The use of digoxin in patients with worsening chronic heart failure.
Reconsidering an old drug to reduce hospital admissions.
Andrew Ambrosy, Javed Butler, Ali Ahmed, Muthiah Vaduganathan, Dirk J. van Veldhuisen, Wilson Colucci & Mihai Gheorghiade.
JACC 2014;63:1823-32.
Digoxin is the oldest cardiac drug still in contemporary use, yet its role in the management of patients with heart failure (HF) remains controversial. A purified cardiac glycoside derived from the foxglove plant, digoxin increases ejection fraction, augments cardiac output, and reduces pulmonary capillary wedge pressure without causing deleterious increases in heart rate or decreases in blood pressure. Moreover, it is also a neurohormonal modulator at low doses. In the pivotal DIG (Digitalis Investigation Group) trial, digoxin therapy was shown to reduce all-cause and HF-specific hospitalizations but had no effect on survival. With the discovery of neurohormonal blockers capable of reducing mortality in HF with reduced ejection fraction, the results of the DIG trial were viewed as neutral, and the use of digoxin declined precipitously. Although modern drug and device-based therapies have dramatically improved the survival of ambulatory patients with HF, outcomes for patients with worsening chronic HF, defined as deteriorating signs and symptoms on standard therapy often leading to unscheduled clinic or emergency department visits or hospitalization, have largely remained unchanged over the past 2 decades. The available data suggest that a therapeutic trial of digoxin may be appropriate in patients with worsening chronic heart failure who remain symptomatic.
Friday, May 23, 2014
Tuesday, May 20, 2014
Short QT syndrome
J Am Coll Cardiol. 2014 Apr 8;63(13):1300-8. doi: 10.1016/j.jacc.2013.09.078. Epub 2013 Nov 28.
Novel insight into the natural history of short QT syndrome.
Mazzanti A1, Kanthan A1, Monteforte N1, Memmi M1, Bloise R1, Novelli V1, Miceli C1, O'Rourke S2, Borio G1, Zienciuk-Krajka A3, Curcio A1, Surducan AE4,Colombo M4, Napolitano C5, Priori SG6.
Abstract
OBJECTIVES:
This study intends to gain further insights into the natural history, the yield of familial and genetic screening, and the arrhythmogenic mechanisms in the largest cohort of short QT syndrome (SQTS) patients described so far.
BACKGROUND:
SQTS is a rare genetic disorder associated with life-threatening arrhythmias, and its natural history is incompletely ascertained.
METHODS:
Seventy-three SQTS patients (84% male; age, 26 ± 15 years; corrected QT interval, 329 ± 22 ms) were studied, and 62 were followed for 60 ± 41 months (median, 56 months).
RESULTS:
Cardiac arrest (CA) was the most frequent presenting symptom (40% of probands; range, <1 0.0000001="" 1.3="" 20="" 40="" 41="" 44="" 4="" a="" age="" and="" arrhythmias="" at="" being="" between="" by="" ca.="" ca="" despite="" disease="" familial="" female="" fibrillation="" first="" follow-up="" genetic="" had="" history="" in="" kindreds.="" life="" low="" mainly="" male="" men="" month="" multiple="" observed="" occurred="" occurrence="" occurrences="" of="" only="" onset="" p="" patients="" patterns="" per="" predictor="" predominance="" present="" probability="" profile="" rate="" recurrences="" reproducible="" rest.="" risk="" screening="" superimposable="" that="" the="" to="" two="" ventricular="" was="" were="" with="" year="" years="" yield="">
CONCLUSIONS:
SQTS is highly lethal; CA is often the first manifestation of the disease with a peak incidence in the first year of life. Survivors of CA have a high CA recurrence rate; therefore, implantation of a defibrillator is strongly recommended in this group of patients.
Fontan - Hemodynamics
JACC Cardiovasc Imaging. 2014 Mar;7(3):215-24. doi: 10.1016/j.jcmg.2013.12.010. Epub 2014 Feb 13.
Geometric characterization of patient-specific total cavopulmonary connections and its relationship to hemodynamics.
Tang E1, Restrepo M2, Haggerty CM2, Mirabella L2, Bethel J3, Whitehead KK4, Fogel MA4, Yoganathan AP5.
Author information
- 1School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia.
- 2Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia.
- 3Westat, Rockville, Maryland.
- 4Division of Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.
- 5Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia. Electronic address: ajit.yoganathan@bme.gatech.edu.
Abstract
Total cavopulmonary connection (TCPC) geometries have great variability. Geometric features, such as diameter, connection angle, and distance between vessels, are hypothesized to affect the energetics and flow dynamics within the connection. This study aimed to identify important geometric characteristics that can influence TCPC hemodynamics. Anatomies from 108 consecutive patients were reconstructed from cardiac magnetic resonance (CMR) images and analyzed for their geometric features. Vessel flow rates were computed from phase contrast CMR. Computational fluid dynamics simulations were carried out to quantify the indexed power loss and hepatic flow distribution. TCPC indexed power loss correlated inversely with minimum Fontan pathway (FP), left pulmonary artery, and right pulmonary artery diameters. Cardiac index correlated with minimum FP diameter and superior vena cava (SVC) minimum/maximum diameter ratio. Hepatic flow distribution correlated with caval offset, pulmonary flow distribution, and the angle between FP and SVC. These correlations can have important implications for future connection design and patient follow-up.
Friday, May 16, 2014
Troponin T: Diurnal Variation
Objectives
The goal of this study was to test the unverified assumption that chronically elevated cardiac troponin T (cTnT) levels fluctuate randomly around a homeostatic set point.
Background
The introduction of high-sensitivity cardiac troponin (cTn) assays has improved sensitivity for acute myocardial infarction (AMI). However, many patients with a single positive cTn test result do not have AMI. Therefore, the diagnosis of AMI relies strongly on serial testing and interpretation of cTn kinetics. Essential in this regard is a profound understanding of the biological variation of cTn.
Methods
Two studies were conducted to assess biological cTnT variation and to investigate the presence of a diurnal rhythm of cTnT. Study 1 comprised 23 male subjects with type 2 diabetes, with no acute cardiovascular disease. Serial venous blood samples were drawn over an 11-h period (8:30 am to 7:30 pm). In study 2, the presence of a diurnal cTnT rhythm was investigated by hourly sampling of 7 subjects from study 1 over 25 h.
Results
In study 1, we observed a gradual decrease in cTnT concentrations during the day (24 ± 2%). This decrease was present in all participants and was most prominent in subjects with the highest baseline cTnT values (Pearson’s R 0.93). Diurnal variation of cTnT, as assessed in study 2, was characterized by peak concentrations during morning hours (8:30 am, 17.1 ± 2.9 ng/l), gradually decreasing values during daytime (8:30 pm, 11.9 ± 1.6 ng/l), and rising concentrations during nighttime (8:30 am the next day, 16.9 ± 2.8 ng/l).
Conclusions
A diurnal cTnT rhythm substantiates the recommendation that all dynamic changes in cTnT should be interpreted in relation to the clinical presentation. Epidemiological studies and risk-stratification protocols with the use of cTnT may benefit from standardized sampling times. (Exercise and Glycemic Control in Type 2 Diabetes; NCT00945165)
MRI - Delayed enhancement (Congenital Aortic Stenosis)
Dusenbery, SM, et al. JACC 2014;63(17):1778-85.
Objectives
This study sought to analyze cardiac magnetic resonance (CMR) measurements of myocardial extracellular volume fraction (ECV) and late gadolinium enhancement (LGE) in children and young adults with congenital aortic stenosis (AS) to determine the extent of fibrosis and examine their association with aortic valve and ventricular function.Background
Patients with congenital AS frequently have impaired diastolic ventricular function and exercise capacity that may be related to myocardial fibrosis.
Methods
A total of 35 patients with congenital AS (median age 16 years) and 27 normal control subjects (median age 16 years) were evaluated by CMR. ECV was calculated from pre- and post-gadolinium contrast T1 measurements of blood and myocardium, and the hematocrit.
Results
ECV was significantly higher in AS patients than in normal subjects (median 0.27 [range 0.22 to 0.42] vs. 0.25 [range 0.18 to 0.27], p = 0.001). LGE was present in 8 (24%) of the AS patients. A higher ECV was correlated with echocardiographic indexes of diastolic dysfunction including a higher mitral E-wave z-score (r = 0.58, p = 0.002), E/septal E′ z-score (r = 0.56, p = 0.003), E/mean E′ z-score (r = 0.55, p = 0.003), and indexed left atrial volume (r = 0.56, p = 0.001). Other factors associated with an elevated ECV (>0.28) included a greater number of aortic valve interventions (p = 0.004) and a greater number of aortic valve balloon valvuloplasties (p = 0.003). ECV was not significantly associated with AS gradient, left ventricular mass, mass/volume ratio, or ejection fraction.
Conclusions
In young patients with AS, myocardial ECV is significantly elevated compared with control subjects and is associated with echocardiographic indexes of diastolic dysfunction. ECV measured by CMR may be a useful method for risk stratification and monitoring therapies targeting fibrosis.
Saturday, May 3, 2014
Pediatric Dilated Cardiomyopathy - Recovery
Recovery of echocardiographic function in children with idiopathic cardiomyopathy. Results from Pediatric Cardiomyopathy Registry.
Melanie D. Everitt, et al. JACC 2014; 63(14): 1405-13.
Editorial: Alan Lewis. JACC 2014; 63(14): 1414-15.
Melanie D. Everitt, et al. JACC 2014; 63(14): 1405-13.
Editorial: Alan Lewis. JACC 2014; 63(14): 1414-15.
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