CARDIOVASCULAR MEDICINE Left ventricular pacing improves haemodynamic variables in patients with heart failure with a normal QRS duration

Objectives: To assess whether patients with congestive heart failure (CHF) and a normal QRS duration can benefit from left ventricular (VDD-LV) pacing. Design: Cardiac resynchronisation is reserved for patients with a broad QRS duration on the premise that systolic resynchronisation is the mechanism of benefit, yet improvement from pacing correlates poorly with QRS duration. In CHF patients with a broad QRS duration, those with a high resting pulmonary capillary wedge pressure (PCWP) . 15 mm Hg benefit. In this acute haemodynamic VDD-LV pacing study, patients with CHF with a normal QRS duration were divided into two groups—patients with a resting PCWP . 15 mm Hg and patients with a resting PCWP , 15 mm Hg—to determine whether benefit is predicted by a high resting PCWP. Patients: 20 patients with CHF, New York Heart Association functional class IIb–IV, all with a normal QRS duration ( 120 ms). Interventions: Temporary pacing wires were positioned to enable VDD-LV pacing and a pulmonary artery catheter was inserted for measurement of PCWP, right atrial pressure, and cardiac output. Results: In patients with a PCWP . 15 mm Hg (n = 10), cardiac output increased from 3.9 (1.5) to 4.5 (1.65) l/min (p , 0.01), despite a fall in PCWP from 24.7 (7.1) to 21.0 (6.2) mm Hg (p , 0.001). In patients with a PCWP , 15 mm Hg there was no change in PCWP or cardiac output. Combined data showed that PCWP decreased from 17.0 (9.1) to 15.3 (7.7) mm Hg during VDD-LV pacing (p , 0.014) and cardiac output increased non-significantly from 4.7 (1.5) to 4.9 (1.5) (p = 0.125). Conclusions: Patients with CHF with a normal QRS duration and PCWP . 15 mm Hg derive acute haemodynamic benefit from VDD-LV pacing.