Atrial tachycardia is a supraventricular tachycardia (SVT) that does not require the atrioventricular (AV) junction, accessory pathways, or ventricular tissue for its initiation and maintenance.
Page Content. Northern Natural Gas Company (Northern) is a subsidiary of Berkshire Hathaway Energy based in Omaha, Nebraska and has been in business since 1930. Northern owns and operates the largest interstate natural gas pipeline system in the United States.
The Williams Companies, one of the largest natural gas pipeline companies in the nation, said yesterday that it had agreed to buy Mapco Inc., the biggest United States pipeline system moving propane and butane, for $2.65 billion in stock and the assumption of $750 million in Mapco debt.