International Journal of Cardiovascular Sciences. 01/Jan/2017;30(1):11-9.

Cardiopulmonary Exercise Testing in Patients With Left Bundle Branch Block and Preserved Ejection Fraction

Milena dos Santos Barros, Rívia Siqueira Amorim, Romerito Oliveira Rocha, Enaldo Vieira de Melo, José Augusto Barreto-Filho, Antônio Carlos Sobral Sousa, Romeu Sérgio Meneghelo, Joselina Luzia Menezes Oliveira

DOI: 10.5935/2359-4802.20170018

Abstract

Background:

Left bundle branch block (LBBB) has prognostic significance in patients with congestive heart failure. However, its influence is not well established in patients with preserved systolic ventricular function.

Objective:

To evaluate the implications of LBBB presence in the cardiovascular performance of patients with preserved left ventricular systolic function (LVEF).

Methods:

26 LBBB patients (61.3 ± 8.2 years of age) and 23 healthy individuals (58 ± 6.8 years of age) with LVEF > 0.5 underwent cardiopulmonary exercise testing (CPET).

Results:

CPET analysis revealed: peak oxygen consumption (VO₂) predicted in the LBBB group was 87.2 ± 15.0% versus 105.0 ± 15.6% (p < 0.0001); peak oxygen pulse predicted in LBBB group was 98.6 ± 18.6% vs 109.9 ± 13.5% (p = 0.02); VO₂ predicted anaerobic threshold in LBBB group was 67.9 ± 13.6% vs 70.2 ± 12.8% (p = 0.55); ΔVO₂/Δload in the LBBB group was 15.5 ± 5.51 versus 20.7 ± 7.3 ml.min^-1.watts^-1 (p = 0.006); ventilation / carbon dioxide production (VE/VCO₂ slope) in LBBB group was 29.8 ± 2.9 versus 26.2 ± 2.9 (p = 0.0001) and VO₂ recovery time in the LBBB group was 85.2 ± 11.8 vs. 71.5 ± 11.0 seconds (p = 0.0001). LBBB was an independent marker for VE/VCO₂ slope increase.

Conclusion:

LBBB presence in individuals with preserved LVEF did not affect cardiovascular performance, but there was an increase of the VE/VCO₂ slope in comparison to the control group.