The E/e' Ratio: As "Critical" As the Left Ventricular Ejection Fraction?

Ascertainment of the left ventricular ejection fraction is the primary reason for ordering echocardiography in the acute care setting; however, this parameter does not provide information regarding a patient's volume status. As such, it cannot be reliably used to inform decisions regarding intravenous fluid resuscitation or diuresis, particularly in undifferentiated dyspnea and hypotension. This is relevant given a national quality improvement exhortation to provide aggressive fluid resuscitation as part of a "sepsis bundle." This initiative must be tempered by the well-established increase in hospital mortality from providing intravenous fluid to patients with unrecognized heart failure, which may occur if sepsis is misdiagnosed. We describe herein, what is to our knowledge, the first description of a critically elevated Doppler ratio of mitral inflow peak E-wave velocity to the mean mitral annular velocity as a harbinger of sudden death from pulmonary edema in a patient treated with aggressive intravenous fluids as part of the "sepsis bundle." This is utilized as a springboard for proposing a clinical algorithm focused on expedited echocardiography. It emphasized the potential value of advancing markedly the diastolic assessment of filling pressure (ratio of mitral inflow peak E-wave velocity to the mean mitral annular velocity) in the acute care setting to a level of import comparable to the left ventricular ejection fraction.

Huffing and twist: Fatal Torsade de pointes associated with Tetrafluoroethane Inhalation and amphetamine use.

Many volatile chemicals inhaled for a recreational high have a chemical structure similar to chloroform and may lead to Ikr blockade and subsequent torsades de pointes. This is one potential mechanism of action for huffing-associated sudden death.

A Point-of-Care Algorithm to Guide Proper Device Selection for Ambulatory Electrocardiography.

In the outpatient setting, ambulatory electrocardiography is the most frequently used diagnostic modality for the evaluation of patients in whom cardiac arrhythmias or conduction abnormalities are suspected. Proper selection of the device type and monitoring duration is critical for optimizing diagnostic yield and cost-effective resource utilization. However, despite guidance from major professional societies, the lack of systematic guidance for proper test selection in many institutions results in the need for repeat testing, which leads to not only increased resource utilization and cost of care, but also suboptimal patient care. To address this unmet need at our own institution, we formed a multidisciplinary panel to develop a concise, yet comprehensive algorithm, incorporating the most common indications for ambulatory electrocardiography, to efficiently guide clinicians to the most appropriate test option for a given clinical scenario, with the goal of maximizing diagnostic yield and optimizing resource utilization. The algorithm was designed as a single-page, color-coded flowchart to be utilized both as a rapid reference guide in printed form, and a decision support tool embedded within the electronic medical records system at the point of order entry. We believe that systematic adoption of this algorithm will optimize diagnostic efficiency, resource utilization, and importantly, patient care and satisfaction.

Subendocardial stress in pre-eclampsia.

A primigravida 26-year-old woman who had developed pre-eclampsia with malignant hypertension at 30 weeks of gestation suffered acute myocardial infarction two days postpartum. Electrocardiogram demonstrated diffuse ST-segment depression suggestive of subendocardial ischemia. Echocardiography demonstrated focal asymmetric left ventricular hypertrophy, with a characteristic "basal septal bulge", and a left ventricular mid-cavitary gradient of 51 mmHg. Coronary angiography revealed normal coronary arteries and vascular flow. Peripartum acute myocardial infarction is rare and portends a high mortality. However, to date, only one case of acute myocardial infarction associated with asymmetric left ventricular hypertrophy and pre-eclampsia has been described in the literature.

Is QTc-Interval Prolongation an Inherent Feature of Eating Disorders? A Cohort Study.

BACKGROUND: Anorexia nervosa is associated with a markedly increased risk of sudden cardiac death, but the mechanism has not been elucidated. Whether QT prolongation is an intrinsic feature of eating disorders is uncertain because previous studies are limited by small sample size, and extrinsic factors associated with QT prolongation were inconsistently reported. This study set to determine population-mean heart-rate-corrected QT interval (QTc) in an unselected cohort of patients with eating disorders. METHODS: Electrocardiogram (ECG) data from 1026 consecutive adults admitted into residential treatment were stratified by subtype: anorexia nervosa (caloric restriction only), anorexia nervosa binge-purge, and bulimia nervosa. Eating disorders not otherwise specified were excluded. Population-mean Fridericia-corrected QTc and categorical QTc threshold analysis were performed. Multivariable regression, controlling for age sex, duration of illness, body mass index (BMI), hypokalemia, QTc-prolonging drugs, purging behaviors, and laxatives was assessed. RESULTS: Among 906 patients, population-mean QTc (424 ± 25 standard deviation [SD]) was normal and lowest among patients with anorexia nervosa (417.3 ± 22.3, P <0.001 vs other subgroups). Only 1.2% (N = 11) had marked QTc prolongation (QTc >500 ms); all 11 patients had hypokalemia and were receiving QTc-prolonging medications or laxatives. After controlling for clinically relevant covariates, differences in mean QTc across eating disorder subtypes diminished yet persisted (P = 0.048). CONCLUSIONS: In the largest study of patients with eating disorders, population-mean QTc was normal and varied by subtype. Marked QTc prolongation occurred solely in the presence of extrinsic factors, suggesting that QTc prolongation is not intrinsic to eating disorders. Therefore, further study is needed to define the etiology of sudden death in patients with eating disorders.

Long-term cardiac arrhythmia and chronotropic evaluation in patients with severe anorexia nervosa (LACE-AN): A pilot study.

BACKGROUND: Anorexia nervosa (AN) is associated with autonomic dysfunction and carries a high risk of sudden death, putatively attributed to ventricular tachyarrhythmias. To date, long-term cardiac monitoring has not been performed to confirm this speculation. METHODS AND RESULTS: We assessed the safety and acceptability of an insertable cardiac monitor (ICM) in patients with severe AN with markedly reduced body mass index (BMI), and investigated heart rate (HR) and rhythm before and after weight restoration. Autonomic function was assessed as HR response to a standardized activity protocol at baseline and four additional visits over 360 days. The Florida Patient Acceptance Survey (FPAS) was used to measure ICM acceptability. During a mean follow-up of 10 months, no ICM-related complications occurred and ICM was well-accepted by the 11 study participants (nine women, aged 19-59 years, baseline BMI = 12.7 ± 1.6 kg/m2 ). Both resting and peak HR increased with weight restoration and were directly associated with BMI (both P < .001). No ventricular tachyarrhythmias occurred during the study period, but two participants (18%) experienced eight sinus pauses (3.0-7.0 seconds) and three runs of supraventricular tachycardia. CONCLUSIONS: Long-term cardiac rhythm monitoring with an ICM is feasible, safe, and acceptable in patients with severe AN. Autonomic dysfunction in AN results in not only profound resting bradycardia, but also some degree of chronotropic incompetence, both of which improve with weight restoration. Clinically significant bradyarrhythmias are more common than ventricular tachyarrhythmias in AN, and may represent a competing underlying mechanism for the high risk of sudden death in this population.

Effect of an active abdominal pulse generator on defibrillation thresholds with a dual-coil, transvenous ICD lead system.

INTRODUCTION: Many patients with implantable cardioverter defibrillators (ICDs) have older lead systems, which are usually not replaced at the time of pulse generator replacement unless a malfunction is noted. Therefore, optimization of defibrillation with these lead systems is clinically important. The objective of this prospective study was to determine if an active abdominal pulse generator (Can) affects chronic defibrillation thresholds (DFTs) with a dual-coil, transvenous ICD lead system. METHODS AND RESULTS: The study population consisted of 39 patients who presented for routine abdominal pulse generator replacement. Each patient underwent two assessments of DFT using a step-down protocol, with the order of testing randomized. The distal right ventricular (RV) coil was the anode for the first phase of the biphasic shocks. The proximal superior vena cava (SVC) coil was the cathode for the Lead Alone configuration (RV --> SVC). For the Active Can configuration, the SVC coil and Can were connected electrically as the cathode (RV --> SVC + Can). The Active Can configuration was associated with a significant decrease in shock impedance (39.5 +/- 5.8 Omega vs. 50.0 +/- 7.6 Omega, P < 0.01) and a significant increase in peak current (8.3 +/- 2.6 A vs. 7.2 +/- 2.4 A, P < 0.01). There was no significant difference in DFT energy (9.0 +/- 4.6 J vs. 9.8 +/- 5.2 J) or leading edge voltage (319 +/- 86 V vs. 315 +/- 83 V). An adequate safety margin for defibrillation (> or =10 J) was present in all patients with both shocking configurations. CONCLUSION: DFTs are similar with the Active Can and Lead Alone configurations when a dual-coil, transvenous lead is used with a left abdominal pulse generator. Since most commercially available ICDs are only available with an active can, our data support the use of an active can device with this lead system for patients who present for routine pulse generator replacement.