Ventricular Dysrhythmias Research Articles

Tricuspid Atresia 18 Years Post Glenn: Is Fontan Necessary in All Cases?

Tricuspid atresia is a rare cyanotic congenital heart disease, first described by Kreysig (1817), has an incidence of 1% to 5%. It is incompatible with longevity without surgical intervention. Glenn (1958) was successful in using a superior vena cava to right pulmonary artery anastomosis. Fontan (1958) was successful in separating the right and left cardiac circulation; this is the surgical method of choice, with death of 17% by 20 years of age. The Fontan circulation has burdens of multisystem abnormalities, including ventricular dysfunction (72%), dysrhythmias (40%) and renal, hepatic, gastrointestinal and pulmonary complications. The index case is the oldest documented report of tricuspid atresia with rudimentary right ventricle and concordant ventriculo-arterial connections, 18 years post Glen only, from two years of age. She is asymptomatic, of high intellect, never used medications and is now functioning at New York Heart Association (NYHA) I-II, at 20 years of age. Her survival and function was secondary to an innate large atrial and ventricular communication with normal left ventricle, mitral, aortic and pulmonary valves, indicating Fontan may not be needed in all structural anatomic cases of tricuspid atresia.

Understanding Brugada syndrome.

Brugada syndrome is an established cause of sudden cardiac arrest in patients without structural cardiac abnormalities. Recognition and diagnosis of this syndrome has been slowly increasing. Syncope, ventricular dysrhythmia, or sudden cardiac arrest may be the presenting symptom, although detection of the characteristic right precordial ST-segment elevation on ECG can be a potentially lifesaving intervention. This article reviews the clinical presentation, pathophysiology, genetics, and current management of Brugada syndrome.

Fontan Circulatory Assist Device1

Fontan Circulatory Assist Device1

Clinical risk factors for in-hospital adverse cardiovascular events after acute drug overdose.

It was recently demonstrated that adverse cardiovascular events (ACVE) complicate a high proportion of hospitalizations for patients with acute drug overdoses. The aim of this study was to derive independent clinical risk factors for ACVE in patients with acute drug overdoses. This prospective cohort study was conducted over 3 years at two urban university hospitals. Patients were adults with acute drug overdoses enrolled from the ED. In-hospital ACVE was defined as any of myocardial injury, shock, ventricular dysrhythmia, or cardiac arrest. There were 1,562 patients meeting inclusion/exclusion criteria (mean age, 41.8 years; female, 46%; suicidal, 38%). ACVE occurred in 82 (5.7%) patients (myocardial injury, 61; shock, 37; dysrhythmia, 23; cardiac arrests, 22) and there were 18 (1.2%) deaths. On univariate analysis, ACVE risk increased with age, lower serum bicarbonate, prolonged QTc interval, prior cardiac disease, and altered mental status. In a multivariable model adjusting for these factors as well as patient sex and hospital site, independent predictors were: QTc > 500 msec (3.8% prevalence, odds ratio [OR]= 27.6), bicarbonate < 20 mEq/L (5.4% prevalence, OR= 4.4), and prior cardiac disease (7.1% prevalence, OR= 9.5). The derived prediction rule had 51.6% sensitivity, 93.7% specificity, and 97.1% negative predictive value, while presence of two or more risk factors had 90.9% positive predictive value. The authors derived independent clinical risk factors for ACVE in patients with acute drug overdose, which should be validated in future studies as a prediction rule in distinct patient populations and clinical settings.

Image diagnosis: aVR, the forgotten lead.

The 12-lead electrocardiogram has been referred to as an “11-lead study” on the basis of the false assumption that lead aVR yields only limited information. As this area is already covered by other leads (I, aVL, V5, V6), aVR was only used to confirm correct arm lead placement and was assumed to reflect only reciprocal changes from the lateral portion of the heart. As a result, the unpaired lead aVR has been largely ignored and has been coined the “forgotten lead.”1 In reality, aVR is an informative lead that also reflects the right ventricular outflow tract and the basal portion of the interventricular septum. Analysis of aVR’s individual waveforms should be performed in concert with all other leads because it can provide critical information in the management of a number of medical conditions. The ST segment in lead aVR is used in the assessment of narrow complex tachyarrhythmia. Ho et al2 reported the presence of ST elevation in aVR has a 71% sensitivity and a 70% specificity of distinguishing atrial ventricular reciprocating tachycardia (such as Wolff-Parkinson-White) from atrial ventricular nodal reentrant tachycardia. In addition, aVR morphology can also be used to distinguish wide complex supraventricular tachycardia from ventricular tachycardia. For example, in 2008 Vereckei et al3 reported a 98% sensitivity in differentiating wide complex supraventricular tachycardia from ventricular tachycardia based solely on the analysis of aVR morphology (Figure 1). Figure 1. aVR criteria from Vereckei et al1 suggestive of ventricular tacychardia: 1) presence of R wave; 2) presence of R wave or Q wave > 40 msec; 3) presence of a notch on the descending limb of the negative QRS complex; 4) voltage change in the first ... The presence of a prominent R wave in aVR is a critical finding in sodium channel blocker poisonings, such as with tricyclic antidepressants.4 Liebelt et al4 concluded that an R wave amplitude > 3.0 mm is more sensitive than QRS interval as a predictor of seizures and ventricular dysrhythmias (Figure 2). Figure 2. 12-lead electrocardiogram with a sinus rhythm characterized by a widened QRS complex, deep S wave in lead I, and prominent R wave in lead aVR. These findings are consistent with cardiotoxicity resulting from tricyclic antidepressant poisoning. Patient ... Finally, aVR is a valuable lead in the management of acute coronary ischemia. Although aVR ST-segment elevation may be an abnormal variant in supraventricular tachycardia, bundle branch blocks, left ventricular hypertrophy, or right ventricular hypertrophy, in the presence of other ischemic changes aVR ST-segment elevation is a sensitive indicator of left main, left anterior descending, or triple vessel disease.5–9 Barrabes et al6 and Kosuge et al7 have reported aVR ST-segment elevation to be an independent risk factor for increased morbidity and mortality. Therefore, the presence of aVR ST-segment elevation, in conjunction with other ischemic changes, should be considered an ST-segment elevation myocardial infarction equivalent and warrants immediate interventional reperfusion6,7,10 (Figure 3). Figure 3. 12-lead electrocardiogram from a 33-year-old man with history of hypercholesterolemia, who presented to the Emergency Department with 5 hours of anterior chest pressure associated with diaphoresis and shortness of breath. Electrocardiogram demonstrates ...

Design of an Experimental Test System to Investigate Parameters Affecting Distal Tip Loads of Pacemaker and Defibrillator Leads

The purpose of this study was to design and evaluate a system to test the mechanical behavior of pacemaker and defibrillator leads. Over 300,000 pacemaker and implantable cardioverter defibrillator (ICD) procedures are performed every year in the U.S. for the treatment of cardiac arrhythmias, ventricular dysrhythmias, and congestive heart failure. These procedures require implanting transvenous leads into the interior wall of the heart. A serious and sometimes fatal complication that may occur during or after lead implantation is perforation of the lead tip through the heart wall. The factors that lead to perforation are not fully understood. This illustrates that the mechanical interactions between the lead tip and the cardiac tissue need to be further investigated to improve the outcome for pacemaker and ICD patients. To improve the performance of lead tips, the testing protocols must reproduce physiological and clinically relevant tip-tissue interactions. As a first step toward this goal, testing parameters that influence those interactions must be identified. We investigated the effect of test system parameters, which reproduce potentially critical physiological constraints, on the load experienced at the distal tip of thirteen pacemaker and defibrillator active-fixation leads. We evaluated the use of a constraint to simulate the effect of the right ventricle (RV constraint) in vivo, how and where the lead was fixed in the test configuration, location of the load cell in the test system, rotation and frequency of the test protocol, and the effect of stylets. Results showed the RV constraint and load cell placement had the largest impact on lead tip load, while rotation of the test setup and test frequency had a minimal impact. Recommendations are made for a test system and protocol for in vitro testing of leads that take into consideration in vivo conditions. Better approximations of the in vivo environment may lead to improved product development. The potential of this system to more effectively evaluate new pacemaker and defibrillator lead designs will require further study.

Ventricular dysrhythmias associated with poisoning and drug overdose: a 10-year review of statewide poison control center data from California.

Ventricular dysrhythmias are a serious consequence associated with drug overdose and chemical poisoning. The risk factors for the type of ventricular dysrhythmia and the outcomes by drug class are not well documented. The aim of this study was to determine the most common drugs and chemicals associated with ventricular dysrhythmias and their outcomes. We reviewed all human exposures reported to a statewide poison control system between 2002 and 2011 that had a documented ventricular dysrhythmia. Cases were differentiated into two groups by type of arrhythmia: (1) ventricular fibrillation and/or tachycardia (VT/VF); and (2) torsade de pointes (TdP). Among the 300 potential cases identified, 148 cases met the inclusion criteria. Of these, 132 cases (89%) experienced an episode of VT or VF, while the remaining 16 cases (11%) had an episode of TdP. The most commonly involved therapeutic classes of drugs associated with VT/VF were antidepressants (33/132, 25%), stimulants (33/132, 25%), and diphenhydramine (16/132, 12.1%). Those associated with TdP were antidepressants (4/16, 25%), methadone (4/16, 25%), and antiarrhythmics (3/16, 18.75%). Drug exposures with the greatest risk of death in association with VT/VF were antidepressant exposure [odds ratio (OR) 1.71; 95% confidence interval (CI) 0.705-4.181] and antiarrhythmic exposure (OR 1.75; 95% CI 0.304-10.05), but neither association was statistically significant. Drug exposures with a statistically significant risk for TdP included methadone and antiarrhythmic drugs. Antidepressants and stimulants were the most common drugs associated with ventricular dysrhythmias. Patients with suspected poisonings by medications with a high risk of ventricular dysrhythmia warrant prompt ECG monitoring.

High Prevalence of Cardiovascular Disease in End-Stage Kidney Disease Patients Ongoing Hemodialysis in Peru: Why Should We Care About It?

Purpose. To determine clinical, biochemical, and pharmacological characteristics as well as cardiovascular disease prevalence and its associated factors among end-stage kidney disease patients receiving hemodialysis in the main hemodialysis center in Lima, Peru. Methods. This cross-sectional study included 103 patients. Clinical charts were reviewed and an echocardiogram was performed to determine prevalence of cardiovascular disease, defined as the presence of systolic/diastolic dysfunction, coronary heart disease, ventricular dysrhythmias, cerebrovascular disease, and/or peripheral vascular disease. Associations between cardiovascular disease and clinical, biochemical, and dialysis factors were sought using prevalence ratio. A robust Poisson regression model was used to quantify possible associations. Results. Cardiovascular disease prevalence was 81.6%, mainly due to diastolic dysfunction. It was significantly associated with age older than 50 years, metabolic syndrome, C-reactive protein levels, effective blood flow ≤ 300 mL/min, severe anemia, and absence of mild anemia. However, in the regression analysis only age older than 50 years, effective blood flow ≤ 300 mL/min, and absence of mild anemia were associated. Conclusions. Cardiovascular disease prevalence is high in patients receiving hemodialysis in the main center in Lima. Diastolic dysfunction, age, specific hemoglobin levels, and effective blood flow may play an important role.

Ventricular tachycardia and thyrotoxicosis

Hyperthyroidism is a commonly encountered endocrine disease that can be associated with a wide array of symptoms. Among the latter, rythmological manifestations are relatively frequent and comprise mainly supraventricular tachycardia (atrial fibrillation, flutter, sinus tachycardia, and atrial tachycardia). However, very few ventricular dysrhythmias have been described in literature. We report here the case of a woman in her late fifties who presented hemodynamically well-tolerated ventricular tachycardia in a context of thyrotoxicosis due to iodine overload.

Evaluation and management of left ventricular noncompaction cardiomyopathy.

Left ventricular (LV) noncompaction cardiomyopathy (LVNC) is a form of cardiomyopathy in which trabeculations fail to "compact" with the left ventricular endocardium during fetal cardiac development and is classically associated with subsequent impairment of LV function, significant mortality, ventricular dysrhythmias, and embolic phenomena. As awareness and medical imaging quality have improved, it is becoming easier to identify trabeculations that traverse the LV cavity and serve as a distinguishing feature of this disorder. Differentiating true noncompaction from mild increases in trabeculations requires prudent imaging and clinical correlation. This review seeks to discuss the potential methods of evaluating left ventricular trabeculations, the role of increased trabeculations in cardiovascular disease, and how their presence may affect clinical management.

Amiodarone-related thyroid dysfunction.

Nowadays, amiodarone is the most commonly used antidysrhythmic drug in clinical practice. It is highly effective in the management of recurrent ventricular dysrhythmias, paroxysmal supraventricular dysrhythmias, including atrial fibrillation and flutter, and in the maintenance of sinus rhythm after electrical cardioversion of atrial fibrillation. Moreover, it has the added benefit of being well tolerated in patients with both normal and impaired left ventricular systolic function. Despite amiodarone's potent antidysrhythmic actions, its use is hampered by numerous adverse effects on various organs, including the thyroid. Adverse effects are becoming more prevalent given the increasing incidence of dysrhythmias and wider amiodarone use. Thus, physicians and patients should both be aware of the potential thyroid-specific sequelae. However, amiodarone is likely to remain a significant problem for endocrinologists as concerns exist over the use of the new alternative antiarrhythmic agent, dronedarone, especially in patients with heart failure and left ventricular dysfunction because of the risk of hepatic injury and increased mortality. The final diagnostic and therapeutic approaches must be discussed among the patient, the general practitioner, the cardiologist, and the endocrinologist.

Daytime peak incidence of death due to the ischemic heart disease

Myocardial infarction, myocardial ischemia, ventricular dysrhythmias, and sudden cardiac death occur most frequently in the morning, especially in the first few hours after awakening. Among individual patients, however, this pattern may vary widely. Up to 80% of individuals who suffer sudden cardiac death have coronary heart disease; the epidemiology of sudden cardiac death to a great extent parallels that of coronary heart disease. This review describes circadian patterns in cardiovascular disease processes and analyses the findings of recent studies by searched, from PubMed, ISI Web of Science, Google Scholar and Scopus databases in a time period between late 1970s through July 2013. The circadian pattern of numerous cardiovascular events (myocardial infarction, sudden cardiac death, stroke) reveals a peak in the early hours of the morning, which occurs in more than 20% of patients with arterial hypertension, and can be regularly detected in combined 24-h-ABPM/EKG examinations. The awareness of an increased incidence of myocardial infarction and sudden cardiac death in the early morning hours, shortly after waking, has stimulated an interest in the relationship of these events and the occurrence of both silent and symptomatic myocardial ischaemia. A number of studies have been reported that examine both the physiological triggers and the underlying causes of these events. Beta-adrenergic blockers have been shown to abolish the early morning peak of myocardial infarction and blunt the morning peak in sudden cardiac death. Newer calcium antagonists, such as amlodipine, have been demonstrated to control angina throughout a 24-hour period. Aspirin is effective in preventing morning infarction. Approaching the pathophysiology of circadian time-dependent sudden cardiac death has implication for future prevention and treatment.

Comparison of echocardiographic measurements in elite and nonelite Arabian endurance horses

To determine whether echocardiographic variables differed between successful (elite) and less successful (nonelite) Arabian endurance horses. 34 Arabian horses that competed in endurance racing. Horses were assigned to either an elite or nonelite group on the basis of results of a previous competition, and a standardized echocardiographic examination was performed on each horse within 1 to 4 weeks after that competition. Multivariable logistic regression with backward stepwise elimination was used to create a prediction model for the determination of horse status (elite or nonelite) as a function of the measured echocardiographic variables. The elite and nonelite groups consisted of 23 and 11 horses, respectively. One horse in the nonelite group had a frequent ventricular dysrhythmia that could have negatively affected its performance and rider's safety, whereas none of the horses in the elite group had remarkable cardiac abnormalities. The left ventricular internal diameter during systole and diastole and left ventricular mass and stroke volume were significantly greater for horses in the elite group, compared with those for horses in the nonelite group. The final logistic regression model correctly predicted the horse status for all of the horses in the elite group and 8 of 11 horses in the nonelite group. Results indicated that heart size was significantly associated with performance for Arabian endurance horses in a manner similar to findings for Thoroughbred and Standardbred racehorses in active competition.

Use of esmolol after failure of standard cardiopulmonary resuscitation to treat patients with refractory ventricular fibrillation

IntroductionWe compare the outcomes for patients who received esmolol to those who did not receive esmolol during refractory ventricular fibrillation (RVF) in the emergency department (ED). MethodsA retrospective investigation in an urban academic ED of patients between January 2011 and January 2014 of patients with out-of-hospital or ED cardiac arrest (CA) with an initial rhythm of ventricular fibrillation (VF) or ventricular tachycardia (VT) who received at least three defibrillation attempts, 300mg of amiodarone, and 3mg of adrenaline, and who remained in CA upon ED arrival. Patients who received esmolol during CA were compared to those who did not. Results90 patients had CA with an initial rhythm of VF or VT; 65 patients were excluded, leaving 25 for analysis. Six patients received esmolol during cardiac arrest, and nineteen did not. All patients had ventricular dysrhythmias refractory to many defibrillation attempts, including defibrillation after administration of standard ACLS medications. Most received high doses of adrenaline, amiodarone, and sodium bicarbonate. Comparing the patients that received esmolol to those that did not: 67% and 42% had temporary return of spontaneous circulation (ROSC); 67% and 32% had sustained ROSC; 66% and 32% survived to intensive care unit admission; 50% and 16% survived to hospital discharge; and 50% and 11% survived to discharge with a favorable neurologic outcome, respectively. ConclusionBeta-blockade should be considered in patients with RVF in the ED prior to cessation of resuscitative efforts.

Left Main Coronary Artery Dissection in Pediatric Sport-Related Chest Trauma

BackgroundTraumatic coronary artery dissection (CAD) after blunt chest trauma (BCT) is extremely rare, particularly in children. Among coronary dissections, left main coronary artery (LMCA) dissection is the least common, with only two pediatric cases reported previously. Manifestations of coronary dissections can range from ST segment changes to sudden death. However, these manifestations are not specific and can be present with other cardiac injuries. To our knowledge we present the first pediatric case of traumatic LMCA dissection after sport-related BCT that was treated successfully with coronary stenting. Case ReportA 14-year-old child sustained BCT during a baseball game. Early in the clinical course, he had episodes of ventricular dysrhythmias, diffuse ST changes, rising troponin I, and hemodynamic instability. Emergent cardiac catheterization revealed an LMCA dissection with extension into the proximal left anterior descending artery (LADA). A bare metal stent was placed from the LMCA to the LADA, which improved blood flow through the area of dissection. He has had almost full recovery of myocardial function and has been managed as an outpatient with oral heart failure and antiplatelet medications. Why Should an Emergency Physician Be Aware of This?Our case highlights that CAD, although rare, can occur after pediatric BCT. Pediatric emergency responders must have a heightened awareness that evidence of ongoing myocardial ischemia, such as evolving and focal myocardial infarction on electrocardiogram, persistent elevation or rising troponin I, and worsening cardiogenic shock, can represent a coronary event and warrant further evaluation. Cardiac catheterization can be both a diagnostic and therapeutic modality in such cases. Early recognition and management is vital for myocardial recovery.

Variability of QT Interval Measurements in Opioid-Dependent Patients on Methadone

Background: Methadone can prolong the QT interval, a precursor to ventricular dysrhythmias. Measurement of the QT interval can vary with intrinsic and extrinsic factors. Our objective was to assess the agreement and repeatability between different QT interval measurements. Methods: We recorded ECGs daily for five consecutive days from adults receiving a stable, single daily dose of methadone for opioid dependence. We compared manually measured QT intervals and the calculated QTc intervals to automated measurements. Results: We obtained 123 ECGs from 26 patients receiving a mean methadone dose of 71 mg/day (range 5 to 240 mg). The manually measured QT intervals from leads II and V5 were similar and consistent (95% limits of agreement -46 to 59 ms), as were the corresponding manual QTc. However, the automated QT reported by the ECG was less consistent (95% limits of agreement -85 to 65 ms), especially at higher QT intervals and at methadone doses over 100 mg/day. Only one of the two subjects at greatest risk for torsades de pointes was identified based on the automated QT reading, while six other patients had at least one automated QTc over 480 ms that could not be confirmed on manual measurement. Conclusions: Accurate identification of QT prolongation in methadone patients is difficult because of intrinsic patient variability in QT length and accuracy of automated measurements. When contemplating ECG screening for this population, these challenges are best overcome with manual and serial QT measurements, especially at doses exceeding 100 mg/day, and interpretation using a QT nomogram to determine risk of ventricular dysrhythmia.

Short QT in a cohort of 1.7 million persons: prevalence, correlates, and prognosis.

Short QT syndrome (QTc ≤ 300 ms) is a novel hereditary channelopathy linked to syncope, paroxysmal atrial fibrillation, and sudden cardiac death. However, its epidemiological features remain unsettled. (1) To assess the prevalence of short QT in a large population-based sample; (2) to evaluate its demographic and clinical correlates and; (3) to determine its prognosis. A database of 6.4 million electrocardiograms (ECGs) obtained between 1995 and 2008 among 1.7 million persons was used. An internal, population-based method for heart rate correction (QTcreg ) was used and all ECGs with QTcreg ≤300 ms were manually validated. Linked health plan databases were used for covariate and survival ascertainment. Of 6,387,070 ECGs, 1086 had an ECG with machine-read QTcreg ≤300 ms. Only 4% (45/1086) were validated yielding a prevalence of 0.7 per 100,000 or 1 of 141,935 ECGs. At the person level, the overall prevalence of QTcreg ≤300 ms was 2.7 per 100,000 or 1 of 37,335. The factors independently and significantly associated with validated QTcreg ≤300 ms were age over 65 years, Black race, prior history of ventricular dysrhythmias, chronic obstructive pulmonary disease, ST-T abnormalities, ischemia, bigeminy pattern, and digitalis effect. After 8.3 years of median follow-up and relative to normal QTcreg , validated QTcreg ≤300 ms was associated after multivariate adjustment with a 2.6-fold (95% confidence interval [CI]= 1.9-3.7) increased risk of death. QTcreg ≤300 ms was extraordinarily rare and was associated with significant ECG abnormalities and reduced survival.

Is oxygen required before atropine administration in organophosphorus or carbamate pesticide poisoning? – A cohort study

Background. Early and adequate atropine administration in organophosphorus (OP) or carbamate insecticide poisoning improves outcome. However, some authors advise that oxygen must be given before atropine due to the risk of inducing ventricular dysrhythmias in hypoxic patients. Because oxygen is frequently unavailable in district hospitals of rural Asia, where the majority of patients with insecticide poisoning present, this guidance has significant implications for patient care. The published evidence for this advice is weak. We therefore performed a patient cohort analysis to look for early cardiac deaths in patients poisoned by anticholinesterase pesticides. Methods. We analysed a prospective Sri Lankan cohort of OP or carbamate-poisoned patients treated with early atropine without the benefit of oxygen for evidence of early deaths. The incidence of fatal primary cardiac arrests within 3 h of admission was used as a sensitive (but non-specific) marker of possible ventricular dysrhythmias. Results. The cohort consisted of 1957 patients. The incidence of a primary cardiac death within 3 h of atropine administration was 4 (0.2%) of 1957 patients. The majority of deaths occurred at a later time point from respiratory complications of poisoning. Conclusion. We found no evidence of a high number of early deaths in an observational study of 1957 patients routinely given atropine before oxygen that might support guidance that oxygen must be given before atropine. The published literature indicates that early and rapid administration of atropine during resuscitation is life-saving. Therefore, whether oxygen is available or not, early atropinisation of OP- and carbamate-poisoned patients should be performed.

Hyperglycemia Is Associated With Corrected QT Prolongation and Mortality in Acutely Ill Patients

The QT interval on an electrocardiogram represents ventricular repolarization time. Increased length of this interval, known as corrected QT (QTc) prolongation, can be a precursor to torsade de pointes, a potentially life-threatening ventricular dysrhythmia. An association exists between blood glucose and QTc interval in ambulatory populations. Because both hyperglycemia and QTc prolongation are common in critically ill patients, we sought to examine the relationship between blood glucose, QTc interval prolongation, and all-cause mortality in critically ill patients. We studied adult patients admitted to cardiac monitoring units. Blood glucose and other clinical variables were abstracted from the medical record. Corrected QT measurements were automatically derived from continuous bedside cardiac monitoring systems. Twenty-five percent (233/940) of the patients had QTc prolongation, and 53% had elevated blood glucose (>140 mg/dL) during hospitalization. Adjusted odds for QTc prolongation were 2.1 (95% confidence interval, 1.5-3.1) for moderately elevated blood glucose (140-180 mg/dL) and 3.7 (95% confidence interval, 2.5-5.4) for severely elevated blood glucose (>180 mg/dL). Mortality rate was highest (16%) in patients experiencing both severely elevated blood glucose (>180 mg/dL) and QTc interval prolongation. Hyperglycemia is linked with QTc prolongation, and both are associated with increased odds of mortality in critically ill patients. Further studies are needed to extrapolate the relationship between glucose and ventricular repolarization, as well as appropriate glucose control parameters and QTc interval monitoring in critical care units.

Pectus Excavatum: Uncommon Electrical Abnormalities Caused by Extrinsic Right Ventricular Compression

We report a case of pectus excavatum associated with ventricular tachycardia provoked by exercise in a 19-year-old man. Although this chest deformity has been associated with supraventricular dysrhythmias, documented ventricular tachycardia has only been reported once. Our patient's ventricular dysrhythmia was treated by surgical correction of his pectus excavatum only, and at 3 years follow-up he has had no recurrence of his ventricular tachycardia.