G A Haywood

Bio: G A Haywood is an academic researcher. The author has contributed to research in topics: QRS complex & Cardiac resynchronization therapy. The author has an hindex of 1, co-authored 1 publications receiving 2487 citations.

Effects of Multisite Biventricular Pacing in Patients with Heart Failure and Intraventricular Conduction Delay

Abstract: BACKGROUND: One third of patients with chronic heart failure have electrocardiographic evidence of a major intraventricular conduction delay, which may worsen left ventricular systolic dysfunction through asynchronous ventricular contraction. Uncontrolled studies suggest that multisite biventricular pacing improves hemodynamics and well-being by reducing ventricular asynchrony. We assessed the clinical efficacy and safety of this new therapy. METHODS: Sixty-seven patients with severe heart failure (New York Heart Association class III) due to chronic left ventricular systolic dysfunction, with normal sinus rhythm and a duration of the QRS interval of more than 150 msec, received transvenous atriobiventricular pacemakers (with leads in one atrium and each ventricle). This single-blind, randomized, controlled crossover study compared the responses of the patients during two periods: a three-month period of inactive pacing (ventricular inhibited pacing at a basic rate of 40 bpm) and a three-month period of active (atriobiventricular) pacing. The primary end point was the distance walked in six minutes; the secondary end points were the quality of life as measured by questionnaire, peak oxygen consumption, hospitalizations related to heart failure, the patients' treatment preference (active vs. inactive pacing), and the mortality rate. RESULTS: Nine patients were withdrawn from the study before randomization, and 10 failed to complete both study periods. Thus, 48 patients completed both phases of the study. The mean distance walked in six minutes was 22 percent greater with active pacing (399+/-100 m vs. 326+/-134 m, P<0.001), the quality-of-life score improved by 32 percent (P<0.001), peak oxygen uptake increased by 8 percent (P<0.03), hospitalizations were decreased by two thirds (P<0.05), and active pacing was preferred by 85 percent of the patients (P<0.001). CONCLUSIONS: Although it is technically complex, atriobiventricular pacing significantly improves exercise tolerance and quality of life in patients with chronic heart failure and intraventricular conduction delay.

2016 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure

Abstract: ACC/AHA : American College of Cardiology/American Heart Association ACCF/AHA : American College of Cardiology Foundation/American Heart Association ACE : angiotensin-converting enzyme ACEI : angiotensin-converting enzyme inhibitor ACS : acute coronary syndrome AF : atrial fibrillation

The effect of cardiac resynchronization on morbidity and mortality in heart failure

Abstract: background Cardiac resynchronization reduces symptoms and improves left ventricular function in many patients with heart failure due to left ventricular systolic dysfunction and cardiac dyssynchrony We evaluated its effects on morbidity and mortality methods Patients with New York Heart Association class III or IV heart failure due to left ventricular systolic dysfunction and cardiac dyssynchrony who were receiving standard pharmacologic therapy were randomly assigned to receive medical therapy alone or with cardiac resynchronization The primary end point was the time to death from any cause or an unplanned hospitalization for a major cardiovascular event The principal secondary end point was death from any cause results A total of 813 patients were enrolled and followed for a mean of 294 months The primary end point was reached by 159 patients in the cardiac-resynchronization group, as compared with 224 patients in the medical-therapy group (39 percent vs 55 percent; hazard ratio, 063; 95 percent confidence interval, 051 to 077; P<0001) There were 82 deaths in the cardiac-resynchronization group, as compared with 120 in the medical-therapy group (20 percent vs 30 percent; hazard ratio 064; 95 percent confidence interval, 048 to 085; P<0002) As compared with medical therapy, cardiac resynchronization reduced the interventricular mechanical delay, the end-systolic volume index, and the area of the mitral regurgitant jet; increased the left ventricular ejection fraction; and improved symptoms and the quality of life (P<001 for all comparisons) conclusions In patients with heart failure and cardiac dyssynchrony, cardiac resynchronization improves symptoms and the quality of life and reduces complications and the risk of death These benefits are in addition to those afforded by standard pharmacologic therapy The implantation of a cardiac-resynchronization device should routinely be considered in such patients

Cardiac Resynchronization in Chronic Heart Failure

Abstract: Background Previous studies have suggested that cardiac resynchronization achieved through atrial-synchronized biventricular pacing produces clinical benefits in patients with heart failure who have an intraventricular conduction delay. We conducted a double-blind trial to evaluate this therapeutic approach. Methods Four hundred fifty-three patients with moderate-to-severe symptoms of heart failure associated with an ejection fraction of 35 percent or less and a QRS interval of 130 msec or more were randomly assigned to a cardiac-resynchronization group (228 patients) or to a control group (225 patients) for six months, while conventional therapy for heart failure was maintained. The primary end points were the New York Heart Association functional class, quality of life, and the distance walked in six minutes. Results As compared with the control group, patients assigned to cardiac resynchronization experienced an improvement in the distance walked in six minutes (+39 vs. +10 m, P=0.005), functional clas...