Dipyridamole stress thallium-201 perfusion abnormalities in patients with hypertrophic cardiomyopathy. Relationship to clinical presentation and outcome

AIMS

Thallium-201 perfusion abnormalities are common in patients with hypertrophic cardiomyopathy and may be associated with an adverse prognosis in the young. The aim of this study was to prospectively determine the relationship between thallium-201 defects during dipyridamole stress to clinical presentation and outcome in a large consecutive series of patients with hypertrophic cardiomyopathy.

METHODS/RESULTS

Thallium-201 single photon computed tomography was performed in 216 patients with hypertrophic cardiomyopathy during dipyridamole stress (0.5 mg. kg-1). Fixed perfusion defects occurred in 25%, and reversible defects in 22%. A combination of defects was present in 7%. Fixed defects were associated with: a history of syncope (17 of 46 with, vs 36 of 170 without syncope, P = 0.03); larger left ventricular end-diastolic (46.9 +/- 7.4 mm vs 43.3 +/- 6.4 mm; P = 0.001) and end-systolic dimension (30.2 +/- 8.4 mm vs 24.5 +/- 5.9 mm, P < 0.0001); increased left atrial diameter (46.1 +/- 8.1 mm vs 40.5 +/- 7.7 mm, P < 0.0001); lower fractional shortening (35.9 +/- 10.4% vs 43.8 +/- 8.6%, P < 0.0001): and lower maximal exercise oxygen consumption (24.2 +/- 8.1 ml. min-1. kg-1 vs 29.4 +/- 8.8 ml. min-1. kg-1, P < 0.0003). Reversible defects did not correlate with symptomatic status, but were associated with: larger left atrial dimensions (44.5 +/- 8.1 mm vs 41.0 +/- 8.0 mm; P = 0.009) and greater maximal left ventricular wall thickness (24.0 +/- 7.0 mm vs 20.6 +/- 7.0 mm, P = 0.003). The mean follow up time was 41 +/- 21 months, range 0.6-124. There was no association between any thallium-201 abnormality and disease related death in young or adult patients.

CONCLUSION

The present study shows that fixed thallium-201 perfusion defects detected during dipyridamole stress in patients with hypertrophic cardiomyopathy are associated with syncope, larger left ventricular cavity dimensions and reduced exercise capacity. Although the event rate was relatively small, there was no evidence for an association between thallium-201 defects and survival.

Low dose imipramine improves chest pain but not quality of life in patients with angina and normal coronary angiograms

AIMS

We investigated patients with chest pain and normal coronary angiograms to determine whether low dose imipramine prescribed as add-on therapy to conventional anti-anginals reduced the incidence of chest pain and whether this led to an overall improvement in quality of life.

METHODS AND RESULTS

We performed a randomized, double-blind, cross-over trial of imipramine 50 mg daily vs placebo in 18 women (median age 53 years; range 35-72) with chest pain and normal coronary angiograms who were suffering at least two anginal episodes per week despite conventional anti-anginal medication. Each treatment phase lasted 5 weeks and the incidences of chest pain and side effects were carefully recorded. Quality of life was monitored using a validated health profile questionnaire scoring perceived distress in six domains (pain, energy, mobility, sleep, emotional reactions and social isolation). The total number of chest pain episodes was significantly less during active treatment compared to placebo [11 (3-22) vs 21 (16-28)--median (interquartile range); P = 0.01]. However, a high incidence (83%) of side effects was reported during active treatment and three patients had to be withdrawn from the study as a consequence. No significant improvement was detected in any of the six quality of life domains when imipramine was compared to placebo.

CONCLUSION

Imipramine reduces the incidence of chest pain in patients with chest pain and normal coronaries who remain symptomatic despite conventional anti-anginal therapy. The failure to demonstrate associated improvements in quality of life may have been due to the high incidence of side effects.

Serum endothelin levels and pain perception in patients with cardiac syndrome X and in healthy controls

The possible algogenic effects of elevated serum endothelin levels in cardiac syndrome X were investigated in a case-control study that examined somatic pain perception in the forearm during submaximal effort tourniquet and cold immersion tests. Pain threshold to both ischemic and cold stimulation of the forearm was demonstrated to be significantly lower in patients with syndrome X than in matched healthy controls, and a negative correlation between ischemic pain threshold and endothelin levels was demonstrated.

Effect of magnesium sulphate in patients with unstable angina. A double blind, randomized, placebo-controlled study

AIMS

Administration of intravenous magnesium sulphate has been shown to be protective during acute myocardial ischaemia and it may therefore have beneficial effects in unstable angina. The purpose of this study was to assess the effects of a 24-h infusion of magnesium in patients with unstable angina.

METHODS AND RESULTS

Patients who presented with unstable angina with electrocardiographic changes were randomized to receive a 24-h intravenous infusion of magnesium or placebo within 12 h of admission. The primary endpoint was myocardial ischaemia, as assessed by 48 h Holter monitoring. Resting 12-lead ECGs, creatine kinase-MB release and urinary catecholamines were also assessed. Patients were followed for 1 month. Thirty-one patients received magnesium sulphate and 31 placebo. Baseline characteristics and extent of coronary disease were similar in both groups. On 48 h Holter monitoring, 14 patients (50%) had transient ST segment shifts in the magnesium group vs 12 patients (46%) in the placebo group. However, there were fewer ischaemic episodes in the magnesium group (51 vs 101, P < 0.001) and there was a trend towards an increase in the total duration of ischaemia in the placebo group compared to the magnesium group in the second 24 h (2176 min vs 719 min respectively, P = 0.08). Regression of T wave changes on the 24 h ECG occurred more frequently in patients who received magnesium compared to those treated with placebo (11 patients vs 0 patients respectively, P < 0.005). Creatine kinase-MB release was significantly less at 6 and 24 h in patients who received magnesium compared to those treated with placebo. Catecholamine excretion was lower in patients treated with magnesium than in those treated with placebo (adrenaline: 1.05 +/- 0.16 vs 1.61 +/- 0.32 ng.mmol-1 creatinine; noradrenaline: 9.99 +/- 1.82 vs 18.48 +/- 2.41 ng.mmol-1 creatinine respectively in the first 12 h sample, P < 0.05).

CONCLUSIONS

Intravenous magnesium reduces ischaemic ECG changes, creatine kinase-MB release and urinary catecholamine excretion in the acute phase of unstable angina. Thus, magnesium may be a beneficial additional therapy for these patients. Further studies are required to confirm these finding.

Elevated Chlamydia pneumoniae antibodies, cardiovascular events, and azithromycin in male survivors of myocardial infarction

BACKGROUND

The clinical significance of the association between elevated anti-Chlamydia pneumoniae (Cp) antibody titres and coronary heart disease (CHD) is unclear. We explored the relationship between antibodies against Cp and future cardiovascular events in male survivors of myocardial infarction (MI). The effect of azithromycin antibiotic therapy was assessed in a subgroup of post-MI patients.

METHODS AND RESULTS

We screened 220 consecutive male survivors of MI for anti-Cp antibodies. Of these, 213 patients were stratified into three groups: group Cp-ve (n=59), no detectable Cp antibodies; group Cp-I (n=74), intermediate titres of 1/8 to 1/32 dilution; and group Cp+ve (n=80), seropositive at > or = 1/64 dilution. Patients with persisting seropositivity of > or = 1/64 were randomized to either oral azithromycin (Cp+ve-A, 500 mg/d for 3 days [n=28] or 500 mg/d for 6 days [n=12]) or placebo (Cp+ve-P, n=20). Cp+ve-NR (n=20) represented patients not recruited into the antibiotic trial. The incidence of adverse cardiovascular events (over a mean follow-up period of 18+/-4 months) was recorded and shown to increase with increasing anti-Cp titre: Cp-ve, n=4 (7%); Cp-I, n=11 (15%); Cp+ve-NR, n=6 (30%); and Cp+ve-P, n=5 (25%). Cp+ve-NR and Cp+ve-P groups had a fourfold-increased risk for adverse cardiovascular events compared with the Cp-ve group (odds ratio [OR], 4.2; 95% confidence interval [CI], 1.2 to 15.5; P=.03). In contrast, the OR for cardiovascular events in patients receiving azithromycin (Cp+ve-A, single or double course) was the same as in the Cp-ve group (OR, 0.9; 95% CI, 0.2 to 4.6, P=NS). Patients receiving azithromycin were more likely to experience a decrease in IgG anti-Cp titres than were those in the placebo group (P=.02).

CONCLUSIONS

An increased anti-Cp antibody titre may be a predictor for further adverse cardiovascular events in post-MI patients. Taking a short course of azithromycin may lower this risk, possibly by acting against Cp.

Effect of oral aminophylline in patients with angina and normal coronary arteriograms (cardiac syndrome X)

BACKGROUND

Patients with syndrome X (exertional angina, positive exercise test, normal coronary arteriogram) have an altered perception of cardiac pain. This symptom may arise from increased sensitivity to adenosine. Previous studies suggest that intravenous aminophylline (an adenosine receptor blocker) improves exercise tolerance in patients with this disorder.

OBJECTIVE

To examine the efficacy of oral aminophylline in syndrome X.

METHODS

13 patients (11 women and two men, mean (SD) 54 (6) years) with syndrome X were studied. Patients were randomised in a double blind crossover study to receive either oral aminophylline or placebo for three weeks. All patients underwent symptom limited exercise testing and ambulatory electrocardiography at the end of each three week period.

RESULTS

10 patients completed the study. The time to angina during exercise testing in patients who were given aminophylline was longer than for the placebo group (mean (SD) 632 (202) seconds v 522 (264) seconds, P = 0.004). Peak exercise ST depression did not differ significantly between patients who received aminophylline and those administered placebo (mean (SD) -1.9 (0.7) mm v -1.5 (0.8) mm). Six patients taking aminophylline reported a reduction in the total number of episodes of chest pain during the three weeks, but the frequency and duration of ST segment depression during Holter monitoring was unchanged.

CONCLUSION

Oral aminophylline has a favourable effect on exercise induced chest pain threshold in patients with syndrome X. The disparate effects on symptoms and ST segment changes are intriguing and further study is warranted.

Endothelial dysfunction in the absence of coronary atheroma causing Prinzmetal's angina

Images

[The polymorphism of the angiotensin I-converting enzyme gene and its association with ischemic cardiopathy]

The role played by angiotensin in the development of coronary heart disease is a subject of increasing interest. This interest is due to the results of several trials suggesting that treatment with angiotensin I-converting enzyme inhibitors decrease the incidence of clinical manifestations of coronary heart disease. The relationship between angiotensin and coronary heart disease is being analyzed both from basic and clinical approaches. As a result of such investigations, a polymorphism in the angiotensin converting enzyme gene has been described and the role of this polymorphism as a possible risk factor for coronary heart disease has been reported. In this paper the current knowledge about the angiotensin-converting enzyme gene is reviewed and its relationship with coronary heart disease is discussed.

Coronary stenosis progression differs in patients with stable angina pectoris with and without a previous history of unstable angina

OBJECTIVES

To compare the evolution of stenoses responsible for acute coronary events with those not associated with acute coronary syndromes.

METHODS AND RESULTS

We prospectively studied angiographic stenosis progression in 190 stable angina patients, with single vessel disease, who were awaiting non-urgent coronary angioplasty. Sixty four patients had a previous history of unstable angina (Group 1) and 126 patients had no history of unstable angina (Group 2). Culprit stenoses were classified as "complex' or "smooth'. At restudy, 8 +/- 4 months after the first angiogram, 12 of 63 culprit stenoses in Group 1 had progressed and seven of 125 in Group 2 (19% vs 6%, P = 0.0044). Thirteen of 68 complex culprit stenoses had progressed, compared with only 6 of 120 smooth culprit stenoses (19% vs 5%, P = 0.003). Coronary events occurred in 12 Group 1 patients and nine Group 2 patients (P = 0.02).

CONCLUSIONS

In patients with stable angina, stenoses associated with previous episodes of unstable angina are more likely to progress than stenoses not associated with previous unstable angina. Unstable coronary atherosclerotic plaques, even those that have been clinically stable for more than 3 months, may retain the potential for rapid progression to total occlusion.

Differential progression of complex culprit stenoses in patients with stable and unstable angina pectoris

OBJECTIVES

This study sought to compare the evolution of complex culprit stenoses in patients with stable and those with unstable angina pectoris.

BACKGROUND

Complex coronary stenoses are associated with adverse clinical and angiographic outcomes. However, it is not known whether the evolution of complex stenoses differs in unstable angina versus stable angina pectoris.

METHODS

We prospectively assessed stenosis progression in 95 patients with unstable angina whose angina stabilized with medical therapy (Group 1) and 200 patients presenting with stable angina (Group 2). After diagnostic angiography, all patients were placed on a waiting list for coronary angioplasty and restudied at 8 +/- 4 (mean +/- SD) months later. In each patient the presumed culprit stenosis was identified and classified as complex (irregular borders, overhanging edges or thrombus) or smooth (absence of complex features). Stenosis progression, as assessed by computerized angiography, was defined as > or = 20% diameter reduction or new total occlusion.

RESULTS

At the first angiogram, 364 stenoses > or = 50% and 383 stenoses < 50% were identified. At restudy, 36 (15%) of 236 stenoses progressed in 29 Group 1 patients and 36 (7%) of 502 stenoses in 31 Group 2 patients (p = 0.001). Forty-five (88%) of 51 stenoses > or = 50% and 6 (29%) of 21 stenoses < 50% that progressed developed to total coronary occlusion (p = 0.001). More culprit stenoses progressed in Group 1 than in Group 2 (p = 0.006), whereas progression of nonculprit stenoses was not significantly different in both groups. Culprit complex stenoses progressed more frequently in Group 1 than in Group 2 (p = 0.01). During follow-up, 3 patients died (myocardial infarction), and 51 had a nonfatal coronary event. Culprit stenoses progressed in 15 (54%) of the 28 patients with a nonfatal coronary event in Group 1 and in 9 (39%) of 23 patients in Group 2 (p = NS). Complex morphology (p < 0.001) and unstable angina at initial presentation (p < 0.01) were predictive factors for progression of culprit stenoses.

CONCLUSIONS

A larger proportion of culprit complex stenoses progress in unstable angina than stable angina, and this is frequently associated with recurrence of coronary events.

The natural history of unheralded complex coronary plaques

OBJECTIVES

This study sought to assess the behavior of unheralded complex lesions in patients with no previous history of acute coronary ischemia.

BACKGROUND

Angiographically complex coronary stenoses appear to originate from plaque disruption and are associated with rapid progression early and late after acute coronary events. Complex lesions may occur without symptoms, but neither the incidence nor the behavior of these unheralded complex lesions is known.

METHODS

We studied 222 patients with chronic stable angina who were on a waiting list for single-vessel percutaneous transluminal coronary angioplasty of an unoccluded lesion and underwent repeat angiography immediately before the procedure as part of routine practice or shortly after a coronary event. Patients with a previous episode of myocardial infarction or unstable angina were not included. Angiograms were analyzed quantitatively and qualitatively using established methods. A change of +/- 15% stenosis severity or total coronary occlusion defined categoric change.

RESULTS

At first angiography, there were 52 unheralded complex target lesions (23%) and 170 smooth target stenoses (77%). Stenosis severity did not differ between complex and smooth target lesions at first and second angiography at a mean (+/- SD) interval of 7 +/- 4 months. At follow-up, seven complex lesions had progressed (14%) compared with six smooth lesions (4%, p < 0.02). Total occlusion developed in four complex lesions and one smooth lesion. Overall, complex stenoses progressed by 3 +/- 13% compared with 0.5 +/- 7% in the smooth stenoses (p = 0.15). Complex stenoses were 4.2 times more likely to progress than smooth stenoses (95% confidence interval 1.2 to 15.2 [Cornfields method]). Clinical events developed in seven patients. One complex lesion regressed and became smooth, and three smooth stenoses became complex at follow-up.

CONCLUSIONS

Morphologically complex stenosis can develop without an episode of acute coronary ischemia and are relatively common in patients awaiting single-vessel angioplasty. Our study demonstrates that like their clinically heralded counterparts, these unheralded complex stenoses are at higher risk of progression than smooth stenoses.

Failure to demonstrate myocardial ischaemia in patients with angina and normal coronary arteries. Evaluation by continuous coronary sinus pH monitoring and lactate metabolism

BACKGROUND

Whether myocardial ischaemia is the mechanism underlying chest pain in patients with angina and normal coronary arteriograms is controversial. We sought to detect the presence of transient myocardial ischaemia using continuous monitoring of coronary sinus blood pH during atrial pacing.

METHODS AND RESULTS

We studied 14 patients (eight women, six men, mean age 51 +/- 3 years) with typical exertional angina and normal coronary arteriograms and nine patients with coronary artery disease (two men, seven women, mean age 61 +/- 7 years). Of the 14 patients with normal coronary arteries, eight had a reduced coronary blood flow reserve (< 2.5-fold increase), 11 had an ischaemic-appearing response to exercise testing, six had reversible perfusion detects on exercise thallium scans and one had resting left bundle branch block. All patients underwent continuous pH monitoring of coronary sinus blood at rest and during incremental atrial pacing (up to 160 bpm). Coronary sinus oxygen saturation and myocardial lactate extraction ratio were also evaluated at rest and at peak pacing. Eleven patients with angina and normal coronary arteries and eight with coronary artery disease had angina during pacing. Both patients with angina and normal coronary arteries (n = 13) and patients with coronary artery disease (n = 9) showed a fall in coronary sinus pH (-0.02 +/- 0.02 vs -0.11 +/- 0.03 pH units, respectively, P < 0.01). Coronary sinus oxygen saturation expressed as a percentage dropped by 19 +/- 6% in patients with coronary artery disease and by 6 +/- 2% in patients with angina and normal coronary arteriograms (P < 0.05). Myocardial lactate extraction ratio decreased from 33 +/- 6% to -1.4 +/- 4% in patients with coronary artery disease and from 23 +/- 8% to 20 +/- 8% in those with angina and normal coronary arteriograms. Three patients with angina and normal coronary arteries had a drop in coronary sinus pH > 0.02 pH units (-0.043 +/- 0.006 pH units) and in coronary sinus oxygen saturation > 8% (16 +/- 3%) consistent with myocardial ischaemia.

CONCLUSION

Despite severe chest pain and reduced coronary flow reserve after pacing, most patients with angina and normal coronary arteriograms do not show metabolic evidence of myocardial ischaemia.

Chest pain during daily life in patients with hypertrophic cardiomyopathy: an ambulatory electrocardiographic study

Patients with hypertrophic cardiomyopathy frequently complain of chest pain during daily activities. ST-segment depression is described in association with sudden death and pacing, but its prevalence during ambulatory electrocardiographic monitoring is unknown. The aim of this study was to determine the relation of ambulatory ST-segment depression to clinical characteristics, risk factors for sudden death and thallium-201 perfusion in patients with hypertrophic cardiomyopathy. Continuous 48 h ambulatory electrocardiographic monitoring was performed in 113 patients (age 38 +/- 14 years) with hypertrophic cardiomyopathy. Ninety-four (83%) recordings were suitable for ST-segment analysis. A total of 109 episodes of ST-segment depression (> or = 1 mm from baseline) were recorded in 25 (27%) patients (mean 4 +/- 5). In patients < or = 30 years of age (but not > 30) there was an association between ST-segment depression and a history of exertional chest pain (seven of 12 vs one of 20; P = 0.001), and dyspnoea NYHA class II/III (seven of 15 vs one of 17; P = 0.008). There was no association between ST-segment depression and risk markers for sudden death, i.e. family history of sudden death, syncope and non-sustained ventricular tachycardia, in any group. Reversible thallium-201 defects occurred in 27 (29%) of the 94 patients with analysed recordings but were not associated with symptoms, risk factors for sudden death or ambulatory ST-segment depression. In young patients with hypertrophic cardiomyopathy, ischaemia-like ST-segment depression is common and is associated with a history of typical angina and dyspnoea. Reversible thallium-201 perfusion defects are associated with neither symptomatic status nor ambulatory ST-segment depression.

Plasma immunoreactive endothelin concentration correlates with severity of coronary artery disease in patients with stable angina pectoris and normal ventricular function

OBJECTIVES

The present study tested the hypothesis that plasma immunoreactive endothelin concentration correlates with the severity and extent of coronary atherosclerosis.

BACKGROUND

Plasma endothelin-1 concentration is increased in patients with unstable coronary syndromes and advanced atherosclerosis. This finding, together with other clinicopathologic observations, suggests that endothelins may participate in the atherogenic process. However, the relation between plasma immunoreactive endothelin and coronary artery disease in patients with stable angina pectoris remains controversial.

METHODS

Ninety consecutive patients undergoing coronary angiography for the investigation of exertional chest pain and 49 normal control subjects were prospectively studied. Eleven patients had normal coronary angiographic findings (group I), 65 had coronary artery stenoses (group II), and 14 had coronary artery disease plus symptoms indicating atheroma in other vascular territories (group III). Computerized angiography was used to determine the extent, severity and morphology of coronary stenoses. Plasma immunoreactive endothelin was measured by radioimmunoassay.

RESULTS

Mean (+/- SD) plasma endothelin concentration (pg/ml) was significantly higher in patients than in control subjects (7.29 +/- 4.07 vs. 3.48 +/- 1.29, p < 0.0001). Endothelin levels were higher in patients of group III than in those of groups II and I (9.43 +/- 5.48, 7.20 +/- 3.72 and 4.94 +/- 2.89, respectively, p = 0.02). In patients of group II, plasma endothelin correlated with the maximal degree of stenosis in each patient (r = 0.25, p = 0.04) and with the number of stenoses with > or = 70% diameter narrowing (r = 0.36, p = 0.002). The highest plasma endothelin levels were found in patients with total occlusions (8.65 +/- 3.78 vs. 6.46 +/- 3.51 p = 0.02).

CONCLUSIONS

Plasma immunoreactive endothelin concentration is increased in patients with chronic stable angina. The higher levels occur in patients with severe stenoses and total coronary occlusion.

Myocardial beta-adrenoceptor density and plasma catecholamines in syndrome X

Recent research has cast doubt on the ischemic hypothesis of etiology of syndrome X (anginal pain, ischemic-like changes in the stress electrocardiogram, but normal coronary arteriogram). Abnormalities of pain perception have been shown and abnormal sympathetic nervous system activation has also been implicated. The aim of this study was to test the hypothesis that downregulation of myocardial beta adrenoceptors is demonstrable in patients with syndrome X. Such downregulation would be consistent with raised myocardial catecholamine concentrations. We performed positron emission tomography with (11)C-CGP-12177 to measure beta-adrenoceptor density. Plasma catecholamines were sampled simultaneously and assayed using high-performance liquid chromatography. Twenty syndrome X patients (11 female, age 57 +/- 9 SD years, range 33 to 69) and 18 matched controls (9 women, age 50 +/- 13 years, range 25 to 65; p = NS vs patients) were studied. Myocardial beta-adrenoceptor density did not differ between syndrome X patients and controls: 8.0 (1.9) pmol/g for patients versus 8.3 (2.1) pmol/g for controls; p = 0.62. No differences were found between patients and controls for plasma norepinephrine (2.82 [1.07] and 2.76 [1.18] nM, respectively; p = 0.89) or for epinephrine (0.29 [0.14] and 0.30 [0.20] nM, respectively; p = 0.84). In patients with syndrome X, beta-adrenoceptor density is normal and, by inference, myocardial catecholamines would also be normal. This weakens the case for a generalized enhancement of sympathetic activation in this disorder, although increased sympathetic reactivity during actual episodes of chest pain remains a possibility.

Low-dose cyclosporine treatment fails to prevent coronary luminal narrowing after heart transplantation

BACKGROUND

Cyclosporine has been reported to induce endothelial dysfunction, arterial vasculitis, and accelerated atherosclerosis in experimental models. The purpose of the present study was to evaluate whether low-dose cyclosporine treatment started 1 year after heart transplantation reduces graft coronary artery narrowing compared with conventional cyclosporine doses.

METHODS

One year after heart transplantation, 30 patients were randomly assigned to receive low-dose cyclosporine A (whole-blood polyclonal cyclosporine target trough levels 200 to 400 micrograms/L; group A; n = 15) or usual cyclosporine dosage (target levels 400 to 600 micrograms/L; group B; n = 15). Proximal and distal diameters of the left anterior descending, circumflex, and right coronary arteries were measured by quantitative coronary angiography at baseline (1 year after transplantation) and at 2 and 3 years after transplantation.

RESULTS

One major cardiac event occurred in group A (retransplantation) and two in group B (sudden deaths). Moderate to severe allograft rejection (International Society for Heart and Lung Transplantation score 3A or higher) occurred in seven patients in group A and five in group B during the study period. Mean biopsy sample rejection score during the same period was increased in group A compared with that in group B (1.44 +/- 0.63 versus 1.05 +/- 0.59; p < 0.05). New angiographic evidence of vascular disease was observed in four patients of group A and in one patient of group B. Proximal coronary artery diameter was slightly, although not significantly, reduced in both groups at follow-up angiography. Distal segments showed a significant diameter reduction, which was greater in group A than in group B (-9.7% +/- 1.1% and -5.2% +/- 1.3%, respectively; p < 0.05).

CONCLUSIONS

Cyclosporine dose reduction started 1 year after heart transplantation is ineffective in reducing coronary luminal narrowing and may be associated with an increased prevalence of cardiac allograft vasculopathy, especially in the distal coronary tree. Low-dose cyclosporine treatment may slightly enhance the risk of allograft rejection. Further investigations are needed to evaluate the effects of cyclosporine dose reduction started at an earlier time after heart transplantation.

Factor V Leiden polymorphism (FV Q506) in patients with ischaemic heart disease, and in different populations groups

A point mutation in the factor V gene (FV Q506) renders factor V resistant to inactivation by activated protein C. The frequency of this mutation is known to be significantly increased in patients with thrombophilia. There are conflicting reports on the significance of the polymorphism in patients with ischaemic heart disease. We determined the frequency of FV Q506 in a control Caucasian population, and compared it with 192 Caucasian patients admitted to coronary care and assessed as having myocardial infarction (MI) or unstable angina plus previous MI. There was no significant difference between the two groups. A cohort of 105 asymptomatic Afro-Caribbeans showed a much reduced frequency of the polymorphism.

Transient autonomic dysfunction precedes ST-segment depression in patients with syndrome X

Increased sympathetic drive has been suggested to play a role in the pathogenesis of syndrome X (angina pectoris, positive exercise testing, and angiographically normal coronary arteries). Heart rate variability (HRV) studies have shown that patients with syndrome X have an imbalance in autonomic nervous system activity (sympathetic predominance). However, it is not known if transient ST-segment depression which occurs in syndrome X during daily activities is related to this autonomic nervous system dysfunction. This study investigates the relation between the response of the autonomic nervous system, as assessed by HRV analysis, and the occurrence of transient ST-segment depression during 24-hour ambulatory electrocardiographic monitoring in 23 patients (4 men and 19 women, mean age 55 +/- 6 years) with syndrome X. The frequency-domain variables of HRV low-frequency (0.04 to 0.15 Hz) and high-frequency (0.15 to 0.40 Hz) power were measured at 6-minute intervals during the 30 minutes preceding the onset of transient ST-segment depression. Fourteen patients (61%) had > or = 1 episode of ST-segment depression in the 24 hours, whereas the remaining 9 patients (39%) had no significant ST-segment change. HRV measures differed according to whether or not ST-segment depression was associated with increased heart rate. Episodes of ST-segment depression associated with increased heart rate were preceded by a reduction of high-frequency power and an increase in the low-frequency--high-frequency ratio, whereas episodes of ST-segment depression not associated with increased heart rate showed no significant HRV changes. Low-frequency power remained unchanged irrespective of heart rate. Thus, in patients with syndrome X, a sympathovagal imbalance (sympathetic predominance due to vagal tone withdrawal) precedes episodes of ST-segment depression that are associated with an increased heart rate.

Angiotensin-converting enzyme insertion/deletion polymorphism in angina pectoris with normal coronary arteriograms

We investigated the relation between angiotensin-converting enzyme gene insertion/deletion polymorphism and syndrome X (angina with normal coronary arteriogram). The results of our study suggest that this polymorphism does not play a major role in the pathogenesis of microvascular angina.

Changes in coronary sinus pH during dipyridamole stress in patients with hypertrophic cardiomyopathy

OBJECTIVES

The presence of angina pectoris and myocardial scarring in patients with hypertrophic cardiomyopathy (HCM) suggests that myocardial ischemia is a factor in the pathophysiology of the disease. The clinical evaluation of ischaemia is problematic in HCM as baseline electrocardiographic abnormalities are frequent and thallium-201 perfusion abnormalities correlate poorly with anginal symptoms. Coronary sinus pH measurement using a catheter mounted pH electrode is a validated sensitive technique for the detection of myocardial ischaemia.

METHODS AND RESULTS

11 patients with HCM and chest pain (eight men; mean (SD) (range) age 36 (11) (19-53) years) and six controls (two men; mean (SD) (range) age 49 (11) (31-62) years) with atypical pain and normal coronary angiograms were studied. Eight patients with HCM had baseline ST segment depression of > or = 1 mm and four had reversible perfusion defects during stress 201TI scintigraphy. A catheter mounted hydrogen ion sensitive electrode was introduced into the coronary sinus and pH monitored continuously during dipyridamole infusion (0.56 mg/kg over four min). The maximal change in coronary sinus pH during dipyridamole stress was greater in patients with HCM than in controls (0.082 (0.083) (0 to -0.275) v 0.005 (0.006) (0 to -0.012), P = 0.02). In six patients (four men; mean (SD) (range) age 29 (9) (19-40 years) the development of chest pain was associated with a gradual decline in coronary sinus pH (mean 0.123 (0.089)), peaking at 442 (106) s. There were no relations among left ventricular dimensions, maximal wall thickness, and maximum pH change. In patients with HCM there was a correlation between maximum pH change and maximum heart rate during dipyridamole infusion (r = 0.70, P = 0.02).

CONCLUSION

This study provides further evidence that chest pain in patients with HCM is caused by myocardial ischaemia. The role of myocardial ischaemia in the pathophysiology of the disease remains to be determined but coronary sinus pH monitoring provides a method for quantifying and prospectively assessing its effects on clinical presentation and prognosis.

Concentration of circulating plasma endothelin in patients with angina and normal coronary angiograms

BACKGROUND

Some patients with angina pectoris and normal coronary arteriograms have reduced coronary flow reserve and abnormal endothelium dependent vasodilator responses. Endothelin-1 (ET-1), a potent vasoconstrictor, is an important modulator of microvascular function and may also have algogenic properties.

METHOD

Plasma ET-1 was measured in peripheral venous blood in 40 patients (30 women) (mean (SD) age 56 (8) years) with angina and normal coronary arteriograms and 21 normal controls (17 women) (mean (SD) age 53 (7) years). Patients with systemic hypertension, left ventricular hypertrophy, or coronary spasm were excluded. Plasma ET-1 was measured using radioimmunoassay.

RESULTS

Thirty five patients had > or = 1 mm ST segment depression during exercise. Left bundle branch block was present in four patients at rest and in one during exercise. Mean (SD) (range) concentration of ET-1 (pg/ml) was higher in patients than in controls (3.84 (1.25) (1.97-7.42) v 2.88 (0.71) (1.57-4.48) P < 0.0001). In patients with "high" (> control mean (one SD)) ET-1 concentrations (n = 23), the time to onset of chest pain during exercise was significantly shorter (6.21 (3.9) v 9.03 (3.9) min; p = 0.01) than in patients with "low" ET-1 concentrations. Of the five patients with left bundle branch block, four had plasma ET-1 concentration > 4.0 pg/ml.

CONCLUSION

Plasma endothelin is raised in patients with angina and normal coronary arteriograms and is consistent with the demonstration of endothelial dysfunction in such patients. The association between "high" plasma ET-1 and an earlier onset of chest pain during exercise suggests that endothelin may also have a role in the genesis of chest pain in patients with normal coronary arteries.

Angina pectoris and normal coronary arteriograms: clinical presentation and hemodynamic characteristics

Up to 30% of patients undergoing coronary angiography for the assessment of chest pain suggestive of coronary artery disease have "normal" studies. Several reports have indicated that a proportion of patients with angina and normal coronary arteriograms have reduced coronary flow reserve. The interpretation of these findings is, however, controversial as the majority of patients do not have definitive evidence for myocardial ischemia and have a good long-term prognosis. The clinical presentation of patients with angina and normal coronary arteriograms differs in different series and this may be just a reflection of the heterogeneous nature of the syndrome. A diversity of pathogenetic mechanisms have been postulated to explain "syndrome X" (chest pain and normal coronary arteriograms) but little is known at present about the true nature of the syndrome. The present article discusses the clinical and hemodynamic features of this intriguing disorder with particular reference to patients with syndrome X and microvascular angina.

Rapid angiographic progression of coronary artery disease in patients with angina pectoris. The role of complex stenosis morphology

BACKGROUND

Rapid disease progression commonly underlies acute coronary events, and "complex" stenosis morphology may play a role in this phenomenon.

METHODS AND RESULTS

We studied the role of complex stenosis morphology in rapid disease progression in 94 consecutive patients awaiting routine coronary angioplasty. Coronary arteriography was repeated at 8 +/- 3 months' follow-up, immediately preceding angioplasty (68 patients) or after an acute coronary event (26 patients). Disease progression of 217 stenoses, of which 79 (36%) were "complex" and 138 (64%) were "smooth," was assessed by computerized angiography. At presentation, 63 patients had stable angina pectoris and 31 had unstable angina that settled rapidly with medical therapy. At follow-up, 23 patients (24%) had progression of preexisting stenoses and 71 (76%) had no progression. Patients with progression were younger (55 +/- 12 years) than those without (58 +/- 9 years) but did not differ with regard to risk factors, previous myocardial infarction, or severity and extent of coronary disease. Twenty-three lesions (11%) progressed, 15 to total occlusion (11 complex and 4 smooth; 65%). Progression occurred in 17 of the 79 complex stenoses (22%) and in 6 of the 138 smooth lesions (4%) (P = .002). Mean stenosis diameter reduction was also significantly greater in complex than in smooth lesions (11.6% versus 3.9% change; P < .001). Acute coronary events occurred in 57% of patients with progression compared with 18% of those without progression (P < .001) and were more frequent in patients who presented with unstable angina (P = .002).

CONCLUSIONS

Rapid stenosis progression is not uncommon, and complex stenoses are at risk more than smooth lesions.

Heart rate variability depression in patients with unstable angina

The degree of reduction in heart rate variability (HRV) after myocardial infarction has been shown to have prognostic significance, but HRV has not been studied extensively in patients with unstable angina. We assessed spectral and nonspectral measurements of HRV in 52 patients with unstable angina, 52 patients with acute myocardial infarction, and 41 normal subjects. The spectral bands of 0.04 to 0.15 Hz (low frequency), 0.15 to 0.4 (high frequency), and nonspectral parameters SDNN, SDANN, SDNN index, rMSSD, and pNN50 were calculated from continuous 24-hour ECGs. All measures of HRV were reduced in patients with acute coronary syndromes compared to normal controls (p < 0.001), and there was no significant difference in measure of HRV between unstable angina and myocardial infarction patients. In patients with unstable angina who stabilized after admission, HRV had increased by the second 24 hours of monitoring. In contrast, HRV was further depressed in patients who had episodes of chest pain or transient ST-segment depression during the second 24 hours. rMSSD, pNN50, and SDNN index were lower in patients with unstable angina who had transient silent ischemia compared to those without silent ischemia. Of the patients with unstable angina, 4 died and 1 had nonfatal acute myocardial infarction within 11 months. HRV was lower in these patients than in patients without further cardiac events.

[The diagnosis of myocardial damage during coronary angioplasty by the analysis of the isoforms of the enzyme creatine kinase MB]

BACKGROUND

The existence of myocardial damage during percutaneous transluminal coronary angioplasty (PTCA) is controversial. Mild elevations in creatine kinase (CK) activity and its isoenzyme MB (CKMB) in patients who underwent PTCA have been reported. However, other authors failed to confirm these elevations. The low sensitivity of total CK and CKMB activity for the detection of myocardial damage in different settings other than myocardial infarction might account for the controversial findings. Measurement of CKMB isoforms has been shown to have a higher sensitivity than the assessment of CK or CKMB activity for early diagnosis of myocardial infarction. Its sensitivity for the diagnosis of myocardial damage in settings other than infarction is not well described.

OBJECTIVES

The aim of our study was two-fold: 1) to assess the incidence of myocardial damage after PTCA and 2) to compare the sensitivity of total CK and CKMB activity and measurement of CKMB isoforms for the detection of myocardial damage.

METHODS

14 patients (11 men and 3 women) with chronic stable angina underwent PTCA. Two electrocardiographic leads were monitored from the beginning of the procedure until 30 minutes after the PTCA. ST segment shifts of at least 1 mm, lasting for more than 1 minute, were considered indicative of myocardial ischemia. The duration of ischemic episodes was measured from the onset of the ST shift until its return to baseline. Total ischemic time, in minutes, was the sum of the duration of every ischemic episode. Blood samples were drawn before PTCA and serially during the first 24 hours post PTCA. CK (normal < 200 U/l) and CKMB (normal < 14 U/l) activities were measured. The CKMB isoforms were separated by electrophoresis, measured by densitometric scanning and their ratio calculated (CKMB2/CKMB1 normal < 1.5).

RESULTS

Vessels which underwent PTCA were: the left anterior descending artery (LDA) in 5 patients, the circumflex coronary artery (Cx) in 3 patients, right coronary artery (RCA) in 3 patients, LDA and Cx in 1 patient and Cx and RCA in 2 cases. Eleven patients underwent balloon dilatation, 1 underwent atherectomy (Rotablator) and two patients had treatment with both Rotablator and balloon angioplasty. Ischemic ST segment shifts were found in ten patients and the median of total ischemic time was 13.5 minutes (interquartile range: 2-15 minutes). Total CK and CKMB activities were within the normal range in every patient whereas in 7 patients (50%) the peak ratio CKMB2/CKMB1 was above the normal range. There were no differences in age, sex, number of vessels or lesions treated or in the time of balloon inflation between patients with and without abnormal CKMB2/CKMB1 peak. However, the ischemic time was significantly higher in patients with CKMB2/CKMB1 > 1.5 (median 15 vs 0 minutes; p = 0.023).

CONCLUSIONS

Myocardial damage during PTCA is not an uncommon finding. The CKMB isoforms are more sensitive markers of myocardial damage during PTCA than total CK or CKMB activities.

Aggressive pattern of angina after successful coronary angioplasty: the role of clinical and angiographic factors

To assess possible clinical and angiographic factors associated with acute coronary events following PTCA, we performed quantitative angiography in 168 consecutive patients who had undergone successful angioplasty in a native vessel (94 for stable angina, 74 for unstable angina), and who were restudied (24 +/- 15 weeks; range 4 to 52) because of recurrent anginal symptoms. Of the 168 patients, 38 (Group 1) were restudied because the pattern of angina was aggressive (unstable angina in 31, myocardial infarction in 7) and 130 because of effort-related angina (Group 2). the two patient groups were well matched for extent of initial disease but patients in Group 1 were younger (P=0.03). PTCA for unstable angina was originally performed more frequently in Group 1 than in Group 2 (27 of 38 patients (71% vs 47 of 130 patients (36%), P=0.0004). Disease progression in non-dilated segments occurred in 10 patients (26%) in Group 1 compared with eight (6%) in Group 2 (P=0.0004). Disease progression in non-dilated segments occurred in nine patients (24%) in Group 1 and in Group 2 (P=0.0004). Disease progression in non-dilated segments occurred in nine patients (24%) in Group 1 and in 10 (8%) in Group 2 (P=0.0006). Our conclusion is that patients who require re-investigation as a result of angina which has become aggressive following PTCA are usually those who originally underwent PTCA for unstable angina. These patients have a higher incidence of occlusive restenosis or disease progression.

Rapid angiographic progression of "target" and "nontarget" stenoses in patients awaiting coronary angioplasty

OBJECTIVES

Our aim was to compare the short-term evolution of "target" versus "nontarget" stenoses in patients awaiting coronary angioplasty.

BACKGROUND

Coronary angioplasty is effective therapy for angina pectoris, but coronary events occur after successful angioplasty that are caused by both restenosis and progression of mild preexisting nontarget stenoses.

METHODS

We prospectively studied 161 consecutive patients with stable angina (124 men and 37 women). After diagnostic angiography, target stenoses for angioplasty and nontarget lesions were identified. Patients were put on a routine waiting list and followed up regularly until repeat coronary arteriography was performed (mean +/- SD 7 +/- 3 months), either immediately before angioplasty (138 patients) or soon after an acute coronary event (23 patients), if one occurred. Stenosis diameter was measured by using computerized arteriography. Progression of disease was defined as > or = 20% lesion diameter reduction, new total occlusion or development of a "new" stenosis > or = 30%.

RESULTS

At study entry, the mean diameter of target (n = 207) and nontarget (n = 184) lesions was 68 +/- 9% and 38 +/- 9%, respectively (p < 0.001). Disease progression occurred in 33 patients (20%). Seven new lesions (one total occlusion) developed. Eighteen target (9%) and 15 nontarget (8%) stenoses progressed. The power of the study to detect a difference of 1% between the risks of progression of target and nontarget stenoses with a 90% probability was < 0.1. Total occlusion developed in 15 (83%) of the 18 target and 6 (40%) of the 15 nontarget stenoses (p = 0.03). During follow-up, a myocardial infarction developed in 3 patients (2%) and unstable angina in 20 (12%). These coronary events were associated with progression of target stenoses in 10 patients and nontarget stenoses in 7 and with the development of new lesions in 1. In five patients coronary events were not associated with stenosis progression.

CONCLUSIONS

Despite differences in baseline severity, a similar proportion of target and nontarget lesions progressed rapidly. However, target stenoses were more likely than nontarget lesions to progress to total occlusion. Progression of nontarget stenoses may contribute to recurrence of angina and new coronary events after successful angioplasty and should be considered when developing strategies aimed at improving outcome after angioplasty.

Clinical factors and angiographic features associated with premature coronary artery disease

BACKGROUND

Clinical, angiographic, and biochemical features may differ in young patients with coronary heart disease compared with older patients.

METHODS

We compared clinical and angiographic characteristics in 100 male patients with clinical onset of disease at age < or = 45 years (group 1) with those of 100 older male patients (clinical onset of disease at > or = 60 years) (group 2). All patients had documented coronary artery disease. The two patient groups were compared in terms of the pattern of angina at disease onset, angiographic features, and coronary risk factors.

RESULTS

Seventy-six patients in group 1 and 49 patients in group 2 presented with acute coronary syndromes (unstable angina or myocardial infarction) at clinical disease onset (p < 0.001). Compared with patients in group 2, younger patients (group 1) showed a preponderance of single-vessel disease (54 vs 36%; p < 0.001) and complex stenosis morphologic features (59 vs 36%; p < 0.01). Family history of coronary artery disease (39 vs 11%; p < 0.001) and smoking (73 vs 46%; p < 0.001) were also more prevalent in younger patients. Mean plasma total cholesterol level was 6.4 +/- 1.3 mmol/L in group 1 and 6.1 +/- 1.2 mmol/L in group 2 (p = NS). Younger patients, however, had lower high-density lipoprotein (HDL) cholesterol (0.9 +/- 0.2 mmol/L and 1.1 +/- 0.4 mmol/L; p < 0.01) and higher plasma triglyceride levels compared with patients of group 2 (2.7 +/- 1.3 mmol/L vs 2.1 +/- 1.1 mmol/L; p < 0.001).

CONCLUSIONS

Patients with premature coronary disease referred to coronary angiography commonly have unheralded acute onset of symptoms, angiographically complex stenosis morphologic features, and less extensive coronary artery disease. In addition to previously identified risk factors such as family history and smoking, we observed that high plasma triglyceride and low HDL cholesterol levels are associated with premature coronary artery disease.

Syndrome X in women is associated with oestrogen deficiency

This study was undertaken to ascertain whether gynaecological history or a reduction in ovarian hormones are triggers of angina in menopausal women with a positive exercise test and normal coronary arteries. The majority of patients with angina pectoris, a positive exercise test and normal coronary arteries are female, suggesting that the female gender may be important in the aetiology. We studied the gynaecological features of 107 women (age 53 +/- 9 years) with syndrome X, taken from a population of 134 patients including 27 males. Cardiological investigations were undertaken and detailed gynaecological history obtained from all the female patients. Menopausal status was confirmed by plasma levels of oestradiol-17 beta < or = 100 pmol.l-1. In 95 of the 107 female patients, chest pain began either during the perimenopausal period (32) or after the menopause (63). Of the 63 menopausal patients, 43 had undergone hysterectomy at an average of 8 +/- 6 years prior to the onset of chest pain. The incidence of hysterectomy in the study population (40%) was four times greater than that of an age-matched population. These findings confirm that the majority of patients with syndrome X are women in whom the chest pain began after the onset of menopause. Ovarian hormone deficiency may, therefore, play a role in the onset of syndrome X in female patients.

Angiographic stenosis progression and coronary events in patients with 'stabilized' unstable angina

BACKGROUND

Recent studies suggest that angiographically complex coronary stenoses are associated with an adverse short-term outcome. It is not known, however, if this applies to unstable angina patients who stabilize on medical therapy.

METHODS AND RESULTS

We prospectively studied 85 consecutive patients with unstable angina who stabilized on medical therapy but were found to require angioplasty for treatment of obstructive coronary disease. Angiography was carried out at admission, and patients were restudied 8 +/- 4 months (mean +/- SD) after the first angiogram. Ischemia-related stenoses were identified and classified as "complex" (irregular borders, overhanging edges, or thrombus) or "smooth" (absence of complex features). Stenosis progression (> or = 20% diameter reduction or new total occlusion) was assessed by automated edge detection. At initial angiography, there were 198 stenoses (> or = 50%, 102), of which 85 (54 complex and 31 smooth) were ischemia related. At restudy, 21 ischemia-related stenoses and 8 non-ischemia-related stenoses progressed (25% versus 7%, P = .001). Seventeen of the 21 ischemia-related stenoses that progressed developed into total occlusion compared with 3 of the 8 non-ischemia-related stenoses (P = .02). Changes in average stenosis severity and in absolute stenosis diameter were significantly larger in ischemia-related stenoses than in non-ischemia-related stenoses (P = .03). Eighteen (34%) complex stenoses progressed, compared with 3 (10%) smooth lesions (P = .02). During follow-up, 1 patient died (myocardial infarction) and 25 patients had nonfatal coronary events that were associated with progression of ischemia-related stenoses in 14 (56%).

CONCLUSIONS

In unstable angina patients who stabilize medically, subsequent short-term stenosis progression and coronary events are common. The unstable coronary lesion (particularly complex stenoses) is often not stabilized and will continue to progress over the ensuing months.

Differential progression of complex and smooth stenoses within the same coronary tree in men with stable coronary artery disease

OBJECTIVES

We sought to compare the evolution of complex and smooth stenoses within the same coronary tree in patients with stable coronary artery disease.

BACKGROUND

Progression of coronary stenosis has prognostic significance and may be influenced by local and systemic factors. Stenosis morphology is a determinant of disease progression, but no previous study has systematically assessed progression of complex and smooth stenoses within the same patient.

METHODS

We studied 50 men with stable angina who 1) had one complex coronary stenosis and one smooth stenosis in different noninfarct-related coronary vessels at initial coronary angiography, and 2) had a second angiogram after a median interval of 9 months (range 3 to 24). Patients with lesions > or = 10 mm long, at a major branching point or with > 85% diameter reduction were not included. Coronary lesions were measured quantitatively from comparable end-diastolic frames. Stenosis morphology was determined qualitatively by two independent observers.

RESULTS

All patients remained in stable condition during follow-up. Progression, defined as an increase in diameter stenosis by > or = 15% was seen in only eight complex stenosis (16%) but in no smooth lesions (p < 0.01). The severity of complex stenoses changed more than that of corresponding smooth stenoses (mean +/- 1 SD 5.8 +/- 13% vs. -0.06 +/- 6%, p < 0.01). On average, the annual rate of growth was 11.4 +/- 28% and 1.5 +/- 14% for complex and smooth lesions, respectively (p < 0.01).

CONCLUSIONS

Few coronary stenoses progress rapidly in stable angina. Complex and smooth coronary stenoses progress at different rates within the same coronary tree. complex stenosis morphology itself is an important determinant of progression of stenosis in patients with apparently clinically stable coronary artery disease.

Cardiac syndrome X: clinical characteristics and left ventricular function. Long-term follow-up study

OBJECTIVES

Our aim was to study the clinical characteristics and evolution of symptoms and left ventricular function in a clinically homogeneous group of patients with syndrome X (angina pectoris, positive exercise test results and normal coronary arteriograms).

BACKGROUND

The syndrome of angina with normal coronary arteriograms is heterogeneous and encompasses different pathogenetic entities. These characteristics may contribute to the existing controversy concerning the cause of syndrome X.

METHODS

We studied 99 patients with syndrome X (78 women, 21 men; mean age +/- SD 48.5 +/- 8 years). All underwent clinical characterization, ambulatory electrocardiographic (ECG) monitoring and echocardiographic assessment of left ventricular function during a follow-up period of 7 +/- 4 years.

RESULTS

The syndrome was more common in women than in men. Of the women, 61.5% were postmenopausal before the onset of chest pain. All 99 patients had exertional angina, and 41 also had rest angina. The average duration of episodes of chest pain was > 10 min in 53% of patients. Sublingual nitrate was effective for relief of pain in 42% of patients. Transient ST segment depression was observed during ambulatory ECG monitoring in 64 patients and myocardial perfusion abnormalities in 22. During the first stage of the exercise test, 32 patients had an increase > 20 mm Hg in systolic blood pressure and showed an earlier onset of ST depression and shorter exercise time than did patients whose blood pressure increased < or = 20%. During follow-up, no deaths or myocardial infarctions occurred, ventricular function was unchanged (shortening fraction 35.4 +/- 4% vs. 35.6 +/- 3%; heart failure developed in only one patient), systemic hypertension occurred in eight patients and conduction disturbances in four. Symptoms lessened in 11 patients, were variable or unchanged in 64 and worsened in 24.

CONCLUSIONS

Syndrome X, as defined in this study, occurs predominantly in postmenopausal women. Patients usually have chest pain typical for angina, but conventional antianginal treatment is not often successful. Myocardial perfusion abnormalities occur in a small proportion of patients. Long-term survival is not adversely affected, and deterioration of cardiac function rarely occurs.

Management of vasospastic angina--role of nicorandil

Clinical and experimental observations have confirmed that an episodic increase in the vasomotor tone of a major coronary artery may play a pathogenetic role not only in "variant angina" but also in other, more common anginal syndromes. In chronic stable angina, dynamic changes of vascular smooth muscle tone at the site of eccentric atheromatous plaques are responsible for "mixed angina." Abnormal coronary vasomotion contributes to myocardial ischemia in acute coronary syndromes as well. Studies have shown that a "primary" reduction of coronary blood flow, usually associated with plaque fissuring and thrombus formation, causes infarction and unstable angina. Abnormal vasoconstriction associated with the release of vasoactive substances by platelets and other constituents of the thrombus can contribute to coronary flow reduction in patients with unstable angina and myocardial infarction. Better understanding of the complex interactions among atherosclerotic coronary obstructions, the vascular smooth muscle, and the vascular endothelium has resulted in novel therapeutic approaches and has stimulated the search for more efficacious and safer coronary vasodilators. Recently interest has focused on vasodilator agents such as nicorandil that influence coronary arterial tone by acting through potassium channel activation. Nicorandil appears to be effective for treatment of vasospastic angina, as suggested by studies in Japan and Europe. In addition to its "antivasospastic" properties, nicorandil dilates coronary artery stenoses in patients with stable angina pectoris.(ABSTRACT TRUNCATED AT 250 WORDS)

Identification of patients at high risk for adverse coronary events while awaiting routine coronary angioplasty

BACKGROUND

Identification of patients at risk for progression of coronary stenosis and adverse clinical events while awaiting coronary angioplasty is desirable.

OBJECTIVE

To determine the standard clinical or angiographic variables, or both, present at initial angiography associated with the development of adverse coronary events (unstable angina, myocardial infarction, and angiographic total coronary occlusion) in patients awaiting routine percutaneous transluminal coronary angioplasty (PTCA).

PATIENTS AND METHODS

Consecutive male patients on a waiting list for routine PTCA. Routine clinical details were obtained at initial angiography. Stenosis severity was measured using computerised angiography.

OUTCOME MEASURES

Development of one or more of myocardial infarction, unstable angina, or angiographic total coronary occlusion while awaiting PTCA were recorded as an adverse event.

RESULTS

Some 214 of 219 patients underwent a second angiogram. One had a fatal myocardial infarction and four (2%) were lost to follow up. Fifty patients (23%) developed one or more adverse events (myocardial infarction five, unstable angina 35, total coronary occlusion 23) at a median (range) interval of 8 (3-25) months. Twenty (57%) of the 35 patients with unstable angina developed adverse events compared with 30 (17%) of the 180 with stable angina (P = 0.0001). Plasma triglyceride concentration was 2.6 (1.2) mmol/l in patients with adverse coronary events compared with 2.2 (1.1) mmol/l in those without such events (P < 0.05). Patients with adverse events were younger than those without (54 (9) years v 58 (9) years, P < 0.01). The relative risk of an adverse event in patients with unstable angina and increased plasma triglyceride concentrations was 6.9 compared with those presenting with stable angina and a normal triglyceride concentration (P < 0.02).

CONCLUSIONS

The study shows that adverse events are not uncommon in patients awaiting PTCA. Patients at high risk for adverse events may be predicted by the presence of acute coronary syndrome, increased concentration of plasma triglyceride, and younger age at the time of the first angiogram.

Creatine kinase MB isoforms: sensitive markers of ischemic myocardial damage

We investigated the use of creatine kinase (CK) MB isoforms as a marker of myocardial cell injury in a preliminary study of 16 patients with chronic stable angina after successful percutaneous transluminal coronary angioplasty (PTCA) and 25 patients after coronary artery bypass grafting (CABG). Three control groups were studied: apparently healthy volunteers (n = 31), patients undergoing thoracotomy (n = 10), and patients undergoing routine coronary angiography (n = 9). Patients in the PTCA group showed an association between ischemic ST segment changes lasting > 3 min and a transient increase in the MB2/MB1 ratio; however, all had total CK-MB activity within normal limits. Routine coronary angiography subjects had no significant change in MB2/MB1. In the CABG patients, MB2/MB1 peaked within 1 h after the cross-clamp release and returned to baseline by 24 h postoperatively. The median time to peak MM3/MM1 and total CK-MB activity was 2 and 8 h after reperfusion, respectively, returning to baseline values by 2 and 5 days, respectively. After thoracotomy, MB2/MB1 was increased only in elderly patients (n = 5) with risk factors for ischemic heart disease; total CK-MB activity was increased in only three of these. Apparently, CK-MB isoforms can detect myocardial damage in clinical settings with less overt damage than myocardial infarction.

Coronary vasodilator reserve, pain perception, and sex in patients with syndrome X

BACKGROUND

It remains unclear whether myocardial ischemia due to coronary microvascular dysfunction is the cause of chest pain in syndrome X (chest pain, ischemic-like stress ECG despite angiographically normal coronary arteries). To assess the function of the coronary microcirculation and its relation to pain perception, we measured myocardial blood flow (MBF) and coronary vasodilator reserve (CVR) in 29 patients with syndrome X and 20 matched normal control subjects.

METHODS AND RESULTS

MBF at rest and after intravenous dipyridamole (0.56 mg.kg-1 over 4 minutes) was measured using positron emission tomography with H2(15)O. CVR was calculated as MBFdipyridamole/MBFrest. ECG changes and chest pain after dipyridamole in syndrome X were compared with those in 35 patients with coronary artery disease (CAD). Resting and postdipyridamole MBFs were homogeneous throughout the left ventricle in syndrome X patients and control subjects. MBF was 1.05 (0.25), mean (SD) versus 1.00 (0.22) mL.min-1.g-1 (P = NS) at rest and 2.73 (0.81) versus 3.00 (1.00) mL.min-1.g-1 (P = NS) after dipyridamole in patients and control subjects, respectively. CVRs were 2.66 (0.76) and 3.06 (1.08) (P = NS) and after correction of resting MBF for rate-pressure product were 2.35 (0.83) and 2.34 (0.90) (P = NS) in patients and control subjects, respectively. Female syndrome X patients had higher resting MBF than males, at 1.18 (0.20) versus 0.88 (0.19) mL.min-1.g-1 (P < .001). Chest pain after dipyridamole occurred in syndrome X as frequently as in CAD (21/29 versus 22/35, P = NS).

CONCLUSIONS

When patients with syndrome X are compared with control subjects, no differences are found in MBF either at rest or after dipyridamole, despite syndrome X patients experiencing chest pain after dipyridamole to the same extent as patients with CAD. These findings, together with the absence of any relation among MBF, chest pain, and ECG changes under stress, cast further doubt on ischemia as the basis of the chest pain, at least in the majority of syndrome X patients.

Creatine kinase MB isoforms: sensitive markers of ischemic myocardial damage

We investigated the use of creatine kinase (CK) MB isoforms as a marker of myocardial cell injury in a preliminary study of 16 patients with chronic stable angina after successful percutaneous transluminal coronary angioplasty (PTCA) and 25 patients after coronary artery bypass grafting (CABG). Three control groups were studied: apparently healthy volunteers (n = 31), patients undergoing thoracotomy (n = 10), and patients undergoing routine coronary angiography (n = 9). Patients in the PTCA group showed an association between ischemic ST segment changes lasting &gt; 3 min and a transient increase in the MB2/MB1 ratio; however, all had total CK-MB activity within normal limits. Routine coronary angiography subjects had no significant change in MB2/MB1. In the CABG patients, MB2/MB1 peaked within 1 h after the cross-clamp release and returned to baseline by 24 h postoperatively. The median time to peak MM3/MM1 and total CK-MB activity was 2 and 8 h after reperfusion, respectively, returning to baseline values by 2 and 5 days, respectively. After thoracotomy, MB2/MB1 was increased only in elderly patients (n = 5) with risk factors for ischemic heart disease; total CK-MB activity was increased in only three of these. Apparently, CK-MB isoforms can detect myocardial damage in clinical settings with less overt damage than myocardial infarction.

Abnormal autonomic control of the cardiovascular system in syndrome X

Anomalies of autonomic control of the coronary circulation may play a role in the development of syndrome X (angina pectoris, ischemic-appearing results on exercise test, and normal coronary arteriograms). Twenty-six patients with syndrome X and 20 healthy sex- and age-matched control subjects were studied by means of analysis of heart rate variability during 24-hour Holter monitoring. Spectral and nonspectral parameters of heart rate variability were investigated. Mean heart rate was similar in patients with syndrome X and in control subjects. Patients with syndrome X had significantly lower standard deviation of all normal RR intervals, a lower percentage of adjacent normal RR intervals > 50 ms in difference (126.4 +/- 22 vs 149 +/- 43 ms, p < 0.05; 6.3 +/- 4 vs 11.2 +/- 7%, p < 0.05; respectively), and a trend toward lower values of time-domain parameters. Lower values of total power and low frequency were also observed in patients with syndrome X (1273 +/- 693 vs 1790 +/- 989 ms2, p < 0.05; 406 +/- 176 vs 729 +/- 455 ms2, p < 0.01, respectively). An inverse correlation between heart rate and measures of heart rate variability was found in syndrome X but not in control subjects. High- and low-frequency power showed a similar circadian pattern in syndrome X patients and control subjects. Patients and control subjects were then allocated into 2 groups according to the median RR duration: syndrome X1 and control 1 with high mean heart rate, and syndrome X2 and control 2 with low mean heart rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of aminophylline on cardiac function and regional myocardial perfusion: implications regarding its antiischemic action

Aminophylline improves exercise capacity in patients with angina. Because this drug does not dilate epicardial coronary vessels, its beneficial effect is from either a reduction of myocardial oxygen consumption or an improvement of myocardial blood flow distribution. This study was performed to assess the effects of aminophylline on cardiac function and on regional myocardial perfusion to establish the mechanisms of its antiischemic action. In 10 patients during cardiac catheterization hemodynamic parameters and cardiac volumes were obtained during baseline and after intravenous infusion of aminophylline. Aminophylline decreased left ventricular end-diastolic pressure (from 11 +/- 4 to 4 +/- 2 mmHg, p < 0.001), mean right atrial pressure (from 5 +/- 2 to 2 +/- 1 mmHg, p < 0.01), and left ventricular end-diastolic volume (from 117 +/- 36 to 88 +/- 36 ml, p < 0.01); it increased peak dp/dt (from 1931 +/- 329 to 2430 +/- 540 mmHg/sec, p < 0.001) and heart rate (from 69 +/- 9 to 76 +/- 14 beats/min, p < 0.05) and did not modify systolic aortic pressure (138 +/- 14 vs 137 +/- 16 mmHg, p = not significant [NS]). Estimated oxygen consumption during aminophylline (6.7 +/- 1.3 ml/min/gm) was similar to that during baseline (6.7 +/- 1.4 ml/min/gm). In another study in nine anesthetized dogs with a critical stenosis of the left anterior descending artery, myocardial perfusion was assessed by microspheres during control atrial pacing and during atrial pacing after aminophylline; left atrial pressure was kept constant throughout the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of angiotensin-converting enzyme inhibition on exercise-induced angina and ST segment depression in patients with microvascular angina

OBJECTIVES

This study was conducted to test the hypothesis that angiotensin-converting enzyme inhibition may lessen myocardial ischemia in patients with microvascular angina.

BACKGROUND

Patients with syndrome X (angina pectoris, positive findings on exercise testing and normal coronary arteriogram) have a reduced coronary vasodilator reserve ("microvascular angina") and may show an increased sympathetic drive. Angiotensin-converting enzyme inhibition attenuates sympathetic coronary vasoconstriction in patients with coronary artery disease.

METHODS

Ten patients (seven women and three men, mean age [+/- SD] 53 +/- 6 years) with syndrome X and a reduced coronary flow reserve underwent a randomized, single-blind, crossover, placebo-controlled study of the effects of the angiotensin-converting enzyme inhibitor enalapril on angina and exercise-induced ST segment depression. Assessment was by symptom-limited treadmill exercise testing after 2 weeks of treatment with 10 mg/day of enalapril and after 2 weeks of placebo administration.

RESULTS

All patients had positive findings on exercise testing (> or = 1 mm ST segment depression and angina) while taking placebo, whereas six patients had a positive test result (four with angina) during enalapril therapy. Total exercise duration and time to 1 mm of ST segment depression were prolonged by enalapril over those obtained with placebo (mean 779 +/- 141 vs. 690 +/- 148 s, p = 0.006 and 690 +/- 204 vs. 485 +/- 241 s, p = 0.007, respectively). The magnitude of ST segment depression was also less with enalapril than with placebo (mean 1.1 +/- 0.4 vs. 1.5 +/- 0.2 mm, p = 0.004). Heart rate and blood pressure at peak exercise and at 1 mm of ST depression were not significantly different during placebo and enalapril treatment.

CONCLUSIONS

Angiotensin-converting enzyme inhibition lessens exercise-induced ischemia in patients with syndrome X and microvascular angina, probably by a direct modulation of coronary microvascular tone, which results in an increased myocardial oxygen supply.

Myocardial ischaemia in the hypertensive patient--the role of coronary microcirculation abnormalities

Clinicians have long suspected that hypertrophied hearts have an inadequate coronary circulation. This clinical suspicion resulted from the observation that a large proportion of patients with left ventricular hypertrophy who have normal coronary arteriograms complain of angina and have ischaemia-like ST segment depression during effort. Hypertension is a known risk factor for the development of coronary artery disease and therefore the presence of angina in a patient with systemic hypertension is usually attributed to obstructive atherosclerotic coronary artery disease. However, angina may occur in hypertensive patients in the absence of coronary stenosis. A limitation of coronary flow reserve is responsible for signs and symptoms of myocardial ischaemia in many of these patients. This article will focus on the role of the coronary microcirculation in the genesis of ischaemia in patients with systemic hypertension who have no obstructive coronary artery disease. It will also briefly discuss other mechanisms potentially responsible for the angina syndrome in patients who have left ventricular hypertrophy but angiographically normal coronary arteries.