Acute Changes in Left Ventricular Volume and Contractility during Ventricular Pacing in Patients with Complete Heart Block
- 1 November 1971
- journal article
- research article
- Published by Wolters Kluwer Health in Circulation
- Vol. 44 (5), 771-781
- https://doi.org/10.1161/01.cir.44.5.771
Abstract
To determine whether changes in preload and contractility may account for clinical improvement in patients with complete heart block (CHB) when the ventricular rate is increased by pacing, 10 hemodynamic studies were performed in nine patients with CHB. Left ventricular end-diastolic volume (EDV) was measured before and during pacing by the dye-dilution and the angiographic techniques. Changes in contractility were assessed from the first derivative of ventricular pressure divided by a common peak isovolumic pressure (CPIP) to correct for afterload and by EDV to correct for preload. EDV decreased during pacing, the mean value decreasing from 242 to 180 ml ( P < 0.001). Since the left ventricular dp/dt is influenced by afterload and preload, improvement in contractility indices was consistent only after allowances were made for changes in aortic diastolic pressure and EDV. The mean dp/dt/CPIP divided by EDV increased from 0.120 to 0.160 ( P < 0.005). The mean left ventricular enddiastolic pressure decreased from 17.0 to 9.7 mm Hg ( P < 0.05) during pacing, while the mean cardiac index increased from 2.0 to 2.5 liters/min/m 2 ( P < 0.025). The clinical improvement seen after pacing in patients with CHB results, in part, from an increase in contractility and a decrease in EDV and pressure.Keywords
This publication has 26 references indexed in Scilit:
- Left ventricular volume and mass and their significance in heart diseaseThe American Journal of Cardiology, 1969
- Usefulness and limitations of the rate of rise of intraventricular pressure (dp/dt) in the evaluation of myocardial contractility in man∗The American Journal of Cardiology, 1969
- Oxygen consumption of the heart: Newer concepts of its multifactoral determinationThe American Journal of Cardiology, 1968
- The use of single plane angiocardiograms for the calculation of left ventricular volume in manAmerican Heart Journal, 1968
- Effects of Increasing Frequency of Contraction on the Force Velocity Relation of Left VentricleCardiovascular Research, 1967
- Continuous measurement of left ventricular volume in the dog: II. Comparison of washout and radiographic technics with the external dimension methodThe American Journal of Cardiology, 1966
- Usefulness and limitations of radiographic methods for determining left ventricular volumeThe American Journal of Cardiology, 1966
- In vitro Evaluation of the Thermodilution Technique for the Measurement of Ventricular Stroke Volume and End-Diastolic VolumeJMIR AI, 1966
- Contractile tension in the myocardiumAmerican Heart Journal, 1963
- The use of biplane angiocardiography for the measurement of left ventricular volume in manAmerican Heart Journal, 1960