Cardiovascular Complaints Among Military Members During Operation Enduring Freedom.

During Operation Enduring Freedom, the US military began deploying a dedicated theater cardiology consultant to Afghanistan in an effort to increase rates of return to duty in service members with cardiovascular complaints. This study was designed to categorize these complaints and determine the effect on both aeromedical evacuation and return to duty rates during a 2.5 year observation period. A total of 1,495 service members were evaluated, with 43% presenting due to chest pain followed by arrhythmias/palpitations (24.5%) and syncope (13.5%). Eighty-five percent of individuals returned to duty, most commonly with complaints of noncardiac chest pain, palpitations, or abnormal electrocardiograms. Fifteen percent were evacuated out of theater, most often with acute coronary syndrome, pulmonary embolus, or ventricular tachycardia. The forward-deployed theater cardiology consultant is vital in the disposition of military members by effectively parsing out life threatening cardiovascular conditions versus low risk diagnoses that can safely return to duty.

Exclusion of left atrial appendage thrombus using single phase coronary computed tomography as compared to transesophageal echocardiography in patients undergoing pulmonary vein isolation.

Background. Transesophageal echocardiography (TEE) is used for the evaluation of the presence of left atrial appendage (LAA) thrombus prior to pulmonary vein isolation (PVI), while coronary computed tomography angiography (CCTA) is used for anatomic mapping during PVI. Methods. We compared the diagnostic performance of single phase CCTA to TEE in excluding the presence of LAA thrombus in patients undergoing PVI in 172 subjects performed during index hospitalization. Results. The mean age was 51 ± 13 years, a median CHADS2 score of 1 [IQR25,75 0,1, range 0-3] and a mean periprocedural INR of 2.1 ± 0.6. The prevalence of an LAA filling defect on single phase CCTA was 9.3% (6/183) and on TEE was 1.2% (2/183). Sensitivity, specificity, positive predictive value, and negative predictive value were 100% (95% CI, 19.8-100%), 91.8% (95% CI, 94-99%), 12.5% (95% CI, 60-76%), and 91.8% (95% CI, 97-100%) for the detection of LAA filling defect, respectively. Conclusion. Given the utility of a preprocedural single phase CCTA for the performance of PVI, the absence of a filling defect negates the need for a subsequent TEE as an adjunct for exclusion of LAA thrombus.

Thermogenic supplement use does not alter characteristics of sudden death in the young.

BACKGROUND: To evaluate supplement use, most notably ephedra, which has been temporally associated with sudden death. Animal models suggest increased myocardial irritability may predispose to primary arrhythmic death. METHODS: Clinical, pathological, and investigative records from the Office of the Armed Forces Medical Examiner's Cardiovascular Death Registry were reviewed. Forty-eight cases of those with known supplement use were compared to 144 age-, gender-, and socioeconomic-matched controls in a 1:3 case:control manner. RESULTS: Of the 48 sudden deaths temporally associated with supplement use, the mean age was 34.2 ± 10.0 years and predominantly male (n = 44, 91.7%). The underlying cause of death was fatal atherosclerotic coronary disease in 18 (37.5%), sudden unexplained death in 16 (33.3%), and hypertrophic cardiomyopathy in six (12.5%). Compared with controls, there were no statistically significant differences in adjudicated cause of death. On autopsy, there were no differences in cardiac mass, ventricular wall thickness, or presence of atherosclerosis in those known to be taking identified supplements compared to a control population. In the subject ≥35 years, and known to be taking supplements, there was a significant increase in causality of death as due to sudden unexplained death (relative risk = 5.1 [95% confidence interval, 1.4-18.7]). CONCLUSIONS: Active surveillance of mortality in an autopsy-derived series of young adults finds atherosclerotic coronary disease and idiopathic sudden death are common etiologies of death when taking supplements, but no cardiac structural or histologic mechanism to suggest different pathologic process than a matched control population.

Management of central venous gradient using excimer laser lead extraction of chronic indwelling pacemaker leads in the setting of ipsilateral arteriovenous fistula.

Device therapy is becoming common in those patients with renal insufficiency. Coexisting need for arteriovenous (AV) fistula placement is often contemplated relative to device placement. We describe the excimer laser lead extraction of a malfunctioning chronic atrial pacemaker lead ipsilateral to an AV fistula.

Chest pain, ST elevation, and positive cardiac enzymes in an austere environment: differentiating smallpox vaccination-mediated myocarditis and acute coronary syndrome in Operation Iraqi Freedom.

BACKGROUND: Myocarditis is a recognized but rare complication of smallpox immunization. It typically presents within 30 days of immunization and on initial presentation shares many characteristics with acute coronary syndrome. Electrocardiogram findings, elevated cardiac enzymes, and undifferentiated chest pain require immediate implementation of therapy directed towards an acute coronary syndrome. In an austere environment, access to advanced care may be limited. OBJECTIVES: Smallpox vaccine-mediated myocarditis may present, typically within 30 days of immunization, in such a fashion that it is impossible to distinguish from acute myocardial infarction. The purpose of this article is to alert the clinician to this problem and to provide information to assist in making a suitable diagnosis and disposition in the absence of an absolute diagnosis. CASE REPORT: We present a case of smallpox vaccine-associated myocarditis in an American serviceman deployed in Iraq, and review the literature to determine management of these cases in an emergency setting. CONCLUSIONS: This case serves to increase awareness of the association of vaccine-mediated myocarditis in the month after immunization, and the fact that it may present similar to infarction. If the clinical probability of myocarditis is greater than infarction, this will lead the clinician to different treatment modalities.

Sudden death in young adults: an autopsy-based series of a population undergoing active surveillance.

OBJECTIVES: The purpose of this study was to define the incidence and characterization of cardiovascular cause of sudden death in the young. BACKGROUND: The epidemiology of sudden cardiac death (SCD) in young adults is based on small studies and uncontrolled observations. Identifying causes of sudden death in this population is important for guiding approaches to prevention. METHODS: We performed a retrospective cohort study using demographic and autopsy data from the Department of Defense Cardiovascular Death Registry over a 10-year period comprising 15.2 million person-years of active surveillance. RESULTS: We reviewed all nontraumatic sudden deaths in persons 18 years of age and over. We identified 902 subjects in whom the adjudicated cause of death was of potential cardiac etiology, with a mean age of 38 ± 11 years. The mortality rate for SCD per 100,000 person-years for the study period was 6.7 for males and 1.4 for females (p < 0.0001). Sudden death was attributed to a cardiac condition in 715 (79.3%) and was unexplained in 187 (20.7%). The incidence of sudden unexplained death (SUD) was 1.2 per 100,000 person-years for persons <35 years of age, and 2.0 per 100,000 person-years for those ≥ 35 years of age (p < 0.001). The incidence of fatal atherosclerotic coronary artery disease was 0.7 per 100,000 person-years for those <35 years of age, and 13.7 per 100,000 person-years for those ≥ 35 years of age (p < 0.001). CONCLUSIONS: Prevention of sudden death in the young adult should focus on evaluation for causes known to be associated with SUD (e.g., primary arrhythmia) among persons <35 years of age, with an emphasis on atherosclerotic coronary disease in those ≥ 35 years of age.

High-velocity penetrating thoracic trauma with suspected cardiac involvement in a combat support hospital.

PURPOSE: The most common cardiac injuries in the United States are blunt trauma from motor vehicle accidents or low-velocity trauma from stabbings. During military conflict, high-velocity injuries, including gunshot wounds (GSW) and fragment injury from improvised explosive devices (IED), are relatively more common. METHODS: This is a retrospective review of cases with high-velocity penetrating injury and suspected myocardial involvement during a 6-month period in Baghdad, Iraq, at a United States Army hospital during Operation Iraqi Freedom. RESULTS: Eleven cases survived to admission (GSW in 5, IED in 6). The mean age of the all-male cohort was 27 years (range, 3-54 years). Eight of the 11 patients (73%) were victims of polytrauma. The entrance involved the right ventricle (n = 3), right atrium (n = 2), left ventricle (n = 1), or mediastinum and pericardial reflections (n = 5). Echocardiography was performed in all 11 patients. In 7 patients, no foreign body was identifiable, and in 2 patients the foreign body was identified within the pericardial fat pad. Three patients were identified as having a suspected ventricular septal defect, ranging in size from 2 to 8 mm. The most common electrocardiographic abnormality was atrioventricular block and right bundle branch block. In 4 patients, the management of the chest injury was nonsurgical, and in 1 patient the treatment was a chest tube only. Four of the patients underwent median sternotomy, 1 underwent emergent lateral thoracotomy, and 1 underwent an infradiaphragmatic approach. CONCLUSION: This case series is too small to draw definitive conclusions; however, a multidisciplinary approach to high-velocity injuries with potential for cardiac involvement augments preoperative assessment for myocardial injury and may allow selective nonoperative management.

Intensive education on evidence-based evaluation of syncope increases sudden death risk stratification but fails to reduce use of neuroimaging.

BACKGROUND: We sought to determine whether aggressive education on evidence-based guidelines would affect the use of resources. Specifically, we sought to educate providers about the role of neuroimaging as well as sudden death risk stratification. METHODS: We reviewed 1092 consecutive cases involving patients who were admitted for syncope. We retrospectively reviewed 30 months of admissions for baseline characteristics and then initiated an intensive monthly education campaign directed toward internal medicine physicians-in-training focusing on evidence-based guidelines for a 13-month period. RESULTS: There were 721 patients (66.0%) evaluated before the education intervention and 371 patients (34.0%) evaluated after the education intervention. After the intervention, there was no change in the use of computed tomography (52.3% vs 55.5%; P = .31) or magnetic resonance imaging (20.2% vs 16.7%; P = .16) of the head or carotid ultrasonography (4.7% vs 6.2%; P = .30). The referral rate for electrophysiologic study significantly increased from 6.4% at baseline to 11.3% (P = .006) after intervention, with an overall diagnostic yield of 28.4%. Of those with identified structural heart disease, the referral rate went from 5.7% to 19.0% (P = .03). Only 66 of 1092 patients who presented with syncope ultimately required a pacemaker or defibrillator implantation during hospitalization. CONCLUSIONS: With intensive education, there was no decrease in neuroimaging, despite a low diagnostic yield. We were able to increase sudden death risk stratification using electrophysiologic studies without evidence of overuse of implantable device-based therapy. Intensive education allows increased adherence to guidelines for mortality reduction; however, further attempts to reduce the lower yield imaging will require methods other than education of hospital-based physicians.

Resource utilization in the management of young patients with syncope in a combat theater of operations.

UNLABELLED: Clinical features of young patients presenting with syncope have been underreported. METHODS: Retrospective review using U.S. Military Health System's Theater Medical Data Store and Joint Medical Workstation identified patients evaluated for syncope from January 2005 to October 2007 while deployed to a combat zone. RESULTS: We identified 848 patients with syncope. The majority (80.8%) were under the age of 40. The diagnostic yield of the ECG was 2.0%. In those <40 years, there were no head CTs or transthoracic echocardiograms that identified a cause of syncope. There was no difference in evacuation out of theater between those <40 years and those >40 years (10.8% vs. 8.6%, p = 0.08). Patients with a prior episode of syncope were more likely to undergo medical evacuation outside of the combat zone (16.0% vs. 7.7%, p < 0.01). DISCUSSION: Evacuation of those <40 years to facilities with advanced imaging did not add diagnostic information.

Differential manifestation of cardiovascular complaints as a function of utilization of ergogenic supplements.

INTRODUCTION: The rate of use of dietary supplements among young adults is significant. While the military makes significant restrictions on the use of certain pharmacologic drugs and actively tests for illegal drugs in a deployed environment, there is a near-unlimited supply of body-enhancing supplements available at military exchanges to deployed personnel. By emphasizing physical performance and providing these for purchase, the military leadership, perhaps unknowingly, endorses the use of these products. Cardiovascular symptoms represent one of the leading nontraumatic causes of aeromedical evacuation from a combat zone. Whether the use of supplements is associated with a differential presentation to cardiovascular complaint is unknown. METHODS: Retrospective review using the US Department of Defense Military Health System data, we identified patients evaluated for cardiovascular complaints of syncope or palpitations while deployed to Iraq and Afghanistan. RESULTS: There were 905 US military personnel who presented with complaint of syncope or palpitations (mean age 31 +/- 10 years, 77% male). There were 83 (9.2%) who self-reported taking an ergogenic supplement. The incidence of reported use of supplements among males was 10.8%, which was significantly higher than its use among females at 3.8% (P = 0.001). In those >30 years, those on supplements had a higher resting pulse (90 +/- 28 vs 79 +/- 24 beats/min, P = 0.032), and the incidence of resting tachycardia was three-fold higher (35.0% vs 11.4%, P = 0.008). Supplement use was seen in 12.3% of those who presented with palpitations, which was significantly higher than those who presented without palpitations (7.8%, P = 0.043). In those taking supplements, symptoms were more likely during exertion (26.5% vs 15.0%, P < 0.001), and immediately postexertional (13.2% vs 4.6%, P < 0.001). An electrocardiogram was suggestive of diagnosis in 103 (16.3%), while head computed tomography, treadmill, and echocardiogram had no diagnostic utility in this patient population. DISCUSSION: In a healthy population serving within a combat zone, there exists a differential expression of disease in those taking supplements. Further study of a prospective nature to determine the impact of supplement use in this environment may allow for a more refined policy toward use and medical evaluation.

Association of electrocardiographic morphology of exercise-induced ventricular arrhythmia with mortality.

BACKGROUND: The prognostic importance of exercise-induced ventricular arrhythmia (EIVA) may be confounded by the presence of lower-risk idiopathic right ventricular outflow tract arrhythmias with left bundle-branch block (LBBB) morphology. OBJECTIVE: To determine whether right bundle-branch block (RBBB)-morphology EIVA was associated with increased mortality. DESIGN: Retrospective cohort. SETTING: Academic medical center. PATIENTS: 585 unique patients with EIVA and 2340 patients without EIVA, matched by age, sex, and risk factor, who were referred for exercise testing in an academic medical center. MEASUREMENTS: Deaths and ischemia and infarction found on perfusion scan. RESULTS: During a mean follow-up of 24 months (SD, 13), 31 deaths occurred in the EIVA group compared with 43 deaths in the group without EIVA (5.3% vs. 1.8%; P < 0.001). Worse survival in patients with RBBB-morphology or multiple-morphology EIVA (6.9%) than in patients without EIVA caused this difference. Patients with LBBB-morphology EIVAs had a mortality rate (2.5%) similar to that of patients without EIVA (P = 0.93, log-rank test). Among patients without known atherosclerotic coronary artery disease, any RBBB-morphology EIVA was associated with death (hazard ratio, 2.73 [95% CI, 1.78 to 4.13]; P < 0.001), but LBBB-morphology EIVA was not (hazard ratio, 0.82 [CI, 0.18 to 2.04]; P = 0.72). LIMITATIONS: Not all LBBB-morphology EIVA can be dismissed, and not all RBBB-morphology EIVA is high risk. Further evaluation of patients for structural heart disease was clinically driven, not protocol-driven. CONCLUSION: Right bundle-branch block- or multiple-morphology EIVA is associated with increased mortality. Inclusion of patients with isolated LBBB-morphology EIVA, which often is idiopathic, may contribute to differences in the prognostic importance of EIVA in previous studies.

Complete heart block following penetrating chest trauma in operation Iraqi freedom.

We present a 30-year-old US army soldier who had penetrating chest trauma from a road side explosive with focal cardiac injury. The soldier had penetration of his right atrium and subsequent traumatic membranous ventricular septal defect and complete heart block. He was brought to a Combat Support Hospital where fortuitously the assigned trauma surgeon on-call was a cardiothoracic surgeon, and the assigned trauma intensivist on-call was a cardiac electrophysiologist. Of course, the only source they knew of a pacemaker was halfway around the world. We discuss the management of this injury in an austere combat environment.

Large, single-center, single-operator experience with transvenous lead extraction: outcomes and changing indications.

BACKGROUND: Lead extraction is increasingly necessary given the exponential growth in cardiac device implantation. Meanwhile, the tools, indications, and outcomes of this procedure continue to change. OBJECTIVE: The purpose of this study was to examine contemporary indications, outcomes, and complications of transvenous lead extraction in a large series of patients at a high-volume lead extraction center. METHODS: We performed a retrospective cohort study of consecutive patients undergoing lead extraction at a single, high-volume center. Patient and lead characteristics and the indications, outcomes, and need for laser assistance were analyzed. RESULTS: From January 2000 to March 2007, a total of 975 chronic endovascular leads were removed from 498 patients. Median implant duration was 5.7 years (range 0.5-32.7 years). Indications were infection (60.3%), mechanical lead failure (29.3%), and upgrade of device system (8.8%). Over the study period, lead malfunction decreased relative to other indications. Laser assistance for extraction was more likely with leads implanted longer than 3.4 years compared to less than 3.4 years (odds ratio 6.15, 95% confidence interval 3.35-11.28) and with implantable cardioverter-defibrillator leads compared to pacemaker leads (odds ratio 3.44, 95% confidence interval 1.84-6.43). Overall, 97.5% of the leads were completely removed. Major complications occurred in 2 (0.4%) patients. Only one patient required cardiac surgery. No deaths occurred. CONCLUSION: In a high-volume center, lead extraction has a high success rate and low complication rate. Infection was the most common indication overall. Lead failure has decreased in relative proportion. Implantable cardioverter-defibrillator leads and longer lead implant time are associated with a requirement for laser lead extraction.

Smallpox vaccination and ischemic coronary events in healthy adults.

Although smallpox vaccine-associated myopericarditis has been reported, the risk of cardiac ischemic events remains uncertain. We identified personnel receiving the smallpox vaccination and compared them to a historical referent population. The rate of cardiac ischemia diagnoses in the 30 days following smallpox vaccination was 140.1 per 100,000 person-years, compared to 143.5 per 100,000 person-years in referent group (RR 1.0 [95% CI: 0.7-1.4]). The rate of cardiac ischemic events in vaccinees was 121.4 per 100,000 person-years before and 175.7 after adopting pre-vaccination cardiac screening (RR 1.4 [95% CI: 0.8-2.7]). Implementation of pre-vaccination cardiac risk factor screening was not associated with a reduction in cardiac events.

Sustained ventricular tachycardia associated with corrective valve surgery.

BACKGROUND: The causes of sustained monomorphic ventricular tachycardia (VT) after cardiac valve surgeries have not been studied extensively, although bundle-branch reentry has been reported. METHODS AND RESULTS: Records of 496 patients referred for electrophysiology study and catheter ablation of recurrent VT were reviewed. Twenty patients (4%) had VT after aortic or mitral valve surgery in the absence of known myocardial infarction. The median age was 53 years, and the median ejection fraction was 45%. In 4 patients, VT occurred early after surgery, and electrophysiology study was performed 3 to 10 days later. In the remaining patients, electrophysiology study was performed a median of 12 years (interquartile range 5 to 15 years) after surgery. Sustained VT was inducible in 17 patients. VT was attributed to scar-related reentry in 14 patients (70%) and to bundle-branch reentry in 2 (10%). Multiple VTs were present in 9 of 14 patients with scar-related reentry. A total of 42 induced VTs were targeted for ablation. Of the 14 patients with scar-related reentry, 9 (64%) had periannular scar, and 10 (71%) had an identifiable endocardial circuit isthmus. Ablation abolished 41 (98%) of the 42 targeted VTs. At a median follow-up of 2.1 years, 3 deaths occurred 8 to 14 months after ablation. One patient with incessant VT early after valve surgery suffered a stroke with residual hemianopsia. Of the 20 patients, 3 required repeat ablation after recurrence, and 2 of these who were not inducible during electrophysiology study had clinical recurrence that necessitated ablation. CONCLUSIONS: Sustained VT after valve surgery appears to be bimodal in presentation, occurring either early after surgery or years later. In this referral population, reentry in a region of scar is more common than bundle-branch reentry. Catheter ablation can be successful.

Myopotentials leading to ventricular fibrillation detection after advisory defibrillator generator replacement.

We present an unusual source of oversensing following an internal cardioverter-defibrillator generator change. The early appearance of reproducible myopotentials in the defibrillator sensing channel is usually due to a technical complication at the time of device implantation. Clues such as abrupt impedance change or reproduction with mechanical stimulation can help to localize a problem. Frequently the complication requires reoperation to examine the system. What do you do when everything seems to be working fine?

Mortality following defibrillator implantation in patients with renal insufficiency.

INTRODUCTION: Patients with renal insufficiency have an increased risk of atherosclerotic coronary artery disease, cardiovascular events, and sudden cardiac death. Due to under-representation of patients with renal disease in large clinical trials, outcomes of implantable cardioverter defibrillator (ICD) implantation in this group remain unclear. METHODS AND RESULTS: Inpatient and ambulatory records were reviewed for 741 consecutive patients undergoing 947 defibrillator implants or replacements at Department of Defense Medical Facilities. Demographics, medical history, and mortality were reviewed. The mean age of the cohort was 64 +/- 14 years and 599 (80.8%) were male. There were 173 patients (23.3%) with chronic renal insufficiency, 22 (3.0%) undergoing hemodialysis, and 546 (73.7%) without reported renal disease. The mean number of annual hospital admissions for heart failure among patients with and without renal failure was 3.8 +/- 4.0 versus 1.2 +/- 1.9 (P < 0.0001), respectively. The 1-year survival for those without renal insufficiency was 96.6%, compared to 87.8% for those with chronic renal insufficiency, and 88.7% for those undergoing hemodialysis. Multivariate analysis demonstrated a significant association between mortality among ICD patients and renal insufficiency, independent of coexisting congestive heart failure, ischemic cardiomyopathy, and diabetes mellitus (P < 0.0001). CONCLUSIONS: Among ICD recipients, those with renal insufficiency have a significantly higher mortality rate than those without renal insufficiency. Among a cohort of patients with ICDs, those with known renal insufficiency have higher rates of health care resource utilization and more heart failure admissions. Development of a national registry for ICDs should include data with regard to renal function.