A cohort study of cardiac resynchronization therapy in patients with chronic Chagas cardiomyopathy.

Aims: Cardiac resynchronization therapy (CRT) is an established procedure for patients with heart failure. However, trials evaluating its efficacy did not include patients with chronic Chagas cardiomyopathy (CCC). We aimed to assess the role of CRT in a cohort of patients with CCC. Methods and results: This retrospective study compared the outcomes of CCC patients who underwent CRT with those of dilated (DCM) and ischaemic cardiomyopathies (ICM). The primary endpoint was all-cause mortality and the secondary endpoints were the rate of non-advanced New York Heart Association (NYHA) class 12 months after CRT and echocardiographic changes evaluated at least 6 months after CRT. There were 115 patients in the CCC group, 177 with DCM, and 134 with ICM. The annual mortality rates were 25.4%, 10.4%, and 11.3%, respectively (P < 0.001). Multivariate analysis adjusted for potential confounders showed that the CCC group had a two-fold [hazard ratio 2.34 (1.47-3.71), P < 0.001] higher risk of death compared to the DCM group. The rate of non-advanced NYHA class 12 months after CRT was significantly higher in non-CCC groups than in the CCC group (DCM 74.0% vs. ICM 73.9% vs. 56.5%, P < 0.001). Chronic Chagas cardiomyopathy and ICM patients had no improvement in the echocardiographic evaluation, but patients in the DCM group had an increase in left ventricular ejection fraction and a decrease in left ventricular end-diastolic diameter. Conclusion: This study showed that CCC patients submitted to CRT have worse prognosis compared to patients with DCM and ICM who undergo CRT. Studies comparing CCC patients with and without CRT are warranted.

Evidence for cardiac safety and antiarrhythmic potential of chloroquine in systemic lupus erythematosus.

AIMS: To perform a comprehensive evaluation of heart rhythm disorders and the influence of disease/therapy factors in a large systemic lupus erythematosus (SLE) cohort. METHODS AND RESULTS: Three hundred and seventeen consecutive patients of an ongoing electronic database protocol were evaluated by resting electrocardiogram and 142 were randomly selected for 24 h Holter monitoring for arrhythmia and conduction disturbances. The mean age was 40.2 ± 12.1 years and disease duration was 11.4 ± 8.1 years. Chloroquine (CQ) therapy was identified in 69.7% with a mean use of 8.5 ± 6.7 years. Electrocardiogram abnormalities were detected in 66 patients (20.8%): prolonged QTc/QTd (14.2%); bundle-branch block (2.5%); and atrioventricular block (AVB) (1.6%). Age was associated with AVB (P = 0.029) and prolonged QTc/QTd (P = 0.039) whereas anti-Ro/SS-A and Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) scores were not (P > 0.05). Chloroquine was negatively associated with AVB (P = 0.01) as was its longer use (6.1 ± 6.9 vs. 1.0 ± 2.5 years, P = 0.018). Time of CQ use was related with the absence of AVB [odds ratio (OR) = 0.103; 95% confidence interval (CI) = 0.011-0.934, P = 0.043] in multiple logistic regression. Holter monitoring revealed abnormalities in 121 patients (85.2%): supraventricular ectopies (63.4%) and tachyarrhythmia (18.3%); ventricular ectopies (45.8%). Atrial tachycardia/fibrillation (AT/AF) were associated with shorter CQ duration (7.05 ± 7.99 vs. 3.63 ± 5.02 years, P = 0.043) with a trend to less CQ use (P = 0.054), and older age (P < 0.001). Predictors of AT/AF in multiple logistic regression were age (OR = 1.115; 95% CI = 1.059-1.174, P < 0.001) and anti-Ro/SS-A (OR = 0.172; 95% CI = 0.047-0.629, P = 0.008). CONCLUSIONS: Chloroquine seems to play a protective role in the unexpected high rate of cardiac arrhythmias and conduction disturbances observed in SLE. Further studies are necessary to determine if this antiarrhythmic effect is due to the disease control or a direct effect of the drug.

Effects of cardiac resynchronization therapy on muscle sympathetic nerve activity.

INTRODUCTION: Muscle sympathetic nerve activity (MSNA) is an independent prognostic marker in patients with heart failure (HF). Therefore, its relevance to the treatment of HF patients is unquestionable. OBJECTIVES: In this study, we investigated the effects of cardiac resynchronization therapy (CRT) on MSNA response at rest and during exercise in patients with advanced HF. METHODS: We assessed 11 HF patients (51 ± 3.4 years; New York Heart Association class III-IV; left ventricular ejection fraction 27.8 ± 2.2%; optimal medical therapy) submitted to CRT. Evaluations were made prior to and 3 months after CRT. MSNA was performed at rest and during moderate static exercise (handgrip). Peak oxygen consumption (VO2 ) was evaluated by means of cardiopulmonary exercise test. HF patients with advanced NYHA class without CRT and healthy individuals were also studied. RESULTS: CRT reduced MSNA at rest (48.9 ± 11.1 bursts/min vs 33.7 ± 15.3 bursts/min, P < 0.05) and during handgrip exercise (MSNA 62.3 ± 13.1 bursts/min vs 46.9 ± 14.3 bursts/min, P < 0.05). Among HF patients submitted to CRT, the peak VO2 increased (12.9 ± 2.8 mL/kg/min vs 16.5 ± 3.9 mL/kg/min, P < 0.05) and an inverse correlation between peak VO2 and resting MSNA (r = -0.74, P = 0.01) was observed. CONCLUSIONS: In patients with advanced HF and severe systolic dysfunction: (1) a significant reduction of MSNA (at rest and during handgrip) occurred after CRT, and this behavior was significantly superior to HF patients receiving only medical therapy; (2) MSNA reduction after CRT had an inverse correlation with O2 consumption outcomes.

Mortality risk score for patients with Chagas cardiomyopathy and pacemaker.

BACKGROUND: Prognosis of Chronic Chagasic Cardiomyopathy (CCC) patients depends on functional and clinical factors. Bradyarrhythmia requiring pacemaker is a common complication. Prognosis of these patients is poorly studied, and mortality risk factors are unknown. We aimed to identify predictors of death and to define a risk score for mortality in a large cohort of CCC patients with pacemaker. METHODS: It was an observational, unicentric and prospective study. The endpoint was all-cause mortality. Cox regression was used to identify predictors of death and to define a risk score. Bootstrapping method was used to internal score validation. RESULTS: We included 555 patients and after a mean follow-up of 3.7±1.5 years, 100 (18%) deaths occurred. Predictors of death were: right ventricular dysfunction (HR [hazard ratio] 2.24; 95%CI 1.41-3.53; P = 0.001); heart failure class III or IV (HR 2.16; 95% confidence interval [95%CI] 1.16-4.00; P = 0.014); renal disease (HR 2.14; 95%CI 1.24-3.68; P = 0.006); left ventricular end-systolic diameter > 44mm (HR 1.97; 95%CI 1.26-3.05; P = 0.003); atrial fibrillation (HR 1.94; 95%CI 1.25-2.99; P = 0.003) and cardiomegaly on X-ray (HR 1.87; 95%CI 1.10-3.17; P = 0.020). The score identified patients with: low (0-20 points), intermediate (21-30 points) and high risk (>31points). The optimism-corrected C-statistic of the predictive model was 0.751 (95% CI 0.696-0.806). Internal validation with bootstrapping revealed a calibration slope of 0.946 (95% CI 0.920-0.961), reflecting a small degree of over-optimism and C-statistic of 0.746 (95% CI 0.692-0.785). CONCLUSIONS: This study identified predictors of mortality in CCC patients with pacemaker defining a simple, validated and specific risk score.

Global and regional ventricular repolarization study by body surface potential mapping in patients with left bundle-branch block and heart failure undergoing cardiac resynchronization therapy.

BACKGROUND: The controversial effects promoted by cardiac resynchronization therapy (CRT) on the ventricular repolarization (VR) have motivated VR evaluation by body surface potential mapping (BSPM) in CRT patients. METHODS: Fifty-two CRT patients, mean age 58.8 ± 12.3 years, 31 male, LVEF 27.5 ± 9.2, NYHA III-IV heart failure with QRS181.5 ± 14.2 ms, underwent 87-lead BSPM in sinus rhythm (BASELINE) and biventricular pacing (BIV). Measurements of mean and corrected QT intervals and dispersion, mean and corrected T peak end intervals and their dispersion, and JT intervals characterized global and regional (RV, Intermediate, and LV regions) ventricular repolarization response. RESULTS: Global QTm (P < 0.001) and QTc(m) (P < 0.05) were decreased in BIV; QTm was similar across regions in both modes (P = ns); QTc(m) values were lower in RV/LV than in Intermediate region in BASELINE and BIV (P < 0.001); only RV/Septum showed a significant difference (P < 0.01) in the BIV mode. QTD values both of BASELINE (P < 0.01) and BIV (P < 0.001) were greater in the Intermediate than in the LV region. CRT effect significantly reduced global/regional QTm and QTc(m) values. QTD was globally decreased in RV/LV (Intermediate: P = ns). BIV mode significantly reduced global T peak end mean and corrected intervals and their dispersion. JT values were not significant. CONCLUSIONS: Ventricular repolarization parameters QTm, QTc(m), and QTD global/regional values, as assessed by BSPM, were reduced in patients under CRT with severe HF and LBBB. Greater recovery impairment in the Intermediate region was detected by the smaller variation of its dispersion.

Cardiac resynchronization therapy evaluated by myocardial scintigraphy with 99mTc-MIBI: changes in left ventricular uptake, dyssynchrony, and function.

PURPOSE: (99m)Tc-MIBI gated myocardial scintigraphy (GMS) evaluates myocyte integrity and perfusion, left ventricular (LV) dyssynchrony and function. Cardiac resynchronization therapy (CRT) may improve the clinical symptoms of heart failure (HF), but its benefits for LV function are less pronounced. We assessed whether changes in myocardial (99m)Tc-MIBI uptake after CRT are related to improvement in clinical symptoms, LV synchrony and performance, and whether GMS adds information for patient selection for CRT. METHODS: A group of 30 patients with severe HF were prospectively studied before and 3 months after CRT. Variables analysed were HF functional class, QRS duration, LV ejection fraction (LVEF) by echocardiography, myocardial (99m)Tc-MIBI uptake, LV end-diastolic volume (EDV) and end-systolic volume (ESV), phase analysis LV dyssynchrony indices, and regional motion by GMS. After CRT, patients were divided into two groups according to improvement in LVEF: group 1 (12 patients) with increase in LVEF of 5 or more points, and group 2 (18 patients) without a significant increase. RESULTS: After CRT, both groups showed a significant improvement in HF functional class, reduced QRS width and increased septal wall (99m)Tc-MIBI uptake. Only group 1 showed favourable changes in EDV, ESV, LV dyssynchrony indices, and regional motion. Before CRT, EDV, and ESV were lower in group 1 than in group 2. Anterior and inferior wall (99m)Tc-MIBI uptakes were higher in group 1 than in group 2 (p<0.05). EDV was the only independent predictor of an increase in LVEF (p=0.01). The optimal EDV cut-off point was 315 ml (sensitivity 89%, specificity 94%). CONCLUSION: The evaluation of EDV by GMS added information on patient selection for CRT. After CRT, LVEF increase occurred in hearts less dilated and with more normal (99m)Tc-MIBI uptake.

Effect of chronic kidney disease in ischemic cardiomyopathy: Long-term follow-up - REVISION-DM2 trial.

A strong association exists between chronic kidney disease (CKD) and coronary artery disease (CAD). The role of CKD in the long-term prognosis of CAD patients with versus those without CKD is unknown. This study investigated whether CKD affects ventricular function.From January 2009 to January 2010, 918 consecutive patients were selected from an outpatient database. Patients had undergone percutaneous, surgical, or clinical treatment and were followed until May 2015.In patients with preserved renal function (n = 405), 73 events (18%) occurred, but 108 events (21.1%) occurred among those with CKD (n = 513) (P < .001). Regarding left ventricular ejection fraction (LVEF) <50%, we found 84 events (21.5%) in CKD patients and 12 (11.8%) in those with preserved renal function (P < .001). The presence of LVEF <50% brought about a modification effect. Death occurred in 22 (5.4%) patients with preserved renal function and in 73 (14.2%) with CKD (P < .001). In subjects with LVEF <50%, 66 deaths (16.9%) occurred in CKD patients and 7 (6.9%) in those with preserved renal function (P = .001). No differences were found in CKD strata regarding events or overall death among those with preserved LVEF. In a multivariate model, creatinine clearance remained an independent predictor of death (P < .001).We found no deleterious effects of CKD in patients with CAD when ventricular function was preserved. However, there was a worse prognosis in patients with CKD and ventricular dysfunction.Resgistry number is ISRCTN17786790 at https://doi.org/10.1186/ISRCTN17786790.

Predictors of death in chronic Chagas cardiomyopathy patients with pacemaker.

BACKGROUND: Chronic Chagas cardiomyopathy (CCC) is the most serious and frequent manifestation of Chagas disease. Conduction abnormalities and bradycardia requiring pacemaker are common. The aim of this study was to determine the rate and predictors of death in CCC patients with pacemaker. METHODS: In this single-center prospective cohort study we assessed the outcome of 396 CCC patients with pacemaker, followed-up for at least 24months. All patients underwent a clinical and device assessment, 12-lead electrocardiography and echocardiography. RESULTS: During the median follow-up of 1.9years (Interquartile range 1.6-2.4), there were 65 (16.4%) deaths, yielding an annual mortality rate of 8.6%. The major cause was sudden death (33.8%), followed by heart failure (HF), 32.3%. All the investigated variables were examined as potential predictors of death. The final multivariate logistic regression model included five independent variables: advanced HF functional class (OR [odds ratio] 6.71; 95% confidence interval [95% CI] 1.95-23.2; P=0.003), renal disease (OR 5.71; 95% CI 1.80-18.0; P=0.003), QRS ≥150ms (OR 2.80; 95% CI 1.08-7.27; P=0.034), left atrial enlargement (OR 2.75; 95% CI 1.09-6.95; P=0.032) and left ventricular ejection fraction ≤43% (OR 2.31; 95% CI 1.07-4.97; P=0.032). The model had good discrimination, confirmed by bootstrap validation (optimism-adjusted c-statistic of 0.78) and the calibration curve showed a proper calibration (slope=0.972). CONCLUSIONS: CCC patients with pacemaker have a high annual mortality rate despite that the pacemaker related variables were not predictors of death. The independent predictors of death can help us to identify the poor prognosis patients.

Impact of diabetes mellitus on ischemic cardiomyopathy. Five-year follow-up. REVISION-DM trial.

BACKGROUND: Patients with ischemic cardiomyopathy and severe left ventricular dysfunction have a worse survival prognosis than patients with preserved ventricular function. The role of diabetes in the long-term prognosis of this patient group is unknown. This study investigated whether the presence of diabetes has a long-term impact on left ventricular function. METHODS: Patients with coronary artery disease who underwent coronary artery bypass graft surgery, percutaneous coronary intervention, or medical therapy alone were included. All patients had multivessel disease and left ventricular ejection fraction measurements. Overall mortality, nonfatal myocardial infarction, stroke, and additional interventions were investigated. RESULTS: From January 2009 to January 2010, 918 consecutive patients were selected and followed until May 2015. They were separated into 4 groups: G1, 266 patients with diabetes and ventricular dysfunction; G2, 213 patients with diabetes without ventricular dysfunction; G3, 213 patients without diabetes and ventricular dysfunction; and G4, 226 patients without diabetes but with ventricular dysfunction. Groups 1, 2, 3, and 4, respectively, had a mortality rate of 21.6, 6.1, 4.2, and 10.6% (P < .001); nonfatal myocardial infarction of 5.3, .5, 7.0, and 2.6% (P < .001); stroke of .40, .45, .90, and .90% (P = NS); and additional intervention of 3.8, 11.7, 10.3, and 2.6% (P < .001). CONCLUSION: In this sample, regardless of the treatment previously received patients with or without diabetes and preserved ventricular function experienced similar outcomes. However, patients with ventricular dysfunction had a worse prognosis compared with those with normal ventricular function; patients with diabetes had greater mortality than patients without diabetes.Trial registration http://www.controlled-trials.com. Registration Number: ISRCTN66068876.

Cardiac sympathetic activity pre and post resynchronization therapy evaluated by 123I-MIBG myocardial scintigraphy.

BACKGROUND: Imaging with (123)I-metaiodobenzylguanidine (MIBG) is used for the assessment of cardiac sympathetic activity (CSA). We analyzed CSA before and after cardiac resynchronization therapy (CRT), and correlated these data with CRT response. METHODS AND RESULTS: Thirty patients with chronic heart failure and classic indications for CRT were prospectively studied before and at least 3 months after CRT. The variables analyzed were: QRS width, left-ventricular ejection fraction (LVEF), left-ventricular end-diastolic diameter (LVEDD), heart/mediastinum MIBG uptake ratio (H/M), and washout rate (WR). After CRT, patients were divided into two groups: group 1 (21 patients), responders improving to functional class (FC) I or II; and group 2 (9 patients), nonresponders remaining in FC III or IV. After CRT, only group 1 showed favorable changes in QRS width (P =.003), LVEF (P =.01), LVEDD (P =.04), and H/M ratio (P =.003). The H/M ratio and WR were associated with CRT response (P =.005 and P =.04, respectively). The H/M ratio was the only independent predictor of CRT response (P =.01). Receiver operating characteristic curves showed that the optimal H/M ratio cutoff point was 1.36 (sensitivity, 75%; specificity, 71%). CONCLUSIONS: Improvement in CSA correlated with a positive CRT response. Lower MIBG uptake before therapy was associated with CRT nonresponse. The H/M ratio could be helpful in selecting patients for CRT.

Repercussions of cardiac resynchronization therapy on the ventricular repolarization of heart failure patients as assessed by body surface potential mapping.

OBJECTIVE: Cardiac resynchronization therapy (CRT) is an adjunct treatment for heart failure (HF) which associates with left bundle-branch block (LBBB) and is refractory to medical therapy. However, nearly 1/3 of the patients still do not respond, the reasons for which have yet to be determined. Additionally, experimental studies proved that epicardial left ventricle (LV) pacing yields reversed electrical activation sequence, increasing QT interval duration and dispersion of the ventricular repolarization, and leaving patients at greater risk for ventricular arrhythmias. METHODS: In this study, a series of 60 patients (61.7% male, mean age 59.2+/-11.54 years) in NYHA functional class III-IV heart failure and LBBB, who received CRT through implantation of atrial-biventricular pacemakers, were assessed by 87-lead body surface potential mapping (BSPM). The BSPM, noninvasive technique with semi-automatic readings, allowed analysis of variables associated with the cardiac ventricular repolarization QT intervals, maximal, minimum and mean Tpeak-end, and QT dispersion (QTmax - min), in addition to transmural dispersion of repolarization (Tpeak-end max - Tpeak-end min), in two different moments: baseline rhythm and during atrial-biventricular pacing. RESULTS: QT dispersion showed a significant 19.6% reduction (p=0.0009) under CRT, as compared with baseline measurements (85.58+/-26.63 msec vs. 68.83+/-25.16 msec). The transmural dispersion of repolarization (Tpeak-end max - Tpeak-end min) showed smaller statistical significance (p=0.0343); however, its values were similarly decreased (55.50+/-15.45 msec vs 49.41+/-14.11 msec) during CRT. CONCLUSION: These results may corroborate findings from major randomized clinical trials. We consider that the electrocardiographic variables obtained with the use of the BSPM, namely, the QT and Tpeak-end intervals, are appropriate for analysis and study of the effects of cardiac resynchronization therapy on the improved electrical dispersion as characterizing the improvement of homogeneity of cardiac ventricular repolarization.

[Myotonic dystrophy and heart disease: behavior of arrhythmic events and conduction disturbances]. / Distrofia miotônica e cardiopatia: comportamento dos eventos arrítmicos e dos distúrbios da condução.

OBJECTIVE: To study the prevalence and natural evolution of arrhythmic events and conduction disturbances in myotonic dystrophy; to correlate the genetic defect with cardiovascular findings; to assess cardiac mortality, frequency, and predictive factors of sudden death; to correlate the severity of the neuromuscular and cardiac involvement; and to define the role of the electrophysiological study (EPS), in myotonic dystrophy. METHODS: Periodic clinical assessment and the following tests were performed in 83 consecutive patients with a mean follow-up of 42+/-30.63 months: complementary examinations, genetic tests, electrocardiography, echocardiography, and Holter; electrophysiological study was performed in 59 cases. RESULTS: Atrial tachyarrhythmia was observed in 10 (12%) patients, NSVT in 14 (17%), first-degree AVB in 24 (29%), LBBB in 19 (23%), and RBBB in 13 (16%). Symptoms, an increase in the PR interval, QRS enlargement, LVEF < 60%, and age were predictive factors of death. Nine patients died (4 sudden deaths; 2 due to heart failure; 3 due to other causes). Electrophysiological study: H-V interval > 70 ms in 34% and > 100 ms in 11% (postprocainamide). CONCLUSION: The prevalence of arrhythmic events and conduction disturbances ranged from 50% to 80% after 6 years, and did not correlate with the genetic defect. Atrial flutter was the most common sustained arrhythmia. Cardiac involvement increased as the neuromuscular disease became aggravated, but progression of the cardiac involvement was more rapid than that of the neuromuscular disease. Overall mortality was low (11%) and sudden death occurred in half of the cases. The EPS identified a group at risk for pacemaker implantation.

Friedreich's ataxia: cardiac evaluation of 25 patients with clinical diagnosis and literature review.

OBJECTIVE: Cardiac evaluation (clinical, electrocardiographic and echocardiographic) of 25 Brazilian patients with clinical diagnosis of Friedreich's ataxia (FA) related to the frequency and the size of GAA repeats (unstable expansion of trinucleotide repeats that results in the disease). METHODS: Clinical and cardiac study including electrocardiogram and echocardiogram of all patients and molecular analysis to detect the frequency and the size of GAA expansion, by polymerase chain reaction analysis. RESULTS: Homozygous GAA expansion was detected in 17 patients (68%) - all typical cases. In 8 (32%) cases (6 atypical and 2 typical), no GAA expansion was observed, therefore it was not considered Friedreich's ataxia. All patients with GAA expansion (100%) had electrocardiographic abnormalities, and only 25% of the cases without GAA expansion had some abnormality on this exam. However, only 6% of all patients revealed some signals/symptoms suggestive of cardiac involvement. CONCLUSION: A molecular analysis is essential to confirm the diagnosis of Friedreich's ataxia; however, an adequate cardiac evaluation, including an electrocardiogram, was extremely useful to better screening the patients which should perform these molecular analysis.

Cardiac damage from chronic use of chloroquine: a case report and review of the literature.

Chloroquine has been widely used in rheumatological treatment, but potential severe side effects require careful follow-up. Cardiac damage is not a common consequence, but its clinical relevance has not yet been described. We report the case of a 58-year-old woman with rheumatoid arthritis, in whom chronic chloroquine use resulted in major irreversible cardiac damage. She presented with syncopal episodes due to complete atrioventricular block confirmed by electrophysiological study whose changes were concluded to be irreversible and a permanent pacemaker was indicated. Endomyocardial biopsy was also performed to search for histopathological and ultrastructural cardiac damage. We also reviewed the 22 cases of chloroquine-induced cardiopathy described to date as well as its pathophysiology.

Biventricular pacing improves clinical behavior and reduces prevalence of ventricular arrhythmia in patients with heart failure.

PURPOSE: To analyze the influence of biventricular pacing (BP) on clinical behavior, ventricular arrhythmia (VA) prevalence, and left ventricular ejection fraction (LV EF) by gated ventriculography. METHODS: Twenty-four patients with left bundle branch block (LBBB) and NYHA class III and IV underwent pacemaker implantation and were randomized either to the conventional or BP group, all receiving BP after 6 months. RESULTS: Sixteen patients were in NYHA class IV (66.6%) and 8 were in class III (33.4%). After 1-year follow-up, 14 patients were in class II (70%) and 5 were in class III (25%). Two sudden cardiac deaths occurred. A significant reduction in QRS length was found with BP (p=0.006). A significant statistical increase, from a mean of 19.13 +/- 5.19% (at baseline) to 25.33 +/- 5.90% (with BP) was observed in LVEF Premature ventricular contraction prevalence decreased from a mean of 10,670.00 +/- 12,595.39 SD or to a mean of 3,007.00 +/- 3,216.63 SD PVC/24 h with BP (p<0.05). Regarding the hospital admission rate over 1 year, we observed a significant reduction from 60. To 16 admissions with BP (p<0.05). CONCLUSION: Patients with LBBB and severe heart failure experienced, with BP, a significant NYHA class and LVEF improvement. A reduction in the hospital admission rate and VA prevalence also occurred.

"Hyper-response" evaluated by 3D echocardiography after cardiac resynchronization therapy.

Cardiac resynchronization therapy consists of a promising treatment for patients with severe heart failure, but about 30% of patients do not exhibit clinical improvement with this procedure. However, approximately 10% of patients undergoing this therapy may have hyperresponsiveness, and three-dimensional echocardiography can provide an interesting option for the selection and evaluation of such patients.

Efficacy of antibiotic prophylaxis before the implantation of pacemakers and cardioverter-defibrillators: results of a large, prospective, randomized, double-blinded, placebo-controlled trial.

BACKGROUND: Although routinely administered, definitive evidence for the benefits of prophylactic antibiotics before the implantation of permanent pacemakers and implantable cardioverter-defibrillators from a large double-blinded placebo-controlled trial is lacking. The purpose of this study was to determine whether prophylactic antibiotic administration reduces the incidence of infection related to device implantation. METHODS AND RESULTS: This double blinded study included 1000 consecutive patients who presented for primary device (Pacemaker and implantable cardioverter-defibrillators) implantation or generator replacement randomized in a 1:1 fashion to prophylactic antibiotics or placebo. Intravenous administration of 1 g of cefazolin (group I) or placebo (group 2) was done immediately before the procedure. Follow-up was performed 10 days, 1, 3, and 6 months after discharge. The primary end point was any evidence of infection at the surgical incision (pulse generator pocket), or systemic infection related to be procedure. The safety committee interrupted the trial after 649 patients were enrolled due to a significant difference in favor of the antibiotic arm (group I: 2 of 314 infected patients-0.63%; group II: 11 of 335 to 3.28%; RR=0.19; P=0.016). The following risk factors were positively correlated with infection by univariate analysis: nonuse of preventive antibiotic (P=0.016); implant procedures (versus generator replacement: P=0.02); presence of postoperative hematoma (P=0.03) and procedure duration (P=0.009). Multivariable analysis identified nonuse of antibiotic (P=0.037) and postoperative hematoma (P=0.023) as independent predictors of infection. CONCLUSIONS: Antibiotic prophylaxis significantly reduces infectious complications in patients undergoing implantation of pacemakers or cardioverter-defibrillators.