OPEN IN READ APP
COMPARATIVE STUDY
JOURNAL ARTICLE

Left ventricular conduction delays induced by right ventricular apical pacing: effect of left ventricular dysfunction and bundle branch block

Niraj Varma
Journal of Cardiovascular Electrophysiology 2008, 19 (2): 114-22
17971145

BACKGROUND: RV apical pacing (RVP) may be deleterious, possibly by simulating LBBB, i.e., prolonging QRS duration (QRSd) and LV activation (LVAT). However, determinants of electrical delays are unknown.

HYPOTHESIS: LV dysfunction (LVEF <or= 40%, HF) and pre-existing conduction system abnormalities may modulate RVP's effects, compared to LBBB.

METHODS: RVP-induced QRSd and LVAT were compared in normal LV to HF, with normal QRS (<120 ms), RBBB, or LBBB. LVAT was estimated by interval from QRS onset to basal inferolateral LV depolarization.

RESULTS: During LBBB and RVP, LVAT/QRSd was >or=85%, i.e., LVAT indicated terminal LV depolarization. In normal LV, LVAT during intrinsic conduction (55 +/- 18 ms) was delayed by RVP (129 +/- 20 ms, n = 58, P < 0.001). RVP's effects were similar to LBBB (P = NS) and unaffected by baseline conduction disease. In HF overall, RVP-induced delays (QRSd 209 +/- 27, LVAT 186 +/- 26 ms, n = 102) were greater than RVP in normal LV (P < 0.001). When baseline conduction system disease was present, RVP's effects were exaggerated (RVP wide QRS [>120 ms]: QRSd 216 +/- 27, LVAT 191 +/- 20 ms, [n = 72] vs RVP normal QRS: QRSd 193 +/- 24, LVAT 169 +/- 24 ms, n = 31, P < 0.001). In patients with LBBB (n = 41), delays during intrinsic conduction (QRSd 163 +/- 29, LVAT 137 +/- 33 ms, n = 41) were enhanced by RVP (QRSd 218 +/- 28, LVAT 191 +/- 22 ms, P < 0.001). RVP's effects were similar in patients with LBBB and RBBB (P = NS).

CONCLUSION: RVP simulated LBBB in normal LV. In HF, RVP induced greater conduction delays than LBBB, enhanced by accompanying conduction disease. These variations may contribute to RVP's mixed clinical effects.

Discussion

You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Available on the App Store

Available on the Play Store
Remove bar
Read by QxMD icon Read
17971145
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"