Coronary recanalization by elective angioplasty prevents ventricular dilation after anterior myocardial infarction.

OBJECTIVES: In a prospective study we evaluated whether late recanalization of the left anterior descending coronary artery (LAD) affects ventricular volume and function after anterior myocardial infarction. BACKGROUND: Persistent coronary occlusion after anterior myocardial infarction leads to ventricular dilation and heart failure. METHODS: We studied 73 consecutive patients with acute anterior myocardial infarction as a first cardiac event; all had an isolated lesion or occlusion of the proximal LAD. Six patients died before hospital discharge. The 67 survivors were classified into two groups: group I (patent LAD and good distal flow, n = 40) and group II (LAD occlusion or subocclusion, n = 27). The 20 patients in group I who had significant residual stenosis and all patients in group II underwent elective percutaneous transluminal coronary angioplasty (PTCA) within 18 days of myocardial infarction. The procedure was successful in 17 patients in group I (group IB) and in 16 patients in group II (group IIA): in the remaining 11 patients of group II, patency could not be reestablished (group IIB). Left ventricular volumes, ejection fraction and a dysfunction score were measured by echocardiography on admission, before PTCA, at discharge and after 3 and 6 months. RESULTS: Although cumulative ST segment elevation was similar in groups I and II, ejection fraction and dysfunction score were significantly worse in group II. However, ventricular function and volumes progressively improved in group IIA, whereas group IIB exhibited progressive deterioration of function (dysfunction score [mean +/- SD] increased from 21 +/- 6 to 25 +/- 8, p < 0.05; ejection fraction decreased from 43 +/- 10% to 37 +/- 11%, p < 0.05); and end-systolic volume increased from 34 +/- 10 to 72 +/- 28 ml/m2, p < 0.05). Patients in group IIB also had worse effort tolerance, higher heart rate at rest, lower blood pressure and significantly greater prevalence of chronic heart failure. CONCLUSIONS: Delayed PTCA of an occluded LAD can frequently restore vessel patency. Success appears to be associated with better ventricular function and a lack of chronic dilation. Large randomized studies are warranted to evaluate the effect of delayed PTCA on late mortality.

Impaired left ventricular filling dynamics in patients with angina and angiographically normal coronary arteries: effect of beta adrenergic blockade.

OBJECTIVE: To assess exercise performance and resting left ventricular filling dynamics in patients with syndrome X (SX) in basal conditions and after 10 days treatment with oral atenolol. DESIGN AND PATIENTS: Exercise performance was studied and left ventricular filling assessed by Doppler-derived transmitral flow pattern analysis in 22 patients (16 female, mean (SD) age 53 (4) years) with angina, a positive exercise test, and angiographically smooth coronary arteries. Patients were studied after two 10 day treatment periods with either atenolol or placebo in a single-blind, randomised, crossover trial. The same protocol was followed in 10 patients with documented coronary artery disease (CAD) and in 13 controls (C). RESULTS: Unlike the controls, patients with SX and those with CAD consistently showed exercise-induced ST segment abnormalities and impaired resting left ventricular filling while on placebo. Atenolol significantly reduced episodes of angina, completely prevented exercise-induced ST segment changes in 18 SX patients, and delayed their onset in all patients with CAD: in both groups the agent significantly improved Doppler-derived indices (mean (SD)) of ventricular filling (E/A 0.97 (0.27) v 1.22 (0.32) and 0.84 (0.21) v 1.19 (0.37), respectively). CONCLUSIONS: The objective documentation of left ventricular filling abnormalities may be useful in confirming the clinical diagnosis of SX and in providing objective evidence of therapeutic benefit. The similarity of the symptoms and electrocardiographic and ventricular filling abnormalities found in patients with SX and in those with CAD suggests that ischaemia is involved in both groups.

Reverse perfusion pattern of Tc-99m MIBI heralding the development of myocardial infarction.

In a patient with sporadic atypical chest pain associated with dyspnea, stress Tc-99m MIBI imaging showed normal perfusion and inferoposterior hypoperfusion on the resting study. Although this reverse perfusion pattern was considered artifactual, the patient later had an acute myocardial infarction involving the same areas. Postinfarction stress Tc-99m MIBI imaging showed a nonreversible defect in the same area that, in the earlier study, showed a reverse perfusion pattern. The authors hypothesize that partial stenosis of the related artery with some nontransmural myocardial necrosis at the time of the initial study may be a possible cause of this peculiar Tc-99m MIBI perfusion pattern.

Beneficial effects of diltiazem during myocardial reperfusion: a randomized trial in acute myocardial infarction.

BACKGROUND: Although in experimental models of coronary occlusion diltiazem administration has been shown to reduce the degree of stunning and of reperfusion injury, the majority of clinical trials has failed to demonstrate significant benefits. The aim of this study was to evaluate the effect of diltiazem, administered before coronary reperfusion, on infarct size, residual myocardial viability and recovery of left ventricular function. METHODS: We studied 90 patients admitted within 3 hours of the onset of symptoms of acute myocardial infarction. They were immediately randomized to either intravenous diltiazem (10 mg bolus + 10 mg/hour for 3 days) (group 1, n = 43) or placebo (group 2, n = 47) and subsequently treated with recombinant tissue-type plasminogen activator. All underwent serial echocardiograms upon admission, 4 days post-admission during low-dose dobutamine stress echo, at discharge and after 6 months. We calculated the dysfunction score (1 = hypokinesia, 2 = akinesia, 3 = dyskinesia) on admission and its percent reduction after dobutamine (viability) and at follow-up (recovery). The 12-lead electrocardiograms were continuously monitored for 3 days and coronary angioplasty was performed whenever the residual stenosis was > 60%. RESULTS: Upon admission, there were no differences in age, sex, infarct location and size, degree of ST-segment elevation, time from onset of symptoms and dysfunction score. Creatine kinase peaked early in 70% of patients in both groups; the incidences of recurrent ischemia, infarct-related vessel patency and the need for coronary angioplasty were also similar. The creatine kinase peak was significantly higher in group 2 (2931 +/- 2456 vs 1726 +/- 1004 IU/l, p < 0.05). Conversely, in group 1 the residual viability was significantly higher (51 +/- 23 vs 36 +/- 30% improvement in dysfunction score, p < 0.05) and the early recovery of regional function was significantly greater (35 +/- 34 vs 18 +/- 22% at discharge, p < 0.05). On the other hand, the delayed recovery was not significantly different (15 +/- 29 vs 21 +/- 32% from the time of discharge to 6 months of follow-up). CONCLUSIONS: Intravenous diltiazem, started before coronary reperfusion, has beneficial effects on the infarct size, residual viability and recovery of regional function. If confirmed by larger trials, these preliminary results suggest the use of diltiazem as adjunctive therapy in patients with acute myocardial infarction and undergoing reperfusion.

[An aneurysm of the interatrial septum and cerebral embolic events: a clinical case and review of the literature]. / Aneurisma del setto interatriale ed eventi embolici cerebrali: caso clinico e revisione della letteratura.

Previous reports have described an association between atrial septal aneurysm and cerebral embolic events. We report the case of 68-year-old woman who was referred for evaluation of two syncopal episodes that had occurred within the previous three months. Physical examination, 12-lead ECG and exercise stress test were unremarkable; a 24-hour Holter monitoring did not show cardiac arrhythmias, and carotid ultrasonography excluded atherosclerotic lesions. Magnetic resonance imaging of the brain revealed multiple areas of decreased tissue density. Two-dimensional transthoracic echocardiography showed an atrial septal aneurysm that was confirmed by transesophageal imaging, which improved its morphologic characterization and ruled out the possibility of other atrial abnormalities with embolic potential. In conclusion, the syncopal episodes observed in our patient were likely due to cerebral embolism. This observation confirms the relation between atrial septal aneurysm and cerebrovascular ischemic events. As previously indicated, the presence of this abnormality dictates the need for anticoagulant therapy.

[Sodium nitroprusside and inhibition of coronary vasoconstriction in isolated hearts of guinea pigs]. / Nitroprussiato di sodio ed inibizione della vasocostrizione coronarica in cuori isolati di cavia.

Recent data suggest that nitrate compounds, beside determining vasodilatation by cGMP-mediated Ca++ uptake in the sarcoplasmic reticulum, may also inhibit vasoconstriction by reducing phosphatidyl inositol bisphosphate hydrolysis, a major step in the biochemical pathway responsible for vasoconstriction induced by a variety of agents including angiotensin II (AII). We assessed the inhibitory effects of Na-nitroprusside (NP) on the coronary resistances induced by increasing doses of AII in Krebs perfused (basal pressure: 2.5-3 KPa) Guinea-pig isolated hearts. AII bolus injections (5 to 100 ng) were given before and 10 min after a 7.6.10(-8) to 7.6.10(-6) M infusion of NP for 10 min. AII produced a highly reproducible, linearly dose-related, increase in perfusion pressure (PP) (5 ng: 4.4 +/- 1.16; 10 ng: 8.1 +/- 2.1; 25 ng: 18.7 +/- 3.06; 50 ng: 23.6 +/- 2.31; 100 ng: 30 +/- 1.37 mmHg) that was persistently and dose-dependently inhibited by NP. Well after (greater than 10 min) full recovery from the initial NP-induced vasodilatation and drop in PP its inhibitory effect was observed, varying from 22.1% at the maximal AII and minimal NP does and 90.6% at the minimal AII and maximal NP doses. This study demonstrates that, apart from causing the well-known immediate vasodilatory response by stimulation of cGMP synthesis, NP also causes delayed inhibition of AII-induced coronary vasoconstriction, possibly by preventing phosphatidyl inositol hydrolysis.

Reverse redistribution of thallium-201 heralding the development of myocardial infarction: description of two cases.

Development of a perfusion defect on the 201Tl image from exercise to redistribution is referred to as reverse redistribution, a finding which has been previously associated with several conditions. We describe here two cases in which the reverse-redistribution phenomenon, observed in a routine stress-redistribution thallium-201 scan performed because of chest pain, was considered to be artifactual. Both patients subsequently developed a myocardial infarction in the areas showing the delayed perfusion defect. The potential clinical significance of the reverse-redistribution phenomenon in these two cases is discussed. When observed in patients with typical anginal pain, the reverse redistribution pattern should be considered a potential marker of tissue at risk in a region with previous, otherwise undetected, subendocardial infarction. In such patients the need for coronary angiography should be carefully considered.

Exercise-induced T-wave normalization predicts recovery of regional contractile function after anterior myocardial infarction.

AIMS: We investigated the ability of T-wave pseudonormalization and ST-segment elevation, which are demonstrated in infarct-related leads during submaximal exercise testing, to predict late recovery of contractile function. METHODS: We studied 88 consecutive patients (73 males, mean age 59 +/- 8 years) with anterior infarction, persistent T-wave inversion and a documented lesion of the proximal segment of the left anterior descending coronary artery. They all underwent 2D-echocardiography on admission, 4 weeks as well as 6 months after myocardial infarction to evaluate the dysfunction score and the ejection fraction. Submaximal (75% of maximal predicted heart rate) exercise testing was performed in 80 patients 2 weeks after myocardial infarction following discontinuation of treatment. RESULTS: During exercise testing, 59 of the 88 patients showing negative T-waves on the resting electrocardiogram exhibited pseudonormalization (group A) in at least three adjacent precordial leads, whilst 29 (group B) did not. Patients of group A more frequently exhibited an early creatine kinase peak (41% vs 24%, P < 0.05) and residual angiographic perfusion (97% vs 69%, P < 0.05). The dysfunction score did not change in group B (from 19 +/- 7 to 22 +/- 4), but decreased in group A (from 18 +/- 4 to 11 +/- 6 P < 0.05). The ejection fraction was similar in the two groups on admission (group A: 48 +/- 7%, group B: 45 +/- 10%), but was significantly different at 4-week (52 +/- 99 vs 42 +/- 11%, P < 0.05) and 6-month follow-up (58 +/- 9 vs 44 +/- 10%, P < 0.01). The concomitant presence of ST-segment elevation and T-wave normalization showed the highest positive predictive value for left ventricular function recovery (100%). CONCLUSIONS: T-wave normalization induced by submaximal exercise test is frequently associated with residual perfusion to the infarct area and predicts progressive improvement in regional wall motion, especially if associated with ST-segment elevation. Therefore, these electrocardiographic findings may be used as easily obtainable markers of residual viability that predict late recovery in contractile function.

High prevalence of the thallium-201 reverse redistribution phenomenon in patients with syndrome X.

OBJECTIVE: To evaluate the stress-myocardial perfusion pattern in patients with angina, positive exercise test and angiographically smooth coronary arteries (syndrome X). DESIGN: Prospective study. PATIENTS AND METHODS: Twenty-five consecutive patients (seven males, mean age 54 +/- 8 years) with typical angina, positive exercise test, normal coronary arteries and no inducible spasm, underwent stress-redistribution thallium-201 myocardial perfusion scintigraphy. Thirty-two consecutive patients (14 males, mean age 49 +/- 7 years) with atypical chest pain and negative exercise test, undergoing stress-redistribution thallium scan, served as controls. RESULTS: Exercise was discontinued for angina and/or ST-segment depression after 12 +/- 3 min. Thallium stress images revealed 40 hypoperfused segments in 27 patients (77%); after 4 h, 16 of these segments had completely normalized, 10 remained unchanged, six exhibited partial reperfusion and eight worsened. Twenty-four patients (69%) exhibited thallium reverse redistribution in 33 segments. Thirty-four patients (97%) had at least one hypoperfused segment in one of the two scintigraphic phases. Of the 24 patients with reverse redistribution, eight also underwent stress-rest 99m Tc-MIBI SPECT: six exhibited reduced tracer uptake that was present at rest, but not on stress images, in the same segments showing thallium reverse redistribution. Thallium stress images revealed four hypoperfused segments in three controls (9%); at redistribution, one segment normalized, two remained unchanged and one exhibited partial reperfusion. Additionally, there were four new underperfused segments appearing on redistribution in four patients (13%). Overall, there were seven controls (22%) with at least one hypoperfused myocardial segment in one of the two scintigraphic phases. CONCLUSIONS: Our study confirms that perfusion abnormalities are present in most syndrome X patients. Additionally, the data show that reverse redistribution (a perfusion defect that develops or becomes more evident on delayed imaging) is a common finding in these patients. The mechanisms of the phenomenon remain obscure: we suggest that it is due to inhomogeneous perfusion, and the hyperaemic response induced by exercise masks resting underperfusion of certain areas.

Thrombolytic therapy reduces the incidence of left ventricular thrombus after anterior myocardial infarction. Relationship to vessel patency and infarct size.

BACKGROUND: Controversial evidence exists as to whether thrombolytic therapy reduces the incidence of left ventricular thrombus in acute myocardial infarction and, if so, how this relates to successful reperfusion. METHODS: Four hundred and eighteen consecutive patients underwent echocardiography and coronary angiography within 3 weeks of an acute myocardial infarction. A dyssynergic score was calculated by analysing regional wall motion in 18 left ventricular segments. The infarct-related artery was considered patent if TIMI grade 2 or 3 flow and less than 90% stenosis were present. Retrograde perfusion by Rentrop's grade 2 or 3 collaterals was considered significant. RESULTS: Large anterior myocardial infarctions were associated with the highest prevalence (39%) of left ventricular thrombosis. Thrombus was also very frequent if the left anterior descending coronary artery was occluded and no collaterals to the infarct area were seen (75%). Anticoagulant therapy reduced the prevalence of left ventricular thrombus, regardless of whether the infarct-related vessel was patent or not. Conversely, in patients undergoing thrombolysis the incidence of left ventricular thrombosis was lower when the left anterior descending coronary artery was patent, and especially when an early creatine kinase peak, suggestive of reperfusion, was recorded (7%). Finally, the presence of left ventricular thrombosis was inversely related to the asynergy score. CONCLUSION: These observations suggest that the presence of left ventricular thrombus is related to the extent of myocardial damage. Thrombolytic therapy reduces thrombus probably by salvaging myocardium at risk.

Soluble E-selectin and intercellular adhesion molecule-1 plasma levels increase during acute myocardial infarction.

Previous studies have shown that adhesion molecules play a crucial role in leukocyte-endothelium interactions that occur during myocardial ischemia and reperfusion. We assessed the plasma levels of the soluble form of E-selectin (sE-selectin) and intercellular adhesion molecule-1 (sICAM-1) in 15 patients with acute myocardial infarction (AMI) and in 15 controls with chronic stable angina. In patients with AMI, the levels of sE-selectin and sICAM-1 increased significantly during the first 8 h after infarction and subsequently decreased. Soluble E-selectin levels were inversely related to the peak plasma levels of creatine kinase-MB (CK-MB), and the time course of their appearance in plasma correlated with that of neutrophil count and plasma D-dimer. In individual patients, peak and mean sICAM-1 levels correlated respectively with plasma D-dimer concentrations and monocyte count, but no correlation were found when their time courses were analyzed. Eight hours after symptom onset, the mean plasma sE-selectin levels were higher in patients with AMI than in those with stable angina, whereas no significant differences were found in mean plasma sICAM-1 levels between the two groups at every time analyzed. In the acute phase of MI (a) sE-selectin and sICAM-1 levels increase during the first 8 h and subsequently decrease; (b) the increase in sE-selectin probably reflects activation of endothelial cells, correlates with other inflammatory and coagulation parameters, and is inversely related to the degree of myocardial damage; and (c) sICAM-1 plasma levels do not represent a good marker of "cell activation" because they reflect activation of different cells and may be affected by different conditions.