Chronic Apical and Nonapical Right Ventricular Pacing in Patients with High-Grade Atrioventricular Block: Results of the Right Pace Study.

OBJECTIVE: The aim of the study was to compare the two approaches to chronic right ventricular pacing currently adopted in clinical practice: right ventricular apical (RVA) and non-RVA pacing. BACKGROUND: Chronic RVA pacing is associated with an increased risk of atrial fibrillation, morbidity, and even mortality. Non-RVA pacing may yield more physiologic ventricular activation and provide potential long-term benefits and has recently been adopted as standard procedure at many implanting centers. METHODS: The Right Pace study was a multicenter, prospective, single-blind, nonrandomized trial involving 437 patients indicated for dual-chamber pacemaker implantation with a high percentage of RV pacing. RESULTS: RV lead-tip target location was the apex or the interventricular septum. RVA (274) and non-RVA patients (163) did not differ in baseline characteristics. During a median follow-up of 19 months (25th-75th percentiles, 13-25), 17 patients died. The rates of the primary outcome of death due to any cause or hospitalization for heart failure were comparable between the groups (log-rank test, p = 0.609), as were the rates of the composite of death due to any cause, hospitalization for heart failure, or an increase in left ventricular end-systolic volume ≥ 15% as compared with the baseline evaluation (secondary outcome, p = 0.703). After central adjudication of X-rays, comparison between adjudicated RVA (239 patients) and non-RVA (170 patients) confirmed the absence of difference in the rates of primary (p = 0.402) and secondary (p = 0.941) outcome. CONCLUSIONS: In patients with indications for dual-chamber pacemaker who require a high percentage of ventricular stimulation, RVA or non-RVA pacing resulted in comparable outcomes. This study is registered with ClinicalTrials.gov (identifier: NCT01647490).

Optimal left ventricular lead placement for cardiac resynchronization therapy in postmyocardial infarction patients.

AIM: To evaluate at a 12-month follow-up, the clinical and echocardiographic outcomes in postmyocardial infarction (MI) heart failure patients who underwent cardiac resynchronization therapy (CRT) device implantation. MATERIALS & METHODS: A total of 100 patients received a CRT device, and the study population was divided into three groups, according to the site of MI and left ventricular (LV) lead placed downstream of the ischemic area, as evaluated by echocardiography. RESULTS: At the end of the 12-month follow-up, we reported a general improvement of LV ejection fraction from 28 ± 7% to 35 ± 9% (p < 0.001) and a significant reverse remodeling: LV end-systolic volume changed from 147 ± 54 to 125 ± 63 (p = 0.001) with a 53% of echocardiographic responders. We also observed 67% of CRT responders in the group with optimal LV lead placement compared with 38% in the remaining population (p = 0.01). CONCLUSION: The optimal positioning of LV lead is a feasible method to improve the percentage of CRT responders in post-MI heart failure patients.

Is there a right place to pace the right ventricle? Evaluation of apical and septal positions in a pacemaker population: study protocol for a prospective intervention-control trial.

INTRODUCTION: The main objective of research in pacemaker therapy has been to provide the best physiologic way to pace the heart. Despite the good results provided by right ventricular pacing minimization and by biventricular pacing in specific subsets of heart failure patients, these options present many limitations for standard pacemaker recipients. In these patients, pacing the right ventricle at alternative sites could result in a lower degree of left intraventricular dyssynchrony. Despite the lack of strong evidence and the difficulty in placing and accurately classifying the final lead position, pacing at alternative right ventricular sites seems to have become a standard procedure at many implanting centers. MATERIAL AND METHODS: The RIGHT PACE study is a multi-center, prospective, single-blind, double-arm, intervention-control trial comparing right ventricular pacing from the apex and from the septal site in terms of left intraventricular dyssynchrony. A total of 408 patients with indications for cardiac pacing but without indications for ICD and/or CRT will be enrolled. Investigators will be divided on the basis of their prior experience of selective site pacing lead implantation and patients will be treated according to the clinical practice of the centers. After device implantation, they will be followed up for 24 months through evaluation of clinical, echocardiographic and safety/system-performance variables. DISCUSSION: This study might provide important information about the impact of the right ventricular pacing on the left ventricular dyssynchrony, and about acute and chronic responses to selective site pacing, as adopted in current clinical practice. This trial is registered at ClinicalTrials.gov (ID:NCT01647490). TRIAL REGISTRATION: Right Ventricular Lead Placement in a Pacemaker Population: Evaluation of apical and alternative position. ClinicalTrials.gov: NCT01647490.

Relationship between pre-implant ejection fraction and outcome after cardiac resynchronization therapy in symptomatic patients.

BACKGROUND: Left-ventricular ejection fraction (LVEF) is regarded as a strong predictor for morbidity and mortality in heart failure patients. The aim of the analysis was to assess the relationship between pre-implant LVEF and outcome of patients with advanced heart failure who received cardiac resynchronization therapy (CRT). METHODS: We analysed the two-year follow-up of 366 patients who had been enrolled in the MASCOT study which included NYHA class III/IV patients with a class I CRT indication. Pre-implant LVEF was stratified by tertile. RESULTS: The boundaries for pre-implant LVEF were < 22% (n = 128; 18.2 +/- 3.1%; T(low)), 22% to 28% (n = 121; 25.4 +/- 1.4%; T(middle)) and > 28% (n = 117; 32.6 +/- 3.9%; T(high)) for each tertile.Two-year post-implant LVEF was 32.0 +/- 11.5% (T(low)), 33.7 +/- 10.8% (T(middle)) and 36.4 +/- 9.9% (T(high)). T(Iow) had a greater increase between pre- and post-implant LVEF compared to T(middle) (P = 0.03) and T(high) (P = 0.0001). NYHA class improved similarly among the three groups as well as the quality of life score. No significant differences were detected between the three groups for all-cause mortality, cardiac death, all-cause hospitalization, and hospitalization due to worsening heart failure. CONCLUSIONS: Symptomatic heart failure patients with a wide QRS complex and a severe impaired LV function had a better improvement of their pre-implant LVEF than patients with a more preserved LVEF. This may be one reason that in these patient groups long-term morbidity and mortality were not related to their pre-implant LVEF. Pre-implant LVEF was in symptomatic CRT patients not predictive for their long-term cardiovascular morbidity and mortality.

Temporal relationship between subclinical atrial fibrillation and embolic events.

BACKGROUND: Among patients with implantable pacemakers and defibrillators, subclinical atrial fibrillation (SCAF) is associated with an increased risk of stroke; however, there is limited understanding of their temporal relationship. METHODS AND RESULTS: The Asymptomatic Atrial Fibrillation and Stroke Evaluation in Pacemaker Patients and the Atrial Fibrillation Reduction Atrial Pacing Trial (ASSERT) enrolled 2580 pacemaker and defibrillator patients aged ≥65 years with a history of hypertension but without a history of atrial fibrillation. Pacemakers and implantable cardioverter-defibrillators precisely logged the time and duration of all episodes of SCAF and recorded electrograms that were adjudicated by experts. We examined the temporal relationship between SCAF >6 minutes in duration and stroke or systemic embolism. Of 51 patients who experienced stroke or systemic embolism during follow-up, 26 (51%) had SCAF. In 18 patients (35%), SCAF was detected before stroke or systemic embolism. However, only 4 patients (8%) had SCAF detected within 30 days before stroke or systemic embolism, and only 1 of these 4 patients was experiencing SCAF at the time of the stroke. In the 14 patients with SCAF detected >30 days before stroke or systemic embolism, the most recent episode occurred at a median interval of 339 days (25th to 75th percentile, 211-619) earlier. Eight patients (16%) had SCAF detected only after their stroke, despite continuous monitoring for a median duration of 228 days (25th to 75th percentile, 202-719) before their event. CONCLUSIONS: Although SCAF is associated with an increased risk of stroke and embolism, very few patients had SCAF in the month before their event. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT00256152.

Gender-related safety and efficacy of cardiac resynchronization therapy.

BACKGROUND: Cardiac resynchronization therapy (CRT) is an established therapy for patients with chronic heart failure (CHF) and a broad QRS complex. Gender-related safety and efficacy data are necessary for informed patient decision-making for female patients with CHF. The aim of the study was to assess the effects of gender on the outcome of CRT in highly symptomatic heart failure patients. HYPOTHESIS: Gender may have an effect on the outcome of heart failure patients undergoing cardiac resynchronisation therapy. METHODS: The study analyzed the 2-year follow-up of 393 New York Heart Association (NYHA) class III/IV patients with a class I CRT indication enrolled in the Management of Atrial Fibrillation Suppression in AF-HF Comorbidity Therapy (MASCOT) study. RESULTS: In female patients (n = 82), compared with male patients (n = 311), CHF was more often due to dilated cardiomyopathy (74% vs 44%, respectively; P < 0.0001). Females also had a more impaired quality-of-life score and a smaller left ventricular end-diastolic diameter (LVEDD). Women were less likely than men to have received a CRT defibrillator (35% vs 61%, respectively; P < 0.0001). After 2 years, the devices had delivered more biventricular pacing in women than in men (96% ± 13% vs 94% ± 13%, respectively; P < 0.0004). Women had a greater reduction in LVEDD than did men (-8.2 mm ± 11.1 mm vs -1.1 mm ± 22.1 mm, respectively; P < 0.02). Both genders improved similarly in NYHA functional class. Women reported greater improvement than men in quality-of-life score (-21.1 ± 26.5 vs -16.2 ± 22.1, respectively; P < 0.0001). After adjustment for cardiovascular history, women had lower all-cause mortality (P = 0.0007), less cardiac death (P = 0.04), and fewer hospitalizations for worsening heart failure (P = 0.01). CONCLUSIONS: Females exhibited a better response to CRT than did males. Because females have such impressive benefits from CRT, improved screening and advocacy for CRT implantation in women should be considered.

One-year outcome after CRT implantation in NYHA class IV in comparison to NYHA class III patients.

BACKGROUND: The aim of the analysis was to compare the outcome of heart failure patients in New York Heart Association (NYHA) class IV to that of NYHA class III patients 1 year after implantation of a CRT device. METHODS: The analysis was based on the 405 CRT patients enrolled in the MASCOT trial. At enrollment, 350 patients (86%) were in NYHA class III and 55 (14 %) were in NYHA class IV. RESULTS: At 1-year follow-up, the improvement of the ejection fraction was not statistically significantly different between NYHA class III (+7.6 ± 11.7%) and NYHA class IV patients (+9.2 ± 14.2 %; p = 0.78). NYHA class IV patients had a better mean NYHA class reduction with -1.93 ± 0.83 than NYHA class III patients with -0.93 ± 0.70 (p < 0.0001). There was a greater mean quality of life improvement in NYHA class IV (-27.2 ± 20.9) compared to NYHA class III (-17.7 ± 23.9; p = 0.02). All-cause mortality as well as cardiac mortality remained higher in NYHA class IV with 25.5 and 16.4% than in NYHA class III with 7.1 and 3.1% (p < 0.0001). CONCLUSIONS: In this study, 14% of all patients receiving a CRT device had NYHA class IV at implantation. The data support the concept to implant a CRT device in NYHA class IV patients, because at 1 year after implantation, they experienced better symptomatic improvement compared to NYHA class III patients. The higher cardiac as well as non-cardiac mortality resulted in a fivefold higher all-cause mortality compared to NYHA class III patients.

A randomized study of cardiac resynchronization therapy defibrillator versus dual-chamber implantable cardioverter-defibrillator in ischemic cardiomyopathy with narrow QRS: the NARROW-CRT study.

BACKGROUND: Current recommendations require a QRS duration of ≥120 ms as a condition for prescribing cardiac resynchronization therapy (CRT). This study was designed to test the hypothesis that patients with heart failure (HF) of ischemic origin, current indications for defibrillator implantation, and QRS <120 ms may benefit from CRT in the presence of marked mechanical dyssynchrony. METHODS AND RESULTS: Patients with intraventricular dyssynchrony on echocardiography were randomly assigned to CRT or dual-chamber defibrillator implantation (CRT defibrillator and dual-chamber implantable cardioverter-defibrillator arm, respectively). The primary end point was the HF clinical composite response, which scores patients as improved, unchanged, or worsened. The secondary end point was the cumulative survival from HF hospitalization and HF death. An additional secondary end point was the composite of HF hospitalization, HF death, and spontaneous ventricular fibrillation. Twenty-three of 56 patients with CRT defibrillator showed an improvement in their clinical composite response at 1 year, compared with 9 of 55 patients with dual-chamber implantable cardioverter-defibrillator (41% versus 16%; P=0.004). After a median follow-up of 16 months, the CRT defibrillator arm showed a nonsignificant higher survival from HF hospitalization and HF death (P=0.077), and a significantly higher survival from the combined end point of HF hospitalization, HF death, and spontaneous ventricular fibrillation (P=0.028). CONCLUSIONS: In this comparison of CRT defibrillator and dual-chamber implantable cardioverter-defibrillator, CRT improved clinical status in some patients with ischemic cardiomyopathy, mild-to-moderate symptoms, narrow QRS duration, and mechanical dyssynchrony on echocardiography. CLINICAL TRIAL REGISTRATION: URL: http://clinicaltrials.gov. Unique identifier: NCT01577446.

Catheter ablation of atrial fibrillation guided by a 3D electroanatomical mapping system: a 2-year follow-up study from the Italian Registry On NavX Atrial Fibrillation ablation procedures (IRON-AF).

AIMS: Clinical trials have established that atrial fibrillation (AF) catheter ablation improves symptoms in appropriately selected patients. Confirmation of these results by long-term prospective observational studies is needed. This registry was created to describe the experience of 16 Italian centers with a large cohort of AF patients treated with catheter ablation guided by the NavX 3D mapping system. METHODS: From November 2006 to May 2008, 545 consecutive patients (age 60.4 ± 9.8, 67 % male) with paroxysmal (44 %), persistent (43 %), and long-standing persistent (13 %) AF referred for catheter ablation guided by the NavX system, were included in this registry. For this paper, follow-up was censored at 24 months; however, patients are being followed in the ongoing registry. RESULTS: Before the ablation, 80 % of patients failed to respond to at least one antiarrhythmic drug aimed at rhythm control. Pulmonary vein (PV) isolation guided by a circular mapping catheter was performed in 70 % of patients whereas non potential-guided PV encircling was performed in 30 % of patients. In 67 % of patients, additional left atrial (LA) substrate modification was performed. Image integration was performed in 9.2 % of patients. Considering a 3-month blanking period, after a single-ablation procedure, the patients had 1- and 2-year freedom from AF recurrence of 67.4 and 57.0 % (36.1 % off antiarrhythmic drugs), respectively. Cox regression analysis showed that AF recurrences during blanking (HR 2.1), and previous AF ablation (HR 3.3) were independent predictors of AF recurrences. Major procedure-related complications occurred in 53 patients (9.7 %). In 35 patients (6.7 %), a repeat procedure was performed at a median of 5 months after the initial procedure. CONCLUSIONS: This prospective, multicenter clinical experience provides significant insights into current ablation care of patients with AF. Despite favorable outcomes, real-world complication rates appear higher than previously recognized.

Lead complications, device infections, and clinical outcomes in the first year after implantation of cardiac resynchronization therapy-defibrillator and cardiac resynchronization therapy-pacemaker.

AIMS: The decision to implant a cardiac resynchronization therapy (CRT) system with (defibrillator, CRT-D) or without (pacemaker, CRT-P) cardioverter defibrillator should weigh its benefits and risks. This study examined the (i) incidence of loss of capture and infectious complications and (ii) 1-year clinical outcomes of 402 CRT-D and CRT-P recipients enrolled in the MASCOT study. METHODS AND RESULTS: The indications for CRT-D or CRT-P were posed by the implanting physicians. All (i) losses of atrial and right and left ventricular capture, (ii) system-related infections, and (iii) clinical outcomes, including hospitalizations for worsening heart failure (HF) and deaths from all causes, were recorded up to 1 year of follow-up. Cardiac resynchronization therapy-defibrillator was implanted in 228 (57%) and CRT-P in 174 (43%) patients. The incidence of loss of capture was greater in CRT-D with 21 patients (9.2%) than in CRT-P with 6 patient (3.5%) recipients (P = 0.01), while the infection rates were 1.3% (3 patients) and 1.2% (2 patients), respectively (ns). In the CRT-D group, 42 of 228 patients (18.4%) died or were hospitalized for HF, compared with 38 of 174 patients (21.8%) in the CRT-P group (ns). In the CRT-D group, 23 patients (10.1%) were hospitalized for worsening HF and 20 (8.8%) patients died, vs. 22 (12.6%) and 19 (10.9%) patients, respectively, in the CRT-P group (ns for both comparisons). CONCLUSIONS: Cardiac resynchronization therapy-defibrillator was implanted in 57% of candidates for CRT. Within 1 year after device implant, the incidence of loss of capture at any lead was nearly three-fold greater among CRT-D than among CRT-P recipients. System-related infections were infrequent and clinical outcomes were similar in both groups.

Low-dose dobutamine test associated with interventricular dyssynchrony: a useful tool to identify cardiac resynchronization therapy responders: data from the LOw dose DObutamine stress-echo test in Cardiac Resynchronization Therapy (LODO-CRT) phase 2 study.

BACKGROUND: Cardiac resynchronization therapy (CRT) is effective in patients with heart failure, but 30% to 50% of subjects are classified as nonresponders. Identifying responders remains a challenging task. AIMS: The LODO-CRT trial investigated the association between left ventricular contractile reserve (LVCR) and clinical and echocardiographic long-term CRT response. METHODS: This is a multicenter, prospective, observational study. Left ventricular contractile reserve was detected using a dobutamine stress echocardiography test, defined as an ejection fraction increase of >5 points. Clinical CRT response was defined as the absence of major cardiovascular events (ie, cardiovascular death or heart failure hospitalization). Echocardiographic response was defined as a left ventricle end-systolic volume reduction of >10%. RESULTS: A total of 221 CRT-indicated patients were studied (80% presented LVCR). During a mean follow-up of 15 ± 5 months, 17 patients died and 16 were hospitalized due to heart failure. The proportion of clinical responders was 155 (88%) of 177 and 33 (75%) of 44 (P = .036) in the groups with and without LVCR, respectively. Kaplan-Meier analysis showed a significant difference in cardiac survival/hospitalization between patients with and without LVCR. The proportion of echocardiographic responders was 144 (87%) of 166 and 16 (42%) of 38 in the groups with and without LVCR (P < .001), respectively; LVCR showed 90% sensitivity and 87% positive predictive value to prefigure echocardiographic CRT responders. Multivariable analysis identified LVCR and interventricular dyssynchrony as independent predictors of CRT response. The concomitant presence of both factors showed 99% specificity and 83% sensitivity in detecting responders. CONCLUSION: The presence of LVCR helps in predicting a clinical and echocardiographic CRT response. Concomitant assessment of LVCR and interventricular dyssynchrony accurately stratifies responder and nonresponder patients.

Presence of left ventricular contractile reserve predicts midterm response to cardiac resynchronization therapy--results from the LOw dose DObutamine stress-echo test in Cardiac Resynchronization Therapy (LODO-CRT) trial.

BACKGROUND: Cardiac resynchronization therapy (CRT) is effective in selected patients with heart failure (HF). Nevertheless, the nonresponder rate remains high. The low-dose dobutamine stress-echo (DSE) test detects the presence of left ventricular (LV) contractile reserve (LVCR) in HF patients of any etiology and may be useful in predicting response to resynchronization. OBJECTIVE: The purpose of this study was to present the results of the LODO-CRT trial, which evaluated whether LVCR presence at baseline increases the chances of response to CRT. METHODS: LODO-CRT is a multicenter prospective study that enrolled CRT candidates according to guidelines. LVCR presence was defined as an LV ejection fraction increase >5 units during DSE test. CRT response is assessed at 6-month follow-up as an LV end-systolic volume reduction ≥10%. RESULTS: Two hundred seventy-one patients were enrolled. The DSE test was feasible without complications in 99% of patients. Nine patients died from noncardiac disease, and 31 presented inadequate data. Two hundred thirty-one patients were included in the analysis. Mean patient age was 67 ± 10 years; 95% were in New York Heart Association class III, and 42% had HF of ischemic etiology. Mean QRS and LV ejection fraction were 147 ± 25 ms and 27% ± 6%, respectively. LVCR presence was found in 185 subjects (80%). At follow-up, 170 (74%) patients responded to CRT, 145/185 in the group with LVCR (78%) and 25/46 (54%) in the group without LVCR. Difference in responder proportion to CRT was 24% (P <.001). Reported test sensitivity is 85%. CONCLUSION: The DSE test in CRT candidates is safe and feasible. LVCR presence at baseline increases the chances of response to CRT.

Low-dose dobutamine stress echocardiography to assess left ventricular contractile reserve for cardiac resynchronization therapy: data from the Low-Dose Dobutamine Stress Echocardiography to Predict Cardiac Resynchronization Therapy Response (LODO-CRT) trial.

Cardiac resynchronization therapy (CRT) is an effective methodology indicated in selected heart failure patients. Identifying responders to the therapy is still challenging. Most studies report that at least 30% of the patients are nonresponders. Baseline characteristics of the Low-Dose Dobutamine Stress Echocardiography to Predict Cardiac Resynchronization Therapy Response (LODO-CRT) trial population are presented. The study investigates dobutamine stress echocardiography's role in predicting CRT response. Two hundred seventy-one CRT candidates were studied. Mean age was 67+/-10 years, 69% were male, 96% had New York Heart Association class III disease, and 39% had heart failure of ischemic etiology. Mean QRS and left ventricular ejection fraction were 146+/-24 ms and 26%+/-6%, respectively. Seventy-seven percent of participants showed contractile reserve. Left ventricular end-diastolic volume was shown to be independently associated with contractile reserve presence. In particular, more dilated ventricles are associated with a lower chance of having contractile reserve. The LODO-CRT trial enrolled a cohort of patients fulfilling criteria for CRT. Dobutamine stress echocardiography was highly feasible and safe in this population. Contractile reserve was associated with healthier ventricles.

Effect of right ventricular apical pacing in survivors of myocardial infarction.

BACKGROUND: Much information is available regarding the possible negative effects of long-term right ventricular (RV) apical pacing, which may cause worsening of heart failure. However, very limited data are available regarding the effects of RV pacing in patients with a previous myocardial infarction (MI). METHODS AND RESULTS: We screened 115 consecutive post-MI patients and matched a group of 29 pacemaker (PM) recipients with a group of 49 unpaced patients, for age, left ventricular (LV) ejection fraction, and site of MI. During a median follow-up of 54 months, echocardiograms showed a decrease in LV ejection fraction in the paced group, from 51 +/- 10 to 39 +/- 11 (P < 0.01), and a minimal change in the unpaced group, from 57 +/- 8 to 56 +/- 7 (P = 0.98). Similar change was observed in systolic and diastolic diameters and volumes. CONCLUSIONS: The study showed that, in post-MI patients, RV apical pacing was associated with a worsening of LV function, suggesting that, among MI survivors, the need for a PM is a marker of worse outcome.

Efficacy of LOw-dose DObutamine stress-echocardiography to predict cardiac resynchronization therapy response (LODO-CRT) multicenter prospective study: design and rationale.

BACKGROUND: Although cardiac resynchronization therapy (CRT) has a well-demonstrated therapeutic effect in selected patients with advanced heart failure on optimized drug therapy, nonresponder rate remains high. The LODO-CRT is designed to improve patient selection for CRT. Design and rationale of this study are presented herein. METHODS: LODO-CRT is a multicenter prospective study, started in late 2006, that enrolls patients with conventional indications for CRT (symptomatic stable New York Heart Association class III-IV on optimized drug therapy, QRS > or =120 milliseconds, left ventricular [LV] dilatation, LV ejection fraction < or =35%). This study is designed to assess the predictive value of LV contractile reserve (LVCR), determined through dobutamine stress echocardiography (defined as an LV ejection fraction increase >5 units), in predicting CRT response during follow-up. Assessment of CRT effects will follow 2 sequential phases: in phase 1, CRT response end point is defined as LV end-systolic volume reduction > or =10% at 6 months; in phase 2, both LV end-systolic volume reduction and clinical status via a clinical composite score will be evaluated at 12 months follow-up. Predictive value of LVCR will be compared to other measures, such as LV dyssynchrony measures, through adjusted multivariable analysis. For the purpose of the study, target patient number is 270 (with 95% confidence, 80% power, alpha < or = .05). Enrollment should be complete by the end of 2008. CONCLUSIONS: The LODO-CRT trial is testing the hypothesis that LVCR assessment, using low-dose dobutamine stress echocardiography test, should effectively predict positive response to CRT both in terms of the reverse remodeling process as well as favorable long-term clinical outcome. Moreover, the predictive value of LVCR will be compared to that of conventional intra-LV dyssynchrony measures.

Atrial fibrillation in recipients of cardiac resynchronization therapy device: 1-year results of the randomized MASCOT trial.

BACKGROUND: Atrial fibrillation (AF) is associated with increased morbidity and mortality in patients suffering from heart failure (HF). Patients in New York Heart Association HF classes III or IV, with systolic dysfunction and a wide QRS, are candidates for cardiac resynchronization therapy (CRT), and might benefit from atrial overdrive pacing (AOP). METHODS: The Management of Atrial fibrillation Suppression in AF-HF COmorbidity Therapy (MASCOT) trial enrolled 409 CRT device recipients (79% men), who were randomly assigned to AOP ON (n = 197), versus AOP OFF (n = 197) and followed up for 1 year. Their mean age was 68 +/- 10 years, left ventricular ejection fraction 25 +/- 6%, QRS duration 163 +/- 29 milliseconds. New York Heart Association class III was present in 86% of patients and 19% had a history of paroxysmal AF. The primary study end point was incidence of permanent AF at 1 year. RESULTS: Atrial overdrive pacing increased the percentage of atrial pacing from 30% to 80% (P < .0001), was well tolerated, and did not interfere with (a) delivery of CRT (95% mean ventricular pacing in both groups), (b) response to CRT (70% responders in the control vs 67% in the treatment group), or (c) cardiac function (left ventricular ejection fraction increased from 24.5% +/- 6.2% to 32.7% +/- 10.9% in the control and from 25.8% +/- 6.8% to 33.1% +/- 12.6% in the treatment group). The incidence of permanent AF was 3.3% in both groups. By logistic regression analysis, a history of AF (P < .001) and absence of antiarrhythmic drugs (P = .002) were associated with permanent AF. CONCLUSIONS: In this first trial of a specific AF prevention algorithm in CRT recipients, AOP was safe and did not worsen HF. The prevention algorithm did not lower the 1-year incidence of AF.

A radial global dyssynchrony index as predictor of left ventricular reverse remodeling after cardiac resynchronization therapy.

BACKGROUND: Cardiac mechanical efficiency requires that opposing left ventricular regions are coupled both in shortening and lengthening during the same phase of cardiac cycle. Aim of this study was to evaluate whether global measures of mechanical dyssynchrony are able to predict reverse remodeling of the left ventricle in patients receiving cardiac resynchronization therapy (CRT). METHODS: Sixty-two patients underwent a clinical examination, including New York Heart Association class evaluation and 6-minute walking distance and both echocardiographic study before and 6 months after CRT. Intraventricular dyssynchrony was evaluated by two-dimensional strain echocardiography, measuring the amount of uncoordinated contraction and relaxation between septum and free wall for both longitudinal and radial function and was presented as the longitudinal global dyssynchrony index (LGDI) and the radial global dyssynchrony index (RGDI). Reverse remodeling was defined by a left ventricular end systolic volume reduction >or= 15%. RESULTS: After CRT 39 patients showed reverse remodeling. In this group, RGDI (0.74 +/- 0.26 vs 0.32 +/- 0.30; P = 0.0001) and LGDI (0.52 +/- 0.28 vs 0.30 +/- 0.24; P = 0.002) were significantly higher than in nonresponders. A receiver-operating characteristic curve analysis showed that RGDI >0.47 and LGDI >0.34 had a sensitivity and a specificity to predict reverse remodeling of 87% and 74%, 82%, and 74%, respectively. Stepwise forward multiple logistic regression analysis showed that RGDI (O.R.:13.4; 95%C.I.:4.2-120.5; P < 0.0001) was an independent determinant of a positive response to CRT. CONCLUSION: A radial global dyssynchrony index predicts left ventricular reverse remodeling after CRT.

End-diastolic wall thickness as a predictor of reverse remodelling after cardiac resynchronization therapy: a two-dimensional echocardiographic study.

BACKGROUND: The aim of this study was to evaluate whether in patients with ischemic heart failure (HF) with mechanical dyssynchrony the echocardiographic assessment of the extent of scarred ventricular tissue by end-diastolic wall thickness (EDWT) could predict reverse remodeling (RR) after cardiac resynchronization therapy (CRT). Recent studies using cardiac magnetic resonance imaging have shown that the burden of myocardial scar is an important factor influencing response to CRT, despite documented mechanical dyssynchrony. EDWT assessed by two-dimensional (2D) resting echocardiography is a simple and reliable marker to identify scar tissue in patients with ischemic left ventricular dysfunction. METHODS: Seventy-four patients with ischemic HF were evaluated 1 week before and 6 months after CRT. Inclusion criteria were New York Heart Association class III or IV, ejection fraction < 35%, QRS duration > 120 ms, and mechanical intraventricular dyssynchrony >/= 65 ms. The left ventricle was divided into 16 segments; left ventricular (LV) segments with EDWT < 6 mm were considered scarred. Percentage global scar area (GSA) was calculated by dividing the number of scarred LV segments by 16. RESULTS: RR, defined as a reduction of LV end-systolic volume >/= 15%, was found in 38 patients (51.4%) with ischemic HF. A significant inverse linear relationship was found between GSA and RR (r = -0.57; P = .0001). Mean percentage GSA was significantly higher in nonresponders (31.6 +/- 18% vs 6.4 +/- 11%; P < .001). GSA