Effect of cardiac resynchronization therapy in patients without left intraventricular dyssynchrony.
Eur Heart J. 2012 Jan 24;
Authors: Auger D, Bleeker GB, Bertini M, Ewe SH, van Bommel RJ, Witkowski TG, Ng AC, van Erven L, Schalij MJ, Bax JJ, Delgado V
Abstract
AimsTo evaluate the effects of cardiac resynchronization therapy (CRT) on long-term survival of patients without baseline left ventricular (LV) mechanical dyssynchrony.Methods and resultsA total of 290 heart failure patients (age 67 ± 10 years, 77% males) without significant baseline LV dyssynchrony (<60 ms as assessed with tissue Doppler imaging) were treated with CRT. Patients were divided according to the median LV dyssynchrony measured after 48 h of CRT into two groups. All-cause mortality was compared between the subgroups. In addition, the all-cause mortality rates of these subgroups were compared with the all-cause mortality of 290 heart failure patients treated with CRT who showed significant LV dyssynchrony (≥60 ms) at baseline. In the group of patients without significant LV dyssynchrony, median LV dyssynchrony increased from 22 ms (inter-quartile range 16-34 ms) at baseline to 40 ms (24-56 ms) 48 h after CRT. The cumulative mortality rates at 1-, 2-, and 3-year follow-up of patients with LV dyssynchrony ≥40 ms 48 h after CRT implantation were significantly higher when compared with patients with LV dyssynchrony <40 ms (10, 17, and 23 vs. 3, 8, and 10%, respectively; log-rank P< 0.001). Finally, the cumulative mortality rates at 1-, 2-, and 3-year follow-up of patients with baseline LV dyssynchrony were 3, 8, and 11%, respectively (log-rank P= 0.375 vs. patients with LV dyssynchrony <40 ms). Induction of LV dyssynchrony after CRT was an independent predictor of mortality (hazard ratio: 1.247; P= 0.009).ConclusionIn patients without significant LV dyssynchrony, the induction of LV dyssynchrony after CRT may be related to a less favourable long-term outcome.
PMID: 22279110 [PubMed - as supplied by publisher]
AimsConventional late gadolinium enhancement (LGE) cardiac magnetic resonance can detect myocardial infarction and some forms of non-ischaemic myocardial fibrosis. However, quantitative imaging of extracellular volume fraction (ECV) may be able to detect subtle abnormalities such as diffuse fibrosis or post-infarct remodelling of remote myocardium. The aims were (1) to measure ECV in myocardial infarction and non-ischaemic myocardial fibrosis, (2) to determine whether ECV varies with age, and (3) to detect sub-clinical abnormalities in ‘normal appearing’ myocardium remote from regions of infarction.Methods and resultsCardiac magnetic resonance ECV imaging was performed in 126 patients with T1 mapping before and after injection of gadolinium contrast. Conventional LGE images were acquired for the left ventricle. In patients with a prior myocardial infarction, the infarct region had an ECV of 51 ± 8% which did not overlap with the remote ‘normal appearing’ myocardium that had an ECV of 27 ± 3% (P < 0.001, n = 36). In patients with non-ischaemic cardiomyopathy, the ECV of atypical LGE was 37 ± 6%, whereas the ‘normal appearing’ myocardium had an ECV of 26 ± 3% (P < 0.001, n = 30). The ECV of ‘normal appearing’ myocardium increased with age (r = 0.28, P = 0.01, n = 60). The ECV of ‘normal appearing’ myocardium remote from myocardial infarctions increased as left ventricular ejection fraction decreased (r = -0.50, P = 0.02).ConclusionExtracellular volume fraction imaging can quantitatively characterize myocardial infarction, atypical diffuse fibrosis, and subtle myocardial abnormalities not clinically apparent on LGE images. Taken within the context of prior literature, these subtle ECV abnormalities are consistent with diffuse fibrosis related to age and changes remote from infarction.
PMID: 22279111 [PubMed - as supplied by publisher]
Predictors of long-term benefit of cardiac resynchronization therapy in patients with right bundle branch block.
Eur Heart J. 2012 Jan 22;
Authors: Leong DP, Höke U, Delgado V, Auger D, Thijssen J, van Erven L, Bax JJ, Schalij MJ, Marsan NA
Abstract
AimsThe aims of this study were: (i) to characterize consecutive cardiac resynchronization therapy (CRT) recipients with right bundle branch block (RBBB) in comparison with left bundle branch block (LBBB) and (ii) to identify independent predictors of long-term outcome among CRT recipients with RBBB. The presence of RBBB has been associated with poorer prognosis after CRT compared with LBBB; however, little is known about the differences in cardiac mechanics between RBBB and LBBB patients. Furthermore, predictors of favourable outcome after CRT in patients with RBBB have not been identified.Methods and resultsFive hundred and sixty-one consecutive CRT recipients (89 with RBBB and 472 with LBBB) underwent echocardiography before and 6 months after CRT to determine left ventricular (LV) size and function, and interventricular and LV dyssynchrony (as measured by tissue Doppler imaging). Long-term follow-up to identify a composite endpoint of all-cause mortality or heart failure hospitalization was available. Right bundle branch block patients exhibited a higher prevalence of male gender, ischaemic heart disease, atrial fibrillation, and lower exercise capacity when compared with LBBB patients, despite smaller LV volumes. In addition, the extent of both interventricular and LV dyssynchrony was less in RBBB patients. Six months after CRT, RBBB patients also showed limited LV reverse remodelling. At long-term follow-up, LV dyssynchrony and mitral regurgitation were identified as independent predictors of all-cause mortality or heart failure hospitalization among RBBB patients.ConclusionLeft ventricular dyssynchrony may be an important determinant of outcome following CRT in patients with RBBB and may help in the selection of CRT candidates.
PMID: 22270539 [PubMed - as supplied by publisher]
Contrast-induced kidney injury: mechanisms, risk factors, and prevention.
Eur Heart J. 2012 Jan 19;
Authors: Seeliger E, Sendeski M, Rihal CS, Persson PB
Abstract
In general, iodinated contrast media (CM) are tolerated well, and CM use is steadily increasing. Acute kidney injury is the leading life-threatening side effect of CM. Here, we highlight endpoints used to assess CM-induced acute kidney injury (CIAKI), CM types, risk factors, and CIAKI prevention. Moreover, we put forward a unifying theory as to how CIAKI comes about; the kidney medulla’s unique hyperosmolar environment concentrates CM in the tubules and vasculature. Highly concentrated CM in the tubules and vessels increases fluid viscosity. Thus, flow through medullary tubules and vessels decreases. Reducing the flow rate will increase the contact time of cytotoxic CM with the tubular epithelial cells and vascular endothelium, and thereby damage cells and generate oxygen radicals. As a result, medullary vasoconstriction takes place, causing hypoxia. Moreover, the glomerular filtration rate declines due to congestion of highly viscous tubular fluid. Effective prevention aims at reducing the medullary concentration of CM, thereby diminishing fluid viscosity. This is achieved by generous hydration using isotonic electrolyte solutions. Even forced diuresis may prove efficient if accompanied by adequate volume supplementation. Limiting the CM dose is the most effective measure to diminish fluid viscosity and to reduce cytotoxic effects.
PMID: 22267241 [PubMed - as supplied by publisher]
Calcitriol protects renovascular function in hypertension by down-regulating angiotensin II type 1 receptors and reducing oxidative stress.
Eur Heart J. 2012 Jan 19;
Authors: Dong J, Wong SL, Lau CW, Lee HK, Ng CF, Zhang L, Yao X, Chen ZY, Vanhoutte PM, Huang Y
Abstract
AimsThe present study investigated whether or not calcitriol, an active form of vitamin D, protects against renovascular dysfunction in hypertension and, if so, whether or not such protection alters the expression of key proteins involved in that dysfunction.Methods and resultsChanges in isometric tension showed that the impaired endothelium-dependent relaxations in renal arteries of hypertensive patients were enhanced by 12 h in vitro treatment with calcitriol. Dihydroethidium fluorescence revealed an elevated level of reactive oxygen species (ROS) in these arteries which was reduced by calcitriol. Immunofluorescence showed that calcitriol treatment reduced the expression of AT(1)R, NOX-2, NOX-4, and p67(phox) and increased that of superoxide dismutase (SOD)-1. Twelve-hour exposure to calcitriol prevented angiotensin (Ang) II-induced increases in ROS and the over-expression of NOX-2, NOX-4, and p67(phox) in renal arteries from normotensive patients. A specific antagonist of the human vitamin D receptor (VDR), TEI-9647, abolished these effects of calcitriol. Both in vitro exposure to and chronic in vivo administration of calcitriol enhanced relaxations to acetylcholine and abolished exaggerated endothelium-dependent contractions in renal arteries of normotensive rats pre-exposed to Ang II or harvested from spontaneously hypertensive rats (SHR). Reactive oxygen species levels and expressions of AT(1)R, NAD(P)H oxidase subunits, SOD-1, and SOD-2 in SHR arteries were normalized by the chronic treatment with calcitriol.ConclusionIn vivo and in vitro activation of VDR with calcitriol improves endothelial function by normalizing the expressions of AT(1)R and radical generating and scavenging enzymes and thus preventing ROS over-production. The present findings suggest that calcitriol is effective in preserving endothelial function in hypertension.
PMID: 22267242 [PubMed - as supplied by publisher]
Age-related effects of exercise training on diastolic function in heart failure with reduced ejection fraction: The Leipzig Exercise Intervention in Chronic Heart Failure and Aging (LEICA) Diastolic Dysfunction Study.
Eur Heart J. 2012 Jan 19;
Authors: Sandri M, Kozarez I, Adams V, Mangner N, Höllriegel R, Erbs S, Linke A, Möbius-Winkler S, Thiery J, Kratzsch J, Teupser D, Mende M, Hambrecht R, Schuler G, Gielen S
Abstract
AimsDiastolic dysfunction (DD) was identified as a predictor of adverse prognosis in heart failure with reduced ejection fraction (HFREF). It is, however, unknown if DD is improved by exercise training, which is known to induce reverse remodelling, and if the training effect is attenuated in elderly HFREF patients. We therefore assessed DD in a cohort of referent controls (RCs) and HFREF patients and studied the response of DD to endurance exercise in two age groups (≤55 years and ≥65 years).Methods and resultsSixty RC (30 ≤ 55 years, mean age 50 ± 5 years; 30 ≥ 65 years, 72 ± 4 years) and 60 HFREF patients (30 ≤ 55 years, 46 ± 5 years; 30 ≥ 65 years, 72 ± 5 years, EF 28 ± 5%) were randomized to 4 weeks of supervised endurance training or to a control group. Exercise training was effective in reducing LV isovolumetric relaxation time by 29% in young and by 26% in old HFREF patients (P< 0.05 for both). As assessed by tissue Doppler, septal E’ increased by 37% in young and by 39% among old HFREF patients (P< 0.005 for both) resulting in a significant decrease in the E/E’ ratio from 13 ± 1 to 10 ± 1 in young and 14 ± 1 to 11 ± 1 in old HFREF patients (P< 0.05 for both). Serum levels of N-terminal pro brain natriuretic peptide were significantly reduced after endurance training in HFREF patients of all ages.ConclusionIn HFREF, diastolic function is significantly impaired in all age groups. Endurance training is highly effective in improving left ventricular diastolic function in HFREF patients regardless of age.This study is registered at ClinicalTrials.gov (number: NCT00176319).
PMID: 22267243 [PubMed - as supplied by publisher]
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