Selective activation of the K(+)(ATP) channel is a mechanism by which sudden death is produced by low-energy chest-wall impact (Commotio cordis)

Commotio cordis: Another cardiac arrest "sine materia". The 1707 early report and interpretation by G.M. Lancisi

Sudden death by commotio cordis is rare. It is the consequence of a blunt trauma of the chest overlying the heart. The mechanism is a cardiac arrest by ventricular fibrillation in the absence of grossly or microscopically apparent myocardial injury. It has been reproduced in animals. The first historical case was reported by Giovanni Maria Lancisi in his book "De Subitaneis Mortibus'' published in 1707. Sudden death occurred in a man receiving a powerful blow under the xiphoid cartilage. Lancisi advanced the hypothesis of acute heart failure by a diastolic stand still ("death in diastole'').

Recurrence of ventricular fibrillation in out-of-hospital cardiac arrest: Clinical evidence and underlying ionic mechanisms

Defibrillation remains the optimal therapy for terminating ventricular fibrillation (VF) in out-of-hospital cardiac arrest (OHCA) patients, with reported shock success rates of ∼90%. A key persistent challenge, however, is the high rate of VF recurrence (∼50-80%) seen during post-shock cardiopulmonary resuscitation (CPR). Studies have shown that the incidence and time spent in recurrent VF are negatively associated with neurologically-intact survival. Recurrent VF also results in the administration of extra shocks at escalating energy levels, which can cause cardiac dysfunction. Unfortunately, the mechanisms underlying recurrent VF remain poorly understood. In particular, the role of chest-compressions (CC) administered during CPR in mediating recurrent VF remains controversial. In this review, we first summarize the available clinical evidence for refibrillation occurring during CPR in OHCA patients, including the postulated contribution of CC and non-CC related pathways. Next, we examine experimental studies highlighting how CC can re-induce VF via direct mechano-electric feedback. We postulate the ionic mechanisms involved by comparison with similar phenomena seen in commotio cordis. Subsequently, the hypothesized contribution of partial cardiac reperfusion (either as a result of CC or CC independent organized rhythm) in re-initiating VF in a globally ischaemic heart is examined. An overview of the proposed ionic mechanisms contributing to VF recurrence in OHCA during CPR from a cellular level to the whole heart is outlined. Possible therapeutic implications of the proposed mechanistic theories for VF recurrence in OHCA are briefly 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: A Comprehensive Review

Commotio cordis is a rare, however, potentially fatal, cardiovascular phenomenon arising from direct chest wall trauma, causing sudden cardiac arrest and potentially death. It is primarily seen in young athletes who participate in contact and organized sports. Though debated, the cause of commotio cordis is believed to involve specific timing of chest impact during ventricular electrical activity leading to severe arrhythmic events. Due to sudden onset, the first step in management is immediate and effective basic life support with automated external defibrillation, followed by advanced cardiac life support. Future considerations should include secondary prevention measures such as protective padding in contact sports. It is paramount that clinicians are vigilant in recognizing potential cases of commotio cordis in the field and provide immediate care. This review consolidates the current understanding of commotio cordis, emphasizing the importance of awareness and early intervention. Future research is warranted, including retrospective and observational studies to identify high-risk patterns or trends associated with the condition.

Advancing Commotio cordis Safety Standards Using the Total Human Models for Safety (THUMS)

Commotio cordis is one of the leading causes of sudden cardiac death in youth baseball. Currently, there are chest protector regulations regarding the prevention of Commotio cordis in baseball and lacrosse; however, they are not fully optimized. For the advancement of Commotio cordis safety, it is vital to include various age groups and a variety of impact angles in the testing process. This study employed finite element models and simulated Commotio cordis-inducing baseball collisions for different velocities, impact angles, and age groups. Commotio cordis risk response was characterized in terms of left ventricular strain and pressure, chest band and rib deformation, and force from impact. Normalized rib and chest band deformation when correlated with left ventricular strain resulted in R2 = 0.72, and R2 = 0.76, while left ventricular pressure resulted in R2 = 0.77, R2 = 0.68 across all velocities and impact angles in the child models. By contrast, the resultant reaction force risk metric as used by the National Operating Committee on Standards for Athletic Equipment (NOCSAE) demonstrated a correlation of R2 = 0.20 in the child models to ventricular strain, while illustrating a correlation to pressure of R2 = 0.74. When exploring future revisions to Commotio cordis safety requirements, the inclusion of deformation-related risk metrics at the level of the left ventricle should be considered.

Commotio Cordis Returns…When We Least Expected It: Cardiac Arrest in A Professional Football Player

For the first time in 52 years, an American professional football player (Damar Hamlin) collapsed in cardiac arrest during a game, viewed in real-time on national television. The cause of this profound event was commotio cordis, that is, blunt non-penetrating chest blow-initiated ventricular fibrillation triggered by physical contact not considered unusual for football. The athlete survived because of timely cardiopulmonary resuscitation and defibrillation provided by first responders organized by the National Football League. Commotio cordis, albeit rare, was most prominently identified initially in competitive and also recreational sports participants. More recently it became apparent that similar events could occur in almost any circumstance involving a chest blow, such as during everyday activities around the home and with innocent play. The determinant of a commotio cordis event is a blow over the heart in a narrow vulnerable electrical window during dispersion of repolarization. Survival from these events has increased substantially to >60% due to enhanced recognition and prompt resuscitation/defibrillation. In conclusion, in this commentary, we take a timely opportunity to describe in detail the relevant demographics, mechanism/pathophysiology, and clinical course of commotio cordis.

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.

An Investigation of Left Ventricular Valve Disorders and the Mechano-Electric Feedback Using a Synergistic Lumped Parameter Cardiovascular Numerical Model

Cardiac diseases and failure make up one of largest contributions to global mortality and significantly detriment the quality of life for millions of others. Disorders in the valves of the left ventricle are a prominent example of heart disease, with prolapse, regurgitation, and stenoses—the three main valve disorders. It is widely known that mitral valve prolapse increases the susceptibility to cardiac arrhythmia. Here, we investigate stenoses and regurgitation of the mitral and aortic valves in the left ventricle using a synergistic low-order numerical model. The model synergy derives from the incorporation of the mechanical, chemical, and electrical elements. As an alternative framework to the time-varying elastance (TVE) method, it allows feedback mechanisms at work in the heart to be considered. The TVE model imposes the ventricular pressure–volume relationship using a periodic function rather than calculating it consistently. Using our synergistic approach, the effects of valve disorders on the mechano-electric-feedback (MEF) are investigated. The MEF is the influence of cellular mechanics on the electrical activity, and significantly contributes to the generation of arrhythmia. We further investigate stenoses and regurgitation of the mitral and aortic valves and their relationship with the MEF and generation of arrhythmia. Mitral valve stenosis is found to increase the sensitivity to arrhythmia-stimulating systolic stretch, and reduces the sensitivity to diastolic stretch. Aortic valve stenosis does not change the sensitivity to arrhythmia-stimulating stretch, and regurgitation reduces it. A key result is found when valve regurgitation is accompanied by diastolic stretch. In the presence of MEF disorder, ectopic beats become far more frequent when accompanied by valve regurgitation. Therefore, arrhythmia resulting from a disorder in the MEF will be more severe when valve regurgitation is present.

Ventricular fibrillation arrest after blunt chest trauma in a 33-year-old man, commotio cordis?

Background

Commotio cordis is an event in which a blunt, non-penetrating blow to the chest occurs, triggering a life-threatening arrhythmia and often sudden death. This phenomenon is often seen in young, male athletes and has become increasingly well-known over the past few decades. We present a unique case in which ventricular fibrillation occurs in an older male athlete after blunt trauma.

Case presentation

Patient with no known medical history was brought to the ER after being found unconscious after a soccer ball kick to the chest. He was found to be in ventricular fibrillation and successfully resuscitated on the soccer field. Patient was admitted to the hospital and lab workup and initial imaging were unremarkable, except elevated troponin and lactate, which returned to normal levels. An echocardiogram showed global left ventricular systolic dysfunction with a visually estimated ejection fraction of 45–50%. Coronary showed angiographically nonobstructive coronary arteries. The patient was diagnosed with commotio cordis and discharged from the hospital in stable condition. Follow-up echocardiogram continued to show low ejection fraction and event monitor demonstrated frequent polymorphic ventricular tachycardia with periods of asystole.

Conclusion

This case is unique in that blunt trauma to the chest from a soccer ball immediately triggered ventricular fibrillation in a patient with a possible cardiomyopathy. It is possible that the blunt trauma caused primary commotio cordis that led to cardiomyopathy in a previous healthy man, or that an underlying cardiomyopathy made it more likely for this to occur. Overall, increased awareness and prevention efforts of blunt chest trauma are required to reduce the high mortality associated life-threatening arrhythmias. There is limited data regarding the interplay between these two entities.

Identifying Vulnerable Impact Locations to Reduce the Occurrence of Deadly Commotio Cordis Events in Children's Baseball: A Computational Approach

Commotio cordis is the second leading cause of sudden cardiac death in young athletes. Currently available chest protectors on the market are ineffective in preventing cases of commotio cordis in young athletes who play baseball. This study focused on using contour maps to identify specific baseball impact locations to the chest that may result in instances of commotio cordis to children during baseball games. By identifying these vulnerable locations, we may design and develop chest protectors that can provide maximum protection to prevent commotio cordis in young athletes. Simulation cases were run using the validated CHARM-10 chest model, a detailed finite element model representing an average 10-year-old child's chest. A baseball model was developed in company with the chest model, and then used to impact the chest at different locations. A 7 × 8 impact location matrix was designed with 56 unique baseball impact simulations. Left ventricle strain and pressure, reaction force between the baseball and chest, and rib deformations were analyzed. Left ventricle strain was highest from baseball impacts directly over the left ventricle (0.34) as well as impacts slightly lateral and superior to the cardiac silhouette (0.34). Left ventricle pressure was highest with impacts directly over the left ventricle (82.94 kPa). We have identified the most dangerous impact locations resulting in high left ventricle strain and pressure. This novel study provided evidence of where to emphasize protective materials for establishing effective chest protectors that will minimize instances of commotio cordis in young athletes.

Cardiovascular mechanosensitive ion channels-Translating physical forces into physiological responses

Cells and tissues are constantly exposed to mechanical stress. In order to respond to alterations in mechanical stimuli, specific cellular machinery must be in place to rapidly convert physical force into chemical signaling to achieve the desired physiological responses. Mechanosensitive ion channels respond to such physical stimuli in the order of microseconds and are therefore essential components to mechanotransduction. Our understanding of how these ion channels contribute to cellular and physiological responses to mechanical force has vastly expanded in the last few decades due to engineering ingenuities accompanying patch clamp electrophysiology, as well as sophisticated molecular and genetic approaches. Such investigations have unveiled major implications for mechanosensitive ion channels in cardiovascular health and disease. Therefore, in this chapter I focus on our present understanding of how biophysical activation of various mechanosensitive ion channels promotes distinct cell signaling events with tissue-specific physiological responses in the cardiovascular system. Specifically, I discuss the roles of mechanosensitive ion channels in mediating (i) endothelial and smooth muscle cell control of vascular tone, (ii) mechano-electric feedback and cell signaling pathways in cardiomyocytes and cardiac fibroblasts, and (iii) the baroreflex.

Developing commotio cordis injury metrics for baseball safety: unravelling the connection between chest force and rib deformation to left ventricle strain and pressure

Commotio cordis is a sudden death mechanism that occurs when the heart is impacted during the repolarization phase of the cardiac cycle. This study aimed to investigate commotio cordis injury metrics by correlating chest force and rib deformation to left ventricle strain and pressure. We simulated 128 chest impacts using a simulation matrix which included two initial velocities, 16 impact locations spread across the transverse and sagittal plane, and four baseball stiffness levels. Results showed that an initial velocity of 17.88 m/s and an impact location over the left ventricle was the most damaging setting across all possible settings, causing the most considerable left ventricle strain and pressure increases. The impact force metric did not correlate with left ventricle strain and pressure, while rib deformations located over the left ventricle were strongly correlated to left ventricle strain and pressure. These results lead us to the recommendation of exploring new injury metrics such as the rib deformations we have highlighted for future commotio cordis safety regulations.

Mechanical activities of self-beating cardiomyocyte aggregates under mechanical compression

Since the discovery of synchronous pulsations in cardiomyocytes (CMs), electrical communication between CMs has been emphasized; however, recent studies suggest the possibility of mechanical communication. Here, we demonstrate that spherical self-beating CM aggregates, termed cardiac spheroids (CSs), produce enhanced mechanical energy under mechanical compression and work cooperatively via mechanical communication. For single CSs between parallel plates, compression increased both beating frequency and beating energy. Contact mechanics revealed a scaling law on the beating energy, indicating that the most intensively stressed cells in the compressed CSs predominantly contributed to the performance of mechanical work against mechanical compression. For pairs of CSs between parallel plates, compression immediately caused synchronous beating with mechanical coupling. Compression tended to strengthen and stabilize the synchronous beating, although some irregularity and temporary arrest were observed. These results suggest that mechanical compression is an indispensable control parameter when evaluating the activities of CMs and their aggregates.

Modelling the cardiac response to a mechanical stimulation using a low-order model of the heart

Heart diseases are one of the leading causes of death worldwide, and a dysfunction of the cardiac electrical mechanisms is responsible for a significant portion of these deaths. One of these mechanisms, the mechano-electric feedback (MEF), is the electrical response of the heart to local mechanical changes in the environment. This electrical response, in turn, leads to macroscopic changes in heart function. In this paper, we demonstrate that the MEF plays a crucial role in mechanical generation and recovery from arrhythmia which has been observed in experimental studies. To this end, we investigate the cardiac response to a mechanical stimulation using a minimal, multiscale model of the heart which couples the organ level dynamics (left ventricular pressure and volume) and contractile dynamics. By including a mechanical stimulation into the model as a (short, sudden) impulse in the muscle microscale stress, we investigate how the timing, amplitude and duration of the impulse affect the cardiac cycle. In particular, when introduced in the diastolic period of the cardiac cycle, the pulse rate can be stabilised, and ectopic beats and bifurcation can be eliminated, either temporarily or permanently. The stimulation amplitude is a key indicator to this response. We find an optimal value of the impulse amplitude above or below which the impulse maximises the stabilisation. As a result a dysfunction of the MEF can be helped using a mechanical stimulation, by allowing the heart to recover its pumping power. On the other hand, when the mechanical stimulation is introduced towards the end of systole, arrhythmia can be generated.

Sudden cardiac death risk in contact sports increased by myocarditis: a case series

Background

Myocarditis is a known cause of sudden cardiac death of the athlete. The impact of direct chest trauma in at-risk sports or activities in patients with a history of myocarditis has never been demonstrated or studied. We report herein two cases of life-threatening ventricular arrhythmia secondary to non-penetrating blunt chest trauma while playing contact sports.

Case summary

The first patient, a 26-year-old man described a brief loss of consciousness after having received blunt impact to the chest (typical intensity) while playing a rugby match. The loss of consciousness was total and proceeded by rapid and regular palpitations. He had a history of viral myocarditis 10 years prior with a fibrotic sequalae in the inferolateral wall on cardiac magnetic resonance imaging (left ventricular ejection fraction 71%). Right apical ventricular pacing induced a sustained monomorphic ventricular tachycardia reproducing the patient's symptoms. A subcutaneous implantable cardioverter-defibrillator was implanted. The second patient is a 22-year-old professional rugby player with no known notable history. During a match, a direct blow to the chest wall was followed by a cardiac arrest. A ventricular fibrillation was cardioverted to pulseless electrical activity. Patient died despite cardiopulmonary resuscitation. An autopsy identified a myocardial sequela of fibrosis with no acute inflammatory remodelling compatible with a previous myocarditis.

Discussion

Myocarditis may increase the risk of life-threatening ventricular arrhythmias caused by blunt impact to the chest, particularly in contact sports. Screening and prevention measures should be considered to reduce this risk.

ACR Appropriateness Criteria® Blunt Chest Trauma-Suspected Cardiac Injury

Blunt cardiac injuries range from myocardial concussion (commotio cordis) leading to fatal ventricular arrhythmias to myocardial contusion, cardiac chamber rupture, septal rupture, pericardial rupture, and valvular injuries. Blunt injuries account for one-fourth of the traumatic deaths in the United States. Chest radiography, transthoracic echocardiography, CT chest with and without contrast, and CT angiography are usually appropriate as the initial examination in patients with suspected blunt cardiac injury who are both hemodynamically stable and unstable. Transesophageal echocardiography and CT heart may be appropriate as examination in patients with suspected blunt cardiac injuries. This publication of blunt chest trauma-suspected cardiac injuries summarizes the literature and makes recommendations for imaging based on the available data and expert opinion. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

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.

Thoracoabdominal Injuries

Trauma to the thorax and abdomen can occur during participation in sports. This chapter reviews some of the more common presentations of such injuries and how such injuries should be best managed. Thoracic injuries reviewed include internal injuries such as pneumothorax, pulmonary contusion, hemothorax, commotio cordis, and cardiac contusion. Chest wall injuries are also reviewed such as rib fractures, costochondritis, and slipping rib syndrome plus sternal and scapular fractures. Abdominal injuries reviewed are focused on internal organ trauma to the spleen and liver, kidney, pancreas, and bowel. There is attention to the effect of Epstein-Barr virus and infectious mononucleosis, seen very frequently in high school and collegiate athletes. Finally, groin pain and athletic pubalgia are described.

In addition to anatomy and clinical presentation, imaging modalities that characterize such trauma are reviewed for each diagnosis. Prevention of thoracoabdominal injuries and return-to-play decisions are described at the chapter conclusion.

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.

Development of a Chest Wall Protector Effective in Preventing Sudden Cardiac Death by Chest Wall Impact (Commotio Cordis)

OBJECTIVE

Commotio cordis, sudden death with chest impact, occurs clinically despite chest wall protectors worn in sports. In an experimental model of commotio cordis, commercially available chest wall protectors failed to prevent ventricular fibrillation (VF). The goal of the current investigation was to develop a chest wall protector effective in the prevention of commotio cordis.

DESIGN

In the Tufts experimental model of commotio cordis the ability of chest protectors to prevent VF was assessed. Impacts were delivered with a 40-mph lacrosse ball, timed to the vulnerable period for VF.

INTERVENTION

A chest wall protector or no chest wall protector (control) was randomly assigned to be placed over the chest. Four iterative series of 2 to 4 different chest wall material combinations were assessed. Materials included 3 different foams (Accelleron [Unequal Technologies, Glen Mills, PA], closed cell high density foam; Airilon [Unequal Technologies, Glen Mills, PA], closed cell low density soft foam; and an open cell memory foam) that were adhered to a layer of TriDur (Unequal Technologies, Glen Mills, PA), a flexible elastomeric coated aramid that was bonded to a semirigid polypropylene polymer (ImpacShield, Unequal Technologies, Glen Mills, PA).

MAIN OUTCOME MEASURE

Induction of VF by chest wall impact was the primary outcome.

RESULTS

Of 80 impacts without chest protectors, 43 (54%) resulted in VF. Ventricular fibrillation with chest protectors ranged from a high of 60% to a low of 5%. Of 12 chest protectors assessed, only 3 significantly lowered the risk of VF compared with impacts without chest protectors. These 3 chest protectors were combinations of Accelleron, Airilon, TriDur, and ImpacShield of different thicknesses. Protection increased linearly with the thicker combinations.

CONCLUSIONS

Effective protection against VF with chest wall protection can be achieved in an experimental model of commotio cordis.

CLINICAL RELEVANCE

Chest protector designs incorporating these novel materials will likely be effective in the prevention of commotio cordis on the playing field.

L-Type Calcium Channels Do Not Play a Critical Role in Chest Blow Induced Ventricular Fibrillation: Commotio Cordis

Background. In a commotio cordis swine model, ventricular fibrillation (VF) can be induced by a ball blow to the chest believed secondary to activation of mechanosensitive ion channels. The purpose of the current study is to evaluate whether stretch induced activation of the L-type calcium channel may cause intracellular calcium overload and underlie the VF in commotio cordis. Method and Results. Anesthetized juvenile swine received 6 chest wall strikes with a 17.9 m/s lacrosse ball timed to the vulnerable period for VF induction. Animals were randomized to IV verapamil (n = 6) or placebo (n = 6). There was no difference in the observed frequency of VF between verapamil (19/26: 73%) and placebo (20/36: 56%) treated animals (p = 0.16). There was also no significant difference in the combined endpoint of VF or nonsustained VF (21/26: 81% in verapamil versus 24/36: 67% in controls, p = 0.22). Conclusions. In this experimental model of commotio cordis, verapamil did not prevent VF induction. Thus, in commotio cordis it is unlikely that stretch activation of the L-type calcium channel with resultant intracellular calcium overload plays a prominent role.

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.

Mechanical effects on KATP channel gating in rat ventricular myocytes

Cardiac K_ATP channels link metabolism with electrical activity. They are implicated in arrhythmias, secretion of atrial natriuretic peptide and protection of the heart from hypertrophy and failure. These processes may involve mechanosensitivity. K_ATP channels can be activated by mechanical stimulation and disrupting the cortical actin increases the activity. We propose that K_ATP channels are modulated by local bilayer tension and this tension is affected by cortical F-actin. Here we measured K_ATP background activity and stretch sensitivity with inside-out patches of rat ventricular myocytes before and after disrupting F-actin. Disrupting F-actin potentiated background activity but did not influence the slope sensitivity in the semilog relationship of NP_o vs. suction that is a measure of the change in dimensions between closed and open states. Thus actin alters prestress on the channel probably by parallel elastic sharing of mean cortical tension with the bilayer.

Effects of mechano-electric feedback on scroll wave stability in human ventricular fibrillation

Recruitment of stretch-activated channels, one of the mechanisms of mechano-electric feedback, has been shown to influence the stability of scroll waves, the waves that underlie reentrant arrhythmias. However, a comprehensive study to examine the effects of recruitment of stretch-activated channels with different reversal potentials and conductances on scroll wave stability has not been undertaken; the mechanisms by which stretch-activated channel opening alters scroll wave stability are also not well understood. The goals of this study were to test the hypothesis that recruitment of stretch-activated channels affects scroll wave stability differently depending on stretch-activated channel reversal potential and channel conductance, and to uncover the relevant mechanisms underlying the observed behaviors. We developed a strongly-coupled model of human ventricular electromechanics that incorporated human ventricular geometry and fiber and sheet orientation reconstructed from MR and diffusion tensor MR images. Since a wide variety of reversal potentials and channel conductances have been reported for stretch-activated channels, two reversal potentials, −60 mV and −10 mV, and a range of channel conductances (0 to 0.07 mS/µF) were implemented. Opening of stretch-activated channels with a reversal potential of −60 mV diminished scroll wave breakup for all values of conductances by flattening heterogeneously the action potential duration restitution curve. Opening of stretch-activated channels with a reversal potential of −10 mV inhibited partially scroll wave breakup at low conductance values (from 0.02 to 0.04 mS/µF) by flattening heterogeneously the conduction velocity restitution relation. For large conductance values (>0.05 mS/µF), recruitment of stretch-activated channels with a reversal potential of −10 mV did not reduce the likelihood of scroll wave breakup because Na channel inactivation in regions of large stretch led to conduction block, which counteracted the increased scroll wave stability due to an overall flatter conduction velocity restitution.

Commotio cordis without arrhythmic event and resuscitation: ECG, echocardiographic, angiographic and cardiovascular resonance imaging study

We describe a case of commotio cordis in which the patient had an extensive cardiac evaluation, including ECGs, a coronary angiogram, a left ventriculogram, repeated echocardiography and cardiovascular MRI (CMRI). A healthy 17-year-old boy sustained an open-handed blow to the anterior part of the chest from a friend with whom he was playing. On admission ECG was performed that showed ST-T alterations and a TNI increase, with echocardiographic evidence of a localised pericardial effusion associated with a persistent myocardial blush at selective angiography. In addition, CMRI confirmed a local delayed enhancement in the same zone. An echocardiogram examination performed 30 days after discharge showed a complete disappearance of pericardial effusion and an improvement on ECG alterations. This is the first case report of a patient with commotio cordis, who did not show any arrhythmias and did not receive any resuscitation procedure, and was extensively studied by imaging methods.

Increasing survival rate from commotio cordis

BACKGROUND

Commotio cordis events due to precordial blows triggering ventricular fibrillation are a cause of sudden death (SD) during sports and also daily activities. Despite the absence of structural cardiac abnormalities, these events have been considered predominantly fatal with low survival rates.

OBJECTIVE

To determine whether expected mortality rates for commotio cordis have changed over time, associated with greater public visibility.

METHODS

US Commotio Cordis Registry was accessed to tabulate frequency of reported SD or resuscitated cardiac arrest over 4 decades.

RESULTS

At their commotio cordis event, 216 study patients were 0.2-51 years old (mean age 15±9 years); 95% were males. Death occurred in 156 individuals (72%), while the other 60 (28%) survived. Proportion of survivors increased steadily with concomitant decrease in fatal events. For the initial years (1970-1993), 6 of 59 cases survived (10%), while during 1994-2012, 54 of 157 (34%) survived (P = .001). The most recent 6 years, survival from commotio cordis was 31 of 53 (58%), with survivor and nonsurvivor curves ultimately crossing. Higher survival rates were associated with more prompt resuscitation (40%<3 minutes vs 5%>3 minutes; P<.001) and participation in competitive sports (39%; P<.001), but with lower rates in African Americans (1 of 24; 4%) than in whites (54 of 166; 33%; P = .004). Independent predictors of mortality were black race (P = .045) and participation in noncompetitive sports (P = .002), with an on-site automated external defibrillator use protective against SD (P = .01).

CONCLUSIONS

Survival from commotio cordis has increased, likely owing to more rapid response times and access to defibrillation, as well as greater public awareness of this condition.

Commotio cordis

Content:

Commotio cordis is blunt, nonpenetrating trauma to the chest resulting in irregular heart rhythm and often leading to sudden death. This article presents the epidemiology, variables leading to commotio cordis, theories on predisposing factors, diagnosis, treatment, treatment outcomes, and return-to-play recommendations.

Evidence Acquisition:

A PubMed (MEDLINE) search for commotio cordis was conducted on July 1, 2008, and it yielded 106 results, of which 26 were used for this review, including experimental models, simulation studies, case analysis studies, case reports, general recommendation, review articles, and editorials.

Results:

There are more than 190 reported cases of commotio cordis in the United States. Forty-seven percent of reported cases occurred during athletic participation. Commotio cordis is the second-most common cause of sudden cardiac death in athletes. Occurrence of commotio cordis is related to time of impact during the cardiac cycle, direct impact over the heart, the hardness and speed of the projectile, and the ineffectiveness of chest barriers. As a result, the US Consumer Product Safety Commission recommends that softer “safety” baseballs be used for youth baseball. Resuscitation using defibrillation was effective in only 15% of cases. Resuscitation within 3 minutes resulted in a survival rate of 25% (17 of 68 cases). Survival drops to 3% when resuscitation is delayed beyond 3 minutes. Survival of commotio cordis has risen from 10% to 15% since 2001. Reduced ventricular ejection fraction has been identified in some commotio cordis survivors.

Conclusion:

Preventive measures, such as using soft “safety” balls and making automated external defibrillators available at sporting venues, can reduce commotio cordis morbidity and mortality. Chest protector designs can be improved to enhance protection. Return to play is best left to clinical judgment given that data are lacking with regard to susceptibility for reoccurrence.

Imprudent blow, catastrophic consequence: a case of commotio cordis associated with violence

Commotio cordis is a rare and catastrophic mechano-electric feedback syndrome, and it is especially apt to occur in male children, adolescents and youths during sports activities. The authors present a case of unexpected sudden death due to commotio cordis associated with violence. In a house of detention, a 19-year-old boy was punched and kicked in the face, neck and chest during a fight with another suspect in their ward. Unfortunately, his precordium was the major injured region. The victim turned pale, then lost the ability to resist and lost consciousness immediately. When the emergency medical personnel arrived, the victim was found in a condition of cardiac and respiratory arrest and he was pronounced dead at the scene without cardiopulmonary resuscitation. Both autopsy signs and forensic morphology were in accord with the criteria for commotio cordis diagnosis, showing no cardiac or other organic fatal lesions and no underlying cardiac diseases; moreover, the toxicological screening was negative for alcohol, drug and common toxicants. In the present case, the whole fight was seen by some witnesses in their ward, and it was recorded by the monitoring unit. Based on the statements of the witnesses and the monitoring videotape, combined with the forensic pathological and toxicological examinations, all the testimonies supported the conclusion that the cause of death was commotio cordis.

Evaluation of injury criteria for the prediction of commotio cordis from lacrosse ball impacts

Commotio Cordis (CC) is the second leading cause of mortality in youth sports. Impacts occurring directly over the left ventricle (LV) during a vulnerable period of the cardiac cycle can cause ventricular fibrillation (VF), which results in CC. In order to better understand the pathophysiology of CC, and develop a mechanical model for CC, appropriate injury criteria need to be developed. This effort consisted of impacts to seventeen juvenile porcine specimens (mass 21-45 kg). Impacts were delivered over the cardiac silhouette during the venerable period of the cardiac cycle. Four impact speeds were used: 13.4, 17.9, 22.4, and 26.8 m/s. The impactor was a lacrosse ball on an aluminum shaft instrumented with an accelerometer (mass 188 g-215 g). The impacts were recorded using high-speed video. LV pressure was measured with a catheter. Univariate binary logistic regression analyses were performed to evaluate the predictive ability of ten injury criteria. A total of 187 impacts were used in the analysis. The criteria were evaluated on their predictive ability based on Somers' D (D) and Goodman-Kruskal gamma (γ). Injury risk functions were created for all criteria using a 2-parameter Weibull distribution using survival analysis. The best criteria for predicting CC were impact force (D=0.52, and γ=0.52) force*compression (D=0.49, and γ=0.49), and impact power (D=0.49, and γ=0.49). All of these criteria proved significant in predicting the probability of CC from projectile impacts in youth sports (p<0.01). Force proved to be the most predictive of the ten criteria evaluated.

Commotio Cordis presenting as a temporary complete atrioventricular block in a 2-year-old girl with congenitally corrected transposition of the great arteries

This report describes a 2-year-old girl with congenitally corrected transposition of the great arteries (ccTGA) who presented with transient complete atrioventricular (AV) block after a mild chest blow. Running around the house with her older sister, she fell to the floor. Her sister also fell and landed on her. The girl became cyanotic and pale and experienced a transient loss of consciousness. At arrival to the emergency department, she had regained consciousness, but she remained pale. An electrocardiogram (ECG) demonstrated complete AV block with a heart rate of 78 beats per minute (bpm). The ECG after admission showed a Wenckebach-type second-degree AV block. Day 2 after admission, a 12-lead ECG showed significant ST and T-wave abnormalities in the precordial leads, but the girl had no chest pain and a normal physical examination. Echocardiography demonstrated normal contractility of the systemic right ventricle. The first-degree AV block and the ST and T-wave abnormalities on the 12-lead ECG improved gradually without abnormal Q-waves. This is the first report of ccTGA in which a transient complete AV block naturally recovered after a presentation with commotio cordis.

Short-term effects of ketamine and isoflurane on left ventricular ejection fraction in an experimental Swine model

Background. General anesthesia is an essential element of experimental medical procedures. Ketamine and isoflurane are agents commonly used to induce and maintain anesthesia in animals. The cardiovascular effects of these anesthetic agents are diverse, and the response of global myocardial function is unknown. Methods. In a series of 15 swine, echocardiography measurements of left ventricular ejection fraction (LVEF) were obtained before the animals received anesthesia (baseline), after an intramuscular injection of ketamine (postketamine) and after inhaled isoflurane (postisoflurane). Results. The mean LVEF of an unanesthetized swine was 47 ± 3%. There was a significant decrease in the mean LVEF after administration of ketamine to 41 + 6.5% (P = 0.003). The addition of inhaled isoflurane did not result in further decrease in mean LVEF (mean LVEF 38 ± 7.2%, P = 0.22). Eight of the swine had an increase in their LVEF with sympathetic stimulation. Conclusions. In our experimental model the administration of ketamine was associated with decreased LV function. The decrease may be largely secondary to a blunting of sympathetic tone. The addition of isoflurane to ketamine did not significantly change LV function. A significant number of animals had returned to preanesthesia LV function with sympathetic stimulation.

Athletes and arrhythmias

Athletes are thought the healthiest segment of the population. Yet, there is a general appearance that athletes are more prone to sudden cardiac death and arrhythmias than nonathletes. Bradycardias in athletes are nearly universal, but advanced heart block is usually pathologic. Athletes may be more prone to atrial fibrillation, but not likely to other types of supraventricular tachycardias. Sudden cardiac death in athletes is rare in the absence of heart disease, with the exception of commotio cordis. Treatment strategies for athletes are focused for the return to athletics. Guidelines for treatment will be derived from the 36th Bethesda Guidelines for athletes, and the European Society of Cardiology (ESC) guidelines for athletes.

Cardiac Arrest after Blunt Chest Injury in a Patient with Undiagnosed Idiopathic Ventricular Fibrillation

We report a case of cardiac arrest occurring in a patient after blunt chest injury with fist during an assault event. The patient survived with prompt cardiopulmonary resuscitation and defibrillation. Subsequent electrophysiology study revealed inducible ventricular fibrillation and automatic implantable cardioverter defibrillator was implanted. The cardiac complications from blunt chest trauma are discussed.

Commotio cordis - under-recognized in Europe?: a case report and review

This case and the review illustrate the induction of a sudden collapse of a football player secondary to a blow to his chest (commotio cordis) [CC]. The article argues that CC probably is under recognized in Europe and cautions that the mounting intensity and speed inherent in modern sports possibly increase the likeliness of CC in the future. If CC occurs, immediate cardiopulmonary resuscitation and automatic external defibrillator should be used.

Sudden cardiac death following blunt chest trauma: commotio cordis

BACKGROUND

There have been numerous reports of sudden cardiac death attributable to the condition of commotio cordis. Primarily, these are reports from the USA. Although three Australian cases have been mentioned in the published literature, the present case appears to be the first described Australian case.

METHODS

A man was brought to the Emergency Department after sudden collapse while playing cricket. His medical history was suggestive of hitting by a cricket ball while batting.

RESULTS

The epidemiology and mechanism of arrhythmia induction in commotio cordis are discussed. The emergency management of commotio cordis is outlined.

CONCLUSIONS

Commotio cordis is rare in sports (and Emergency Medicine). However it has a high mortality rate, and rapid recognition of the condition allows early defibrillation, generally with a good outcome. The improvement of participant care is recommended at community and other sport events.

Models of stretch-activated ventricular arrhythmias

One of the most important components of mechanoelectric coupling is stretch-activated channels, sarcolemmal channels that open upon mechanical stimuli. Uncovering the mechanisms by which stretch-activated channels contribute to ventricular arrhythmogenesis under a variety of pathologic conditions is hampered by the lack of experimental methodologies that can record the 3-dimensional electromechanical activity simultaneously at high spatiotemporal resolution. Computer modeling provides such an opportunity. The goal of this review is to illustrate the utility of sophisticated, physiologically realistic, whole heart computer simulations in determining the role of mechanoelectric coupling in ventricular arrhythmogenesis. We first present the various ways by which stretch-activated channels have been modeled and demonstrate how these channels affect cardiac electrophysiologic properties. Next, we use an electrophysiologic model of the rabbit ventricles to understand how so-called commotio cordis, the mechanical impact to the precordial region of the heart, can initiate ventricular tachycardia via the recruitment of stretch-activated channels. Using the same model, we also provide mechanistic insight into the termination of arrhythmias by precordial thump under normal and globally ischemic conditions. Lastly, we use a novel anatomically realistic dynamic 3-dimensional coupled electromechanical model of the rabbit ventricles to gain insight into the role of electromechanical dysfunction in arrhythmogenesis during acute regional ischemia.

A simple automated stimulator of mechanically induced arrhythmias in the isolated rat heart

Transient stretching of the ventricle can trigger arrhythmias and evoke ventricular fibrillation, especially when the stimulation occurs in the vulnerable period. To explore the sensitivity of small hearts we used a commercial pressure servo to study the kinetic relationship of left ventricular pressure to excitability and arrhythmias in the rat heart. Stimulation protocols were readily composed on the computer and programmed to vary the stimulus amplitude and timing relative to pacing. The pressure-induced premature ventricular excitations were similar to those observed in larger hearts, but the convenience of using small hearts allows the use of inexpensive transgenic animals to explore the molecular basis of transduction.