Atrioventricular plane displacement is the major contributor to left ventricular pumping in healthy adults, athletes, and patients with dilated cardiomyopathy

Abstract

Previous studies using echocardiography in healthy subjects have reported conflicting data regarding the percentage of the stroke volume (SV) of the left ventricle (LV) resulting from longitudinal and radial function, respectively. Therefore, the aim was to quantify the percentage of SV explained by longitudinal atrioventricular plane displacement (AVPD) in controls, athletes, and patients with decreased LV function due to dilated cardiomyopathy (DCM). Twelve healthy subjects, 12 elite triathletes, and 12 patients with DCM and ejection fraction below 30% were examined by cine magnetic resonance imaging. AVPD and SV were measured in long- and short-axis images, respectively. The percentage of the SV explained by longitudinal function (SV(AVPD%)) was calculated as the mean epicardial area of the largest short-axis slices in end diastole multiplied by the AVPD and divided by the SV. SV was higher in athletes [140 +/- 4 ml (mean +/- SE), P = 0.009] and lower in patients (72 +/- 7 ml, P < 0.001) when compared with controls (116 +/- 6 ml). AVPD was similar in athletes (17 +/- 1 mm, P = 0.45) and lower in patients (7 +/- 1 mm, P < 0.001) when compared with controls (16 +/- 0 mm). SV(AVPD%) was similar both in athletes (57 +/- 2%, P = 0.51) and in patients (67 +/- 4%, P = 0.24) when compared with controls (60 +/- 2%). In conclusion, longitudinal AVPD is the primary contributor to LV pumping and accounts for approximately 60% of the SV. Although AVPD is less than half in patients with DCM when compared with controls and athletes, the contribution of AVPD to LV function is maintained, which can be explained by the larger short-axis area in DCM.

Relations Between Aortic Stiffness and Left Ventricular Mechanical Function in the Community

“…The relation between aortic stiffness and diastolic function is often attributed to hemodynamic effects, while the relation between GLS and diastolic function has been attributed to recoil of contracted LV muscle fibers 49, 50. Recent studies have suggested that diastolic recoil of the aorta and left atrium, which are stretched during systole, facilitates LV filling and ejection 12, 51, 52, 53, 54, 55. The association between increased aortic stiffness and worse GLS observed in our study may relate to both the systolic and diastolic components of direct mechanical ventricular–vascular coupling and requires further study 48…”

Short-axis epicardial volume change is a measure of cardiac left ventricular short-axis function, which is independent of myocardial wall thickness

“…We studied 12 healthy volunteers, 12 Swedish national elite triathletes, and 12 patients with dilated cardiomyopathy (ejection fraction Ͻ30%). We have studied this population previously (6).…”

“…All subjects underwent CMR imaging in the supine position. Imaging was undertaken with a 1.5T scanner (Intera; Philips, Best, The Netherlands) using a five-element cardiac synergy coil and a cine steady-state free precession sequence as previously described (6). Cine image acquisition included a contiguous short-axis stack and also the two-chamber, four-chamber, and left ventricular outflow tract long-axis views.…”

“…The stroke volume can be seen as the sum of two parts, namely the volumes of blood generated by long-and short-axis function. We have previously shown that 1) long-axis function corresponds to the volume of blood generated by atrioventricular plane displacement (AVPD), 2) short-axis function corresponds to the volume of blood generated by the epicardial volume change (EVC) of the heart, and 3) the sum of these two volumes equals the stroke volume (5,6). Using these definitions, the normal heart has been shown to have a left ventricular stroke volume, which is generated by 60% long-axis function and 40% short-axis function, whereas the right ventricular stroke volume is generated by 80% long-axis function and 20% short-axis function (5).…”

Correlation between Transient Ischemic Left Ventricular Dilation and Severity of Coronary Artery Disease

“…(10) The mechanism for TID appears to be multifactorial, with sub endocardial ischemia temporary systolic dysfunction (11) and a true increase in the size of the left ventricle having been proposed as explanations for the phenomenon. (12,13) MAPSE has been proposed as a well-established clinically useful echocardiographic parameter for the assessment of LV longitudinal function and correlates with global systolic function of the LV (14,15) . Previous clinical studies showed that, MAPSE, which reflects the mitral ring displacement at systole, can be used to assess cardiac global longitudinal function and is a sensitive parameter to define slight abnormalities in various patients with cardiovascular diseases at early stage where longitudinal function is affected before other components (which can even be increased in compensation).…”