Electrocardiographic patterns in biventricular pacing delivered by second-generation cardiac resynchronization devices

Abstract

BackgroundWith increasing use of cardiac resynchronization therapy (CRT), treating physicians should be familiar with different electrocardiographic (ECG) patterns of left ventricular (LV) lead and biventricular (BiV) pacing. However, there are a few publications on ECG patterns during BiV pacing.PurposeThis study was sought to determine different ECG patterns in patients with BiV pacing.MethodsTwelve-lead ECGs during BiV pacing (right ventricular leads at apex and LV leads in one of the lateral coronary veins) were analyzed in 181 consecutive patients (121 male; mean age, 62.0 ± 13.5 years) with advanced heart failure and baseline left bundle branch block pattern after at least 6-month of uncomplicated CRT.ResultsDuring BiV pacing, 65% of the patients showed a dominant R wave in V1. There was a right axis deviation in 57% in frontal plane. However, a left superior axis emerged in 34% and normal frontal plane axis in 9%. Sequential BiV pacing (73% vs. 58%, P = 0.04) and pacing from posterolateral coronary vein (80% vs. 60%, p = 0.045) were more likely to present with a dominant R wave in V1. In sequential pacing, AV interval was significantly longer in patients with negative complex in V1 than in those with positive complex (124 ± 21 vs. 116 ± 8.0, p = 0.005). A Q/q wave was detected in 85% of patients in lead I and 78% in lead aVL.ConclusionsBiV pacing from lateral coronary venous branches and right ventricular apex characteristically presented with dominant R wave in V1, Q/q wave in leads I and aVL, and right or left superior axis. However, a negative complex in V1, QRS axis in other quadrants, and lack of Q/q wave in leads I and aVL did not necessarily indicate a problem.

Additional benefits of nonconventional modalities of cardiac resynchronization therapy using His bundle pacing

“…The frontal plane QRS axis has only seldom been assessed in CRT studies, mostly as a preimplantation predictor of response, and with modest and contrasting results 16,18–20 ; the paced QRS axis has also been used to assess the relative contribution of RV and LV pacing at different VV intervals or pacing sites 21,22 . In general, the paced QRS axis has not reached the level of confidence required for its use in clinical practice.…”

“…[3][4][5][6][7] We found that HBP + CS and TRIPLE configurations, but not HBP alone, yielded additional shortening of The frontal plane QRS axis has only seldom been assessed in CRT studies, mostly as a preimplantation predictor of response, and with modest and contrasting results 16,[18][19][20] ; the paced QRS axis has also been used to assess the relative contribution of RV and LV pacing at different VV intervals or pacing sites. 21,22 In general, the paced QRS axis has not reached the level of confidence required for its use in clinical practice. "Quasi-normal" axis is an original definition that combines both frontal and horizontal planes in a simple way; it suggests a balanced electrical activation of the LV from the right and left sides and from up to down, as observed in normal subjects.…”

Electrocardiography of cardiac resynchronization therapy: Pitfalls and practical tips

“…Loss of the q wave in lead I during biventricular pacing is always predictive of loss of LV capture. 27 Thus, analysis of the Q/q wave or a QS complex in lead I may be a reliable way to assess LV capture during biventricular pacing. Less commonly, a q wave is also noted in lead aVL.…”

“…During biventricular pacing with the RV lead in the outflow tract, the paced QRS in lead V1 is often negative (QS), while the frontal-plane paced QRS axis is often directed to the right inferior quadrant (right axis deviation). 19,27 Biventricular pacing with the RV lead in the RV septum may still show a QS pattern in V1, but the axis may be located in the left inferior or superior quadrant (Figure 7, panel A).…”

“…midseptum) (Figure 8, panel B), 30 or an R or R/S pattern with right inferior axis when the LV lead is located in the anterolateral cardiac vein branch (RV lead at the RV apex). 27…”