“Ventricular function curve” from a single diagnostic left ventriculogram: Technique, results and value

Abstract

A programmable atrial pacemaker was used to vary sequential left ventricular end-dlastolic volumes. Left ventricular stroke volume and end-diastolic volume were used to construct a left ventricular “function curve”. Four successive beats from one diagnostic left ventricular angiogram were analyzed—a beat during atrial pacing at 5 to 10 beats faster than sinus rate, an atrial extrastimulus beat in the sinus nodal reset zone, a postextrastimulus beat and a sinus beat. Excluding measurements in postextrastimulus beats, left ventricular stroke volume decreased from 124 to 59 cc ( P < 0.001) and ejection fraction from 0.67 to 0.52 ( P < 0.001) as end-dlastolic volume decreased from 188 to 123 ce ( P < 0.001). Mean rate of circumferential fiber shortening was independent of end-diastolic volume but was greater for postextrastimulus beats (1.54 circumferences/sec) than for sinus beats (1.28 circumferences/sec) ( P < 0.001). Among six patients with increased left ventricular end-dlastolic volume (greater than 110 cc/m 2), ejection fraction was abnormal (less than 0.54) in only one patient at increased end-diastolic volume but in three patients at reduced end-diastolic volume, despite a reduced afterload. However, in seven patients with a normal mean rate of circumferential fiber shortening, ejection fraction was normal at both increased and reduced end-diastolic volumes. This technique is safe and easy to use in man. This study demonstrates that ejection fraction is dependent on end-dlastolic volume with rapid changes of R-R interval. Therefore, both ejection fraction and end-diastolic volume should be measured when ejection fraction is used as an index of left ventricular performance, particularly if ejection fractions obtained from different angiograms are being compared.