INITIAL EXPERIENCES WITH BIVENTRICULAR CARDIAC PACING FOR THE TREATMENT
OF HEART FAILURE. P
Hereford-Ashley*, S Nicholls, W Saw and J W Leitch. Cardiovascular
Unit, John Hunter Hospital, Newcastle. Introduction: Biventricular (BV) cardiac
pacing has been proposed to benefit patients with heart failure. We describe
our initial experiences with biventricular pacing, through our participation in
the Medtronic InSync Registry. Results: We enrolled 12 patients in
the Registry aged 70±5 years, with an ejection
fraction of 18±4%, left bundle
branch block and a QRS duration of 159±25 msec. The mean
procedure time was 129 minutes (range 87 to 270), with a mean fluoroscopy time
of 45 minutes (range 14 to 174). The mean results at baseline and with
follow-up are summarised in the table below. QRS
duration (msec) 6
minute walk (meters) E
wave A
wave BV Baseline 0.78 0.56 N/A Implant N/A N/A N/A N/A 2.0 Predischarge N/A N/A N/A 1.5 1
month 1.00 0.90 1.9 3
month 0.91 0.64 2.3 Placement
of the left ventricular (LV) lead in a lateral or postero-lateral vessel (8
patients) resulted in lower BV pacing threshold when compared with thresholds
of leads placed in an anterior branch (1.8 vs 2.8 volts respectively). LV lead
placement was limited by variations between patients in coronary venous
vasculature and lead stability. Three patients were in atrial fibrillation, in
these patients a standard dual chamber pacemaker was inserted with the LV lead
connected to the atrial port of the header.
The procedure was unsuccessful in 2 patients because of failure to
cannulate the coronary sinus (1 patient) or failure to find a stable site in a
LV vein (1 patient). One procedure was complicated by an AV fistula, which was
closed percutaneously. Conclusion: Biventricular
pacing is technically feasible with acceptable thresholds in most patients but
prolonged procedures are required in some individuals. Assessment of clinical
benefit requires controlled trials.
(m/sec)
(m/sec)
Threshold
(volts)
