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Articles by K Abozguia
Total Records ( 2 ) for K Abozguia
  K Abozguia , P Elliott , W McKenna , T. T Phan , G Nallur Shivu , I Ahmed , A. R Maher , K Kaur , J Taylor , A Henning , H Ashrafian , H Watkins and M. Frenneaux
  Background—

Hypertrophic cardiomyopathy patients exhibit myocardial energetic impairment, but a causative role for this energy deficiency in the pathophysiology of hypertrophic cardiomyopathy remains unproven. We hypothesized that the metabolic modulator perhexiline would ameliorate myocardial energy deficiency and thereby improve diastolic function and exercise capacity.

Methods and Results—

Forty-six consecutive patients with symptomatic exercise limitation (peak Vo2 <75% of predicted) caused by nonobstructive hypertrophic cardiomyopathy (mean age, 55±0.26 years) were randomized to perhexiline 100 mg (n=24) or placebo (n=22). Myocardial ratio of phosphocreatine to adenosine triphosphate, an established marker of cardiac energetic status, as measured by 31P magnetic resonance spectroscopy, left ventricular diastolic filling (heart rate normalized time to peak filling) at rest and during exercise using radionuclide ventriculography, peak Vo2, symptoms, quality of life, and serum metabolites were assessed at baseline and study end (4.6±1.8 months). Perhexiline improved myocardial ratios of phosphocreatine to adenosine triphosphate (from 1.27±0.02 to 1.73±0.02 versus 1.29±0.01 to 1.23±0.01; P=0.003) and normalized the abnormal prolongation of heart rate normalized time to peak filling between rest and exercise (0.11±0.008 to –0.01±0.005 versus 0.15±0.007 to 0.11±0.008 second; P=0.03). These changes were accompanied by an improvement in primary end point (peak Vo2) (22.2±0.2 to 24.3±0.2 versus 23.6±0.3 to 22.3±0.2 mL · kg–1 · min–1; P=0.003) and New York Heart Association class (P<0.001) (all P values ANCOVA, perhexiline versus placebo).

Conclusions—

In symptomatic hypertrophic cardiomyopathy, perhexiline, a modulator of substrate metabolism, ameliorates cardiac energetic impairment, corrects diastolic dysfunction, and increases exercise capacity. This study supports the hypothesis that energy deficiency contributes to the pathophysiology and provides a rationale for further consideration of metabolic therapies in hypertrophic cardiomyopathy.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00500552.

  T. T Phan , G. N Shivu , K Abozguia , C Davies , M Nassimizadeh , D Jimenez , R Weaver , I Ahmed and M. Frenneaux
 

Background— This study assessed the chronotropic response to exercise and heart rate (HR) recovery after exercise in a carefully phenotyped group of patients with heart failure with preserved left ventricular ejection fraction (HfpEF) and a control group of similar age and gender distribution.

Methods and Results— We studied 41 patients with HfpEF, 41 healthy controls, and 16 hypertensive controls. None were taking HR-limiting medications. All study participants had clinical examination, 12-lead ECG, pulmonary function test, echocardiogram, and metabolic exercise test with HR monitoring throughout exercise. Chronotropic response was measured by the percentage of the HR reserve used during maximal exercise and the peak exercise HR as a percentage of predicted maximal HR. Patients with HfpEF were generally women (70%), overweight, aged 69±8 years. Controls were of similar gender (63%) and age (67±6 years). Patients with HfpEF had significantly reduced peak VO2 compared with controls (20±4 mL · kg–1 · min–1 versus 31±6 mL · kg–1 · min–1, P<0.001) and greater minute ventilation-carbon dioxide production relationship (Ve/Vco2 slope) (33±6 versus 29±4, P<0.001). Chronotropic incompetence was significantly more common in patients with HfpEF compared with matched healthy controls as measured by the percentage of the HR reserve used during maximal exercise (63% versus 2%, <0.001) and percentage of predicted maximal HR (34% versus 2%, <0.001). In addition, abnormal HR recovery 1-minute after exercise (defined as the reduction in the HR from peak exercise 1-minute after exercise) was also significantly more common in patients with HfpEF compared with controls (23% versus 2%, P=0.01). Hypertensive controls showed similar chronotropic response to peak exercise and HR recovery after exercise as healthy controls.

Conclusions— Patients with HfpEF have impaired chronotropic incompetence during maximal exercise and abnormal HR recovery after exercise.

 
 
 
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