Cardiac resynchronization therapy in the real world: comparison with the COMPANION study.

BACKGROUND: Several clinical trials have confirmed that cardiac resynchronization therapy (CRT) improves outcomes in well defined patient populations. It is uncertain, however, whether outcomes are similar in real-world clinical settings. This study compared outcomes after CRT with defibrillator (CRT-D) in a large real-world private-practice cardiology setting with those in the COMPANION multicenter trial. METHODS AND RESULTS: A total of 429 consecutive patients who received CRT-D for standard indications (group 1) were retrospectively compared with the 595 patients (group 3) in the COMPANION CRT-D cohort regarding survival and survival free of cardiovascular (CV) hospitalization. A subgroup of the group 1 patients who met the COMPANION entrance criteria (group 2) was also compared with the COMPANION cohort (group 3) both with and without propensity-matching statistical analysis. Survival and survival free of CV hospitalization was better in group 1 than in group 3. Survival in group 2 with and without propensity matching was similar to group 3. However, survival free of CV hospitalization was better in the real-world patients (group 2) even after adjustment for differences in baseline characteristics. CONCLUSIONS: Survival and CV hospitalization outcomes in a real-world clinical setting are as good as, or better than, those demonstrated in the COMPANION research trial.

Sustained quality-of-life improvement post-cryoballoon ablation in patients with paroxysmal atrial fibrillation: Results from the STOP-AF Post-Approval Study.

BACKGROUND: Pulmonary vein isolation by catheter ablation is a class IA indication for the treatment of symptomatic, drug-refractory, paroxysmal atrial fibrillation (PAF). Quality of life (QoL) has been identified as a clinically meaningful endpoint but has not been comprehensively evaluated to date. OBJECTIVE: The purpose of this study was to evaluate the effects of cryoballoon ablation on long-term QoL. METHODS: As part of the STOP-AF Post-Approval Study, QoL was assessed using the Short Form-12 Health Survey (SF-12) along with evaluation of arrhythmia-related symptoms through 36 months. A multivariate linear mixed effects regression was used to determine the association between atrial fibrillation symptoms and QoL scores, and univariate linear regressions were used to assess predictors of 36-month change in QoL scores. RESULTS: Three hundred thirty-five subjects fully completed SF-12 forms at baseline, with 319, 308, 291, and 278 subjects completing surveys at the subsequent follow-up visits. Both physical and mental composite scores increased significantly from baseline (P <.001), and all arrhythmia symptoms significantly decreased from baseline (P <.001), with 62.0% of subjects reporting no symptoms at 6 months compared to 5.7% at baseline (P <.001). Presence of dyspnea and fatigue at baseline were univariate predictors of physical QoL improvement (P = .045 and 0.0497, respectively), whereas each year of age and each year of PAF duration were predictors of a decrease in mental QoL (P = .014 and .04, respectively). CONCLUSION: Cryoballoon ablation for treatment of PAF results in a significant, and sustained, QoL improvement. The observed improvement in physical and mental health likely may be mediated by a reduction in symptom and arrhythmia burden.

Results of the Prospective Minnesota Study of ECHO/TDI in Cardiac Resynchronization Therapy (PROMISE-CRT) study.

BACKGROUND: Retrospective single-center studies have shown that measures of mechanical dyssynchrony before cardiac resynchronization therapy (CRT), or acute changes after CRT, predict response better than QRS duration. The Prospective Minnesota Study of Echocardiographic/TDI in Cardiac Resynchronization Therapy (PROMISE-CRT) study was a prospective multicenter study designed to determine whether acute (1 week) changes in mechanical dyssynchrony were associated with response to CRT. METHODS AND RESULTS: Nine Minnesota Heart Failure Consortium centers enrolled 71 patients with standard indications for CRT. Left ventricular (LV) size, function, and mechanical dyssynchrony (echocardiography [ECHO], tissue Doppler imaging [TDI], speckle-tracking echocardiography [STE]) as well as 6-minute walk distance and Minnesota Living with Heart Failure Questionnaire scores were measured at baseline and 3 and 6 months after CRT. Acute change in mechanical dyssynchrony was not associated with clinical response to CRT. Acute change in STE radial dyssynchrony explained 73% of the individual variation in reverse remodeling. Baseline measures of mechanical dyssynchrony were associated with reverse remodeling (but not clinical) response, with 4 measures each explaining 12% to 30% of individual variation. CONCLUSIONS: Acute changes in radial mechanical dyssynchrony, as measured by STE, and other baseline mechanical dyssynchrony measures were associated with CRT reverse remodeling. These data support the hypothesis that acute improvement in LV mechanical dyssynchrony is an important mechanism contributing to LV reverse remodeling with CRT.

Long-Term Outcomes After Ablation for Paroxysmal Atrial Fibrillation Using the Second-Generation Cryoballoon: Final Results From STOP AF Post-Approval Study.

OBJECTIVES: STOP AF PAS (Sustained Treatment of Paroxysmal Atrial Fibrillation Post-Approval Study) is the first prospective, multicenter, 3-year study in North America to assess long-term safety and effectiveness of the cryoballoon for treatment of patients with drug-refractory symptomatic pAF. BACKGROUND: The STOP AF PAS was required by the U.S. Food and Drug Administration at the time of approval of the first-generation cryoballoon for the treatment of paroxysmal atrial fibrillation (pAF). The second-generation cryoballoon (CB2) was commercially released shortly after this trial was initiated. METHODS: The study was nonrandomized. Enrollment was completed with 344 eligible patients undergoing pulmonary vein isolation (PVI) using the CB2. Procedure-related safety and freedom from AF and symptomatic atrial flutter/atrial tachycardia through 3 years were determined. Documented atrial arrhythmias ≥30 s were considered treatment failures. RESULTS: Acute PVI was achieved in 99.3% (1,341 of 1,350) of veins. Mean follow-up was 34 ± 7 months. The rate of major complications was 5.8%, including a 3.2% rate of phrenic nerve injury, which resolved in all but 1 patient by 36 months. At 36 months, 11.7% of patients were prescribed antiarrhythmic agents, inclusive of "pill-in-the-pocket" administration. Freedom from AF was 81.6% at 12 months, 73.8% at 24 months, and 68.1% at 36 months. Freedom from AF and symptomatic atrial flutter/atrial tachycardia was 79.0% at 12 months, 70.8% at 24 months, and 64.1% at 36 months. Freedom from a repeat ablation procedure was 80.9% at 36 months. CONCLUSIONS: PVI using the CB2 was an effective treatment for patients with pAF, with freedom from all atrial arrhythmias of 64% at 36 months. (Sustained Treatment of Paroxysmal Atrial Fibrillation Post-Approval Study [STOP AF PAS]; NCT01456949).

Extraction of chronically implanted coronary sinus leads active fixation vs passive fixation leads.

BACKGROUND: The Medtronic model 4195 (StarFix) left ventricular lead is an active fixation lead that provides additional support within the coronary sinus (CS) via deployable lobes. While this lead has been shown to have excellent stability within the CS, concerns about its extractability have been raised. OBJECTIVE: The aim of this study was to compare the safety and efficacy of the extraction of the model 4195 lead vs other Medtronic CS leads in a prospective cohort study. METHODS: Patients undergoing extraction of this and other CS leads for standard indications were prospectively enrolled and studied. The primary outcomes of interest were the removal success rates and associated complication rates. Patients were followed for a month postprocedure. RESULTS: The overall left ventricular lead extraction success rate was 97.6% (n = 205). Among 40 patients with chronic model 4195 leads, there were 37 successful extractions (92.5%) as compared to 98.8% for the 165 non-4195 leads. However, in 2 of the 3 StarFix lead extraction failures, standard extraction techniques were not used. All 10 of the model 4195 leads that had been implanted for less than 6 months were extracted without incident. CONCLUSION: In this largest study of CS lead extractions published to date, the overall success rate of the extraction of chronically implanted CS leads is high and the complication rate is similar in these lead models. The extraction of the model 4195 lead is clearly more challenging, but it can be accomplished in high-volume extraction centers with experienced operators. It is recommended that the model 4195 lead be extracted by experienced operators.

Intramural dyssynchrony from acute right ventricular apical pacing in human subjects with normal left ventricular function.

Ventricular pacing causes early myocardial shortening at the pacing site and pre-stretch at the opposing ventricular wall. This contraction pattern is energetically inefficient and may lead to decreased cardiac function. This study was designed to describe the acute effects of right ventricular apical (RV(a)) pacing on dyssynchrony and systolic function in human subjects with normal left ventricular (LV) function and compare these effects to pacing from alternate ventricular sites. Patients (n = 26) undergoing an electrophysiology evaluation were studied during atrial pacing (AAI) and dual chamber pacing from the RV(a), left ventricular free wall (LV(fw)), and the combination of RV(a) and LV(fw) (BiV). Tissue Doppler imaging was used to measure intramural dyssynchrony by utilizing an integrated cross-correlation synchrony index (CCSI) from the apical 4-chamber view. RV(a) and BiV pacing significantly reduced systolic function as measured by longitudinal systolic contraction amplitude (SCA(long)) (p < 0.05) and LV velocity time integral (VTI) (p < 0.05) compared to AAI and LV(fw) pacing. RV(a) (and to a lesser extent BiV) pacing resulted in septal and lateral intramural dyssynchrony as indicated by significantly (p < 0.05) lower CCSI values as compared to AAI. CCSI was significantly (p < 0.05) worse during RV(a) than LV(fw) pacing. In patients with normal LV function, acute ventricular pacing in the RV(a) alone, or in conjunction with LV(fw) pacing (BiV), results in impaired regional and global LV systolic function and intramural dyssynchrony as compared to LV(fw) pacing alone.

Lead extraction in the contemporary setting: the LExICon study: an observational retrospective study of consecutive laser lead extractions.

OBJECTIVES: This study sought to examine the safety and efficacy of laser-assisted lead extraction and the indications, outcomes, and risk factors in a large series of consecutive patients. BACKGROUND: The need for lead extraction has been increasing in direct relationship to the increased numbers of cardiovascular implantable electronic devices. METHODS: Consecutive patients undergoing transvenous laser-assisted lead extraction at 13 centers were included. RESULTS: Between January 2004 and December 2007, 1,449 consecutive patients underwent laser-assisted lead extraction of 2,405 leads (20 to 270 procedures/site). Median implantation duration was 82.1 months (0.4 to 356.8 months). Leads were completely removed 96.5% of the time, with a 97.7% clinical success rate whereby clinical goals associated with the indication for lead removal were achieved. Failure to achieve clinical success was associated with body mass index <25 kg/m(2) and low extraction volume centers. Procedural failure was higher in leads implanted for >10 years and when performed in low volume centers. Major adverse events in 20 patients were directly related to the procedure (1.4%) including 4 deaths (0.28%). Major adverse effects were associated with patients with a body mass index <25 kg/m(2). Overall all-cause in-hospital mortality was 1.86%; 4.3% when associated with endocarditis, 7.9% when associated with endocarditis and diabetes, and 12.4% when associated with endocarditis and creatinine > or =2.0. Indicators of all-cause in-hospital mortality were pocket infections, device-related endocarditis, diabetes, and creatinine > or =2.0. CONCLUSIONS: Lead extraction employing laser sheaths is highly successful with a low procedural complication rate. Total mortality is substantially increased with pocket infections or device-related endocarditis, particularly in the setting of diabetes, renal insufficiency, or body mass index <25 kg/m(2). Centers with smaller case volumes tended to have a lower rate of successful extraction.

Cardiac resynchronization therapy: role of patient selection.

Cardiac resynchronization therapy (CRT) is a well-accepted and effective therapy for treating patients with a wide QRS complex, significant left ventricular systolic dysfunction, and symptoms of advanced heart failure. However, approximately 25% to 30% of patients fail to respond to this therapy. Most large studies have used electrical dyssynchrony (wide QRS) as a main entrance criterion. Emerging data suggest that mechanical dyssynchrony may be a more important factor in selecting appropriate candidates for CRT. New echocardiographic (ECHO) imaging modalities such as tissue Doppler imaging, three-dimensional ECHO, and speckle tracking ECHO are able to quantify left ventricular mechanical dyssynchrony. These techniques are currently being used to assist in the selection of patients for CRT. Recently published and ongoing studies are addressing the use of CRT in patients who do not meet the standard criteria, such as patients with atrial fibrillation, mild to moderate heart failure, narrow QRS complex, and acute myocardial infarction.

Combined efficacy of atrial septal lead placement and atrial pacing algorithms for prevention of paroxysmal atrial tachyarrhythmia.

INTRODUCTION: The combined role of atrial septal lead location and atrial pacing algorithms in the prevention of atrial tachyarrhythmias (AT/AF), including both atrial fibrillation and flutter, is unknown. We tested the hypothesis that atrial prevention pacing algorithms could decrease AT/AF frequency in patients with atrial septal leads, bradycardia, and paroxysmal AT/AF. METHODS AND RESULTS: A total of 298 patients (age 70 +/- 10 years; 61% male) from 35 centers were implanted with a DDDRP pacing system including three AT/AF prevention pacing algorithms. Lead site was randomized at implant to right atrial septal or nonseptal. Patients were randomized 1 month postimplant to AT/AF prevention ON or OFF for 3 months and then crossed over for 3 months. Patients logged symptomatic AT/AF episodes via a manual activator. Prevention efficacy was evaluated based on intention-to-treat in 277 patients (138 septal) with complete follow-up. No changes in device-recorded AT/AF frequency or burden were observed with algorithms OFF versus ON or between patients randomized to septal versus nonseptal lead location. Analysis of other secondary outcomes revealed that AT/AF prevention pacing resulted in decreased atrial premature contractions in both the septal (1.9 [0.2-8.7] vs 3.3 [0.3-10.6]x 103/day; P < 0.01) and nonseptal groups (0.9 [0.2-3.3] vs 1.3 [0.3-5.5]x 103/day; P < 0.001). Patients with septal leads had fewer symptomatic AT/AF episodes ON versus OFF (1.4 +/- 3.0 vs 2.5 +/- 5.2/month, P = 0.01). CONCLUSION: The combination of three atrial prevention pacing algorithms did not decrease device classified atrial tachyarrhythmia frequency or burden during a 3-month cross-over period in bradycardic patients and septal or nonseptal atrial pacing leads. Prevention pacing was associated with decreased frequency of premature atrial contractions and with decreased symptomatic atrial tachyarrhythmia frequency in patients with atrial septal leads.