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PubMed1996

Stable quantitative EEG difference in post-LSD visual disorder by split-half analysis: evidence for disinhibition.

Hallucinogen persisting perceptual disorder (HPPD) may follow the ingestion of LSD or other hallucinogens in a subset of users. It is characterized by chronic, intermittent or constant visual hallucinations of many sorts persisting beyond the period of acute drug effects. We studied 44 LSD-induced HPPD subjects and 88 matched controls to search for spectral and evoked potential differences using quantitative EEG (qEEG). HPPD subjects demonstrated faster alpha frequency and shorter VER (visual evoked response) latency, consistent with prior animal and human data on response to acute LSD administration which suggest LSD-induced cortical disinhibition. AER (auditory evoked response) latency was prolonged consistent with a differential LSD effect upon visual and auditory systems. The exploratory T-statistic significance probability mapping (T-SPM) technique demonstrated HPPD-control differences mostly involving temporal and left parietal scalp regions, confirmed by a split-half analysis. Significant variables were all derived from the long latency flash VER and click AER. None were derived from spectral analyzed EEG data. Canonical correlation between SPM-derived measures and variables reflecting disease severity was highly significant. A between-group stepwise discriminant analysis based upon a full set of qEEG measures demonstrated 87% prospective classification success by jackknifing and 88% success in a separate split-half analysis.

Adolescent↗

PubMed1992

Measurement of myocardial perfusion and cardiac output using intravenous injection methods by ultrafast (cine) computed tomography.

Ultrafast (or cine) computed tomography (CT) uses a novel scanning electron beam technology to obtain multi-level images of the beating heart in rapid succession. Recent investigations have demonstrated that it can be used to define the transit of iodinated contrast media through the cardiac chambers and myocardium. Using classical indicator dilution principles and rapid intravenous injection of iodinated contrast media, ultrafast CT can quantify cardiac output and, to a limited extent, myocardial perfusion. A caveat to the application requires that careful calibration be made on a subject-by-subject basis prior to quantification of cardiac output. Although global myocardial perfusion and flow reserve can be evaluated by ultrafast CT, spatially variable imaging artifacts may limit the application in all regions of the left ventricular myocardium. Advances in study design, image reconstruction and post-image processing continue. Ultrafast CT technology offers a means to define cardiac anatomy, function and flow in man rapidly, conveniently and accurately in a noninvasive fashion employing intravenous contrast media injection.

Cardiac Output↗

PubMed1997

Viability after myocardial infarction: can it be assessed within five minutes by low-dose dynamic iodine-123-iodophenylpentadecanoic acid imaging with a multicrystal gamma camera?

Although positron emission tomography (PET) assesses myocardial viability (V) accurately, a rapid, inexpensive substitute is needed. Therefore, the authors developed a low-dose (1 mCi) Iodine-123-Iodophenylpentadecanoic Acid (IPPA) myocardial viability scan requiring analysis of only the first three minutes of data acquired at rest with a standard multicrystal gamma camera. Twenty-one patients > 2 weeks after myocardial infarction (MI) (24 MIs, 10 anterior, 14 inferoposterior, 21 akinetic or dyskinetic) had cardiac catheterization and resting IPPA imaging. V was determined by either transmural myocardial biopsy during coronary bypass surgery (12 patients, 14 MIs) or reinjection tomographic thallium scan (9 patients, 10 MIs), and 50% of MIs were viable. The IPPA variables analyzed were: time to initial left ventricular (LV) uptake in the region of interest (ROI), the ratio of three-minute uptake in the ROI to three-minute LV uptake, three-minute clearing (counts/pixel) in the ROI (decrease in IPPA after initial uptake), and three-minute accumulation (increase in IPPA after initial uptake) in the ROI. Rules for detecting V were generated and applied to 10 healthy volunteers to determine normalcy. While three-minute uptake in nonviable MIs was only 67% of volunteers (P < 0.0001) and 75% of viable MIs, uptake alone identified only 50% of viable MIs and 75% of nonviable MIs. IPPA clearing, however, was > or = 13.5 counts/pixel in 10/12 (83%) of viable MIs, and IPPA accumulation > or = 6.75 counts/pixel identified one more viable MI, for a sensitivity for V of 11/12 (92%), with a specificity of 11/12 (92%), and a 100% normalcy rate. The authors conclude low-dose IPPA (five-minute acquisition with analysis of the first three minutes of data) has potential for providing rapid, inexpensive V data after MI. Since newer multicrystal cameras are mobile, IPPA scans can be done in emergency rooms or coronary care units generating information that might be useful in decisions regarding thrombolysis, angioplasty, or bypass surgery.

Case-Control Studies↗

PubMed1983

Wolff-Parkinson-White syndrome with gradual transition from type A to type B.

This report documents a case which showed type A, type B and intermediate patterns of pre-excitation on different days. A vagotonic maneuver and digitalis induced a type A pattern, while exercise, atropine and isoproterenol caused a type B pattern of activity. A gradual transition from type A to B was demonstrated with vectorcardiograms. Despite the variations in the QRS morphology, the direction of the initial vector was not altered and was directed straight anteriorly. In this case, an accessory pathway may be located in the posterior paraseptal region or the lateral free wall of the left ventricle, and a variable size of pre-excited area may have caused type A and type B patterns of pre-excitation.

Delta Rhythm↗

PubMed1995

Myocardial contrast echocardiography for assessment of papaverine vasodilator response in patients with angiographically normal coronary arteries and in patients after orthotopic heart transplantation.

Myocardial contrast echocardiography has the potential for assessing changes in regional myocardial perfusion. We used this method to compare papaverine vasodilator response in 10 patients after orthotopic heart transplantation without acute rejection of left ventricular hypertrophy (HTX) and in 15 patients with angiographically normal coronary arteries (control group). Injections of 2 ml of sonicated iopromid (9 paired injections in HTX and 24 paired injections in the control group) were performed before and after intracoronary application of papaverine (8 or 10 mg) into the left or right coronary artery. From regional time-intensity curves, alpha (variable of curve width), area under the curve (area), peak contrast intensity (Imax) and contrast decay half-time (T1/2) were derived by from a gamma variate function. T1/2 increased from 4.2 +/- 1.2 to 7.2 +/- 4.0 s (p < 0.01) after papaverine in HTX compared to a change from 4.8 +/- 1.0 to 6.0 +/- 1.7 s (p < 0.001) in normal subjects. Alpha decreased in HTX from 0.44 +/- 0.15 to 0.27 +/- 0.10 s-1 (p < 0.01) after intracoronary papaverine injection. In the control group alpha was 0.37 +/- 0.08 s-1 at rest compared to 0.30 +/- 0.08 s-1 at hyperemic conditions (p < 0.002). Area increased in HTX from 444 +/- 261 to 910 +/- 732 U.s (p < 0.01) and in normal subjects from 352 +/- 171 to 585 +/- 262 U.s (p < 0.001). Hyperemic to baseline flow ratios for area varied from 0.9 to 3.8 (mean 2.17 +/- 1.11) in HTX compared to 1.76 +/- 0.52 (1.03 to 2.71) in normal subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1998

[Measurement of coronary flow reserve using adenosine 5'-triphosphate in dogs].

Adenosine 5'-triphospate (ATP) was compared with adenosine and papaverine for the measurement of coronary flow reserve in 12 anesthetized dogs. Intracoronary bolus injection of ATP (1 ml, 1-500 microM) produced a dose dependent increase in the blood flow of the left anterior descending artery, which attained the plateau at the dose of 100 microM. The ratio of peak to resting coronary flow volume (coronary flow reserve) with 100 microM of ATP (3.5 +/- 0.5) was similar to that with 200 microM of adenosine (4.0 +/- 0.7) and 50 mM of papaverine (3.7 +/- 0.8). Hemodynamic variables did not change after administration of each drug, except left ventricular regional wall motion abnormality during papaverine injection. The coronary flow reserve as measured after intracoronary ATP administration (100 microM) decreased as the grade of stenosis of the left anterior descending artery progressed. In addition, the flow reserve was similar to that of adenosine or papaverine administration at each stenosis grade. Intravenous administration of ATP (1,000 micrograms/min) caused a similar increase in coronary blood flow as intracoronary ATP injection (100 microM). However, premedication with 8-phenyltheophylline, an adenosine receptor blocker, significantly suppressed the coronary dilatory effect of intravenous ATP and intracoronary adenosine but not the effect of intracoronary ATP. These results indicate that intracoronary ATP is useful for measuring coronary flow reserve and that its coronary dilatory effect is not mediated by metabolysis to adenosine.

Adenosine↗

PubMed1989

Left ventricular regional function after acute anterior myocardial infarction in diabetic patients.

To elucidate the pathophysiological role of diabetes mellitus in determining the left ventricular regional function of the noninfarcted area, 55 patients with acute Q wave anterior myocardial infarction (MI) were studied. The regional ejection fraction of the noninfarcted area was obtained by radionuclide angiocardiography and was used to estimate the left ventricular regional function of the noninfarcted area. Multiple regression analysis was performed to determine the important variables contributing to the regional ejection fraction based on 10 clinical variables: age, sex, QRS score, diabetes mellitus, hypertension, smoking, postinfarction angina, body mass index, serum cholesterol, and coronary atherosclerosis. A high QRS score (P less than .001) and the association of diabetes mellitus (P less than .05) were the important factors contributing to regional left ventricular dysfunction. The regional ejection fraction and QRS score had an inverse linear relationship in the diabetic and nondiabetic groups, and the regional ejection fraction was significantly lower in diabetic patients at every QRS score (P less than .05). The association of hypertension, severity of coronary atherosclerosis, serum cholesterol level, age, and body mass index did not differ between diabetic and nondiabetic patients, which indicates that diabetes mellitus was not mediated through these atherogenic traits. Thus, diabetes mellitus is another discrete cause of regional left ventricular dysfunction of the noninfarcted area after acute MI.

Diabetes Mellitus, Type 2↗

PubMed1996

The mechanism of sympathovagal imbalance in patients with myocardial ischemia.

To investigate the mechanism of sympathovagal imbalance due to myocardial ischemia, we studied 42 consecutive patients undergoing successful percutaneous transluminal coronary angioplasty by correlating frequency domain and time domain measures of heart rate variability with parameters such as echocardiography, stress thallium scanning and radionuclide angiography before, immediately after and 2 months after the procedure. Of these, 20 patients (Group N) had normal and 22 patients (Group A) had abnormal regional wall motion. A control group of 20 healthy subjects (Group C) underwent echocardiography and examination of heart rate variability twice at 2-month intervals to check for spontaneous variations. At baseline, frequency domain measures such as low and high frequency power and time domain measures such as SDANN index (the mean of the standard deviations of the average of RR intervals) were lower in Group A than in Groups N and C, whereas no differences were detectable in ultra low and very low frequency, total power, SDNN index (the mean of the standard deviations of the mean of normal RR intervals), and r-MSSD (the root mean square of successive RR differences). There was high association between the diastolic wall stress index and both high frequency (r = -0.82) and low frequency power (r = -0.77). There were similar findings for the systolic wall stress index (r = -0.72 for high frequency and r = -0.64 for low frequency power). After successful coronary angioplasty, regional wall motion, left ventricular wall stress indices and all measures of heart rate variability were unchanged in Group N. In Group A the mean summed segment score improved from 15.9 +/- 2.6 to 12.2 +/- 1.7 (p < 0.0001), and mean low frequency, mean high frequency power (logarithmic units), and SDANN index (msec) increased from 6.10 +/- 0.23 to 6.36 +/- 0.28 (p < 0.005), from 5.36 +/- to 0.40 to 5.70 +/- 0.39 (p < 0.01) and from 70 +/- 18 to 83 +/- 18 (p < 0.01) respectively. In addition, low and high frequency power and SDANN index, lower at baseline in Group A than in the other two groups, were comparable in the three groups after coronary angioplasty. The evolution of diastolic and systolic wall stress indices paralleled that of the above three parameters. In conclusion, diastolic and systolic wall stress indices, in addition to segmental left ventricular dysfunction, were synergistically involved in determining sympathovagal imbalance in patients with significant coronary artery disease; the reversal of left ventricular dysfunction and wall stress indices improves the profile of heart rate variability. Alterations in cardiac geometry and wall stress influence mainly the discharge of afferent sympathetic and efferent parasympathetic innervations and also principally the long-term heart rate variations instead of short-term modulation.

Angioplasty, Balloon, Coronary↗

PubMed1987

Electroencephalographic spectra and coherence in the diagnosis of Alzheimer's-type and multi-infarct dementia. A pilot study.

The accurate diagnosis of dementia is difficult because there are no specific physiologic tests. Computer-analyzed electroencephalography (EEG) has shown promise as a tool for the differential diagnosis of dementia, but topographic methods for data collection and analysis have seldom been used. We used these methods to investigate EEG differences among three groups of elderly subjects: those with mild to moderate dementia of the Alzheimer's type (DAT), those with mild to moderate multi-infarct dementia (MID), and age- and sex-matched normal controls. The two groups of demented subjects were distinguished from the control group by a new criterion, the ratio of high-frequency to low-frequency electrical activity in the left temporal region, which was greatly diminished in demented subjects. Using this single variable, all control subjects and 15 of 18 demented subjects were correctly classified (sensitivity 83%, specificity 100%). The three misclassified subjects were among the least impaired subjects with DAT. Examination of coherence, or synchronization of the EEG signal, enabled us to distinguish subjects with DAT from those with MID. Using discriminant analysis of both EEG frequency and coherence, 92% (22/24) of subjects were accurately classified. These results justify further evaluation of topographic, computer-based EEG analysis as a test for the differential diagnosis of dementia.

Alzheimer Disease↗

PubMed1993

Heterogeneity of reperfusion after reversible regional myocardial ischemia in a canine model.

Variability of regional myocardial blood flow (RMBF) during reflow after 20 minutes of left anterior descending (LAD) coronary occlusion was measured by the radioactive microsphere technique in nine open-chest dogs. Preocclusion RMBF in the LAD territory was 0.89 +/- 0.27 ml/min/gm. Twenty minutes of LAD occlusion resulted in uniform and severe ischemia (RMBF < or = 0.25 ml/min/gm). After 1 minute of reperfusion, RMBF in the LAD territory rose to 3.48 +/- 1.88 ml/min/gm, and declined to 1.06 +/- 0.29 ml/min/gm after 20 minutes of reperfusion. RMBF variance increased significantly from 0.046 preocclusion to 0.2857 after 1 minute of reperfusion (p < 0.01) and declining to 0.086 after 20 minutes of reperfusion. By contrast, RMBF variance analysis of myocardial segments from the nonischemic left circumflex territory exhibited no significant change throughout the experiment. In any given dog this heterogeneous reperfusion of previously ischemic tissue resulted in a disorganized topography of blood flow rates. Myocardium with relatively high regional flow was intermingled with islands of tissue with relatively low blood flow. In conclusion, despite a relatively uniform and severe myocardial ischemic insult, the subsequent initial hyperemic response during reperfusion exhibits marked spatial heterogeneity. The juxtaposition of myocardial regions exposed to vastly differing rates of oxygen delivery and washout of toxic metabolites may set the stage for nonuniform recovery of myocardial function.

Analysis of Variance↗

PubMedDate not supplied

Reduction of myocardial infarct size by trapidil in anesthetized dogs.

We studied the effect of trapidil on acute experimental myocardial infarction in anesthetized, openchest dogs. The size of myocardial infarction 8 h after ligation of the left anterior descending coronary artery was determined by planimetry of myocardial slices stained by the nitroblue tetrazolium method. Systemic hemodynamic variables, epicardial ST-segment elevation, activity of serum creatine phosphokinase (CPK), and changes of myocardial blood flow in the ischemic area were measured. Infusion of 3 mg/kg trapidil reduced the size of infarction and ameliorated the infarction-induced deterioration of systemic hemodynamic variables, such as the decrease in left ventricular dP/dt, aortic blood flow, and regional endomyocardial blood flow in the ischemic area. This dose of trapidil also suppressed ST elevation and significantly inhibited the increase in activity of serum CPK. Hyaluronidase also reduced the size of infarction significantly. These results suggest that trapidil alters the course of acute myocardial infarction favorably, presumably by increasing regional endomyocardial blood flow.

Animals↗

PubMed2001

Cerebral cortical representation of reflexive and volitional swallowing in humans.

The purpose of this study was to compare cerebral cortical representation of experimentally induced reflexive swallow with that of volitional swallow. Eight asymptomatic adults (24-27 yr) were studied by a single-trial functional magnetic resonance imaging technique. Reflexive swallowing showed bilateral activity concentrated to the primary sensory/motor regions. Volitional swallowing was represented bilaterally in the insula, prefrontal, cingulate, and parietooccipital regions in addition to the primary sensory/motor cortex. Intrasubject comparison showed that the total volume of activity during volitional swallowing was significantly larger than that activated during reflexive swallows in either hemisphere (P < 0.001). For volitional swallowing, the primary sensory/motor region contained the largest and the insular region the smallest volumes of activation in both hemispheres, and the total activated volume in the right hemisphere was significantly larger compared with the left (P < 0.05). Intersubject comparison showed significant variability in the volume of activity in each of the four volitional swallowing cortical regions. We conclude that reflexive swallow is represented in the primary sensory/motor cortex and that volitional swallow is represented in multiple regions, including the primary sensory/motor cortex, insular, prefrontal/cingulate gyrus, and cuneus and precuneus region. Non-sensory/motor regions activated during volitional swallow may represent swallow-related intent and planning and possibly urge.

Adult↗

PubMed1990

Heterogeneous delivery of cardioplegic solution in the absence of coronary artery disease.

The prevention of intraoperative myocardial damage with cardioplegic solution depends in large measure on the completeness of its delivery. We created a model to study the regional flow distribution of cardioplegic solutions in nondiseased, diastolically arrested, maximally vasodilated canine hearts. Global and regional myocardial flows were measured at different perfusion pressures in hearts perfused either with blood cardioplegic solution (n = 8) or oxygenated crystalloid cardioplegic solution (n = 2). As coronary perfusion decreased, flow in all layers fell significantly (p less than 0.001). This fall was most dramatic in the subendocardium (p less than 0.05). With both types of cardioplegic solutions, the relationship between pressure and flow was nonlinear: At low coronary perfusion pressures, a given change in pressure resulted in a smaller change in flow than at higher perfusion pressures. In addition, we found that in all dogs and at all pressures there was profound variability in the delivery of cardioplegic solution to different small regions of the left ventricular free wall. At a perfusion pressure of 40 mm Hg, the extremes of regional flow differed on average by 203%. This heterogeneity increased significantly with decreasing perfusion pressures. At the lowest perfusion pressure measured (20 mm Hg), the extremes of regional flow differed on average by 365%. These findings emphasize the importance of coronary pressure on the delivery of cardioplegic solution. At low perfusion pressures, not only is mean flow reduced, but a greater number of regions receive limited amounts of cardioplegic solution. These observations may explain the patchy nature of subendocardial damage seen with inadequate myocardial protection.

Animals↗

PubMed2002

Combined effects of metoprolol and spironolactone in dilated cardiomyopathic hamsters.

The use of beta-blockers reduces angiotensin II levels, but could not adequately suppress aldosterone production. Thus, the combination of a beta-blocker with an aldosterone receptor antagonist could exert additive effects. The effects of metoprolol and spironolactone and their combination on hemodynamics and cardiac remodeling in cardiomyopathic hamsters (CMH) were investigated. The Bio TO-2 dilated strain of CMH was treated orally with metoprolol (10 mg/kg/day), spironolactone (20 mg/kg/day), or both according to a 2 x 2 factorial design (24 animals per group) from 120 days of age and during 120 days. As compared to corresponding untreated groups, metoprolol significantly decreased mean blood pressure (-7%), and metoprolol and spironolactone significantly increased cardiac output (18% and 19%, respectively), mesenteric blood flow (11% and 14%), and femoral blood flow (13% and 17%), and significantly decreased systemic (-24% and -15%), mesenteric (-14% and -13%) and femoral (-19% and -10%) vascular resistances. Metoprolol significantly increased renal blood flow (22%) and significantly decreased renal vascular resistance (-23%). Metoprolol and spironolactone significantly decreased the cavity area of the left ventricle (-21% and -32%, respectively) and the collagen density of the left (-36% and -39%) and right (-38% and -43%) ventricles. Although the combination did not induce stronger effects than each drug alone on the systemic and most regional hemodynamic variables, it did have a stronger effect on the cardiac remodeling (compared to control group: -24%, -34%, and -46% for the left ventricle cavity area, -33%, -35%, and -62% for collagen density in the left ventricle, and -52%, -57%, and -59% for collagen density in the right ventricle, respectively, in the metoprolol, spironolactone, and metoprolol + spironolactone groups). In CMH, metoprolol and spironolactone combined did not improve hemodynamics more than each drug alone, but did exert additive effects on cardiac remodeling.

Animals↗

PubMed1993

Clinical applications of coronary sinus retroperfusion during high risk percutaneous transluminal coronary angioplasty.

OBJECTIVES: This study was designed to determine the efficacy of synchronized coronary sinus retroperfusion of arterial blood in reducing myocardial ischemia associated with the performance of high risk coronary angioplasty. BACKGROUND: Previous animal and clinical work has demonstrated the efficacy of this technique in supporting ischemic myocardium. METHODS: Twenty-one patients were randomized to alternately receive coronary sinus retroperfusion support during either the second or the third coronary angioplasty balloon inflation, after an initial unsupported brief control inflation. Myocardial ischemia was assessed by the extent of echocardiographic left ventricular wall motion abnormality, quantified ST segment deviation and hemodynamic and anginal variables during balloon inflations performed with and without coronary sinus retroperfusion support. Regional wall motion score was defined as hyperkinesia (-1), normokinesia (0), hypokinesia (+1), akinesia (+2) and dyskinesia (+3). RESULTS: A reduction in the echocardiographic left anterior descending regional wall motion score in retroperfusion-supported (1.7 +/- 2.1) versus unsupported (2.7 +/- 1.6) inflations (p < 0.05) was noted. Twelve-lead electrocardiographic monitoring revealed no additional ST segment deviation during supported (173 +/- 95 s) compared with unsupported (129 +/- 87 s) angioplasty inflations despite a significantly longer duration of supported inflations (p < 0.004). Mean and peak systolic coronary sinus pressures differed during supported inflations (21 +/- 6 and 44 +/- 13 mm Hg) versus unsupported inflations (10 +/- 4 and 16 +/- 5 mm Hg) (p < 0.001). There was no difference in hemodynamic or anginal variables. CONCLUSIONS: A reduction in ischemia as defined by wall motion abnormality during retroperfusion-supported compared with unsupported angioplasty balloon inflations was documented. No additional ST segment deviation occurred during retroperfusion-supported compared with unsupported balloon inflations despite a significantly longer duration of supported inflations. No difference in hemodynamic or anginal variables was noted.

Adult↗

PubMed2006

Automated interpretation of regional left ventricular wall motion from cardiac magnetic resonance images.

UNLABELLED: Magnetic resonance (MR) diagnosis of regional left ventricular (LV) dysfunction relies on visual interpretation of cine images that suffers from wide inter-observer variability, especially when performed by readers not specifically trained in the assessment of LV wall motion. Quantitative analysis tools, though widely available, are rarely used because they provide large amounts of detailed information, the interpretation of which requires additional time-consuming processing. We tested the feasibility of fast automated interpretation of regional LV function using computer analysis of this wall motion information. METHODS: Dynamic, ECG-gated, steady-state free precession short-axis images were obtained in 6-10 slices in 28 subjects (10 normal volunteers; 18 patients). Images were reviewed by an expert cardiologist who provided "gold standard" grades (normal, abnormal) for regional wall motion and, independently, by four radiologists. Same images were then analyzed using custom software. Regional fractional area changes computed in normal volunteers were used to obtain the optimal segment- and slice-specific threshold values for automated classification of regional wall motion for each patient. The levels of agreement with the "gold standard" grades were compared between the radiologists and the automated interpretation. RESULTS: While the visual interpretation required 2-5 minute per patient, the automated interpretation required < 1 sec, after endocardial border detection was complete. The automated interpretation resulted in higher sensitivity, specificity, and accuracy (84%, 77%, 79%, respectively) than the radiologists' grades (80%, 76%, 77%, respectively) and eliminated the high interobserver variability. CONCLUSION: Once the endocardial boundaries are defined, computer analysis of the regional wall motion information allows accurate, fully automated, immediate, objective and experience-independent interpretation of regional LV function.

Automation↗

PubMed1986

[Experimental studies of the evaluation of the size of infarct and perfusion defects using analysis of regional wall motion from 2-dimensional echocardiography].

In an experimental study with laboratory animals we studied the relation between the extent of a disorder of regional wall motion as determined by echocardiography and size of a perfusion defect following occlusion of a coronary vessel for 5 hours. It was demonstrated that wall motion is not uniform in a normal left ventricle and that there is a wide range of variability in wall motion within a given myocardial segment. For this reason we determined the extent of a disorder of regional wall motion in two echocardiographic planes with reference to defined normal values. Analysis of interobserver and intraobserver variability showed that reproducible determinations of the circumferential extent of a disorder of regional wall motion and the ejection fraction are possible with an acceptable degree of certainty. There was a significant correlation between morphological determinations of the size of a perfusion defect in the left ventricle and the circumferential extent of a disorder of regional wall motions as demonstrated in the echocardiogram (r = 0.83). The regression curve (y = 4.26 + 0.95x) for determinations of the size of the perfusion defect approached the identity line with a standard error of estimation for the echocardiographic examination of 7.4%. Size of the zone of infarction was overestimated by an average of 8% with echocardiography (r = 0.81), with a standard error of estimation of 6.6% (y = -2.41 + 0.85x). There was no significant correlation between ejection fraction and size of the perfusion defect or the size of infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1981

Regional ischemic ventricular dysfunction in myocardium supplied by a narrowed coronary artery with increasing halothane concentration in the dog.

The effects of increasing inspired halothane concentration (0.5, 1.0, 1.5, 2.0 per cent) upon left ventricular myocardium supplied by a critically narrowed coronary artery and a normal coronary artery were studied in 11 open-chested dogs. Regional ventricular function was measured by continuous recording of ventricular segment length using pairs of implanted miniature ultrasonic length detectors in the left anterior descending coronary artery (LAD) and left circumflex coronary artery (LC) territories before and during critical stenosis of the LAD by a micrometer-controlled snare. Critical narrowing was documented by ischemic regional ventricular function (i.e., post-systolic shortening; systolic lengthening) limited to the LAD territory when FIO2 = 0 for 90 seconds. Hemodynamic variables (aortic, left atrial and left ventricular pressure, and heart rate) were measured, ECG lead II was recorded, and the first derivative of left ventricular pressure (LV dP/dt) and coronary perfusion pressure derived for each halothane concentration before and during LAD narrowing. Increasing halothane was associated with equivalent progressive depression of global ventricular function before and during LAD constriction. Prior to LAD constriction, no ischemic changes in regional function occurred. Regional ventricular function was normal during 0.5 percent halothane in the presence of LAD constriction. With increasing halothane during LAD constriction, ischemic regional ventricular function was observed in the LAD territory in eight of eleven hearts, whereas regional ventricular function remained normal in the LC territory. The epicardial ECG was recorded in three dogs and was insensitive as an indicator of ischemia, becoming abnormal only after severe ischemic changes were established. In these studies, in which heart rate remained constant, arterial blood pressure and LV dP/dt decreased, and left ventricular end-diastolic pressure increased, decrease in blood flow and oxygen delivery due to a lower perfusion pressure distal to the coronary artery narrowing appears to be primarily responsible for the observations. The authors hypothesize that clinically unapparent episodes of regional myocardial ischemia distal to narrowed coronary arteries may be an important cause of perioperative myocardial infarction.

Animals↗