This study demonstrates that preserved synchronous ventricular activation with RVOT pacing prevents the long-term deleterious effects of RVA pacing on myocardial perfusion and function in patients implanted with a permanent pacemaker.

In an offset printing factory with 56 workers, 20 (36%) developed symptomatic peripheral neuropathy due to exposure to n-hexane. Another 26 workers (46%) were found to have subclinical neuropathy. The initial change in the nerve conduction study was N-hexane, present in many commonly used organic solvents, is known to cause peripheral neuropathy.' Outbreaks have been reported in laminating,2 3 pharmaceutical,4 sandal and shoe making,'9 furniture production'0 and adhesive bandage manufacturing" industries.In the printing industry, n-hexane is used to remove residual colouring agents on the roller and has caused two outbreaks of neuropathy in the past.'2 13 We report our investigation on the clinical, electrophysiological and pathological features of n-hexane neuropathy in a printing factory. ResultsThe factory was situated on a multi-storey building with a floor area of 2000 m2 and a floor height of 4 m. There were 17 offset printing machines placed on two floors.There were no MSDS sheets on substances available in the factory, as the law did not require it. Cleaning solvents, such as, petroleum spirit and white gasoline were stored in large containers. They were used for manual cleaning of ink stains and dirts on rubber roller blankets, ink rollers, ink containers and zinc plates. The word n-hexane, a symbol for harmful substance, and a brief description on general precautions were printed on the container labels but the percentage of n-hexane was not specified. Analysis by gas chromatography revealed that they contained 14-20% nhexane. These solvents and the emusifying oil, kerosene, diesel and solvent blend also contained a variable percentage of toluene but no methyl n-butyl ketone (MBK) or methyl ethyl ketone (MEK). The moistening solutions contained only trace amounts of phosphate at 42 ppm. The printing inks contained 0-68-2 pg/g lead, <0 05-0 95 pg/g mercury and no volatile organic compound.Dilution ventilation was provided by air distribution ducts of air conditioning units. These were recycling units wth limited fresh 538 on 10 May 2018 by guest. Protected by copyright.

Left ventricular (LV) pacing is increasingly used in the management of congestive heart failure. Optimization of the atrioventricular (AV) interval is essential to maximize the hemodynamic benefits of this therapy. Although Doppler echocardiography (echo) is the most widely used method, it is time-consuming, expensive, and operator-dependent. We examined the value of an impedance cardiography (IC)-based method of cardiac output (CO) measurement to optimize the AV interval in 5 men and 1 woman (mean age = 72 +/- 11 years) during permanent LV pacing with a 4.8 Fr unipolar coronary sinus pacing lead. Simultaneous measurements of CO by IC and echo were performed at AV intervals of 50, 80, 110, 150, 180, and 225 ms during DDD pacing at 85 beats/min. The optimal AV interval varied between 110 and 180 ms. In 5 of 6 patients (83%), the optimal AV interval by echo and IC was identical. While CO measurements were higher with IC than with echo (6.1 +/- 0.4 L/min vs 4.7 +/- 0.3 L/min, P < 0.05), CO measurements by IC and echo were closely correlated r = 0.67, P < 0.001). In conclusion, our initial experience suggests that IC is a reliable method of AV interval optimization during LV pacing. IC and echo measurements of CO during LV pacing were closely correlated.