High Risk Of Sudden Death Research Articles

Syncope... one more case. Arrhythmogenic cardiomyopathy of the right ventricle

Introduction: Syncope is defined as a transitory alteration of the consciousness with spontaneous recovery due to an alteration in general cerebral perfusion and is a very common medical condition in the primary care centers and Emergency. It could be the first manifestation of a cardiac condition (6-30% prevalence), being considered in this situation a bad prognosis marker and high-risk marker of sudden death. Clinical case: Male, 25 years old in the emergency because of syncope. He has had these events three times in the last four months. The patient denies chronic-degenerative diseases and resting EKG shows alteration in repolarization in right precordial electrodes. Discussion: Syncope is a high-prevalence clinical manifestation in the primary care medical centers and ER, the meticulous medical approach in each of the events as the first paraclinical studies are directed toward a cardiac condition as the first differential diagnosis, considering primary electro conduction alteration such as myocardiopathy vs alteration in ion transporting channels which have a genetic origin and have a high risk of sudden death. Conclusions: When following the protocol of one more case of syncope in the ER service, clinical and paraclinical studies conclude a defi nitive diagnosis of arrhythmogenic myocardiopathy in the right ventricle, showing two mayor and two minor principles of genotypifi cation with a report of plakophilin 2 polymorphism.

Usefulness of the WCD in patients with suspected tachymyopathy.

The wearable cardioverter defibrillator (WCD) is used for temporary protection of patients deemed to be at high risk for sudden death. There is limited experience regarding the clinical development of patients with tachymyopathy. We aimed to evaluate the clinical development of tachymyopathy patients protected with a WCD in a single-center non-randomized patient cohort. We fitted 130 consecutive patients deemed to be at high risk for ventricular tachyarrhythmias with the WCD. Of these, 20 patients (15%) presenting with newly diagnosed heart failure in the setting of rapidly conducted atrial fibrillation/flutter were suspected to suffer from tachymyopathy. The control group consisted of the remaining 110 patients with other indications for WCD therapy. LVEF increased by more than 10% in 13/20 (65%) tachymyopathy patients compared to 40/110 (36%) patients in the control population (p = 0.01). Similarly, BNP levels decreased in 15/20 (75%) tachymyopathy patients compared to 41/110 (37%) in the control group (p = 0.05). ICD implantation rates were lower in the tachymyopathy group (3/20) compared to the control population (40/110; p = 0.04). On further follow-up (mean 12 ± 8months), patients with suspected tachymyopathy had no sustained ventricular arrhythmias. Compared to 5/110 patients in the control group, no tachymyopathy patient died. Most of the patients with suspected tachymyopathy have a favorable clinical outcome. The WCD is useful for temporary protection while LV function recovers.

Presence of obesity is associated with lower mortality in elderly patients with implantable cardioverter defibrillator.

Higher body mass index (BMI) is associated with greater prevalence of cardiovascular risk factors, yet an inverse relationship between obesity and survival after cardiovascular events has been described. It is unclear whether a similar relationship exists for patients with implantable cardioverter defibrillators (ICDs) at high risk for mortality. We aimed to assess the impact of BMI on mortality and cardiovascular hospitalization in patients with ICD. Patients who underwent ICD implantation in 2010-2011 were divided into normal (<25 kg m-2), overweight (25-29.9 kg m-2) and obese (⩾30 kg m-2) groups based on BMI. Clinical parameters were compared and long-term outcomes were determined using χ2 test, Wilcoxon's rank-sum test, logistic regression models and Kaplan-Meier curves. Of 904 patients (mean age 67±13 years), 26% had normal BMI, 32% were overweight and 42% were obese. No significant baseline differences in ventricular ejection fraction, ICD for primary or secondary prevention, history of heart failure, syncope or cardiac arrest existed. Despite a greater prevalence of diabetes, hypertension and prior myocardial infarction, the obese and overweight groups had lower mortality (10.1% and 7.9%, respectively) than the normal group (22.9%, P<0.001). On multivariate logistic regression, BMI in the obese and overweight range (odds ratio (OR): 0.35; 95% confidence interval (CI): 0.21-0.58 and OR: 0.25; 95% CI: 0.13-0.40, respectively) was protective against mortality, whereas history of diabetes (OR: 2.01; 95% CI: 1.30-3.09), myocardial infarction (OR: 1.76; 95% CI: 1.11-2.80), heart failure (OR: 3.88; 95% CI: 1.56-9.66), stroke (OR: 3.19; 95% CI: 1.63-6.23) and history of cardiac arrest (OR: 2.65; 95% CI: 1.37-5.15) were independent risk factors for higher mortality. A paradoxical relationship between BMI and mortality risk is present in elderly patients with ICD at high risk of sudden death with a lower mortality in obese or overweight patients than in those with normal BMI.

Chinese doctors are under a high risk of sudden death

Since 2015, the Chinese health-care system reforms have been emphasizing the importance of constructing hierarchical medical system. Hierarchical medical system policy was aimed to enhance the development of primary medical care and redistribute medical resources more rationally. At present, most of patients prefer to go to tertiary hospitals, which increases the working load on doctors there.

Cardiorespiratory arrest at the age of 30

The cardiovascular risk of women is specific and polymorphous. Delays in treatment in women are evident and caused by multiple social and anthropological factors as well as changes to lifestyle habits which are becoming similar to those of men. Young women thereby have a higher risk of sudden death than the rest of the female and general population. A nurse who experienced cardiorespiratory arrest at the age of 30 shares her story.

Cell models of arrhythmogenic cardiomyopathy: advances and opportunities.

ABSTRACTArrhythmogenic cardiomyopathy is a rare genetic disease that is mostly inherited as an autosomal dominant trait. It is associated predominantly with mutations in desmosomal genes and is characterized by the replacement of the ventricular myocardium with fibrous fatty deposits, arrhythmias and a high risk of sudden death. In vitro studies have contributed to our understanding of the pathogenic mechanisms underlying this disease, including its genetic determinants, as well as its cellular, signaling and molecular defects. Here, we review what is currently known about the pathogenesis of arrhythmogenic cardiomyopathy and focus on the in vitro models that have advanced our understanding of the disease. Finally, we assess the potential of established and innovative cell platforms for elucidating unknown aspects of this disease, and for screening new potential therapeutic agents. This appraisal of in vitro models of arrhythmogenic cardiomyopathy highlights the discoveries made about this disease and the uses of these models for future basic and therapeutic research.

Introduction to anomalous aortic origin of a coronary artery.

Anomalous aortic origin of a coronary artery (AAOCA) occurs when both coronary arteries arise from the same aortic sinus from a single ostium or two separate ostia. While most coronary anomalies are benign, the two most common subtypes that predispose to sudden cardiac death in the young are interarterial anomalous right coronary artery and interarterial anomalous left coronary artery. Practitioners face many challenges with AAOCA. Diagnosing patients may be difficult because children and adolescents are often asymptomatic and first presentation may be sudden death or sudden cardiac arrest. Risk stratification is also challenging as determining which unique characteristics place the child at highest risk of sudden death has not been adequately delineated and ischemic testing may give false negative results. Last, there is significant variability in decision making regarding management of youth with AAOCA. Future research is needed to help determine the best way to identify at-risk children and which treatment is the safest and most efficacious.

Arrhythmogenic right ventricular cardiomyopathy: an overview and update

Arrhythmogenic right ventricular cardiomyopathy consists in partial or total progressive replacement of cardiac muscle fibers with a fibro-adipose tissue. This is a hereditary disease with an autosomal dominant inheritance with incomplete penetrance and variable expressivity, except two autosomal recessive syndromes. The most frequent abnormal proteins are that of desmosomal intercellular junctions, such as junctional plakoglobin, plakophilin-2, desmoplakin, desmoglein-2, and desmocollin-2, although other types of non-desmosomal components may be also involved. Desmosomal disorders result in myocardial fibers necrosis and their progressive replacement with fibro-adipose tissue. The morphological modifications are usually beginning in the subepicardial layer and develop towards the endocardium, being associated with the ventricular wall degeneration, thinning, and progressive increase of the amount of adipose tissue. The average age of clinical manifestations onset is around 30-40 years old, with ventricular arrhythmia and high risk of sudden death. Currently, the diagnosis is based on the 2010 Task Force Diagnostic criteria. The current review presents an overview on traditional knowledge about this disease, adding updated information regarding molecular and genetic data. The knowledge of this disease is important for medical practice as a possible cause of arrhythmia and sudden death and its prognosis might be improved by appropiate genetic testing as family screening.

Seattle Heart Failure and Proportional Risk Models Predict Benefit From Implantable Cardioverter-Defibrillators

BackgroundRecent clinical trials highlight the need for better models to identify patients at higher risk of sudden death. ObjectivesThe authors hypothesized that the Seattle Heart Failure Model (SHFM) for overall survival and the Seattle Proportional Risk Model (SPRM) for proportional risk of sudden death, including death from ventricular arrhythmias, would predict the survival benefit with an implantable cardioverter-defibrillator (ICD). MethodsPatients with primary prevention ICDs from the National Cardiovascular Data Registry (NCDR) were compared with control patients with heart failure (HF) without ICDs with respect to 5-year survival using multivariable Cox proportional hazards regression. ResultsAmong 98,846 patients with HF (87,914 with ICDs and 10,932 without ICDs), the SHFM was strongly associated with all-cause mortality (p < 0.0001). The ICD−SPRM interaction was significant (p < 0.0001), such that SPRM quintile 5 patients had approximately twice the reduction in mortality with the ICD versus SPRM quintile 1 patients (adjusted hazard ratios [HR]: 0.602; 95% confidence interval [CI]: 0.537 to 0.675 vs. 0.793; 95% CI: 0.736 to 0.855, respectively). Among patients with SHFM-predicted annual mortality ≤5.7%, those with a SPRM-predicted risk of sudden death below the median had no reduction in mortality with the ICD (adjusted ICD HR: 0.921; 95% CI: 0.787 to 1.08; p = 0.31), whereas those with SPRM above the median derived the greatest benefit (adjusted HR: 0.599; 95% CI: 0.530 to 0.677; p < 0.0001). ConclusionsThe SHFM predicted all-cause mortality in a large cohort with and without ICDs, and the SPRM discriminated and calibrated the potential ICD benefit. Together, the models identified patients less likely to derive a survival benefit from primary prevention ICDs.

Prevalence of Electrocardiographic Patterns Associated With Sudden Cardiac Death in the Spanish Population Aged 40 Years or Older. Results of the OFRECE Study

Introduction and objectivesSome electrocardiographic patterns are associated with an increased risk of sudden cardiac death due to ventricular arrhythmias. There is no information on the prevalence of these patterns in the general population in Spain. The objective of this study was to analyze the prevalence of these patterns and associated clinical and epidemiological factors. MethodsThis subanalysis of the OFRECE study selected a representative sample of the Spanish population aged ≥ 40 years. We studied the presence or absence of electrocardiographic patterns of Brugada syndrome and QT interval abnormalities. Clinical data and electrocardiograms were available in all participants. Electrocardiograms were evaluated by 2 cardiologists and a third cardiologist was consulted if there was disagreement in the diagnosis. We calculated the weighted prevalence and clinical factors associated with the presence of Brugada-type patterns or QT segment abnormalities. ResultsOverall, 8343 individuals were evaluated (59.2 years, 52.4% female). There were 12 Brugada cases (type 1, 2 cases; type 2, 10 cases; weighted prevalence, 0.13%). For corrected QT (QTc) analysis, we excluded participants with left bundle branch block or without sinus rhythm. Weighted prevalences were as follows: short QTc (< 340ms) 0.18%, borderline QTc (441-469ms) 8.33%, long QTc (≥ 470ms criterion) 1.01% and long QTc (≥ 480 criterion) 0.42%. ConclusionsA total of 0.6% to 1.1% of the Spanish population aged ≥ 40 years has an electrocardiographic pattern associated with a higher risk of sudden death (Brugada syndrome, long QT, or short QT).

Genetic testing in cardiomyopathies: an update on indications and benefits.

As rapid genetic testing has become increasingly accessible in a timely fashion, more genetic mutations are identified in inherited conditions such as cardiomyopathies. Understanding when to consider genetic testing is an important part of the management of patients whose presentations vary from decompensated heart failure to sudden cardiac death. We describe the benefits of genetic testing for risk stratification of family members, prognostication of probands, and identification of novel disease-causing mutations and examine the possible role of genetic predisposition in seemingly acquired cardiomyopathies such as peripartum and anthracycline-induced cardiomyopathy. Genetic screening for the recognition of family members who have inherited a cardiomyopathy is important, and testing may identify patients at higher risk of sudden death. However, genetic testing does have its limitations, such as the identification of variants of unknown significance that often complicate the clinical picture.

The Comparison of Voluntary and Forced Exercises on Cardiac Function of DCM Model Mice

Background:Recent studies have demonstrated that exercise has beneficial effects as therapy for heart failure (HF). However, effects of exercise on patients with inherited dilated cardiomyopathy (DCM), one of major causes of HF, has not been established because DCM is associated with high risk of sudden death (SD) by lethal arrhythmia. Recently, a knock-in mouse model of inherited DCM was created. They show similar characteristics to DCM patients and are useful model for evaluating therapeutic effects. We compared effects of voluntary exercise and forced exercise on this model mouse.Methods: We used a knock-in mouse model having one of human inherited DCM mutation, TNNT2 ΔK210, which have decreased Ca2+ sensitivity of myofilaments and show enlarged heart and frequent SD with t1/2 of ∼70 days. Homozygous ΔK210 mice (DCM mice) at 1 month-old were housed with a running wheel (diameter = 12 cm), and daily voluntary running distance was recorded. Other group of DCM mice underwent a forced treadmill exercise every 1-2 days (4 times a week) from 1 month of age. Running period and speed were gradually increased from 11m/min of speed for 15 min to 20m/min for 60 min in initial 2 weeks and kept constant for the rest of the weeks. Following each exercise until 2 month-old, cardiac function was assessed by echocardiography and ECG. Heart, lung and body weights were excised and weighed. Gene expressions of heart failure-related genes were quantified by q-PCR analysis.Results and discussion: Voluntary exercise significantly prolonged t1/2 of DCM mice (from 77 days to 128 days) and attenuated deterioration of left ventricular systolic function. Forced exercise also similarly attenuated the deterioration of systolic function, though the left ventricular wall was significantly thicker than that of voluntary exercise group. Gene expression of αMHC was consistently higher in forced exercise group. We will also discuss other differences between two exercise groups.

Prevalencia de patrones electrocardiográficos asociados a muerte súbita en la población española de 40 años o más. Resultados del estudio OFRECE

Introduction and objectivesSome electrocardiographic patterns are associated with an increased risk of sudden cardiac death due to ventricular arrhythmias. There is no information on the prevalence of these patterns in the general population in Spain. The objective of this study was to analyze the prevalence of these patterns and associated clinical and epidemiological factors. MethodsThis subanalysis of the OFRECE study selected a representative sample of the Spanish population aged ≥ 40 years. We studied the presence or absence of electrocardiographic patterns of Brugada syndrome and QT interval abnormalities. Clinical data and electrocardiograms were available in all participants. Electrocardiograms were evaluated by 2 cardiologists and a third cardiologist was consulted if there was disagreement in the diagnosis. We calculated the weighted prevalence and clinical factors associated with the presence of Brugada-type patterns or QT segment abnormalities. ResultsOverall, 8343 individuals were evaluated (59.2 years, 52.4% female). There were 12 Brugada cases (type 1, 2 cases; type 2, 10 cases; weighted prevalence, 0.13%). For corrected QT (QTc) analysis, we excluded participants with left bundle branch block or without sinus rhythm. Weighted prevalences were as follows: short QTc (< 340ms) 0.18%, borderline QTc (441-469ms) 8.33%, long QTc (≥ 470ms criterion) 1.01% and long QTc (≥ 480 criterion) 0.42%. ConclusionsA total of 0.6% to 1.1% of the Spanish population aged ≥ 40 years has an electrocardiographic pattern associated with a higher risk of sudden death (Brugada syndrome, long QT, or short QT).Full English text available from: www.revespcardiol.org/en

Catecholaminergic polymorphic ventricular tachycardia: a model for genotype-specific therapy.

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a life-threatening syndrome defined by exercise-induced or emotion-induced ventricular arrhythmias, typically caused by gain-of-function mutations in RYR2-encoded ryanodine receptor-2 (RyR2). This review will discuss recent advances and ongoing challenges in devising genotype-specific CPVT therapies. CPVT patients were once universally thought to be at high risk of sudden death; however, as more cases emerge, CPVT is being re-defined as a complex syndrome of variable expressivity. Treatment was traditionally limited to β-blockers and implantable cardioverter defibrillators, and although β-blockers remain a mainstay of treatment, implantable cardioverter defibrillator use is associated with adverse events and should be limited. New applications for older therapies, like flecainide and cardiac denervation, appear to better target the mechanistic basis of CPVT arrhythmias. Recent advances in our understanding of RyR2 structure and function can help in identifying novel therapeutic targets. CPVT is usually related to RyR2 or associated proteins. Emerging studies reveal several genotype-phenotype correlations, which may eventually influence therapeutic decision-making. Flecainide has improved CPVT outcomes and will likely have broader clinical indications in the near future. Gene therapy has shown promise in animal models but has yet to be studied in humans. Sudden death can occur as a sentinel symptom, making preventive therapy that targets molecular mechanism(s) of arrhythmia a key area of ongoing investigation. VIDEO ABSTRACT.

Management of functional Sprint Fidelis leads at cardiac resynchronization therapy-defibrillator generator replacement: a novel option for preventing inappropriate shocks from lead failure in fragile patients with high risk of sudden death.

In patients with a functional Sprint Fidelis lead at generator replacement, the manufacturer recommended to either continue to use the existing lead or replace it with a new lead. For those patients who continue to use a functional Fidelis lead, the risk of inappropriate shocks remains present if the lead fails in the future. We evaluated the feasibility of an alternative approach at the time of cardiac resynchronization therapy-defibrillator (CRT-D) generator replacement in patients with a functional bipolar left ventricular (LV) lead for prevention of inappropriate shocks from future Fidelis lead failure. During the procedure, the pace/sense IS-1 connection pin of the functional Fidelis lead was intentionally inserted into the LV port of the new CRT-D generator, while the existing bipolar LV lead IS-1 connection pin was inserted into the right ventricular (RV) pace/sense port. After such switching, the existing bipolar LV lead was used for functional LV pacing/sensing, while the Fidelis lead was used for functional RV pacing and high voltage shock only and could no longer be used for the purpose of sensing and detecting. This approach precluded oversensing and inappropriate shocks should the functional Fidelis lead fail in the future. Six fragile patients, who were not considered suitable candidates for lead replacement, underwent the alternative approach. During a follow-up of 35 ± 23 months, the CRT-D system functioned normally in five patients. The Fidelis lead fractured in one patient 7 months after generator replacement. The malfunction was detected promptly and the defected lead was replaced. No inappropriate detections or shock was triggered. In CRT-D patients with a functional Fidelis lead and a bipolar LV lead, switching of the Fidelis lead pace/sense IS-1 pin with the bipolar LV lead IS-1 pin at generator replacement did not affect normal system function. This novel approach may be valuable in fragile patients with high risk of sudden death for prevention of inappropriate shocks triggered by oversensing from a malfunctioning Fidelis lead.

The wearable cardioverter-defibrillator in a real-world clinical setting: experience in 102 consecutive patients.

The wearable cardioverter-defibrillator (WCD) is used for temporary protection of patients deemed to be at high risk for sudden death (SCD) not yet meeting indications for the implantable defibrillator (ICD). To evaluate the efficacy, safety, and compliance of/to WCD use and subsequent medium-term outcome of patients in a single-center observational study. A total of 102 consecutive patients were fitted with the WCD from 2012 to 2015 and followed for a mean of 11months (±8months). The most common clinical indication for WCD-prescription (63%) was a new diagnosis of severely impaired LV function (LVEF ≤35%). The median wear time of the WCD was 54days with a daily use of 23h. Appropriate WCD therapy occurred in four patients (seven shocks for VF, one shock for VT). An ICD was finally implanted in 56 patients (55%). Improvement in LV function was the most common reason not to implant an ICD (HR 0.37; 95% CI 0.19-0.73; p=0.004). Two patients had inappropriate shocks from their WCD due to atrial fibrillation/flutter. Five patients fitted with an ICD after the end of WCD therapy suffered VT/VF episodes. After wearing the WCD, six patients died (five ICD recipients and one non-ICD recipient). WCD therapy was well accepted by patients and provided temporary protection against ventricular tachyarrhythmias in patients at risk for SCD. The WCD may help to avoid unnecessary ICD implantations in a significant proportion of patients.

Sudden unexpected infant death in Jordan and the home environment.

The aim of this study was to evaluate maternal common practice for infant sleep care and the home environment, in order to explore the major risk factors associated with sudden unexpected infant death in Jordan. Data were collected via semi-structured questionnaire interview to investigate the sociodemographic features, infant sleep practices and home environments. The sample included 604 mothers with infants <1 year old. Descriptive statistics were generated. Sleep practices were identified as leading factors in unexpected infant death. They included infant head covering (84%), heavy bedding with multiple quilts (81%) or blankets (67%), and co-bedding (66%). Environmental risk factors included high incidence of smoking, exposure to toxic solid fuel heaters during winter and inadequate room ventilation. Factors leading to unexpected infant death were high in Jordan. Unsafe infant sleeping practices and poor environmental factors put infants at high risk of sudden death. Lack of awareness of risk factors increases the risk.

Perioperative morbidity in children with elastin arteriopathy.

Children with elastin arteriopathy (EA), the majority of whom have Williams-Beuren syndrome, are at high risk for sudden death. Case reports suggest that the risk of perioperative cardiac arrest and death is high, but none have reported the frequency or risk factors for morbidity and mortality in an entire cohort of children with EA undergoing anesthesia. The aim of this study was to present one institution's rate of morbidity and mortality in all children with EA undergoing anesthesia and to examine patient characteristics that pose the greatest risk. We reviewed medical records of children with EA who underwent anesthesia or sedation for any procedure at our institution from 1990 to 2013. Cardiovascular hemodynamic indices from recent cardiac catheterization or echocardiography were tabulated for each child. The incidence, type, and associated factors of complications occurring intraoperatively through 48 h postoperatively were examined. Forty-eight patients with confirmed EA underwent a total of 141 anesthetics. There were seven cardiac arrests (15% of patients, 5% of anesthetics) and nine additional intraoperative cardiovascular complications (15% of patients, 6% of anesthetics). Extracorporeal life support was initiated in five cases. There were no perioperative deaths. All children having a cardiac arrest or complication were <3 years old and had biventricular outflow tract obstruction (BVOTO). Subgroup analysis demonstrated high rates of cardiac arrest in two groups: children with BVOTO (44%) and age <3 years old (21%). We have confirmed that the rate of cardiac arrest and complications is significantly elevated in children with EA undergoing anesthesia. Children <3 years old and with BVOTO were at the greatest risk in our population.

Treatment and follow-up study of long QT syndrome with syncope in 11 children

Objective To assess the clinical features and treatment of children with long QT syndrome(LQTS) and syncope. Methods Eleven cases of children with LQTS and syncope between January 2009 and July 2014 in Hunan Children's Hospital were retrospectively analyzed for clinical features, treatment and long term follow-up. Results There were 11 cases of children with LQTS aged 4.0-14.5(9.16±2.71) years, 8 male and 3 female, with syncope more than once.The range of QTc was 460-521(483.72±22.90) ms.For 3 cases of acquired LQTS, 1 case was parathyroid hypothyroidism causing hypocalcemia, 1 case was myocarditis complicated with third degree atrioventricular block, and 1 case showed atrial flutter receiving amiodarone post congenital cardiac surgery.All patients recovered after the inducement removed and primary illness cured.For 8 cases of congenital LQTS, 3 cases of LQTS underwent genetic test (1 case of KCNQ1 gene mutation, 2 cases of KCNH2 gene mutation). One case died after frequent torsade de pointes (Tdp) and ventricular fibrillation during hospitalization, the remaining 7 patients were given oral propranolol, potassium chloride sustained-release tablets after discharge.Follow-up time was 8 to 75 months, an average of (45.73±24.42) months.One case died suddenly at home after 25 months of follow-up.The remaining 6 cases of children with congenital LQTS could withstand general activities without syncope, in which 4 cases had normal QTc by electrocardiography(ECG), and the findings in 2 cases did not change compared with those previously.The QTc returned to normal in children with acquired LQTS in the follow-up review. Conclusions Children with congenital LQTS should receive early genetic screening and genotyping for rational use of drugs.For children with higher risk of sudden death, drug therapy combined with implantable cardioverter defibrillator should be considered.For acquired LQTS, it should be better to remove the inducement and treat primary disease actively. Key words: Child; Long QT syndrome; Syncope; Torsade de points

Ventricular arrhythmias and sudden cardiac death

### Key points There are 50–100 unexpected, sudden cardiac deaths (SCDs) per 100 000 population per year in Europe and USA, categorized by symptom onset to cardiac arrest time of <1 h.1 Despite the decline in coronary artery disease mortality and advancements in resuscitation services, survival from these events remains low. Unfortunately, they often occur outside the hospital environment and are associated with a survival rate of <10%. The majority occur in adults over 35 yr of age and at least half of these events can be attributed to ventricular arrhythmias, although the true incidence is unknown due to inevitable degeneration to asystole if unwitnessed. These arrhythmias may be the presenting complaint in the emergency department and may feature throughout the perioperative period, including at preoperative assessment, during surgery and in the recovery phase, for example in intensive care. They may also be the direct target of therapy in the case of electrophysiological catheter ablation and implantable cardioverter defibrillators (ICDs). They are more frequent and carry greater risks in patients with structural heart disease, but younger patients with ion-channel abnormalities can also be susceptible.2 This review classifies the causes and significance of ventricular arrhythmias based on the presence or absence of structural heart disease and provides a simple system to aid confident distinction from supraventricular arrhythmias. …