ABSTRACT
Heart failure (HF) is increasingly common and, despite advances in pharmacotherapeutic management, often progresses. Progression is marked by structural and electrical changes-remodelling. In approximately one-third of patients, ventricular dilatation is accompanied by intraventricular conduction delays, most commonly the left bundle branch block (LBBB). The presence of LBBB is associated with mechanical dyssynchrony of the heart. Cardiac resynchronisation therapy (CRT), the use of special pacemakers with or without implantable cardioverter defibrillators, aims to resynchronise the failing heart, improving myocardial contraction without increased energetics. Several, large, randomised clinical trials have now established the benefit of CRT in a select group of HF patients, providing functional and, recently shown, mortality benefits. However, a substantial proportion of patients are considered non-responders to CRT, and studies are now underway to identify the patients most likely to respond to CRT.
Subject(s)
Cardiac Pacing, Artificial/methods , Heart Failure/therapy , Animals , Disease Progression , Heart Failure/physiopathology , Humans , Myocardial Contraction/physiology , Treatment OutcomeABSTRACT
BACKGROUND: The determinants of release of brain natriuretic peptide (BNP) in heart failure (HF) are incompletely understood, particularly, the effect of heart rhythm and haemodynamic stress. AIMS: To investigate the effect of haemodynamic stress on cardiac BNP release in HF and differentiate this response for atrial fibrillation (AF) and sinus rhythm (SR). METHODS: In 18 HF patients (ejection fraction<40%, 9 in AF and 9 in SR) haemodynamics and BNP levels were measured from arterial and coronary sinus samples at baseline, after 10 min of 20 degrees passive head up tilt (HUT) and after 10 min of isometric handgrip (IHG) exercise. From these data, we calculated a transcardiac BNP gradient and compared results between the AF and SR cohort. RESULTS: During haemodynamic stress in both groups, there were no significance differences in left sided filling pressures. At baseline, there were no differences in BNP measurements between the SR and AF group. The transcardiac BNP gradient increased significantly in the SR (p=0.02) but not the AF cohort, after HUT. During IHG exercise, there was a significant decrease in cardiac BNP release in the AF cohort (p=0.03) but not the SR cohort. CONCLUSION: These data imply in HF, cardiac rhythm influences cardiac BNP release in response to haemodynamic stress.
Subject(s)
Atrial Fibrillation/metabolism , Blood Pressure , Heart Failure/metabolism , Myocardium/metabolism , Natriuretic Peptide, Brain/metabolism , Aged , Exercise , Female , Heart Rate , Humans , Male , Middle Aged , PostureABSTRACT
The number of reported cases of physical child abuse in Georgia from July 1975 to June 1978 increased. Of 4,292 cases reported, 57% were confirmed. School officials most often reported cases of suspected abuse; 69% were confirmed by social work investigation. Metropolitan black female children had the highest residence/race/sex-specific abuse rates. The highest abuse rate for boys was for the 0- to 3-year-old group, while for girls the highest abuse rates were for the 13- to 16-year-old group. Both natural parents were present in 39% of the confirmed cases, and a natural parent was the abuser in 62% of the cases. Of the natural mothers who were confirmed abusers, 53% had been pregnant as teen-agers. Thirty-eight children died after being abused, with the highest death-case ratio being 62 per 1,000 abused children for black girls aged 0 to 4 years.
