Alternate site right ventricular pacing: defining template scoring.

BACKGROUND: Prolonged right ventricular (RV) apical pacing produces dysynchronous ventricular contraction, which may result in left ventricular (LV) dysfunction, whereas septal pacing sites might reflect a more synchronous LV activation. This study examined a method of evaluating alternate RV pacing sites using a template scoring system based on measuring the angle of lead attachment in the 40° left anterior oblique (LAO) fluoroscopic view and its effect on altering the loop of lead in the RV. METHODS: Twenty-three consecutive patients for RV pacing were enrolled. Conventional active fixation leads were positioned in either the RV outflow tract (RVOT) or mid RV using a stylet designed for septal placement (Model 4140, St. Jude Medical, St. Paul, MN, USA). Using LAO cine fluoroscopy, a generous loop of lead was inserted into the RV chamber and the change in angle of attachment determined. RESULTS: Successful positioning of pacing leads at the RVOT septum (18 patients) and mid-RV septum (five patients) was achieved. With introduction of more lead into the RV chamber, the angle of attachment in the LAO projection altered over a range of 6°-32° for all patients with a mean of 14.6 ± 6.6°. In 87% of patients, the range was predominantly within the same template score with only minor overlap into another zone. CONCLUSIONS: This study shows that the angle of lead attachment in the RV is altered by introducing more lead, but in most cases, the template score remains the same. Further studies are required to determine the accuracy and efficacy of the templates.

Right ventricular septal pacing: a comparative study of outflow tract and mid ventricular sites.

BACKGROUND: Prolonged right ventricle (RV) apical pacing is associated with left ventricle (LV) dysfunction due to dysynchronous ventricular activation and contraction. Alternative RV pacing sites with a narrower QRS compared to RV pacing might reflect a more physiological and synchronous LV activation. The purpose of this study was to compare the QRS morphology, duration, and suitability of RV outflow tract (RVOT) septal and mid-RV septal pacing. METHODS: Seventeen consecutive patients with indication for dual-chamber pacing were enrolled in the study. Two standard 58-cm active fixation leads were passed to the RV and positioned in the RVOT septum and mid-RV septum using a commercially available septal stylet (model 4140, St. Jude Medical, St. Paul, MN, USA). QRS duration, morphology, and pacing parameters were compared at the two sites. The RV lead with less-satisfactory electrical parameters was withdrawn and deployed in the right atrium. RESULTS: Successful positioning of the pacing leads at the RVOT septum and mid-RV septum was achieved in 15 patients (88.2%). There were no significant differences in the mean stimulation threshold, R-wave sensing, and lead impedance between the two sites. The QRS duration in the RVOT septum was 151 ± 14 ms and in the mid-RV septum 145 ± 13 ms (P = 0.150). CONCLUSIONS: This prospective observational study shows that septal pacing can be reliably achieved both in the RVOT and mid-RV with active fixation leads using a specifically shaped stylet. There are no preferences in regard to acute lead performance or paced QRS duration with either position.

Right ventricular septal pacing: the success of stylet-driven active-fixation leads.

BACKGROUND: The detrimental effects of right ventricular (RV) apical pacing on left ventricular function has driven interest in alternative pacing sites and in particular the mid RV septum and RV outflow tract (RVOT). RV septal lead positioning can be successfully achieved with a specifically shaped stylet and confirmed by the left anterior oblique (LAO) fluoroscopic projection. Such a projection is neither always used nor available during pacemaker implantation. The aim of this study was to evaluate how effective is the stylet-driven technique in septal lead placement guided only by posterior-anterior (PA) fluoroscopic view. METHODS: One hundred consecutive patients with an indication for single- or dual-chamber pacing were enrolled. RV septal lead positioning was attempted in the PA projection only and confirmed by the LAO projection at the end of the procedure. RESULTS: The RV lead position was septal in 90% of the patients. This included mid RV in 56 and RVOT in 34 patients. There were no significant differences in the mean stimulation threshold, R-wave sensing, and lead impedance between the two sites.In the RVOT, 97% (34/35) of leads were placed on the septum, whereas in the mid RV the value was 89% (56/63). CONCLUSIONS: The study confirms that conventional active-fixation pacing leads can be successfully and safely deployed onto the RV septum using a purposely-shaped stylet guided only by the PA fluoroscopic projection.