Search

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is prominently associated with risk for sudden death and disease progression, largely in young patients. Whether patients of more advanced age harbor similar risks is unresolved, often creating clinical dilemmas, particularly in decisions for primary prevention of sudden death with implantable defibrillators. METHODS AND RESULTS: We studied 428 consecutive HCM patients presenting at >=60 years of age and followed for 5.8±4.8 years; 53% were women. Of the 428 patients, 279 (65%) survived to 73±7 years of age (range, 61-96 years), most (n=245, 88%) with no/mild symptoms, including 135 with >=1 conventional sudden death risk factors and 50 (37%) with late gadolinium enhancement. Over follow-up, 149 (35%) died at 80±8 years of age, mostly from non-HCM-related causes (n=133, 31%), including a substantial proportion from noncardiac disease (n=54). Sixteen patients (3.7%) had HCM-related mortality events (0.64%/y), including embolic stroke (n=6), progressive heart failure or transplantation (n=3), postoperative complications (n=2), and arrhythmic sudden death events (n=5, 1.2% [0.20%/y]). All-cause mortality was increased in HCM patients >=60 years of age compared with an age-matched US general population, predominantly as a result of non-HCM-related diseases (P<0.001; standard mortality ratio, 1.5). CONCLUSIONS: HCM patients surviving into the seventh decade of life are at low risk for disease-related morbidity/mortality, including sudden death, even with conventional risk factors. These data do not support aggressive prophylactic defibrillator implantation at advanced ages in HCM. Other cardiac or noncardiac comorbidities have a greater impact on survival than HCM in older patients. [ABSTRACT FROM AUTHOR]

Physiologic LV remodeling in young trained athletes as a consequence of chronic training can occasionally mimic certain pathologic conditions associated with sudden death, such as HCM. A small but important subset ofelite male athletes may show a borderline increased LV wall thickness of 13 to 15 mm, which defines a gray zone of overlap between the extreme expressions of athlete's heart and a mild HCM phenotype. Such diagnostic ambiguity can be resolved by using the paradigm of noninvasive parameters including testing with echocardiography (and, more recently, with CMR): left atrial and LV chamber dimensions and shape, brief periods of deconditioning to alter LV mass, measurement of oxygen consumption and diastolic filling, and recognition of familial occurrence of HCM or a pathogenic HCM-causing sarcomere mutation. Such distinctions between physiologic/benign athlete's heart and HCM, the most common cause of sudden death in the young in the United States, can be crucial. The recognition of HCM leads to disqualification from intense competitive sports to reduce sudden death risk and, when appropriate, permits initiation of therapeutic interventions.Copyright © 2012 by Elsevier Inc. [ABSTRACT FROM AUTHOR]

Objective: Athletic field risks associated with blunt, nonpenetrating chest blows (commotio cordis) are receiving increasing attention, but the epidemiology of these events is incomplete. Methods: We assessed our Sudden Death in Young Athletes Registry, 1980-2008, to formulate a clinical profile of those sudden deaths attributed to commotio cordis (and other causes) occurring in competitive lacrosse, the most rapidly growing youth sport in the United States. Results: Twenty-three sudden deaths or cardiac arrests were identified in high school and college lacrosse participants. Ages were 18 +/- 2 years; each athlete was male. Ten died after blunt precordial blows, including 4 goalies wearing commercially available chest protectors. Twelve others collapsed because of presumed or documented cardiovascular disease, including hypertrophic cardiomyopathy, long QT syndrome, mitral valve prolapse, or ruptured cerebral aneurysm. The mortality rate associated with lacrosse was 1.46 deaths per 100 000 person-years and was similar to that of other sports including baseball, basketball, football, and hockey. However, deaths attributed to commotio cordis were more frequent in lacrosse (0.63 deaths per 100 000 person-years) than in other sports (P < .02), with the exception of hockey. Conclusions: Sudden deaths in competitive lacrosse participants are rare and no more common than in most other sports. These catastrophic events were caused disproportionately by commotio cordis and included athletes wearing chest barriers, thereby underscoring the importance of developing effective chest protection to create a safer athletic environment for our youth. [ABSTRACT FROM AUTHOR]

Dynamic obstruction to left ventricular (LV) outflow was recognized from the earliest (50 years ago) clinical descriptions of hypertrophic cardiomyopathy (HCM) and has proved to be a complex phenomenon unique in many respects, as well as arguably the most visible and well-known pathophysiologic component of this heterogeneous disease. Over the past 5 decades, the clinical significance attributable to dynamic LV outflow tract gradients in HCM has triggered a periodic and instructive debate. Nevertheless, only recently has evidence emerged from observational analyses in large patient cohorts that unequivocally supports subaortic pressure gradients (and obstruction) both as true impedance to LV outflow and independent determinants of disabling exertional symptoms and cardiovascular mortality. Furthermore, abolition of subaortic gradients by surgical myectomy (or percutaneous alcohol septal ablation) results in profound and consistent symptomatic benefit and restoration of quality of life, with myectomy providing a long-term survival similar to that observed in the general population. These findings resolve the long-festering controversy over the existence of obstruction in HCM and whether outflow gradients are clinically important elements of this complex disease. These data also underscore the important principle, particularly relevant to clinical practice, that heart failure due to LV outflow obstruction in HCM is mechanically reversible and amenable to invasive septal reduction therapy. Finally, the recent observation that the vast majority of patients with HCM have the propensity to develop outflow obstruction (either at rest or with exercise) underscores a return to the characterization of HCM in 1960 as a predominantly obstructive disease. [ABSTRACT FROM AUTHOR]

Commotio cordis (CC), sudden death as a result of a blunt, often innocent-appearing chest wall blow, is being reported with increasing frequency. The clinical spectrum is diverse; however, a substantial number of cases occur in youth athletics. In events that occur during sport, victims are struck by projectiles regarded as standard implements of the game. Sudden death is instantaneous and victims are most often found in ventricular fibrillation (VF). Overall survival is poor; however, successful resuscitation can be achieved with early defibrillation. Autopsy is notable for the absence of any significant cardiac or thoracic injury. Development of an experimental model has allowed for substantial insights into the underlying mechanisms of sudden death. In anesthetized juvenile swine, induction of VF is instantaneous following chest wall blows occurring during a vulnerable window before the T wave peak. Crucial variables including the velocity of impact, impact location, and hardness of the impact object have been identified. Rapid left ventricular (LV) pressure rise following chest impact likely results in activation of ion channels via mechano-electric coupling. The generation of inward current via mechano-sensitive ion channels likely results in augmentation of repolarization and nonuniform myocardial activation, and is the cause of premature ventricular depolarizations that are triggers of VF in CC. While softer-than-standard safety baseballs reduce the risk of CC, commercially available chest protectors are ineffective in preventing CC. The development of more effective chest protectors and more widespread use of automated external defibrillators at youth sporting events are needed. [ABSTRACT FROM AUTHOR]

Medical practice encompasses a diverse spectrum of specialties. Factors that impact selection of clinical disciplines by young physicians may have recently evolved associated with changes in medical school demographics. We assessed whether physicians gravitate to certain practice specialties due to preexisting personality traits. The Neuroticism-Extraversion-Openness Personality Inventory Revised Test was administered prospectively to 130 first-year students the week before they began medical school. Scores for five traits (neuroticism, extraversion, openness, agreeableness, conscientiousness) were compared with the selection among nine medical residencies at the conclusion of medical school. Personality scores for medical students selecting psychiatry residencies showed greater degrees of neuroticism (P < 0.01) and openness (P < 0.03). Students electing family practice also deviated from other specialties, showing a lower degree of neuroticism (P < 0.03). Unexpectedly, personality traits in prospective surgical residents did not differ from those of students choosing nonsurgical residencies. Personality profiles present before medical school appear to predict the selection of some residencies and clinical specialties but not others. [ABSTRACT FROM AUTHOR]

Background: The implanted cardioverter-defibrillator (ICD) has been shown to improve survival in adult patients with high risk acquired cardiac disease, with a cost-effectiveness ratio in the range of $30,000 to $185,000 per quality-adjusted-life-year saved. However, data on the benefit and cost-effectiveness of device therapy in high-risk patients with inherited cardiac disorders are limited.Methods: We developed two separate computer-based analytical models to compare non-ICD with ICD therapy in patients (age range: 10-75 years) with long QT syndrome (LQTS) and hypertrophic cardiomyopathy (HCM). In each disease entity patients were stratified into low-risk (no known risk factors); high-risk (known risk factors [primary prevention]); and very high-risk (prior near-fatal events [secondary prevention]). Net costs were defined as the difference between costs resulting from treatment of the disease and savings due to gained productivity attributable to prevention of sudden cardiac death. Outcome was defined as costs per quality-adjusted life-years saved.Results: In LQTS, defibrillator therapy was shown to be cost effective in high-risk male patients (incremental cost-effectiveness ratio [ICER]=$3328 per quality-adjusted-life-year saved), and cost saving in high-risk females (ICER=$7102 gained per quality-adjusted-life-year saved) and very high-risk males and females (ICER=$15,483 and 19,393 gained per quality-adjusted-life-year saved, respectively). In HCM, defibrillator therapy was cost saving in both male and female high-risk (ICER=$17,892 and $17,526 gained per quality-adjusted-life-year saved, respectively) and very high-risk (ICER $22,944 and $22,329 gained per quality-adjusted-life-year saved, respectively) patients. Defibrillator therapy was not shown to be cost effective in low-risk patients with either LQTS or HCM (ICER in the range of $400,000 to $600,000 lost per quality-adjusted-life-year saved). Sensitivity analyses were consistent with the results in each risk group.Conclusions: In appropriately selected patients with inherited cardiac disorders, early intervention with ICD therapy is cost-effective to cost saving due to added years of gained productivity when the lifespan of an individual at risk is considered. [ABSTRACT FROM AUTHOR]

Stretch-Activated Channel in Commotio Cordis. Introduction:Deaths secondary to low-energy impacts to the precordium in young individuals (commotio cordis) have been reported with increasing frequency. In a swine model, baseball impacts induce ventricular fibrillation when directed at the center of the left ventricle during the vulnerable portion of repolarization just prior to the T-wave peak. It has been hypothesized that activation of stretch-sensitive channels could be crucial for this electrophysiological phenomenon. In this study, a nonselective stretch-activated cation channel was pharmacologically blocked prior to chest blows to determine whether this channel represents a possible pathway by which commotio cordis events occur.Methods:In a randomized and blinded experiment, 12 swine (mean 17.1± 2.5 kg) received either 2-g streptomycin intramuscularly (mean serum concentration 115± 18[mu]M) or sterile water prior to chest impact. Each animal received six precordial impacts with a baseball propelled at 40 mph.Results:There was no significant difference in the frequency of induced VF in the animals administered streptomycin (10 of 19 impacts: 53%) compared to those control animals receiving only sterile water (10 of 31: 32%) (P= 0.15). However, the magnitude of ST segment elevation was less in the streptomycin-treated animals (19± 19 mV) versus controls (61± 46 mV) (P= 0.015).Conclusion:Streptomycin did not alter the frequency of ventricular fibrillation in our commotio cordis model, indicating that the stretch-activated channel is not implicated in the genesis of chest blow-induced cardiac arrest. However, streptomycin did reduce ST elevation following impact suggesting that the stretch-activated channel may play a role in ST segment elevation following chest wall blows.(J Cardiovasc Electrophysiol, Vol. 16, pp. 433-438, April 2005) [ABSTRACT FROM AUTHOR]