Left ventricular dysfunction is related to the presence and extent of a septal flash in patients with right ventricular pacing.

Aims: Septal flash (SF), a marker of left ventricular (LV) dyssynchrony in the presence of a left bundle branch block (LBBB), has been shown to predict improved ventricular function and outcome when corrected with cardiac resynchronization therapy. We hypothesized that a SF is present in patients receiving right ventricular (RV) pacing and its presence and extent could predict the development of LV dysfunction and remodelling. Methods and Results: Seventy-four consecutive patients receiving conventional RV pacing (>6 months, >85% paced) were studied with two-dimensional (2D) echocardiography. Indications for pacing were sinus-node dysfunction and atrioventricular conduction disorders. The presence of a SF was determined on stepwise advanced 2D echocardiographic views and confirmed using greyscale M-mode. Septal flash excursion was quantified by the amplitude of the early inward motion, measured from QRS onset to maximal inward motion. Fifty-seven (of 74; 77%) patients receiving RV pacing had a detectable SF. Patients with a SF had lower LV ejection fraction (EF) (52 ± 10 vs. 60 ± 4%, P < 0.001) and greater indexed end-systolic volume (33 ± 16 vs. 23 ± 5 mL/m2, P < 0.001). Receiver operating characteristic analysis demonstrated that a SF of 3.5 mm was the optimal cut-off value (area under the curve = 0.95) to identify reduced LV function (EF < 50%) with a sensitivity of 91% and a specificity of 90%. Conclusion: A SF was present in a majority of patients receiving conventional RV pacing and its magnitude was related to LV dysfunction and adverse remodelling. Given the similarities observed in LBBB and pacemaker-induced dyssynchrony, SF magnitude might be a predictor for the development of LV dysfunction and adverse remodelling in patients receiving conventional RV pacing.

Improvement in hemodynamic response using a quadripolar LV lead.

BACKGROUND: The Quartet quadripolar lead (St. Jude Medical Inc., St. Paul, MN, USA) offers 10 different left ventricle pacing configurations that may further influence hemodynamic parameters compared to traditional bipolar pacing configurations. The purpose of this study was to evaluate whether pacing from additional quadripolar lead vectors could enhance cardiac output (CO). METHODS: For each patient, CO was measured in "no-pacing" and in all the 10 configurations available, within 7 days of implantation of the device. Tip-ring, tip-right ventricular coil (RVC), and ring-RVC vectors were considered as traditional vectors. The seven additional configurations available in the quadripolar lead were considered as nontraditional vectors. CO was measured by ECHO. The best configuration was defined as the one presenting the highest CO measurement within configurations, which have a capture threshold <3 V and a safety margin between the capture and the phrenic nerve stimulation thresholds. RESULTS: Fifty-one standard cardiac resynchronization therapy patients were enrolled. The mean of each patient's best CO obtained with traditional vectors was higher than the baseline nonpaced CO (4.16 L/min vs 3.64 L/min). The mean of each patient's best CO, including all 10 available configurations, was also higher than the baseline nonpaced CO (4.33 L/min vs 3.64 L/min). In addition, the mean of each patient's best CO obtained with the best configuration available through a quadripolar lead was better than the mean of each patient's best CO obtained with a traditional configuration. In 53% of patients, the best CO was obtained with a nontraditional vector unique to the quadripolar lead. CONCLUSIONS: A quadripolar lead offers multiple additional pacing options to increase CO acutely compared to conventional bipolar leads.