Cardiac output after direct current conversion of atrial fibrillation.

Thereisscant agreement regarding theeffect on cardiac output ofconversion ofatrial fibrillation to sinus rhythm.Someworkers havereported aconsiderable increase inresting cardiac output; others havefound nochange. Theinterval between conversion andtherepeat measurement ofcardiac outputhasvaried widely. Ingeneral, measurements madewithin afewhours ofconversion haveshown little change fromtheresting value, whilethose madeafter longer intervals haveshownanincrease (Table I).Inprevious workreported fromthis laboratory (Halmos andPatterson, 1965), anaverage rise of53percentincardiac output wasdemonstrated oneweekafter direct current (DC)conversion.Thepresent workwasundertaken tostudy thechanges incardiac output occurring inthesame patient atdifferent intervals after restoration of sinus rhythm.