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Angel R León

Publications and source records attributed to Angel R León.

10 recordsLinked to original sources
PubMed2005

Safety of transvenous cardiac resynchronization system implantation in patients with chronic heart failure: combined results of over 2,000 patients from a multicenter study program.

OBJECTIVES: The purpose of this study was to evaluate the safety of implanting a cardiac resynchronization therapy (CRT) system. BACKGROUND: Clinicians and patients require data on the safety of the CRT implant procedure to estimate procedural risk. METHODS: We evaluated outcomes of transvenous CRT system implantation in 2,078 patients from the Multicenter InSync Randomized Clinical Evaluation (MIRACLE) study, the MIRACLE Implantable Cardioverter-Defibrillator (ICD) study, and the InSync III study. We compared the MIRACLE study to the InSync III study and the MIRACLE ICD study randomized phase to its general phase to evaluate the effect of new technologies. RESULTS: The implant attempt succeeded in 1,903 of 2,078 (91.6%) patients. Implant time decreased from 2.7 h in the MIRACLE study to 2.3 h in the InSync III study (p < 0.001), and from 2.8 h in the MIRACLE ICD study randomized phase to 2.4 h in the general phase (p < 0.001). The implant procedure produced 62 perioperative complications in 53 (9.3%) MIRACLE trial patients; 159 in 135 (21.1%) MIRACLE ICD study randomized phase patients and 71 in 62 (13.9%) general phase patients (p < 0.05 vs. randomized); and 41 in 37 (8.8%) InSync III study patients (p = NS vs. the MIRACLE study). We observed 73 postoperative complications in 62 (11.7%) MIRACLE trial patients, 77 in 68 (11.9%) MIRACLE ICD study randomized phase patients and 56 in 45 (11.0%) general phase patients (p = NS), and 37 in 34 (8.6%) InSync III study patients (p = NS). A total of 8% of patients required reoperation to treat lead dislodgement, extracardiac stimulation, or infection during follow-up. CONCLUSIONS: Transvenous CRT system implantation appears safe, well-tolerated, has a high success rate, and improves with operator experience and the addition of new technologies.

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PubMed2005

Cardiac resynchronization with sequential biventricular pacing for the treatment of moderate-to-severe heart failure.

OBJECTIVES: The InSync III study evaluated sequential cardiac resynchronization therapy (CRT) in patients with moderate-to-severe heart failure and prolonged QRS. BACKGROUND: Simultaneous CRT improves hemodynamic and clinical performance in patients with moderate-to-severe heart failure (HF) and a wide QRS. Recent evidence suggests that sequentially stimulating the ventricles might provide additional benefit. METHODS: This multicenter, prospective, nonrandomized, six-month trial enrolled a total of 422 patients to determine the effectiveness of sequential CRT in patients with New York Heart Association (NYHA) functional class III or IV HF and a prolonged QRS. The study evaluated: whether patients receiving sequential CRT for six months experienced improvement in 6-min hall walk (6MHW) distance, NYHA functional class, and quality of life (QoL) over control group patients from the reported Multicenter InSync Randomized Clinical Evaluation (MIRACLE) trial; whether sequential CRT increased stroke volume compared to simultaneous CRT; and whether an increase in stroke volume translated into greater clinical improvements compared to patients receiving simultaneous CRT. RESULTS: InSync III patients experienced greater improvement in 6MHW, NYHA functional class, and QoL at six months compared to control (all p < 0.0001). Optimization of the sequential pacing increased (median 7.3%) stroke volume in 77% of patients. No additional improvement in NYHA functional class or QoL was seen compared to the simultaneous CRT group; however, InSync III patients demonstrated greater exercise capacity. CONCLUSIONS: Sequential CRT provided most patients with a modest increase in stroke volume above that achieved during simultaneous CRT. Patients receiving sequential CRT had improved exercise capacity, but no change in functional status or QoL.

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PubMed2005

Cardiac resynchronization therapy: strategies for device programming, troubleshooting and follow-up.

Cardiac resynchronization therapy (CRT) improves symptoms, exercise performance, ventricular function, and survival in patients with left ventricular dysfunction, prolonged QRS, and drug-refractory moderate to severe CHF. The growing application of CRT has created a large number of patients with complicated devices that need follow-up care from general practitioners, cardiologists, heart failure specialists and electro-physiologists. Optimal care of the CRT patient includes recognition and management of peri-implantation complications, optimal programming of atrio-ventricular and sequential ventricular timing, and troubleshooting device-related problems during long-term follow-up. A basic awareness of fundamental device features, the techniques to maximize the response to CRT, and an understanding of stored device data to track the response to therapy provide clinicians the ability to maximize clinical outcomes in the CHF patient. As evolving technology continues to increase the complexity of device therapies, clinicians must understand these therapies in order to properly treat heart failure patients. This work summarizes many of the issues involving early complications of CRT device implant, the strategies to optimize device function, and suggests a scheme for follow-up care of patients with CRT devices.

Cardiac Pacing, Artificial↗
PubMed2005

Cardiac resynchronization therapy.

Cardiac resynchronization therapy (CRT) addresses abnormal left ventricular (LV) activation that produces detrimental effects on cardiac systolic and diastolic function. CRT improves symptoms and ventricular performance, promotes reverse remodeling, and decreases mortality and hospitalization in patients with congestive heart failure (CHF). Atrial-synchronized biventricular stimulation reverses many of the temporal delays in mechanical activation associated with LV dysfunction and conduction system disease. The therapy evolved from anecdotal application through surgical implantation of LV pacing leads to transvenous delivery of LV pacing leads for use with dedicated CRT devices. The controlled clinical trials included specific patient groups, and provided data leading to widely adopted indications for the therapy. Current indications exclude the use of CRT in patients with permanent atrial fibrillation, although small series suggest a benefit of the therapy in these patients. The role of cardiac imaging with echocardiography to detect cardiac dyssynchrony promises to improve patient selection by not only excluding likely nonresponders, but also extending the therapy to those with dyssynchrony in the absence of QRS prolongation. Expanded indications under evaluation include the role of CRT in patients with mildly symptomatic CHF, mild to moderate LV dysfunction, dyssynchrony in the absence of QRS prolongation, and dyssynchrony induced by right ventricular pacing.

Atrial Fibrillation↗
PubMed2005

Predictors of response to cardiac resynchronization therapy (PROSPECT)--study design.

BACKGROUND: Cardiac resynchronization therapy (CRT) is currently indicated in patients with moderate to severe heart failure, a wide QRS complex and significant left ventricular dysfunction despite optimal medical therapy. Adoption of these criteria for CRT results in a favorable response in only two thirds of candidates. METHODS: "Predictors of response to cardiac resynchronization therapy (PROSPECT)," a prospective, multicenter, nonrandomized study, aims to identify echocardiographic measures of dyssynchrony and evaluate their ability to predict response to CRT. PROSPECT will enroll approximately 300 patients in up to 75 centers in the United States, Asia, and Europe with clinical follow-up for 6 months. We will prospectively and individually test a variety of conventional echocardiographic and tissue Doppler imaging parameters against measures of clinical response. The primary response criteria are improvement in the heart failure Clinical Composite Score and left ventricular reverse remodeling. Enrollment began in March 2004 and is expected to conclude early 2005.

Asia↗
PubMed2005

The impact of cardiac resynchronization therapy on ventricular tachycardia/fibrillation: an analysis from the combined Contak-CD and InSync-ICD studies.

OBJECTIVES: To determine the potential influence of cardiac resynchronization therapy (CRT) on the frequency and types of ventricular arrhythmia (VA) in patients with an indication for the implantable cardioverter-defibrillator (ICD), we performed a retrospective electrogram (EGM) analysis of stored VA events from the two largest CRT-ICD trials. BACKGROUND: Previous reports suggest that CRT might promote polymorphic VT (PVT), while a beneficial effect of CRT on ventricular function might reduce the frequency of monomorphic VT (MVT). Theoretically, a balanced effect produces no change in overall VA. METHODS: We analyzed stored EGMs from patients in the Contak-CD and Insync-ICD studies receiving appropriate therapy for VA. EGM inspection distinguishes MVT and PVT using morphologic criteria rather than cycle length classification alone. RESULTS: Of 1,041 subjects entering the two trials, 880 were randomized CRT (N = 439) or control (N = 441). We were able to analyze 840 EGMs in 150 patients with VA, including 678 MVT episodes and 162 PVT episodes. These events were distributed among 68 patients with active CRT (390 MVT vs 111 PVT) and 82 patients assigned to control (288 MVT compared to 51 PVT). The apparent increase in PVT episodes in the CRT group is not significant and can be explained by a disproportionate number of episodes in a few patients. We were unable to identify clinical variables predictive of PVT during CRT. CONCLUSIONS: CRT is not associated with a measurable increase in the incidence of PVT, or in a reduction in MVT in the combined InSync-ICD and Contak-CD populations.

Defibrillators, Implantable↗
PubMed2005

New tools for the effective delivery of cardiac resynchronization therapy.

Cardiac resynchronization therapy (CRT) has been shown to provide symptom relief to many patients who have congestive heart failure (CHF). Still, there are technical concerns with implanting CRT systems, and these range from inadequate venous anatomy to a variety of left ventricular (LV) lead problems. Fortunately, there are several new implant tools to help physicians achieve a stable and adequate LV pacing site. There are a number of guiding catheter shapes to tailor the choice to specific anatomic abnormalities that may be encountered during implants. Key to success was the development of over-the-wire LV leads that are capable of maneuvering within complex venous anatomy. Improvements in LV leads have included increasing lead diameter and bipolar design. In some cases, epicardial LV lead placement may be necessary at surgery. The latest systems have begun to integrate disease management modalities, which hopefully will reduce the need for CHF hospitalizations.

Cardiac Catheterization↗
PubMed2004

Effects of cardiac resynchronization on disease progression in patients with left ventricular systolic dysfunction, an indication for an implantable cardioverter-defibrillator, and mildly symptomatic chronic heart failure.

BACKGROUND: The effects of cardiac resynchronization therapy (CRT) in patients with mildly symptomatic heart failure have not been fully elucidated. METHODS AND RESULTS: The Multicenter InSync ICD Randomized Clinical Evaluation II (MIRACLE ICD II) was a randomized, double-blind, parallel-controlled clinical trial of CRT in NYHA class II heart failure patients on optimal medical therapy with a left ventricular (LV) ejection fraction < or =35%, a QRS > or =130 ms, and a class I indication for an ICD. One hundred eighty-six patients were randomized: 101 to the control group (ICD activated, CRT off) and 85 to the CRT group (ICD activated, CRT on). End points included peak VO2, VE/CO2, NYHA class, quality of life, 6-minute walk distance, LV volumes and ejection fraction, and composite clinical response. Compared with the control group at 6 months, no significant improvement was noted in peak VO2, yet there were significant improvements in ventricular remodeling indexes, specifically LV diastolic and systolic volumes (P=0.04 and P=0.01, respectively), and LV ejection fraction (P=0.02). CRT patients showed statistically significant improvement in VE/CO2 (P=0.01), NYHA class (P=0.05), and clinical composite response (P=0.01). No significant differences were noted in 6-minute walk distance or quality of life scores. CONCLUSIONS: In patients with mild heart failure symptoms on optimal medical therapy with a wide QRS complex and an ICD indication, CRT did not alter exercise capacity but did result in significant improvement in cardiac structure and function and composite clinical response over 6 months.

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PubMed2004

Usefulness of the peak velocity difference by tissue Doppler imaging technique as an effective predictor of response to cardiac resynchronization therapy.

Cardiac resynchronization therapy (CRT) improves symptoms and functional status in heart failure patients; however, current selection criteria need improvement. A novel tissue Doppler imaging parameter, the peak velocity difference (PVD), defined as the greatest difference in time to peak velocity between any of 6 left ventricular regions, may better select responders to CRT. Subjects were divided into 2 groups based on the PVD. Clinical and echocardiographic parameters significantly improved in subjects with dyssynchrony by the baseline PVD and had a better overall response to CRT.

Aged↗