RV electrical activation in heart failure during right, left, and biventricular pacing

Niraj Varma, Ping Jia, Charulatha Ramanathan, Yoram Rudy
JACC. Cardiovascular Imaging 2010, 3 (6): 567-75

OBJECTIVES: To compare right ventricular (RV) activation during intrinsic conduction or pacing in heart failure (HF) patients.

BACKGROUND: RV activation during intrinsic conduction or pacing in patients with left ventricular (LV) dysfunction is unclear but may affect the prognosis. In cardiac resynchronization therapy (CRT), timed LV pacing (CRT-LV) may be superior to biventricular pacing (CRT-BiV), and is hypothesized to be due to the merging of LV-paced and right bundle branch-mediated wavefronts, thus avoiding perturbation of RV electrical activation.

METHODS: Epicardial RV activation duration (RVAD) (onset to end of free wall activation) was evaluated noninvasively by electrocardiographic imaging in healthy control subjects (n = 7) and compared with that of HF patients (LV ejection fraction 23 +/- 10%, n = 14). RVAD in HF was contrasted during RV pacing, CRT-BiV, and CRT-LV at optimized AV intervals.

RESULTS: During intrinsic conduction in HF (n = 12), the durations of QRS and precordial lead rS complexes were 158 +/- 24 and 77 +/- 17 ms, respectively, indicating delayed total ventricular depolarization but rapid initial myocardial activation. Echocardiography demonstrated no significant RV disease. RV epicardial voltage, activation patterns, and RVAD in HF did not differ from normal (RVAD 32 +/- 15 vs. 28 +/- 3 ms, respectively, p = 0.42). In HF, RV pacing generated variable areas of slow conduction and prolonged RVAD (78 +/- 33 ms, p < 0.001). RVAD remained delayed during CRT-BiV at optimized atrioventricular intervals (76 +/- 32 ms, p = 0.87). In contrast, CRT-LV reduced RVAD to 40 +/- 26 ms (p < 0.016), comparable to intrinsic conduction (p = 0.39) but not when atrioventricular conduction was poor or absent.

CONCLUSIONS: In HF patients without RV dysfunction treated with CRT, normal RV free wall activation in intrinsic rhythm indicated normal right bundle branch-mediated depolarization. However, the RV was vulnerable to the development of activation delays during RV pacing, whether alone or with CRT-BiV. These were avoided by CRT-LV in patients with normal atrioventricular conduction.

Full Text Links

Find Full Text Links for this Article


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

Related Papers

Remove bar
Read by QxMD icon Read

Save your favorite articles in one place with a free QxMD account.


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"