Arnold K. Gash

Normal left ventricular systolic function in adults with atrial septal defect and left heart failure

Systolic left ventricular contractile function has not been extensively evaluated in patients with atrial septal defect who have symptoms of left-sided congestive heart failure. This study examined left ventricular systolic function hemodynamically and angiographically in 6 such adult patients (Group A), 12 adult patients with atrial septal defect without heart failure (Group B) and 20 normal subjects. The mean ( +/- standard error of the mean) left ventricular end-diastolic pressure was higher in patients in Group A (17 +/- 0.8 mm Hg) than in patients in group B (6.9 +/- 0.6 mm Hg) (p less than 0.001). Both right atrial pressure ( 11 +/- 1.3 versus 4.9 +/- 0.5 mm Hg) (p less than 0.001) and mean pulmonary arterial pressure (30 +/- 1.8 versus 15 +/- 1 mm Hg) were also higher in Group A than in Group B. Left ventricular cardiac index and stroke work index did not differ in the two groups. Variables of left ventricular systolic function were similar in both groups of patients and in normal subjects: Ejection fraction was 0.71 +/- 0.05 in Group A, 0.74 +/- 0.02 in Group B and 0.74 +/- 0.01 in normal subjects. Velocity of circumferential shortening was 1.38 +/- 0.14 circumferences/s in Group A, 1.38 +/- 0.07 circumferences/s in Group B and 1.27 +/-0.04 circumferences/s in normal subjects. There was no difference in left ventricular contractile function as indicated by the ratio of end-systolic wall stress to end-systolic volume index among the three groups: normal subjects, average 5.6 +/- 0.19 versus 6.1 +/- 0.5 in Group B and 6.0 +/- 0.6 dynes X 10(3)/cm(2)/(ml/m(2) in Group A. This study of patients with atrial septal defect and left heart failure indicates that abnormal left ventricular systolic contractile function is probably not the cause of the symptoms and elevated left heart filling pressures observed in this group. An abnormality in left ventricular diastolic filling, perhaps related to the volume loaded right ventricle, may explain these changes.

Absolute left ventricular volume from gated blood pool imaging with use of esophageal transmission measurement

A new method for determining absolute left ventricular (LV) volume from equilibrium gated blood pool images was validated in 36 patients by comparing gated blood pool (GBP) imaging with contrast ventriculography (CV) using both Simpsons rule (SR) and area-length (AL) calculations. The technique is geometry-independent and is the first to correct for tissue attenuation with use of an in vivo point source. An orally administered capsule containing 1 to 2 mCi of technetium-99m (Tc-99m) sulfur colloid is used for this purpose. Left ventricular volumes are determined by dividing attenuation and background-corrected count rates obtained from semiautomated LV regions of interest by the count rate per milliliter from a blood sample. The correlation between GBP and CV (SR) was 0.96 (CV [SR] = 0.99 GBP + 1.32 ml; standard error of the estimate [SEE] = 21.2 ml) for diastole and 0.97 (CV [SR] = 0.93 GBP - 0.03 ml; SEE = 11.9 ml) for systole. The correlation between GBP and CV (AL) was 0.92 (CV [AL] = 0.90 GBP + 16.72 ml; SEE = 27.8 ml) for diastole and 0.95 (CV [AL] = 0.87 GBP + 4.56 ml; SEE = 14.4 ml) for systole. The method is noninvasive and can be performed easily as part of routine gated blood pool imaging and analysis.

Pericatheterization risk factors in left main coronary artery stenosis.

Patients with left main (LM) coronary artery disease (CAD) have an unexplained high incidence of complications during diagnostic cardiac catheterization. This study identifies pericatheterization risk factors for major complications in patients with LM CAD (stenosis at least 50%). Complications were defined as ventricular fibrillation not related temporally to coronary injection, persistent angina, acute myocardial infarction, profound hypotension and death during or within 24 hours of catheterization. One hundred seven consecutive cases of LM CAD (11 with complications and 96 without) were reviewed with respect to variables potentially related to complications. Patients who had angina in the 24 hours before catheterization were at increased risk. Four of 13 patients with angina (31%) and 7 of 94 (7%) without angina had complications (p less than 0.05). Distance from the catheter tip to the lesion also was related to complications (9 of 38 [24%] with tip 6.0 mm or less from lesion and 2 of 65 [3%] with tip more than 6.0 mm from lesion, p less than 0.05). No relaxation was found between complications and New York Heart Association functional class, technique (femoral vs brachial), performance of ventriculography, number of coronary injections, amount of contrast injected, severity of LM stenosis, number of major arteries with 75% or more diameter stenosis, mean arterial pressure, left ventricular end-diastolic pressure and left ventricular ejection fraction.

Assessment of Ventricular Muscle Function in Man: The End-Systolic Index

Accurate assessment of ventricular muscle contractile function is clinically important, but difficult to achieve. Cardiac muscle function before valve replacement [1-7] and before coronary surgery [1, 2, 8-10] is a major determinant of outcome. Selection of appropriate medical therapy for other forms of cardiac disease depends upon knowledge of ventricular muscle contractile function. Full assessment of new cardiac drugs also requires determination of the drugs’ effects on cardiac muscle. Unfortunately, accurate assessment of ventricular muscle contractile function in heart disease is impaired by the alterations in afterload, preload, and wall thickness which often accompany disease. Thus, standard ejection phase indices of contractile function which have been used extensively can be misleading. For example, a disease which increases afterload may artificially lower ventricular ejection fraction, while a disease which either lowers afterload or increases preload may artificially elevate the ejection fraction and thus obscure a true reduction of contractile function. The relationship between pressure and volume at end-systole is thought to provide a contractile index which is independent of preload and which accounts for afterload. We have recently used the relationship of end-systolic stress to end-systole volume index to assess ventricular muscle contractile function in several disease states where preload, afterload, wall thickness, and pump function may be abnormal. This technique of assessing ventricular contractile performance appears clinically useful and it is now possible to acquire the needed measurements of end-systolic pressure, thickness, and volume using several available techniques.