An Assessment of Dual Site Left Ventricular Endocardial Pacing (DOUBLE-CRT)

We are investigating ways to help patients with heart failure, which is caused by damaged hearts which function less well, and cause symptoms of breathlessness, fatigue, lack of energy and swelling. Cardiac Resynchronisation Therapy (CRT) pacemakers are used to improve the pumping function of the main heart chamber in certain suitable people with heart failure. CRT requires a pacemaker with 2 wires, one placed inside the right heart chamber and one normally placed on the outside of the left heart chamber. These two wires act together to re-time the coordination of the heartbeat, which is known to improve heart function. The investigators are assessing whether they might be able to improve heart function even more by placing two wires on the inside of the left heart chamber, rather than one around the outside. The investigators wish to assess whether: Using two wires within the left side of the heart gives a greater increase in heart function than one. It is possible to choose the best spot inside of the heart by measuring the pattern of the heart beat. Is it possible to use a different type of heart monitor placed outside the body instead of a monitor wire inside the heart to assess improvement in heart function? They are investigating this in people with hearts that beat less effectively than normal.

Atrial Fibrillation/flutter (AF) or Ventricular Tachycardia (VT) ablation with multi-site pacing protocol

Pacing at several endocardial sites in isolation and individually will be performed, with response to this assessed by LV dp/dt max

Acute haemodynamic response to pacing (change in Left Ventricular dP/dt max) between dual site Left Ventricular pacing and biventricular pacing Pacing protocols were performed with a baseline of 30 seconds of right ventricular pacing followed by two 30-second test configurations, and then a further baseline. The pacing configurations were tested, in a randomized order, 3 times each. Electrophysiology catheters were positioned at the right ventricular mid septum for baseline pacing, and at the left ventricular septum and at the left ventricular lateral wall, at the site of latest electrical activation i identified from a left ventricular electrical activation map This provided two single-site left ventricular pacing configurations, which could be combined to allow right ventricular and left ventricular lateral (Biventricular pacing) and left ventricular septal and left ventricular lateral (dual left ventricular pacing)

Inclusion Criteria: Participant is willing and able to give informed consent for participation in the study. Male or Female, aged 60 years or above. Having a suitable Atrial Fibrillation/flutter or Ventricular Tachycardia ablation procedure Evidence of abnormal Left Ventricular structure and function, as shown by Left Ventricular ejection fraction of less than 40% Exclusion Criteria: Severe peripheral vascular disease (that would make arterial access more risky) Haemodynamic instability (such that a longer procedure is inadvisable)

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