[Time course of changes in left ventricular twist in the presence of idiopathic left bundle branch block during exercise testing]. / Dinamika skruchivaniia levogo zheludochka pri idiopaticheskoi blokade levoi nozhki puchka Gisa vo vremia nagruzochnoi proby.

AIM: To investigate left ventricular (LV) deformation properties, rotation, and twist during a bicycle ergometer exercise test among patients with idiopathic left bundle branch block (LBBB). SUBJECTS AND METHODS: Thirty-four patients with idiopathic LBBB having a mean QRS duration of 153±24 msec were examined. A control group included 18 apparently healthy volunteers. All the patients and apparently healthy individuals underwent echocardiography to determine LV hemodynamic parameters, deformity, rotation and twist at rest and after exercise test. RESULTS: As compared with the control, the idiopathic LBBB group at rest showed decreases in LV global longitudinal deformity (-15.6±4.7 and -18.4±3.1%, respectively; p=0.037), apical rotation (4.59±4.2° and 8.99±3.68°; p=0.0067) and twist (9.08±4.59° and 13.96±4.61°; p=0.0156), whereas there were no differences in LV ejection fraction and end-systolic and end-diastolic volumes. After exercise testing there were no augmentations in basal and apical rotation and resulting ΔTwist in the idiopathic LBBB group compared with the control (-2.05±8.35 and 4.66±8.49%; p=0.0463). The described changes in LV rotation and twist during exercise testing occurred in the presence of elevated pulmonary artery systolic pressure (PASP) in the LBBB group compared with the control (41.6±3.81 and 32.4±3.81 mm Hg, respectively; p=0.0201). CONCLUSION: Decreases in LV basal, apical and resulting twist may lead to elevated PASP in patients with idiopathic LBBB during exercise.

[LEFT HIS BUNDLE BRANCH BLOCK ASSOCIATED WITH LEFT VENTRICULAR TORSION AND REDUCED EJECTION FRACTION].

The influence of left His bundle branch block (LBBB) on left ventricular (LV) torsion in patients with cardiomyopathy remains to be elucidated. The aim of this study was to evaluate LV torsion associated with LBBB and hemodynamic consequences of possible changes. We studied 64 patients with ischemic and dilatation cardiomyopathy (LV ejection fraction less than 40%) divided into 2 groups, with narrow and middle (153 ms) duration QRS complexes. Despite similar LV contractility, patients with LBBB had much less pronounced LV rotation and torsion. Torsion in patients with LBBB and narrow QRS complex was estimated at 2.95 ± 3.34 and 5.87 ± 3.83 respectively (p < 0.01). Moreover; the group of patients with LBBB contained much more subjects with abnormal unidirectional rotation of the basal and apical parts than the group with narrow QRS complex, namely 11 (50%) and 9 (21.9%) respectively (p < 0.001). Patients with LBBB and abnormal LV rotation sowed much longer delay of posterior wall contractility (63.3 ± 35.1 mc) compared with those having LBBB and multidirectional physiological LV rotation (8.0 ± 17/9 mc) (p < 0.001) which suggests a higher degree of mechanical desynchronization. T is concluded that LBBB has negative effect on LV electrical activation and contractility resulting in abnormal torsion and mechanical desynchronization.