Marked Variability in Susceptibility to Ventricular Fibrillation in an Experimental Commotio Cordis Model

Pulmonary contusion with hemoptysis from lacrosse ball strike: A case report

Lacrosse, a sport of increasing popularity, is played with netted sticks and a firm rubber ball propelled at speeds frequently reaching over 100 miles/hour. While lacrosse injuries have been previously described, little published literature exists on lacrosse balls causing pulmonary contusion. We present a case of a 17-year-old male lacrosse player athlete who suffered a lacrosse ball strike to the left posterolateral chest, leading to a clinical presentation of local bruising, shortness of breath, and hemoptysis. Despite delayed arrival to the emergency room, where imaging revealed pulmonary contusion, multidisciplinary supportive management led to favorable clinical outcome with no residual effect on athletic ability and quality of life. Although pulmonary contusion may be a rare injury in the setting of thoracic trauma from lacrosse ball strikes, prompt evaluation and a high index of suspicion can rule out more life-threatening processes and ensure an excellent clinical prognosis.

2024 HRS expert consensus statement on arrhythmias in the athlete: Evaluation, treatment, and return to play

Youth and adult participation in sports continues to increase, and athletes may be diagnosed with potentially arrhythmogenic cardiac conditions. This international multidisciplinary document is intended to guide electrophysiologists, sports cardiologists, and associated health care team members in the diagnosis, treatment, and management of arrhythmic conditions in the athlete with the goal of facilitating return to sport and avoiding the harm caused by restriction. Expert, disease-specific risk assessment in the context of athlete symptoms and diagnoses is emphasized throughout the document. After appropriate risk assessment, management of arrhythmias geared toward return to play when possible is addressed. Other topics include shared decision-making and emergency action planning. The goal of this document is to provide evidence-based recommendations impacting all areas in the care of athletes with arrhythmic conditions. Areas in need of further study are also discussed.

Development of the NOCSAE Standard to Reduce the Risk of Commotio Cordis

BACKGROUND

Commotio cordis, sudden cardiac death (SCD) caused by relatively innocent impact to the chest, is one of the leading causes of SCD in sports. Commercial chest protectors have not been demonstrated to mitigate the risk of these SCDs.

METHODS

To develop a standard to assess chest protectors, 4 phases occurred. A physiological commotio cordis model was utilized to assess variables that predicted for SCD. Next, a surrogate model was developed based on data from the physiological model, and the attenuation in risk was assessed. In the third phase, this model was calibrated and validated. Finally, National Operating Committee on Standards for Athletic Equipment adopted the standard and had an open review process with revision of the standard over 3 years.

RESULTS

Of all variables, impact force was the most robust at predicting SCD. Chest wall protectors which could reduce the force of impact to under thresholds were predicted to reduce the risk of SCD. The correlation between the experimental model and the mechanical surrogate ranged from 0.783 with a lacrosse ball at 30 mph to 0.898 with a baseball at 50 mph. The standard was licensed to National Operating Committee on Standards for Athletic Equipment which initially adopted the standard in January 2018, and finalized in July 2021.

CONCLUSIONS

An effective mechanical surrogate based on physiological data from a well-established model of commotio cordis predicts the reduction in SCD with chest protectors. A greater reduction in force provides a great degree of protection from commotio cordis. This new National Operating Committee on Standards for Athletic Equipment standard for chest protectors should result in a significant reduction in the risk of commotio cordis on the playing field.

Commotio cordis in non-sports-related injury: A scoping review

Commotio cordis is a rare but life-threatening condition characterized by sudden cardiac arrest resulting from a blunt chest impact. While commotio cordis has traditionally been associated with sports-related activities, a significant proportion of cases occur in non-sport-related settings, such as assaults, motor vehicle accidents (MVAs), and daily activities. This critical review examines the epidemiology, clinical characteristics, and outcomes of non-sports-related commotio cordis cases, highlighting the need for increased awareness and improved management in these contexts. The review analyzes existing literature, drawing attention to the demographics of non-sports-related cases, which predominantly affect adolescents and young adults, with males being the primary demographic. In contrast to sport-related cases, non-sports-related commotio cordis cases exhibit a wider age range and a higher proportion of female subjects. Mortality rates are significantly higher in non-sports-related commotio cordis cases, largely due to lower rates of cardiopulmonary resuscitation (CPR), limited access to automated external defibrillators (AEDs), and delayed initiation of resuscitative efforts compared to sport-related incidents. This underscores the critical importance of increasing awareness and preparedness in non-sport-related settings. To mitigate the risks associated with non-sports-related commotio cordis, efforts should focus on early recognition of the condition, timely administration of CPR, and the widespread availability and accessibility of AEDs in various environments. Enhanced awareness and education can potentially lead to a reduction in mortality and improved outcomes for individuals affected by commotio cordis outside of sports-related activities. In conclusion, commotio cordis is not exclusive to sports and presents a significant health risk in non-sport-related scenarios. This review emphasizes the urgent need for increased awareness, preparedness, and resuscitation measures in non-sports contexts to address the higher mortality associated with these cases.

Commotio Cordis in Non-Sport-Related Events: A Systematic Review

BACKGROUND

Commotio cordis is an increasingly recognized cause of sudden cardiac death. Although commonly linked with athletes, many events occur in non-sport-related settings.

OBJECTIVES

The goal of this study was to characterize and compare non-sport-related vs sport-related commotio cordis.

METHODS

PubMed and Embase were searched for all cases of commotio cordis from inception to January 5, 2022.

RESULTS

Of 334 commotio cordis cases identified, 121 (36%) occurred in non-sport-related contexts, which included assault (76%), motor vehicle accidents (7%), and daily activities (16%). Projectiles were implicated significantly less in non-sport-related events (5% vs 94%, respectively; P < 0.001). Nonprojectile etiologies in non-sport-related events mostly consisted of impacts with body parts (79%). Both categories affected similar younger aged demographic (P = 0.10). The proportion of female victims was significantly higher in non-sport-related events (13% vs 2%, respectively; P = 0.025). Mortality was significantly higher in non-sport-related events (88% vs 66%, respectively; P < 0.001). In non-sport-related events, rates of cardiopulmonary resuscitation (27% vs 97%, respectively; P < 0.001) and defibrillation (17% vs 81%, respectively; P < 0.001) were both lower and resuscitation was more commonly delayed beyond 3 min (80% vs 5%, respectively; P < 0.001).

CONCLUSIONS

Commotio cordis occurs across a spectrum of non-sport-related settings including assault, motor vehicle accidents, and daily activities. Both categories affected a younger and male-predominant demographic. Mortality is higher in non-sport-related commotio cordis, likely owing to lower rates of cardiopulmonary resuscitation, defibrillation, automated external defibrillator availability, and extended time to resuscitation. Increased awareness of non-sport-related commotio cordis is essential to develop a means of prevention and mortality reduction, with earlier recognition and prompt resuscitation measures.

A Soccer Shot with Lengthy Consequences—Case Report & Current Literature Review of Commotio Cordis

(1) Background: Commotio cordis, caused by objects being directly delivered to the chest, may cause cardiac arrest in young athletes, even without identifiable structural damage to the sternum, ribs or heart itself. Its prevention and management often remain suboptimal, resulting in dismal outcomes. (2) Case summary: A 32-year semi-professional goalkeeper suffered from a non-penetrating blunt thoracic trauma after being struck by a high-velocity shot during a regional league soccer game. He immediately lost consciousness, collapsed, and was successfully resuscitated through early defibrillation of ventricular fibrillation. After an uneventful follow-up for approximately 6 years, recurrent episodes of ventricular tachycardia occurred, which could ultimately only be prevented by epicardial ablation. (3) Conclusion: Very late recurrences of ventricular tachyarrhythmias may occur after ventricular fibrillation due to blunt chest trauma, even in the primary absence of evident structural myocardial damage.

Blunt Trauma to the Heart: A Review of Pathophysiology and Current Management

Blunt cardiac injury (BCI), defined as an injury to the heart from blunt force trauma, ranges from minor to life-threatening. The majority of BCIs are due to motor vehicle accidents; however, injuries caused by falls, blasts, and sports-related injuries also can be sources of BCI. A significant proportion of patients with BCI do not survive long enough to receive medical care, succumbing to their injuries at the scene of the accident. Additionally, patients with blunt trauma often have coexisting injuries (brain, spine, orthopedic) that can obscure the clinical picture; therefore, a high degree of suspicion often is required to diagnose BCI. Traditionally, hemodynamically stable injuries suspicious for BCI have been evaluated with electrocardiograms and chest radiographs, whereas hemodynamically unstable BCIs have received operative intervention. More recently, computed tomography and echocardiography increasingly have been utilized to identify injuries more rapidly in hemodynamically unstable patients. Transesophageal echocardiography can play an important role in the diagnosis and management of several BCIs that require operative repair. Close communication with the surgical team and access to blood products for potentially massive transfusion also play key roles in maintaining hemodynamic stability. With proper surgical and anesthetic care, survival in cases involving urgent cardiac repair can reach 66%-to-75%. This narrative review focuses on the types of cardiac injuries that are caused by blunt chest trauma, the modalities and techniques currently used to diagnose BCI, and the perioperative management of injuries that require surgical correction.

Commotio Cordis Resulting from Sibling Rivalry

A 17-year-old girl with no significant medical, surgical, or family history presented to the emergency department following an episode of sudden cardiac arrest after being punched in the chest by her brother. Bystander CPR was immediately initiated, and she was found to be in ventricular fibrillation by emergency services. The patient had return of spontaneous circulation after one defibrillation event. No other significant injuries were found, and she eventually experienced a complete neurologic recovery and was discharged with no other identified cause for her arrest. The objective of this clinical case report is to highlight this unusual and rare injury to increase awareness and avoid incorrect diagnosis.

Cardiac Mechano-Electric Coupling: Acute Effects of Mechanical Stimulation on Heart Rate and Rhythm

The heart is vital for biological function in almost all chordates, including humans. It beats continually throughout our life, supplying the body with oxygen and nutrients while removing waste products. If it stops, so does life. The heartbeat involves precise coordination of the activity of billions of individual cells, as well as their swift and well-coordinated adaption to changes in physiological demand. Much of the vital control of cardiac function occurs at the level of individual cardiac muscle cells, including acute beat-by-beat feedback from the local mechanical environment to electrical activity (as opposed to longer term changes in gene expression and functional or structural remodeling). This process is known as mechano-electric coupling (MEC). In the current review, we present evidence for, and implications of, MEC in health and disease in human; summarize our understanding of MEC effects gained from whole animal, organ, tissue, and cell studies; identify potential molecular mediators of MEC responses; and demonstrate the power of computational modeling in developing a more comprehensive understanding of ‟what makes the heart tick.ˮ.

Commotio cordis and L-type calcium channel mutation: Is there a link?

Commotio cordis is a rare phenomenon when ventricular fibrillation and sudden death occurs with a blunt, nonpenetrating blow to the chest. Individual susceptibility to commotio cordis has been demonstrated in swine models, and might be present in humans as well. We report a case of commotio cordis in an adolescent with a heterozygous mutation on the gene CACNA1C, encoding for an L-type calcium channel expressed in the heart. This genetic mutation has been previously associated with a phenotype of long-QT syndrome; however, this was not demonstrated in our patient despite extensive investigations. To the best of our knowledge, this is the first report of commotio cordis in which an ion-channel gene mutation involved in repolarization abnormalities has been documented. This finding might corroborate the hypothesis that a genetic predisposition plays a role in the individual susceptibility to this rare cause of cardiac arrest.

Idiopathic short-coupled ventricular tachyarrhythmias: Systematic review and validation of electrocardiographic indices

INTRODUCTION

Idiopathic short-coupled ventricular tachyarrhythmias make up a considerable proportion of ventricular tachyarrhythmias in structurally normal hearts and are the cause of 5-10% of unexpected sudden cardiac deaths. There is disparity in the literature regarding their description and a lack of formal diagnostic criteria to define them.

OBJECTIVE

To validate ECG indices for the diagnosis of these ventricular tachyarrythmias and to subsequently unify their differing descriptions in the literature under a new terminology: Idiopathic Short-Coupled Ventricular Tachyarrhythmias.

METHODS

We conducted a systematic review of all published studies describing short-coupled torsades de pointes, idiopathic ventricular fibrillation and polymorphic ventricular tachycardia. Published tracings were analysed using a standard set of criteria to define the different ECG intervals. Previously proposed diagnostic indices were validated using a control group of previously published long-coupled torsades de pointes cases.

RESULTS

Validation of the ECG indices revealed that a coupling interval < 400 ms was the most reliable measurement (sensitivity 100%, specificity 97%), followed by a coupling interval/QT < 1 (sensitivity 96%, specificity 100%).

CONCLUSION

Idiopathic short-coupled ventricular tachyarrhythmias encompass all previous descriptions of this tachyarrhythmia including idiopathic ventricular fibrillation, short-coupled torsades de pointes, Purkinje-related torsades de pointes and idiopathic polymorphic ventricular tachycardia. This arrhythmia can be diagnosed by newly proposed criteria with high sensitivity and specificity.

Size as an Important Determinant of Chest Blow-induced Commotio Cordis

PURPOSE

Commotio cordis is sudden cardiac death caused by a relatively innocent blow to the left chest wall. Adolescents account for the majority of the cases; whether this is due to the higher frequency of adolescents playing ball sports or whether there is some maturational reduction of risk is not known.

METHODS

In a swine model of commotio cordis, the effect of body weight/size (directly related to age) to the susceptibility of chest impact-induced ventricular fibrillation (VF) is examined.

METHODS

Ball impacts were delivered at escalating velocities from 48.3 to 96.9 km·h (30-60 mph) to 128 swine ranging in weight from 5 to 54 kg.

RESULTS

VF occurred in 29% of impacts to the smallest animals compared with 34% in the 14- to 239-kg group, 27% in the 24- to 33.9-kg group, 30% in 34- to 43-kg group, and 15% in the 44- to 54-kg animals. The highest-weight group was associated with a significantly lower incidence of VF compared with other weights (P = 0.002). In a multivariate logistic regression analysis, controlling for repeated measures, four variables predicted VF: body weight (P = 0.0008), velocity (P < 0.0001), distance from the center of the heart, (P < 0.0001), and peak left ventricular pressure induced by the blow (P = 0.0007).

CONCLUSIONS

In this experimental model, animals weighing <44 kg seem to have a similar susceptibility to commotio cordis, whereas animals weighing ≥44 kg have a lower susceptibility. An increase in size of the individual, rather than reduced play of ball sports, is the likely reason for the decreased commotio cordis incidence in older individuals.

Mechanically Induced Ectopy via Stretch-Activated Cation-Nonselective Channels Is Caused by Local Tissue Deformation and Results in Ventricular Fibrillation if Triggered on the Repolarization Wave Edge (Commotio Cordis)

Supplemental Digital Content is available in the text.

Background—

External chest impacts (commotio cordis) can cause mechanically induced premature ventricular excitation (PVE_M) and, rarely, ventricular fibrillation (VF). Because block of stretch-sensitive ATP-inactivated potassium channels curtailed VF occurrence in a porcine model of commotio cordis, VF has been suggested to arise from abnormal repolarization caused by stretch activation of potassium channels. Alternatively, VF could result from abnormal excitation by PVE_M, overlapping with normal repolarization-related electric heterogeneity. Here, we investigate mechanisms and determinants of PVE_M induction and its potential role in commotio cordis–induced VF.

Methods and Results—

Subcontusional mechanical stimuli were applied to isolated rabbit hearts during optical voltage mapping, combined with pharmacological block of ATP-inactivated potassium or stretch-activated cation-nonselective channels. We demonstrate that local mechanical stimulation reliably triggers PVE_M at the contact site, with inducibility predicted by local tissue indentation. PVE_M induction is diminished by pharmacological block of stretch-activated cation-nonselective channels. In hearts where electrocardiogram T waves involve a well-defined repolarization edge traversing the epicardium, PVE_M can reliably provoke VF if, and only if, the mechanical stimulation site overlaps the repolarization wave edge. In contrast, application of short-lived intraventricular pressure surges neither triggers PVE_M nor changes repolarization. ATP-inactivated potassium channel block has no effect on PVE_M inducibility per se, but shifts it to later time points by delaying repolarization and prolonging refractoriness.

Conclusions—

Local mechanical tissue deformation determines PVE_M induction via stretch-activation of cation-nonselective channels, with VF induction requiring PVE_M overlap with the trailing edge of a normal repolarization wave. This defines a narrow, subject-specific vulnerable window for commotio cordis–induced VF that exists both in time and in space.

Sudden cardiac death in the young: the bogeyman

Sudden cardiac death in the young is a relatively uncommon but marked event usually related to congenital diseases or anomalies. Despite the prevalence of each condition being variable, most common causes include primary myocardial diseases and arrhythmic disorder, frequently with inheritance pattern. Sudden cardiac death is usually preceded by symptoms, thus making personal and family history fundamental for its prevention. Nevertheless, in more than 50% of cases, sudden cardiac death is the first manifestation of the disease. In this review, we describe the different causes of sudden cardiac death, their incidence, and currently used preventive strategies.

Pathophysiology, prevention, and treatment of commotio cordis

Commotio cordis is increasing described and it is now clear that this phenomenon is an important cause of sudden cardiac death on the playing field. Victims are predominantly young, male, and struck in the left chest with a ball. An animal model has been developed and utilized to explore the important variables and mechanism of commotio cordis. Impact during a narrow window of repolarization causes ventricular fibrillation. Other important variables include location, velocity, shape, and hardness of the impact object. Biological characteristics such as gender, pliability of the chest wall, and genetic susceptibility also play a role in commotio cordis. The mechanism of ventricular fibrillation appears to be an increase in heterogeneity of repolarization caused by induced abnormalities of ion channels activated by abrupt increases in left ventricular pressure. In the setting of altered repolarization a trigger of ventricular depolarization (premature ventricular depolarization caused directly by the chest blow) initiates a spiral wave that quickly breaks down into ventricular fibrillation. Prevention of commotio cordis is possible. Improved recognition and resuscitation have led to an improvement in outcome.

Normal electrocardiographic and echocardiographic (M-mode and two-dimensional) values in Polish Landrace pigs

BACKGROUND

Swine are recognized animal models of human cardiovascular diseases. Normal values of cardiac morphology and function have been published for swine but for smaller number of pigs and not for swine whose weights ranged up 100 kg. In order to improve the value of results of an investigation on cardiac morphology and function in swine when such data are extrapolated to humans, the aim of this study was to document electrocardiographic and echocardiographic measures of cardiac morphology and function in swine. The study comprised 170 single and repeated measurements that were made in 132 healthy domestic swine (Sus domesticus) whose weights ranged between 20-160 kg and were used as controls in three different experiments. All electrocardiographic and echocardiographic measurements in all swine were done under general anaesthesia.

RESULTS

Statistically significant correlations were found between body weight and heart rate (HR), the duration of the P-wave, the duration of the QRS interval, the duration of the QT interval, and the corrected QT ratio (QTc). Since body weight was positively correlated with age, statistically significant correlations were also found between age and HR, the duration of the P-wave, the duration of the QRS interval, the duration of the QT interval, and the QTc. We found that the thickness of the left ventricular wall and the internal diameter of the left ventricle increased with age and body weight. We also found positive trends between body weight and ejection fraction and body weight and fractional shortening. We also found a positive relationship between age, body weight, and the ratio of the left ventricular internal diameter to its wall thickness, as well as the relative left atrial size.

CONCLUSION

Many electro- and echocardiographic measures of cardiac morphology and function of healthy swine are related to their body weight. When the electro- and echocardiographic measures of domestic swine and humans are compared, the most comparable electrocardiographic values are those that were determined in swine whose body weights are not greater than 70 kg. In contrast, the most comparable echocardiographic measures are those that were determined in swine with a body weight of 40-110 kg.

Effects of Pre- and Postconditioning on Arrhythmogenesis in the In Vivo Rat Model

The antiarrhythmic potential of postconditioning in in vivo models remains poorly defined. We compared the effects of pre- and postconditioning on ventricular arrhythmogenesis against controls with and without reperfusion. Wistar rats (n = 40, 269 ± 3 g) subjected to ischemia (30 minutes)–reperfusion (24 hours) were assigned to the following groups: (1) preconditioning (2 cycles), (2) postconditioning (6 cycles), or (3) no intervention and were compared with (4) nonreperfused infarcts and (5) sham-operated animals. Infarct size was measured, and arrhythmogenesis was evaluated with continuous telemetric electrocardiographic recording, heart rate variability indices, and monophasic action potentials (MAPs). During a 24-hour observation period, no differences in mortality were observed. Reperfusion decreased infarct size and ameliorated sympathetic activation during the late reperfusion phase. Preconditioning decreased infarct size by a further 35% ( P = .0017), but only a marginal decrease (by 18%, P = .075) was noted after postconditioning. Preconditioning decreased arrhythmias during ischemia and early reperfusion, whereas postconditioning almost abolished them during the entire reperfusion period. No differences were noted in MAPs or in the magnitude of sympathetic activation between the 2 interventions. Compared to postconditioning, preconditioning affords more powerful cytoprotection, but both interventions exert antiarrhythmic actions. In the latter, these are mainly evident during the ischemic phase and continue during early reperfusion. Postconditioning markedly decreases reperfusion arrhythmias during a prolonged observation period. The mechanisms underlying the antiarrhythmic effects of pre- and postconditioning are likely different but remain elusive.

Mechanisms of ventricular arrhythmias: a dynamical systems-based perspective

Defining the cellular electrophysiological mechanisms for ventricular tachyarrhythmias is difficult, given the wide array of potential mechanisms, ranging from abnormal automaticity to various types of reentry and kk activity. The degree of difficulty is increased further by the fact that any particular mechanism may be influenced by the evolving ionic and anatomic environments associated with many forms of heart disease. Consequently, static measures of a single electrophysiological characteristic are unlikely to be useful in establishing mechanisms. Rather, the dynamics of the electrophysiological triggers and substrates that predispose to arrhythmia development need to be considered. Moreover, the dynamics need to be considered in the context of a system, one that displays certain predictable behaviors, but also one that may contain seemingly stochastic elements. It also is essential to recognize that even the predictable behaviors of this complex nonlinear system are subject to small changes in the state of the system at any given time. Here we briefly review some of the short-, medium-, and long-term alterations of the electrophysiological substrate that accompany myocardial disease and their potential impact on the initiation and maintenance of ventricular arrhythmias. We also provide examples of cases in which small changes in the electrophysiological substrate can result in rather large differences in arrhythmia outcome. These results suggest that an interrogation of cardiac electrical dynamics is required to provide a meaningful assessment of the immediate risk for arrhythmia development and for evaluating the effects of putative antiarrhythmic interventions.

Sudden cardiac death in young athletes and nonathletes

PURPOSE OF REVIEW

This article will review the incidence and most common causes of sudden cardiac death (SCD) in healthy young adults, including competitive athletes, as well as members of the general population.

RECENT FINDINGS

SCD is rare but devastating in a young individual. The incidence of SCD in the young ranges from as low as 0.4 per 100,000 patient-years to as high as 13.4 per 100,000 patient-years. SCD occurs in all populations, not only in athletes.

SUMMARY

Whether SCD is more common in athletes is the cause of continued debate stemming from conflicting data. Hypertrophic cardiomyopathy is the most common underlying cause of SCD in young athletes in most series; however, in nonathletic populations, the underlying causes of SCD are more varied.