Pre-excitation of the right branch of the bundle of his

A patient with an ECG exhibiting a short P-R interval followed by a QRS resembling complete left bundle-branch block (CLBBB) is presented. The Wolff-Parkinson-White (WPW) syndrome complicated by left bundle-branch block was suspected. The vectorcardiogram (YCG) closely approximated that of CLBBB but the characteristic delta segment of WPW conduction was absent. Subsequently, typical delta vectors appeared, and upon abolition of pre-excitation with procainamide, no LBBB was found. Evidence is assembled that a James bundle-like bypass was responsible for the accelerated atrioventricular (AY) conduction in thefirst tracings with transmission directly into the right bundle system causing functional LBBB; later, the impulse was re-routed either directly or via Mahaim fibres into septal muscle, creating a typical WPW-QRS loop. Six other possible mechanisms for the short P-R-CLBBB pattern arediscussed.S. Afr. Med. J., 48, 1790 (1974

Association of serum leptin with future left ventricular structure and function: The Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND/OBJECTIVES: Earlier studies differ on whether serum leptin is associated with adverse or beneficial cardiac structure. We determined the association between serum leptin with subsequent cardiac structure and function. METHODS: Multicenter longitudinal study of Black, White, Hispanic and Asian-American men and women. Cardiac MRI (CMR) was completed 6 to 8 years after leptin was measured. Left ventricular (LV) mass and volumes were indexed to body surface area. Multivariable linear regression models were constructed to assess the associations between leptin and risk factor adjusted (age, race, gender, systolic blood pressure, anti-hypertensive usage, LDL, HDL, hyperlipidemia medication usage, diabetes, diabetic medication usage, chronic kidney disease, alcohol and tobacco use, adiponectin and BMI) CMR variables. RESULTS: Relative to participants in the lowest quintile of leptin concentration, participants in the highest quintile had a lower risk factor adjusted LV mass (-14g), LV mass index (-9g/m(2)), LV end diastolic volume index (LVEDVi) (-7 ml/m(2)), LV end systolic volume index (LVESVi) (-3 ml/m(2)) and stroke volume (-5 ml) (all p≤ 0.05). On regression analysis, a doubling of leptin concentration was associated with lower LV mass (-2.5g±0.7g), LV mass index (-1.7±0.3 g/m(2)), LVEDVi (-1.5±0.4 ml/m(2)), LVESVi (-0.7±0.2 ml/m(2)) and stroke volume (-1.0±0.5ml) (all p≤ 0.05). CONCLUSIONS: Higher leptin was associated with more favorable subsequent cardiac structure. Further study is needed to assess the prognostic and therapeutic implications of these observations