Pass Radionuclide Angiography Research Articles

Right ventricular functional analysis utilizing first pass radionuclide angiography for pre-operative ventricular assist device planning: a multi-modality comparison

BackgroundAdvanced heart failure treated with a left ventricular assist device is associated with a higher risk of right heart failure. Many advanced heart failures patients are treated with an ICD, a relative contraindication to MRI, prior to assist device placement. Given this limitation, left and right ventricular function for patients with an ICD is calculated using radionuclide angiography utilizing planar multigated acquisition (MUGA) and first pass radionuclide angiography (FPRNA), respectively. Given the availability of MRI protocols that can accommodate patients with ICDs, we have correlated the findings of ventricular functional analysis using radionuclide angiography to cardiac MRI, the reference standard for ventricle function calculation, to directly correlate calculated ejection fractions between these modalities, and to also assess agreement between available echocardiographic and hemodynamic parameters of right ventricular function.MethodsA retrospective review from January 2012 through May 2014 was performed to identify advanced heart failure patients who underwent both cardiac MRI and radionuclide angiography for ventricular functional analysis. Nine heart failure patients (8 men, 1 woman; mean age of 57.0 years) were identified. The average time between the cardiac MRI and radionuclide angiography exams was 38.9 days (range: 1 - 119 days). All patients undergoing cardiac MRI were scanned using an institutionally approved protocol for ICD with no device-related complications identified. A retrospective chart review of each patient for cardiomyopathy diagnosis, clinical follow-up, and echocardiogram and right heart catheterization performed during evaluation was also performed.ResultsThe 9 patients demonstrated a mean left ventricular ejection fraction (LVEF) using cardiac MRI of 20.7% (12 – 40%). Mean LVEF using MUGA was 22.6% (12 – 49%). The mean right ventricular ejection fraction (RVEF) utilizing cardiac MRI was 28.3% (16 – 43%), and the mean RVEF calculated by FPRNA was 32.6% (9 – 56%). The mean discrepancy for LVEF between cardiac MRI and MUGA was 4.1% (0 – 9%), and correlation of calculated LVEF using cardiac MRI and MUGA demonstrated an R of 0.9. The mean discrepancy for RVEF between cardiac MRI and FPRNA was 12.0% (range: 2 – 24%) with a moderate correlation (R = 0.5). The increased discrepancies for RV analysis were statistically significant using an unpaired t-test (t = 3.19, p = 0.0061). Echocardiogram parameters of RV function, including TAPSE and FAC, were for available for all 9 patients and agreement with cardiac MRI demonstrated a kappa statistic for TAPSE of 0.39 (95% CI of 0.06 – 0.72) and for FAC of 0.64 (95% of 0.21 – 1.00).ConclusionHeart failure patients are increasingly requiring left ventricular assist device placement; however, definitive evaluation of biventricular function is required due to the increased mortality rate associated with right heart failure after assist device placement. Our results suggest that FPRNA only has a moderate correlation with reference standard RVEFs calculated using cardiac MRI, which was similar to calculated agreements between cardiac MRI and echocardiographic parameters of right ventricular function. Given the need for identification of patients at risk for right heart failure, further studies are warranted to determine a more accurate estimate of RVEF for heart failure patients during pre-operative ventricular assist device planning.

Significant Physiologic and Hemodynamic Differences Between Adenosine with and without Low-level Treadmill Exercise in Patients Complaining of Dyspnea

PURPOSE: Adenosine with low-level treadmill exercise is preferred due to superior images and favorable side-effect profile. Surprisingly, little data exists on the hemodynamic effects of additional exercise on adenosine infusion in largely sedentary patients. First Pass Radionuclide Angiography (FPRNA) can simultaneously evaluate both ventricles, and pulmonary function at rest and at peak stress using well-validated non-invasive hemodynamic parameters. We used adenosine testing with and without exercise to evaluate consecutive patients presenting with dyspnea to determine the hemodynamic effects of the additional exercise.

Non-invasive hemodynamic evaluation of patients with LV dysfunction and intractable dyspnea with first pass radionuclide angiography: comparison with echocardiography

Introduction: Advanced heart failure is characterized by recurrent episodes of dyspnea with or without obvious signs of congestion and fluid retention. These patients have many potential cardiac and pulmonary causes for recurrent dyspnea and repeating an echo each time is often uninformative and frequently limited technically in CHF patients, particularly if significant pulmonary disease also exists. We therefore sought to use first pass radionuclide angiography (FPRNA) to non-invasively evaluate the hemodynamic status of these very symptomatic and failing patients. Methods: Consecutive patients with LV dysfunction and severe dyspnea underwent upright FPRNA after injection of 15-45 millicurie of sestamibi. Imaging was performed using a Sim-400 multicrystal camera. All hemodynamic data were based on acquired raw and derived data. Included patients also underwent echocardiography which was independently reviewed. Results: 52 patients (80% male) met criteria. Mean age 68.7 years. Mean LVEF by echo 29.7% and 32.2% by FPRNA (NS p=0.53). Mean RVEF by FPRNA was 43.85%. 65% had RVEF <40%. Peak LV filling was 1.41 +/− 0.58 (normal value is >2.5), suggesting marked diastolic dysfunction. Mean cardiac output was 6.2 and mean index was 3.2. The LV was markedly enlarged in this population reflecting advanced heart disease. Mean LV end diastolic volume was 230 cc and end systolic volume was 162cc, both values over twice the accepted normal range. 69.2% had MR by echo (21.2% were rated as 1+, 13.5% as 2+, 17.3% each as 3+ and 4+). Most importantly, the normalized mean pulmonary transit time (corrected for heart rate) was found to directly correlate with the degree of MR on echo (Spearman's rho 0.346, p=0.02). This has not been previously shown in severe CHF. Conclusion: In this study we sought to establish that reliable non-invasive hemodynamic data can easily be obtained from very symptomatic patients with LV dysfunction. The advantages of FPRNA are that patients are imaged upright and the results are quantitative. Accurate evaluation of MR is possible by normalizing the PMTT, thereby allowing this normally subjective echo data to be quantified and followed serially. In addition quantitative data on LV and RV systolic function, LV diastolic function and pulmonary circulation can be obtained and followed serially. By comparing such serial results, abnormalities in specific parameters may yield clues to whether dyspnea is of cardiac or pulmonary origin in severe CHF.

Semi-quantitative assessment of tibial blood flow and distribution in response to surgical intervention using first pass radionuclide angiography and intravascular vital dye

The acute vascular response in bone to surgical trauma was investigated utilizing a sheep model. Blood flow and distribution were determined using two methods; perfusion of the vasculature with an intravascular vital dye (Disulphine blue) prior to euthanasia and by radionuclide angiography (RNA) before and after each surgical intervention. The pattern of Disulphine blue distribution provided a good indication of local perfuslon and response to surgical trauma (drilling holes). Radionuclide angiography provided a dynamic image of the vascular response to surgical trauma. The generation of time activity curves of the first pass of radionuclide bolus enabled calculation of the relative blood flow through selected regions. For both techniques areas of ischaemia were apparent which were directly related to the location of screw holes. We conclude that factors other than bone plate contact influence the ischaemia that develops in bone subsequent to the application of bone plates.

HEMODYNAMIC RESPONSES WITH POSITIVE AND NEGATIVE HEART RATE DEFLECTION

1426 The relationship between cycle power output and HR during incremental exercise is usually (≈85% of cases) sinusodial, with a flattening (- def) of HR near peak exercise. Some individuals (10-15%) display a disproportionate increase in HR (+def). To determine whether there might be an overriding physiologic reason for this difference in pattern, we evaluated LV function in individuals with + (n=10) & - (n=10) def. LV function was measured during upright cycle exercise at ventilatory threshold (VT) and maximal effort (Max) using first pass radionuclide angiography TableTableAlthough there were trends for more negative responses in LVEF and a smaller normalized increase in SV in the +def group, there were no statistically significant differences between the groups. These data suggest that the different pattern of HR response between + and - def groups does not represent a compensatory mechanism to defend cardiac output in the presence of other abnormalities of LV function.

A prospective, randomised trial evaluating transatrial and transventricular approaches to repair of tetralogy of Fallot

AbstractThe traditional approach to repair of tetralogy of Fallot involves a right ventriculotomy for closure of ventricular septal defect. During the past two decades, reports of progressive right ventricular dilation and dysfunction, and late occurrence of ventricular arrhythmias, have led investigators to re-evaluate this approach and advocate instead the transatrial-transpulmonary approach, hoping to preserve global right ventricular function. We studied the short term effects on right ventricular function of either of the two approaches through a prospective randomised study, involving two comparable groups of patients operated in the same time frame.Between June 1993 and February 1994, 40 patients having tetralogy of Fallot with comparable preoperative characteristics, were assigned randomly to each of two groups for surgical correction.In 20 patients, correction was achieved via the transatrial-transpulmonary route. In the other 20 patients, transventricular correction was the chosen option. Six months after surgery, patients were evaluated clinically, by Doppler echocardiography, cardiac catheterisation, first pass radionuclide angiography and by 24 hours ambulatory electrocardiographic monitoring, taking note of hemodynamics, abnormalities in rhythm, and global right ventricular function.There were no early deaths or morbidity in either group. Mean immediate postoperative ratio between peak right ventricular and systemic pressures was 0.62 ± 0.22 after transatrial and 0.70 ± 0.007 after transventricular correction. All patients were in functional class I. Six months after surgery the mean ratio between peak ventricular pressures was similar in the two groups (transatrial group: 0.37 ± 0.02, transventricular group: 0.38 ( 0.01), but significantly lower than that measured in the operating room. There were no significant arrythmias in either group. Mean right ventricular ejection fraction was nearly the same in both groups (transatrial group versus transventricular group; 44.83 ± 5.65% versus 42.37 ± 8.70%). Significant global hypokinesia of the right ventricle was documented in three patients, and mild hypokinesia in another three, undergoing repair through the transventricular route while in the group undergoing transatrial repair only one patient had mild hypokinesia.We conclude that comparable hemodynamic results are obtained on short term follow-up after repair of tetralogy of Fallot by either the transatrial or transventricular route. Although more patients in the transventricular group were found to have global hypokinesia of the right ventricle, longer follow-up is necessary to establish the clinical relevence of these findings.

Measurement of right ventricular ejection fraction by contrast echocardiography

We evaluated 20 healthy subjects with no cardiac disease (8 males, 12 females, age 49±12) to determine the accuracy of right ventricular ejection fraction measurement with contrast echocardiography performed with d-galactose (Echovist 300). All patients underwent two dimensional echocardiography where the right ventricular ejection fraction was calculated by the Simpson's rule first without contrast, then after the injection of 5 ml d-galactose in the same position and compared to the right ventricular ejection fraction measured by the first pass radionuclide angiography on the same day. Subjects had a normal left ventricular ejection fraction of 66±5 and a body mass index of 28.9±1.2. The correlation between echocardiographic and radionuclide derived right ventricular ejection fraction significantly increased when contrast was used ( r=0.81 vs. r=0.6). The r value for interobserver variability also increased significantly with contrast use ( r=0.98 vs. r=0.7). We conclude that d-galactose contrast injection significantly enhances border detection and improves the accuracy of right ventricular ejection fraction calculations with echocardiography making it a simple and reliable method.

Accuracy of left ventricular ejection fraction measurement from gated Tc-99m-sestamibi myocardial SPECT: Validation with first pass radionuclide angiography (FPRA)

Accuracy of left ventricular ejection fraction measurement from gated Tc-99m-sestamibi myocardial SPECT: Validation with first pass radionuclide angiography (FPRA)

Pulmonary transit time and diffusion limitation during heavy exercise in athletes

To investigate relationships between pulmonary transit times (PTT) and pulmonary diffusion limitation during exercise, 10 high aerobic capacity athletes (V̇ O 2max = 5.15 ± 0.52 l · min −1) who had multiple inert gas elimination analysis evidence suggestive of diffusion disequilibrium were studied at rest and maximal exercise. Diffusing capacity for oxygen (D l O 2 ) was calculated from the inert gas data. First pass radionuclide angiography was performed using 99mTechnecium labeled erythrocytes and whole lung PTT and pulmonary blood volume (PBV) were calculated. PTT decreased from 9.32 ± 1.41 sec at rest, to 2.91 ± 0.30 sec during exercise and was correlated with diffusion limitation suggested by the inert gases (r = -0.58, P < 0.05). PBV increased during exercise to over 25% of whole blood volume and correlated with D l O 2 (r = 0.82, P < 0.01). These data suggest that diffusion limitation is related to shortened PTT in athletes and that maximal recruitment of PBV may defend against diffusion limitation.

Detection of early systolic dysfunction in ischemia by sequential radionuclide imaging of ejection rates

The effectiveness of sequential imaging of early regional left ventricular contraction in the detection of ischemic abnormalities was assessed in 47 patients (15 with previous infarction) with angiographically proven coronary artery disease, and 11 normal volunteers, undergoing first pass radionuclide angiography with a multielement gamma camera at rest and at peak exercise. Global left ventricular hemodynamic parameters, and functional images of regional ejection fraction and ejection rate were compared to 6 pairs of sequential rate images showing the decrease and the increase of regional left ventricular volume during a time-interval of 80-280 ms (at rest) and 50-175 ms (at stress) from end-diastole. Diagnostic accuracy of sequential images (67-91%) was higher than that of ejection rate image (71-72%), and of global hemodynamic parameters (33-60%), in the detection of coronary patients. Regional sensitivity of stress sequential increase and decrease image achieved 77% and 100%, respectively. During early systole sensitivity of stress sequential increase and decrease images approached 100% even at rest, subsequently decreasing because of normalizing contraction. Thus, the analysis of early systolic dysfunction provided by dynamic sequential functional images of ejection rates proved to be an effective diagnostic tool in the detection of myocardial ischemic dysfunction.

What's the Price to be Paid for Rate Response: AV Sequential Versus Ventricular Pacing?

The purpose of this study was to compare the effects of atrioventricular (AV) sequential and ventricular pacing at rest and during exercise on parameters of left ventricular performance. Twenty-five patients were studied by means of first pass radionuclide angiography. Pacing rates increased significantly (P less than 0.001) during exercise in both pacing modes, resulting in a significant increase in the cardiac index (P less than 0.001). Pulmonary transit times decreased significantly (P less than 0.001) during exercise in both pacing modes with a significantly shorter pulmonary transit time for AV sequential pacing at rest (P less than 0.01) and during exercise (P less than 0.05), indicating impaired left ventricular function in ventricular pacing. Regional left ventricular wall movement deteriorated significantly during exercise in both pacing modes (P less than 0.02), with a significantly worse performance during ventricular pacing at rest (P less than 0.05) and during exercise (P less than 0.05). Therefore, the price to be paid for rate response is a deterioration of regional wall movement. An additional loss of AV synchrony worsens the situation. It is concluded that rate modulated pacing requires preservation of AV coordination to optimize left ventricular performance.

Exponential fit of QT interval-heart rate relation during exercise used to diagnose stress-induced myocardial ischemia

The aim of this study was to analyze the dynamic changes of QT interval-heart rate relation during exercise, fitting their reciprocal variations to an exponential formula (QT = A − B · exp(−k · RR)), in order to see whether diagnostic contributions might so be derived. The authors studied 139 patients who underwent a simultaneous assessment of regional myocardial perfusion and ventricular function by means of two injections of 99mTc-methoxy-isobutyl-isonitrile at rest and at peak of a submaximal exercise test, using first pass radionuclide angiography with multielement gamma-camera and single photon emission computerized tomography, in order to detect and localize the presence of stress-induced myocardial ischemia. According to radionuclide results, patients were divided into three groups: group A, 7 individuals with no sign of stress-induced myocardial ischemia; group B, 79 patients with evidence of ischemia in 1 (16.5%), 2 (65.5%), or 3 (17.7%) main coronary territories; and group C, 53 patients with previous infarction and evidence of ischemia in other territories. Conventional analysis of the exercise test (≥0.1 mV ST depression) showed a pathological response in no individual of group A, in 34 patients of group B (43%), and in 27 patients of group C (50.9%); overall sensitivity was 46.2%, specificity 100%, and diagnostic accuracy 48.9%. Exponential coefficients A, B, and k showed wide overlap of values among the three groups, although a significant difference was present in mean k values between groups A and B (p < 0.001), and group C (p < 0.05). The algebraic sign of k was negative in 6 of 7 (85.7%) subjects of group A, in 11 of 79 patients of group B (13.9%), and in 10 of 53 patients of group C (18.9%). Using this criterion to define the response to exercise as abnormal overall sensitivity was 84.1%, specificity 85.7%, and diagnostic accuracy 84.2%. The sign of B and k coefficients represents the shift of the slope of the exponential curve relating QT interval (ie., the duration of the electrical systole) to heart rate (ie, the major determinant of myocardial oxygen consumption) during exercise. However, B values varied much interindividually, whereas k value variation was limited in the study group. Therefore, the change of k status might be indirectly related to the shift from aerobic to anaerobic metabolism, as supported by the higher sensitivity of the k coefficient to detect myocardial ischemia, in comparison to ST-segment depression. These results need now to be confirmed in larger series of patients, using multiparametric statistical analyses capable of accounting for the independent contribution of other variables that could theoretically affect QT interval changes during exercise.

Segmental analysis of SPECT99mTc-methoxy isobutyl isonitrile and201Tl myocardial imaging in ischaemic heart disease

To study the potential usefulness of 99mTc-methoxy isobutyl isonitrile (99mTc-MIBI) as a substitute for 201Tl in assessing patients with ischaemic heart disease, 24 patients underwent 1 day rest and exercise 99mTc-MIBI single photon emission computerised tomography (SPECT) 1 week after SPECT exercise 201Tl. All patients were catheterized within 1 month after myocardial imaging. In 17 patients, resting first pass radionuclide angiography (FPRNA) was performed with 99mTc-MIBI. The heart to lung ratio for 99mTc-MIBI and 201Tl was calculated both at rest and exercise. The segmental analysis for myocardial perfusion reveals that 87/96 segments (91%) were correctly classified by SPECT 201Tl and 84/96 segments (88%) were correctly classified by 99mTc-MIBI. A significant correlation was present between LVEF measured by 99mTc-MIBI FPRNA and contrast ventriculography (r = 0.85, P less than 0.0001). The heart to lung ratio both at rest and exercise for 99mTc-MIBI is significantly higher than 201Tl (P less than 0.01 and less than 0.001 respectively). We conclude that 99mTc-MIBI is a promising agent for simultaneous evaluation of myocardial perfusion and cardiac function.

Influence of respiratory variations on right ventricular function.

Respiratory effort during inspiration, expiration, and the Valsalva manoeuvre changes right ventricular preload and afterload. On inspiration these changes should improve systolic emptying of a larger end diastolic volume and so increase the ejection fraction, whereas on expiration the reverse should be true. The resting right ventricular ejection fraction was measured by first pass radionuclide angiography with gold-195m (half life 30.5 s) in 17 individuals at maximal inspiration and expiration and in eight at rest and during the strain phase (phase 2) of the Valsalva manoeuvre. The right ventricular ejection fraction was significantly lower during expiration than during inspiration. There were, however, no significant differences in bolus duration or right ventricular transit time. The Valsalva manoeuvre, in contrast, significantly increased the ejection fraction and also significantly prolonged both the bolus duration and right ventricular transit time. The conformation of the bolus curves during the Valsalva manoeuvre suggested the development of tricuspid regurgitation. These data suggest that relative influences of venous return, pulmonary arterial pressure, pulmonary vascular resistance, and possible functional tricuspid regurgitation vary during inspiration, expiration, and the Valsalva manoeuvre and can affect the right ventricular ejection fraction. Changes in right ventricular function on exercise assessed by first pass radionuclide angiography must be interpreted with caution because maximal respiratory effort may alter the right ventricular ejection fraction independently of ischaemia or other non-ischaemic factors.

Hemodynamic Effects of Labetalol in Patients with Combined Hypertension and Left Ventricular Failure

To investigate the safety of labetalol in the treatment of hypertension in patients with heart failure, sixteen hypertensive patients with a history of congestive heart failure and an ejection fraction at rest less than 45%, had measurements of ejection fraction and cardiac output by first pass radionuclide angiography at baseline, at the end of 2 weeks maintenance with labetalol (titrated to the effective antihypertensive dose of 200-1600 mg daily), and in the post-treatment placebo period. On labetalol, heart rate and blood pressure were significantly lower than placebo at rest and the ejection fraction was higher (30 vs 25%) (p less than 0.05). At maximal exercise on labetalol the heart rate and blood pressure were lower than at placebo maximal exercise (p less than 0.05) and the ejection fraction was higher (32 vs 27%) (p less than 0.01). Exercise tolerance was not changed by labetalol. No patient was discontinued from the study because of worsening heart failure. Dizziness was reported in 5 of 16 patients usually at one visit. Dyspnea that was reported in 4 of 16 patients improved with minor adjustments in digitalis or diuretic dose. In conclusion, labetalol reduces blood pressure in hypertensive patients with left ventricular dysfunction without reducing cardiac performance.

Oral Terbutaline Augments Cardiac Performance in Chronic Obstructive Pulmonary Disease

In previous research, we have demonstrated that parenterally administered terbutaline can augment resting cardiac function in patients with chronic obstructive pulmonary disease (COPD). Because the oral form of terbutaline is more widely utilized, a double-blind, randomized, crossover, placebo-controlled trial of the cardiopulmonary effects of oral terbutaline was conducted in ten patients with COPD. Right and left ventricular ejection fractions (RVEF and LVEF) were determined by first pass radionuclide angiography. There were no differences in spirometry and hemodynamic measurements between treatment and placebo days. Following 5 mg of oral terbutaline, there was a small but statistically significant increase in forced expiratory volume in 1 second and in heart rate, but no significant change in forced vital capacity or blood pressure. LVEF improved significantly with terbutaline both at rest (62% +/- 6% vs. 67% +/- 9%, mean +/- SD) and during submaximal steady state exercise (61% +/- 5% vs. 67% +/- 10%). RVEF improved significantly at rest (64% +/- 6% vs. 69% +/- 5%), but not during submaximal steady state exercise (65% +/- 6% vs. 68% +/- 7%). Thus, oral terbutaline produces significant improvement in biventricular systolic pump performance at rest, and increases left ventricular ejection fraction during submaximal exercise in patients with moderate to severe COPD.

Effects of nisoldipine on left ventricular function during exercise or cold pressor stress.

The effects of a single oral dose of nisoldipine, 10 mg, were investigated in two groups of patients. Firstly, the effects of nisoldipine on exercise left ventricular function were assessed in 20 patients with chronic stable angina and coronary disease. Secondly, the effects of nisoldipine on the left ventricular response to cold pressor stimulation were examined in 12 patients with normal coronary arteries, who presented with typical ischaemic chest pain and abnormal exercise tests. All studies were performed using first pass radionuclide angiography and the new short half-life radiopharmaceutical, gold-195m. In patients with coronary disease, mean exercise time improved after nisoldipine (P less than 0.01). Both at the identical workload to that before treatment, and at a new peak workload, mean exercise left ventricular ejection fraction (LVEF) improved significantly after nisoldipine (P less than 0.01 and P less than 0.05 vs pretreatment levels, respectively). At the identical workload to that before treatment, 10 of 16 patients, who had initially developed angina, did not develop angina after nisoldipine, and 23 of 46 exercise-induced regional left ventricular abnormalities had normalized. In the patients with normal coronary arteries undergoing cold pressor stimulation, imaging was carried out at rest, and after 1 and 2.5 minutes of cold stimulation, before and one hour after oral nisoldipine. LVEF fell significantly during cold stimulation before nisoldipine administration, with 10 of the 12 patients showing an abnormal response. Nisoldipine did not lead to any attenuation of the heart rate and blood pressure response to cold, but mean LVEF did not fall at any cold pressor stage and only three patients showed an abnormal response.(ABSTRACT TRUNCATED AT 250 WORDS)

Global and regional right ventricular function after acute myocardial infarction: dependence upon site of left ventricular infarction.

The relation of global and regional right and left ventricular function during the acute phase after a first myocardial infarction was assessed by first pass radionuclide angiography in 20 patients (10 after anterior and 10 after inferior myocardial infarction). The right ventricular ejection fraction did not differ significantly between the groups, but left ventricular ejection fraction was significantly depressed after anterior myocardial infarction. There was evidence of right ventricular dilatation and impaired transit in the group with inferior infarction. Five patients with anterior infarction and six with inferior infarction had abnormal right ventricular ejection fractions. Right ventricular wall motion abnormalities affected the septal wall in the group with anterior infarction and the free wall in the group with inferior infarction. The relation between right and left ventricular ejection fractions was markedly different in the two groups. In the group with anterior infarction there was a significant linear relation between right and left ventricular ejection fraction, whereas in the group with inferior infarction there was not. Thus right ventricular dysfunction commonly occurs after both anterior and inferior myocardial infarction. Right and left ventricular impairment are related after anterior myocardial infarction, but are independent after inferior myocardial infarction. Finally, the different effects of anterior and inferior myocardial infarction on right ventricular function may be explained by differences in septal and free wall involvement.

Sex differences in exercise induced left ventricular dysfunction in patients with syndrome X.

Clinical, electrocardiographic, and scintigraphic data were reviewed from 32 patients (18 men and 14 women) who had syndrome X (chest pain, evidence of ischaemia, and normal coronary arteries without coronary vasospasm). The mean (SD) resting left ventricular ejection fraction, determined by first pass radionuclide angiography was 62.6 (9.2)% and was greater than 50% in all subjects. There was no significant difference between men and women. On exercise, left ventricular ejection fraction decreased significantly to 57.4 (13.0)%. In 17 of 32 subjects there was a fall in left ventricular ejection fraction of greater than 5%, and regional wall motion abnormalities developed in 12 subjects. The fall in left ventricular ejection fraction on exercise was significant in women (from 61.9 (8.5)% at rest to 54.0 (9.8)% on exercise) but not in men (from 63.2 (9.8)% at rest to 60.0 (14.8)% on exercise). Exercise left ventricular ejection fraction fell by greater than 5% in 10 (71%) of 14 women and in seven (39%) of 18 men. Dyskinetic segments developed in eight (57%) of 14 women and only four (22%) of men. Exercise duration in women was significantly shorter than in men (4.1 (1.5) vs 6.6 (2.1) minutes) and was the only one of several clinical and scintigraphic variables that correlated with the change in left ventricular ejection fraction on exercise. In this selected group of subjects with chest pain and angiographically normal coronary arteries, exercise induced left ventricular dysfunction, as shown by a fall in ejection fraction or the development of regional abnormalities, is a common finding. These are more likely to occur in women than men and are associated with a lower exercise capacity. The data suggest that the sex of the patient is important in the interpretation of the non-invasive evaluation of subjects suspected of having syndrome X.

Relation between coronary anatomy and serial changes in left ventricular function on exercise: a study using first pass radionuclide angiography with gold-195m.

Serial changes in left ventricular function on exercise were assessed by first pass radionuclide angiography with gold-195m (half life 30.5 s) in 25 men with known coronary anatomy. In the seven patients with three vessel disease, abnormalities of global left ventricular function and regional wall motion occurred earlier during exercise, were of greater extent at peak exercise, and persisted longer after exercise than in the 11 patients with one and two vessel disease or the seven with normal coronary arteries. Although there were significant differences between the groups in absolute change in ejection fraction and the rate of change in ejection fraction related to exercise duration and heart rate, a considerable overlap of values between groups precluded the accurate prediction of coronary anatomy in individuals. These data suggest that the amount of myocardium at risk from ischaemia in some patients with one and two vessel disease may resemble that in patients with three vessel disease. This study shows that an anatomical classification based solely on the number of diseased vessels will not predict the extent of the impairment of left ventricular function on exercise.