Clinical usefulness of quantitative two-dimensional echocardiographic analysis of segmental kinesis of the left ventricle in monitoring of patients with neoplasms treated with anthracyclines]

To determine whether serial quantitative two-dimensional echocardiographic analysis of left ventricular wall motion could be effective in selecting patients in whom anthracycline treatment must be stopped, 26 patients (18 M and 8 F, mean age 10 +/- 3, range 6 to 16 years) with malignancy, receiving doxorubicin or daunomycin were followed up. Left ventricular regional wall motion abnormalities were detected in 11 patients (42%), while left ventricular ejection fraction at rest (although progressively decreased from baseline value [63 +/- 2 vs 55 +/- 2%; p = 0.0001]) was still in normal range. The following distribution of left ventricular contraction abnormalities was noted: septal, anteroseptal and posteroseptal akinesis with posterior wall hypokinesis in one patient; septal, anteroseptal and posteroseptal akinesis with anterolateral free-wall hypokinesis in another; septal, anteroseptal and posteroseptal hypokinesis in four; lateral and posterolateral free-wall hypokinesis in one; septal, anteroseptal, posteroseptal and posterior hypokinesis in four. The drug was discontinued in only two patients with akinesis, since we regarded this contraction abnormality as a predictive index of more serious and extensive myocardial damage. We began to detect hypokinesis when cumulative doses of doxorubicin or daunorubicin were 155-420 mg/m2 and 270-285 mg/m2 respectively, while akinesis was seen at doses of 395 mg/m2 of body-surface area for doxorubicin and 575 mg/m2 for daunorubicin. Follow-up examination was conducted six months after the last dose of anthracycline, and improvement or recovery of left ventricular regional wall motion abnormalities was noted in all patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Accuracy of left ventricular ejection fraction using the nuclear stethoscope in left ventricular aneurysm

Although the nuclear stethoscope, a nonimaging probe, accurately determines left ventricular (LV) ejection fraction (EF), its reliability in patients with LV aneurysm has not been established. Accordingly, LVEF was determined using the nuclear stethoscope and compared with that determined by equilibrium gated blood pool scanning in 29 patients, 1 studied on 2 separate occasions, for a total of 30 patient studies. Patient studies were separated into 2 groups. Patients in group I (n = 20) had no gated blood pool evidence for aneurysm, and those in group II (n = 10) had discrete focal akinesia or dyskinesia. Nineteen patients (13 in group I and 6 in group II) had 2 separate nuclear stethoscope acquisitions. In group I, EF determined by gated blood pool scanning (53 +/- 4%, mean +/- standard error) did not differ from that determined by nuclear stethoscope (51 +/- 4%). EF determined using either gated blood pool scanning (32 +/- 6%) or nuclear stethoscope (35 +/- 5%) was significantly lower in group II than in group I, although nuclear stethoscope and gated blood pool scanning did not differ. Reproducibility was excellent (r = 0.96). Overall, nuclear stethoscope and gated blood pool EFs correlated closely (r = 0.93), and the correlation coefficients were similar in groups I (r = 0.92) and II (r = 0.92). The slopes of the regression curves for group I (0.97) and group II (0.92) were not statistically different. These results confirm the accuracy and reproducibility of LVEF determination by nuclear stethoscope and specifically demonstrate its reliability in patients with LV aneurysm.     

Regional ventricular function before and after sublingual administration of nitroglycerin in patients with recent myocardial infarction in the subacute and chronic stage

Seven patients with a recent myocardial infarction and mostly normal left ventricular end-diastolic pressure were investigated by radionuclide ventriculography after 3-4 days and three weeks before and after 1.6 mg nitroglycerin. Between day 3-4 and the third week global ejection fraction (EF) rose insignificantly (p greater than 0.05) from 31 +/- 4 to 37 +/- 6 percent. The regional EF in the non infarcted area remained nearly stable (74 +/- 5 to 85 +/- 13 relative percent, p greater than 0.05). However, the EF in the infarcted area rose from 22 +/- 9 to 38 +/- 11 relative percent (p less than 0.05 percent). On day 3-4 nitroglycerin induced a clear increase of the EF in the infarcted area from 22 +/- 9 to 35 +/- 11 relative percent (p less than 0.05). The global EF and the EF in the non infarcted area remained nearly constant (global EF from 31 +/- 4 to 34 +/- 5 percent, EF in the non infarcted area from 74 +/- 5 to 77 +/- 7 relative percent; p greater than 0.05). Three weeks after myocardial infarction 1.6 mg nitroglycerin did not produce a significant alteration of the ejection fraction (slight increase of the global EF from 37 +/- 6 to 40 +/- 6, the regional EF in the infarcted area from 38 +/- 11 to 48 +/- 11 relative percent and from 85 +/- 13 to 90 +/- 11 relative percent in the non infarcted area; p greater than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Asynergy and left ventricular performance in dilative cardiomyopathy

The purpose of this work was to evaluate the presence and importance of asynergy in dilative cardiomyopathy. A semiautomatized analysis of left ventriculograms was performed in 18 cases, the morphology of longitudinal and transverse axes time-length curves was evaluated, and mathematical indices of asynchrony and hypokinesis were defined. Ten normal subjects and 9 patients affected by aortic regurgitation were used as controls. In dilative cardiomyopathy, anomalous (polyphasic) time-length curves were present in 55% of the cases, while they were absent in aortic regurgitation and in all normal subjects but one. In addition, the asynchrony index was slightly increased and the hypokinesis index significantly increased (28.8 +/- 7.2% vs. 17.8 +/- 7.1%, p less than 0.001). A negative correlation existed between the asynchrony index and the ejection fraction (r = -0.483, p less than 0.05) and both the ejection fraction and the maximum normalized velocity of contraction were reduced in the patients with the anomalous curves (29.7 +/- 6.9% vs. 46.0 +/- 11.5%, p less than 0.01; 1.66 +/- 0.52 s-1 vs. 2.86 +/- 1.33 s-1, p less than 0.02). It was concluded that asynergy, and especially asynchrony, is frequent in dilative cardiomyopathy and it is strongly associated with a major impairment of overall left ventricular function.     

Reversibility of akinetic segments in coronary heart disease

Akinetic wall segments not exhibiting contractions following nitroglycerin administration or in a post-extrasystolic beat are usually considered to consist of scar tissue; i.e. even by re-established or improved blood supply following aorto-coronary bypass surgery no functional improvement is expected. In the present study, the pre- and postoperative ventriculograms (RAO projection) of 24 patients undergoing bypass surgery were analyzed. Ventriculography was routinely performed following sublingual nitroglycerin and a post-extrasystolic contraction. In each patient the akinetic segment had received a bypass graft which was found to be patent on reangiography. In 7 of 24 patients (29%) the formerly akinetic segment exhibited improved contraction postoperatively; in 17 patients the segment remained akinetic. Global ejection fraction rose in the group of patients with improved akinesia from 47 +/- 10 to 65 +/- 10% (p less than 0.05). In the patients with unchanged contraction pattern, ejection fraction was found to be 56 +/- 12% prior to surgery and 54 +/- 16% after surgery (n.s.). The increase in ejection fraction was more pronounced in those patients showing improvement of anterior wall akinesia (from 39 to 72%) than it was in patients exhibiting improved inferior wall akinesis (from 54 to 59%). According to these findings, the regional ejection fraction was found to be higher postoperatively in patients with former anterior wall akinesis (78%) than in those showing inferior wall contraction abnormalities (49%). End-diastolic and end-systolic left ventricular volume changes postoperatively did not reach statistical significance, although end-systolic volume showed a clear trend to decrease (preoperative: 114 +/- 54 ml/1.73 m2; postoperative: 79 +/- 29 ml/1.73 m2; n.s.).(ABSTRACT TRUNCATED AT 250 WORDS)     

Vasoconstriction of stenotic coronary arteries during dynamic exercise in patients with classic angina pectoris: reversibility by nitroglycerin

To study the vasomotility of normal and diseased coronary arteries during dynamic exercise, symptom-limited supine bicycle exercise during cardiac catheterization was performed by 18 patients with classic angina pectoris. The cardiovascular response was assessed by hemodynamic measurements and computer-assisted determination of normal and stenotic coronary artery luminal areas from biplane coronary angiograms made before, during, and after exercise. After baseline measurements were recorded, 12 patients (group 1) performed bicycle exercise for 3.4 min (mean), reaching a maximum workload of 81 W (mean); at the end of exercise they received 1.6 mg sublingual nitroglycerin. After measurements at rest in six other patients (group 2), 0.1 mg intracoronary nitroglycerin was given, followed by exercise (3.8 min, 96 W; NS) and sublingual nitroglycerin as in group 1. During exercise in group 1, luminal area of the coronary stenosis decreased to 71% of resting levels (p less than .001), while area of the normal coronary artery increased to 123% of control (p less than .001). After sublingual nitroglycerin at the end of exercise, area of the normal vessel further increased to 140% of control (p less than .001), while luminal area of the stenosis dilated to 112% of resting levels (p less than .001 vs exercise, NS vs rest). Pretreatment with intracoronary nitroglycerin increased both normal (121%; p less than .05) and stenotic (122%; p less than .05) luminal areas, while preventing the previously observed narrowing of stenosis during exercise (114%; NS). Exercise resulted in a similar heart rate-systolic pressure product and caused angina pectoris in two-thirds of the patients in each group. However, patients pretreated with intracoronary nitroglycerin (group 2) had a lower mean pulmonary arterial pressure during maximum exercise (35 mm Hg) than those patients (group 1) not receiving pretreatment (47 mm Hg; p less than .001). Group 2 patients reached a percentage of their predicted work capacity (65%) that was about the same as that during previous upright bicycle exercise (71%; NS), while group 1 patients had a significantly lower work capacity (51% of predicted) than that before catheterization (82%; p less than .001). Hence, narrowing of coronary artery stenosis during dynamic exercise is attributable to active vasoconstriction due to its reversibility by preexercise intracoronary nitroglycerin. Patients who did not experience narrowing of stenosis during exercise (group 2) had less evidence of myocardial ischemia (lower mean pulmonary arterial pressure) and maintained their work capacity.(ABSTRACT TRUNCATED AT 400 WORDS)     

Measurement of left ventricular ejection fraction in pediatric patients using the nuclear stethoscope

Left ventricular (LV) ejection fraction (EF) was measured in 25 patients, aged 2 weeks to 20 years (mean 8.6 years), using a portable nonimaging scintillation stethoscope. Technically satisfactory studies were obtained in 23 patients. LVEF was validated by cineangiography in 19 patients and by standard gated blood pool scintigraphy in 4. EF measured by the nuclear stethoscope correlated well with values obtained by cineangiography or scintigraphy (r = 0.869, p less than 0.001) over a wide range of EF values (18 to 79%). In children younger than 5 years (n = 11), the correlation (r = 0.728, p less than 0.02) was less satisfactory than in those older than 5 years (r = 0.926; p less than 0.001). Although modifications in the instrument and further clinical trials with the stethoscope are needed before the device becomes clinically useful to pediatric cardiologists, our data indicate that the nuclear stethoscope can provide reliable assessment of LVEF in pediatric patients.     

Quantitative assessment of short axis wall motion using myocardial strain rate imaging

Although left ventricular wall motion has been usually assessed with four-point scale (1 = normal; 2 = hypokinesis; 3 = akinesis; 4 = dyskinesis) based on the visual assessment, this method is only qualitative and subjective. Recently, a new echocardiographic system that enables calculation of myocardial strain rate based on tissue Doppler information has been developed. We investigated whether myocardial strain rate could quantify regional myocardial contraction in 17 patients with and without wall motion abnormalities including 6 patients undergoing dobutamine stress echocardiography. Left ventricular short-axis wall motion was assessed with standard two-dimensional echocardiography at basal, mid-ventricular, and apical levels. The same levels were imaged with tissue Doppler method to determine regional myocardial strain rate. Sixty-four segments were judged normokinesis, 53 segments hypokinesis, and 18 segments akinesis at rest; 16 segments were judged normokinesis and 6 segments hypokinesis at stress. No segments characterized dyskinesis. Strain rates of normokinetic, hypokinetic, and akinetic wall segments at rest were significantly different each other (-2.0 +/- 0.6 for normokinesis,-0.6 +/- 0.5 for hypokinesis,P < 0.0001 vs. normokinesis, and-0.008 +/- 0.3 for akinesis, P < 0.0001 vs. normokinesis and hypokinesis). Further, strain rates well reflected the change in wall motion induced by dobutamine challenge: strain rates in the 15 segments revealing augmented wall motion changed from -2.0 +/- 0.7 to -4.7 +/- 1.7 (1/sec) (P < 0.0001) and those in the 7 segments revealing deteriorated or unchanged wall motion changed from -2.1 +/- 1.0 to -1.7 +/- 0.8 (1/sec) (P < 0.05). In conclusion, strain rate agreed well with assessed wall motion. Strain rate imaging may be a new powerful tool to quantify regional wall contraction.     

Comparison of segmental and global ejection fraction in ischaemic heart disease

In order to evaluate whether segmental ejection fraction (SEF) is a better index of left ventricular (LV) performance than global ejection fraction (EF), 25 patients with significant coronary stenosis and normal EF were studied. SEF was estimated from the LV cineangiogram after dividing the LV into eight segments by means of a long axis and three equally spaced chords perpendicular to it. The area of a given segment was measured in the end-diastole and the end-systole and SEF was calculated by determining the percent decrease in area for each segment. 12 out of the 25 patients presented hypokinesis, akinesis or dyskinesis of at least two segments; the inferior apical and both diaphragmatic segments were the regions most frequently affected. In 7 patients, these abnormalities were compensated by hyperkinesis of two or three other segments, whereas in the remaining 5 patients contraction abnormalities were not accompanied by hyperkinesis in spite of a normal EF. It is concluded that SEF is a more sensitive index of regional LV function than EF in patients with ischaemic heart disease.     

Ischemic myocardial dysfunction assessed by temporal Fourier transform of regional myocardial wall thickening

A Fourier analysis including the first 20 harmonics was performed on sonomicrometric measurements of regional myocardial wall thickness in eight conscious dogs under control conditions and at four levels of ischemia produced by a hydraulic occluder on the left circumflex coronary artery. Systolic wall thickening was reduced from 26.47 +/- 6.20% (S.D.) (control) to 22.05 +/- 5.73% (mild stenosis), 17.00 +/- 5.86% (moderate stenosis), 11.46 +/- 3.56% (severe stenosis), and 3.69 +/- 2.57% (30-second occlusion), values significantly different from each other (p less than 0.01). The amplitude of the first harmonic decreased stepwise from 1.35 +/- 0.31 to 1.08 +/- 0.29 mm, 0.90 +/- 0.27 mm, 0.69 +/- 0.24 mm, and 0.43 +/- 0.12 mm, all significantly different from each other (p less than 0.05). These amplitude values correlated to percent systolic wall thickening (r = 0.894, p = 0.001). A phase shift of the first harmonic from 137 +/- 11 to 139 +/- 14 degrees, 150 +/- 15 degrees (p less than 0.05 vs control), 161 +/- 21 degrees (p less than 0.01 vs control), and 191 +/- 21 degrees (p less than 0.01 vs control and severe stenosis) correlated with the increase in time from end diastole to the point of maximum wall excursion (r = 0.662, p less than 0.001). These data indicate that the extent of ischemic regional myocardial hypokinesis can be adequately described by the amplitude of the first harmonic, and that the asynchrony of ventricular contraction and relaxation can be detected from the phase of the first harmonic.     

Regional ejection fraction: a quantative radionuclide index of regional left ventricular performance.

Radionuclide measurements of regional left ventricular ejection fraction were evaluated as a quantitative index of regional left ventricular function. Left ventricular regional ejection fractions were derived from background-corrected, time-activity curves in 43 patients assessed by both gated equilibrium radionuclide angiocardiography and left ventricular contrast angiography. From a single, modified left anterior oblique projection, the regional change in background corrected counts was determined in each of three anatomic regions. The normal range for regional radionuclide ejection fraction was determined in 10 patients with normal contrast ventriculograms and without obstructive coronary artery disease at coronary arteriography. Regional ejection fraction was compared with percent segmental axis shortening and extent of akinetic segments in corresponding regions of the contrast ventriculogram. Radionuclide and roentgenographic methods were in agreement as to the presence or absence of abnormal wall motion in 83 of 99 left ventricular regions (84%) in 33 patients evaluated prospectively. Comparison of regional ejection fraction demonstrated significant differences between regions with roentgenographically determined normokinesis (75 +/- 3%, mean +/- SEM), hypokinesis (44 +/- 3%, p less than 0.0005) and akinesis (24 +/- 5%, p less than 0.005). We conclude that the left ventricular regional ejection provides a reliable quantitative assessment of regional left ventricular performance.     

Acute changes in infranodal conduction time following left ventriculography and sublingual nitroglycerin administration in man

During diagnostic cardiac catheterization for the evaluation of chest pain, His bundle electrograms were obtained in 32 male patients before and 2 to 5 minutes after each of two interventions known to acutely affect left ventricular volume and left ventricular end-diastolic pressure (the injection of 40 to 60 cc of contrast medium during left ventriculography and the administration of 0.4 mg of sublingual nitroglycerin). Changes in left ventricular end-diastolic pressure (18 +/- 6 vs 30 +/- 7 mm Hg, p less than 0.001 following ventriculography and 32 +/- 8 vs 19 +/- 8 mm Hg, p less than 0.005 following nitroglycerin administration) were accompanied by parallel alterations in HQ (48 +/- 8 vs 54 +/- 10 msec, p less than 0.005 following ventriculography and 57 +/- 10 vs 53 +/- msec, p less than 0.005 following nitroglycerin administration), but there were no significant changes in atrioventricular (AV) nodal conduction (AH). Significantly greater changes in HQ were seen in patients with triple-vessel coronary artery disease than in the remainder of the population, although there was clinical and/or ECG evidence of ischemia in only one patient. We conclude that factors other than progression of intrinsic conduction system disease may affect infranodal conduction. HQ should be interpreted cautiously in situations with rapidly changing hemodynamics, especially in patients with severe coronary artery disease.     

Assessment of abnormal systolic intraventricular flow patterns by Doppler imaging in patients with left ventricular dyssynergy

Few data exist regarding the consequences of abnormalities of segmental contraction on intraventricular flow patterns. The development of color Doppler flow imaging has now permitted the visualization of intraventricular blood flow patterns. Therefore, we performed Doppler flow mapping in 41 patients (12 with normal left ventricular contraction, eight with hypokinesis or akinesis, and 21 with dyskinesis) and compared these findings with left ventriculography. Systolic blood flow by Doppler mapping in subjects with normal ventricular contraction was characterized primarily by flow through the left ventricular outflow tract and into the aorta. In patients with dyskinesis, paradoxical systolic flow toward the abnormal segment was present, and persisted for at least 50% of systole in 18 of 21 patients. Mean duration of paradoxical flow in dyskinetic patients was 77% of systole. Paradoxical flow was also observed in two of five patients with akinesis but in no patients with hypokinesis. A good correlation was observed between the duration of paradoxical systolic flow and indexes of regional wall motion (radian shortening of the involved myocardium) (r = 0.77) and global ejection fraction derived from cineangiography (r = 0.79). Correlations between the area of the paradoxical systolic flow stream in midsystole and indexes of left ventricular function were less close, with r equaling 0.57 for both regional wall motion and ejection fraction. Thus, paradoxical systolic flow can be detected in most patients with left ventricular dyskinesis, and correlates with the magnitude of regional and global left ventricular dysfunction by cineangiography.     

Failure of nitroglycerin introduced after prolonged myocardial ischemia to improve collateral blood flow and function in tranquilized dogs

This study investigated whether nitroglycerin can improve ischemic zone blood flow and function when its infusion is delayed following left anterior descending (LAD) occlusion. Nitroglycerin (200 micrograms/min, 11 dogs) or saline (six dogs) was infused for 2 hours starting 2 hours after occlusion. Regional myocardial blood flow (MBF) was measured (9 +/- 1 micron radioactive microspheres) before and at 2 and 4 hours after occlusion. Segmental contraction was determined by cineroentgenography of implanted tantalum markers. For all ischemic samples (defined as MBF less than or equal to 0.4 ml/min/gm), the average improvement in MBF in the epicardial half (EPI) was 0.05 +/- 0.02 ml/min/gm (mean +/- SEM) with nitroglycerin vs 0.06 +/- 0.06 with saline (p greater than 0.5). Improvement in the endocardial half (ENDO) averaged 0.03 +/- 0.03 ml/min/gm with nitroglycerin vs 0.09 +/- 0.08 with saline (p = 0.5). Contraction in the ischemic zone ceased following occlusion and was unaffected by nitroglycerin or saline. Control blood flows in the ischemic region were 22% less in the ENDO (p less than 0.001) and 19% less in the EPI (p less than 0.005) than in nonischemic myocardium. These results indicate that 2 hours after LAD occlusion in dogs, nitroglycerin was unable to improve ischemic zone collateral flow or contractile function compared to untreated controls. Lower ischemic zone control flows indicate that infarct volume expansion may occur within 4 hours after coronary occlusion.     

Left ventricular ejection fraction response during exercise in asymptomatic systemic hypertension

To study the effect of mild-to-moderate elevations in diastolic blood pressure (BP) on systolic left ventricular (LV) function, 28 hypertensive patients and 20 normal subjects underwent upright exercise first-pass radionuclide angiography. All were asymptomatic, had normal rest and exercise electrocardiographic findings and no evidence of LV hypertrophy or coronary artery disease. LV function at rest was similar in the 2 groups, but with exercise hypertensive patients had a greater end-systolic volume (69 +/- 19 vs 51 +/- 19 ml, p less than 0.002) and lower ejection fraction (EF) (0.59 +/- 0.09 vs 0.72 +/- 0.07, p less than 0.0001), stroke volume (101 +/- 28 vs 130 +/- 36 ml, p less than 0.005) and peak oxygen uptake (23 +/- 7 vs 33 +/- 9 ml/kl/min, p less than 0.05). Hypertensive patients were separated into 3 groups: group 1-12 patients with an increase in EF with exercise greater than or equal to 0.05; group 2-7 patients with a change in EF with exercise less than 0.05; and group 3-9 patients with a decrease in EF with exercise greater than or equal to 0.05. Group 3 hypertensive patients were older, had a higher heart rate at rest and lower peak oxygen uptake. Rest LV function was similar in the 3 hypertensive subgroups, but exercise end-systolic volumes were higher in groups 2 and 3. Exercise thallium-201 images was normal in all but 1 of 14 hypertensive group 2 or 3 patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Abnormal coronary vasomotion during exercise in patients with normal coronary arteries and reduced coronary flow reserve

A reduced coronary flow reserve has been reported in patients with ischemialike symptoms and normal coronary arteries. In 13 such patients, both coronary vasomotion and flow reserve were studied. The luminal area of the proximal and distal third of the left anterior descending and left circumflex artery were determined by biplane quantitative coronary arteriography using a computer-assisted system. Patients were studied at rest, during submaximal supine bicycle exercise (4.0 minutes, 116 W), and 5 minutes after sublingual administration of 1.6 mg nitroglycerin. Heart rate, mean pulmonary pressure, and mean aortic pressure as well as the percent change of both proximal and distal luminal area were determined. In 10 of the 13 patients, coronary sinus blood flow was measured by coronary sinus thermodilution technique at rest and after dipyridamole infusion (0.5 mg/kg in 15 minutes) 10 +/- 5 days after quantitative coronary arteriography. Coronary flow ratio (dipyridamole/rest) and coronary resistance ratio (rest/dipyridamole) were determined in these patients. Patients were divided into two groups according to the behavior of the coronary vessels during exercise (vasodilation, group 1; vasoconstriction, group 2). Coronary vasodilation of the proximal (luminal area +26%, p less than 0.001) and distal (+45%, p less than 0.001) artery was observed in seven patients (group 1) during exercise and after sublingual nitroglycerin (+46%, p less than 0.001; and +99%, p less than 0.001, respectively). In group 2 (n = 6), however, there was coronary vasoconstriction of the distal vessel segments (-24%, p less than 0.001) during exercise, whereas the proximal coronary artery showed vasodilation (+26%, p less than 0.001) during exercise. After sublingual nitroglycerin, both vessel segments elicited vasodilation (distal coronary, +44%, p less than 0.001; proximal coronary artery, +47%, p less than 0.001). Coronary flow ratio amounted to 2.5 in group 1 and 1.2 in group 2 (p less than 0.05) and coronary resistance ratio to 2.7 in group 1 and to 1.2 in group 2 (p less than 0.05), respectively. Thus, among patients with ischemialike symptoms and normal coronary arteries, there is a group of patients (group 2) with an abnormal dilator response of the distal coronary arteries to the physiologic dilator stimulus of exercise and a reduced dilator capacity of the resistance vessels after dipyridamole (abnormal coronary vasodilator syndrome). The nature of this exercise-induced distal coronary vasoconstriction is not clear but might be due to an abnormal neurohumoral tone that may cause or contribute to the blunted vascular response during exercise.     

A comparative evaluation of hemodynamic and neurohumoral effects of nitroglycerin and nifedipine in congestive heart failure

Nitroglycerin and nifedipine have been suggested as useful agents in the therapy of congestive heart failure. Because of the rapid action and feasability for sublingual administration of both drugs, their comparative hemodynamic and neurohumoral effects were studied in 12 patients with congestive heart failure. After sublingual nitroglycerin, there was a significant decrease in mean arterial pressure (96 +/- 17 to 90 +/- 15 mm Hg, p less than 0.01), left ventricular (LV) filling pressure (30 +/- 12 to 22 +/- 10 mm Hg, p less than 0.01), right atrial pressure (15 +/- 6 to 10 +/- 5 mm Hg, p less than 0.01) and systemic vascular resistance (21.5 +/- 7.7 to 19.3 +/- 6.2 units, p less than 0.05) and an increase in cardiac index (2.2 +/- 0.6 to 2.4 +/- 0.7 liters/min/m2, p less than 0.05) and LV stroke work index (20.4 +/- 7.0 to 24.5 +/- 8.6 gm-m/m2, p less than 0.01). After sublingual nifedipine, there was also a significant decrease in mean arterial pressure (96 +/- 16 to 89 +/- 14 mm Hg, p less than 0.01) and systemic vascular resistance (22.1 +/- 7.1 to 18.0 +/- 6.1 units, p less than 0.01) and an increase in cardiac index (2.1 +/- 0.6 to 2.4 +/- 0.6 liters/min/m2, p less than 0.01); in contrast to nitroglycerin, this was unaccompanied by significant changes in right- or left-sided filling pressures or LV stroke work index.(ABSTRACT TRUNCATED AT 250 WORDS)     

Apical left ventricular asynergy in chronic aortic regurgitation

Apical left ventricular (LV) wall motion abnormalities have been described in chronic volume overload. To evaluate if these abnormalities are due to an actual hypokinesia we analyzed the percent shortening of apical LV radiants (PS%) by an angiographic computerized method and the endocardial systolic movement (ESM) and thickening (%Th) of the same region using M-mode echocardiographic technique in 11 patients affected by pure aortic regurgitation (AR). In these patients mean apical radii shortening was reduced with respect to normal values. Both %Th and ESM were significantly reduced in AR when compared to normal subjects (24.5 +/- 31.7% vs. 63.8 +/- 35.8%, p less than 0.01 and 4 +/- 7 vs. 10 +/- 3 mm, p less than 0.01, respectively). In addition, %Th and ESM directly correlated with PS% (r = 0.79, p less than 0.01 and r = 0.77, p less than 0.01, respectively). PS% correlated positively with systolic eccentricity and inversely with end-systolic volume index (r = 0.64, p less than 0.05 and r = 0.57, p less than 0.05, respectively). Finally, in AR %Th was related to a normalized peak rate of systolic wall thickening (r = 0.85, p less than 0.01) and to a normalized peak rate of diastolic wall thinning (r = 0.68, p less than 0.05). These results showed that in AR a reduced apical radii percent shortening was associated with a reduced normalized peak rate of systolic wall thickening and of diastolic wall thinning, thus indicating an actual hypokinesis and an impaired contractility. Moreover, the observed abnormalities correlated with an altered LV dynamic geometry linked to chronic volume overload.     

Myocardial perfusion assessed by dynamic computed tomography, with respect to viable muscle in the infarcted region

To clarify the significance of regional myocardial perfusion, 31 patients of old myocardial infarction including 11 cases undergoing PTCA with a left anterior descending artery lesion were studied using dynamic transmission computed tomography with excellent time resolution. Serial one-second dynamic scans with an electrocardiographic triggering system were performed at the middle level of the left ventricle using a bolus injection of contrast medium via the inferior vena cava. The F/V (F = flow, V = volume) ratio, a parameter of perfusion per unit of myocardium, was calculated from gamma-variate fitted time density curves obtained in the myocardium and in the left ventricular cavity. The F/V ratio was significantly lower in patients not only with severe but also mild and no coronary artery stenosis (post PTCA: 185 +/- 54, 50-75% stenosis: 193 +/- 47, 90% stenosis: 181 +/- 51, 99% stenosis: 140 +/- 34, 100% stenosis: 142 +/- 27 ml/min/100 g, control value: 243 +/- 51 ml/min/100 g, post PTCA, 50-75% stenosis, 90% stenosis vs control p less than 0.05, 99%, 100% stenosis vs control p less than 0.005). The functional images depicting myocardial perfusion frequently revealed abnormal perfusion findings in patients not only with severe but also mild and no coronary stenosis. In the patients with mild or insignificant coronary stenosis, the F/V ratio was dependent on the severity of left ventricular wall motion abnormalities (hypokinesis: 192 +/- 51, akinesis or dyskinesis: 141 +/- 32 ml/min/100 g; p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Left ventricular regional wall stress in dilated cardiomyopathy

Left ventriculography with simultaneous pressure micromanometry was performed in 11 normal control subjects and 17 patients with dilated cardiomyopathy (DCM). Left ventricular silhouettes in the right anterior oblique projection were divided into eight areas, and regional wall stress was computed by Janz's method in each area excluding the two most basal areas. Wall stress was higher in DCM patients than in control subjects (p less than 0.01). The percent area changes from end diastole to end systole in each area were lower in DCM patients than in control subjects (mean for six areas, 22 +/- 14% versus 54 +/- 9%, respectively, p less than 0.01), but the coefficient of variation for the percent area changes in the six areas of the left ventricle in DCM patients was greater than that in control subjects (32 +/- 17% versus 15 +/- 4%, respectively, p less than 0.01), indicating regional differences in hypokinesis. There was a significant negative correlation between end-systolic regional wall stress and percent area change (r = -0.60 to -0.86, p less than 0.05) in each area. Thus, excessive regional afterload may play an important role in causing regional hypokinesis in DCM.