Abstract
BackgroundHeart failure patients with stable angina, acute coronary syndromes and valvular heart disease may benefit from revascularisation and/or valve surgery. However, the mortality rate is increased- 5-30%. Biventricular pacing using temporary epicardial wires after surgery is a potential mechanism to improve cardiac function and clinical endpoints.Method/designA multi-centred, prospective, randomised, single-blinded, intervention-control trial of temporary biventricular pacing versus standard pacing. Patients with ischaemic cardiomyopathy, valvular heart disease or both, an ejection fraction ≤ 35% and a conventional indication for cardiac surgery will be recruited from 2 cardiac centres. Baseline investigations will include: an electrocardiogram to confirm sinus rhythm and measure QRS duration; echocardiogram to evaluate left ventricular function and markers of mechanical dyssynchrony; dobutamine echocardiogram for viability and blood tests for renal function and biomarkers of myocardial injury- troponin T and brain naturetic peptide. Blood tests will be repeated at 18, 48 and 72 hours. The principal exclusions will be subjects with permanent atrial arrhythmias, permanent pacemakers, infective endocarditis or end-stage renal disease.After surgery, temporary pacing wires will be attached to the postero-lateral wall of the left ventricle, the right atrium and right ventricle and connected to a triple chamber temporary pacemaker. Subjects will be randomised to receive either temporary biventricular pacing or standard pacing (atrial inhibited pacing or atrial-synchronous right ventricular pacing) for 48 hours.The primary endpoint will be the duration of level 3 care. In brief, this is the requirement for invasive ventilation, multi-organ support or more than one inotrope/vasoconstrictor. Haemodynamic studies will be performed at baseline, 6, 18 and 24 hours after surgery using a pulmonary arterial catheter. Measurements will be taken in the following pacing modes: atrial inhibited; right ventricular only; atrial synchronous-right ventricular; atrial synchronous-left ventricular and biventricular pacing. Optimisation of the atrioventricular and interventricular delay will be performed in the biventricular pacing group at 18 hours. The effect of biventricular pacing on myocardial injury, post operative arrhythmias and renal function will also be quantified.Trial RegistrationClinicalTrials.gov: NCT01027299
Highlights
Heart failure patients with stable angina, acute coronary syndromes and valvular heart disease may benefit from revascularisation and/or valve surgery
2-3% of the general population are diagnosed with heart failure [1] and the primary aetiology is coronary artery disease
The reduction in ventricular volumes correlates to a reduction in heart failure events, arrhythmias and death [11,12]
Summary
The prevalence of heart failure is increasing throughout the industrialised world. Approximately 2-3% of the general population are diagnosed with heart failure [1] and the primary aetiology is coronary artery disease. ACE inhibitors [4,5], beta blockers [6,7,8] and aldosterone antagonists [9,10] modulate the renin-angiotensin-aldosterone axis and neurohormonal cascade which reduces major adverse events These medications arrest the cascade of progressive ventricular remodelling and dilatation observed in heart failure. The Coronary-Artery Bypass Surgery in Patients with LV Dysfunction (STICH) trial was designed to address this issue and compared optimal medical therapy to surgical revascularisation, in subjects with severe LV systolic impairment [16]. An acute haemodynamic response has been observed in previous studies during implantation of permanent BiV pacemakers - Table 2 These studies were conducted on subjects after optimising medical therapy including ACE inhibitors and beta blockers.
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