human ventricle modified to describe ischemia. The simulation results clearly reveal that ectopic beats emerge from micro-reentries that are sustained by the heterogeneous structure of the infarct regions. Because microscopic information about the heterogeneous structure of the infarct regions is not available, Monte-Carlo simulations are used to identify the probabilities of an infarct region to behave as an ectopic focus for different levels of ischemia and different percentages of non-conducting cells. From the proposed model, it is observed that ectopic beats are generated when a percentage of non-conducting cells is near a topological metric known as the percolation threshold. Although the mechanism for micro-reentries was proposed half a century ago to be a source of ectopic beats or premature ventricular contractions during myocardial infarction, the present study is the first to reproduce this mechanism in-silico using patient-specific data.