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Objectives: This investigation studied the relation between regional myocardial blood flow and left ventricular function during dobutamine stress in patients with coronary artery disease., Background: Dobutamine stress is becoming more frequently used as an alternative to dynamic exercise in patients with ischemic heart disease., Methods: We studied 12 patients with coronary artery disease. Dobutamine was infused from 5 micrograms/kg body weight per min up to 40 micrograms/kg per min or until chest pain or other intolerable side effects. Regional myocardial blood flow was measured with positron emission tomography and oxygen-15-labeled water. Regional wall motion was assessed in three short-axis slices by magnetic resonance imaging. Each slice was subdivided into four regions: septal, anterior, lateral and inferior. A total of 140 regions were suitable for comparison., Results: During stress, new wall motion abnormalities developed in 27 regions. Myocardial blood flow (mean +/- SD) increased in 113 regions that did not develop wall motion abnormalities (0.98 +/- 0.26 [baseline] vs. 1.98 +/- 0.87 [dobutamine] ml/min per g, p < 0.001), whereas it did not change significantly in regions with stress-induced wall motion abnormalities (1.00 +/- 0.28 [baseline] vs. 1.30 +/- 0.62 [dobutamine] ml/min per g, p = NS). An absolute decrease in myocardial blood flow below the value at rest was observed in seven segments that developed wall motion abnormalities during stress., Conclusions: The normal functional response to dobutamine stress is paralleled by an increase in coronary flow, whereas mechanical dysfunction is accompanied by a blunted increase, or even a paradoxic decrease, in regional coronary flow.

Objectives: We sought to characterize myocardial echodensity in asymptomatic patients with insulin-dependent diabetes and normal conventional two-dimensional echocardiographic findings to determine whether ultrasound tissue characterization can detect ultrastructural changes in myocardium, such as an increase in collagen content., Background: Fibrosis alters the acoustic properties of the heart in animals and humans, and these changes are detectable by cardiac tissue characterization with ultrasound. Early changes detected in the diabetic heart include increased interstitial collagen deposition., Methods: Using two-dimensional echocardiography, we evaluated 26 asymptomatic patients with insulin-dependent diabetes with normal regional and global rest function, and 17 age- and gender-matched control subjects. By selection, all diabetic patients were normotensive and had negative maximal exercise stress test results to avoid the confounding effects of hypertension and coronary artery disease. Using an echocardiographic instrument implemented at the Institute of Clinical Physiology, we performed an on-line radiofrequency analysis to obtain quantitative operator-independent measurements of the integrated back-scatter signal of the ventricular septum and posterior wall. The integrated values of the radiofrequency signal from the myocardial wall were normalized for those from the pericardial interface and were expressed as percentages (integrated backscatter index)., Results: Diabetic patients showed a significant increase in myocardial echodensity both in the septum ([mean +/- SD] 36.6 +/- 8.1 vs. 23.6 +/- 4.4, p < 0.0001) and posterior wall (21.2 +/- 5.3 vs. 18.4 +/- 3.7, p < 0.001). By individual patient analysis, 17 patients exceeded the 95% confidence limits for normal myocardial echocardiographic reflectivity found in normal subjects, and only 3 had a relatively abnormal transmitral Doppler filling pattern (E/A ratio), mainly consisting of an abnormally increased late peak flow velocity (65% vs. 11%, p < 0.001). The increased myocardial intensity was similar in patients with (n = 16) and without (n = 10) noncardiac complications, such as retinopathy or nephropathy (37.5 +/- 7.9% vs. 35.0 +/- 8.3%, p = 0.35)., Conclusions: Abnormally increased myocardial echodensity, possibly related to collagen deposition, can be detected in asymptomatic diabetic patients with normal rest function. Theoretically, this finding might be considered a very early preclinical alteration potentially related to subsequent development of diabetic cardiomyopathy.

Background: Pre and post treatment perfusion scintigraphy with Tc-99m-sestamibi is an accurate method to evaluate the effectiveness of thrombolytic therapy in patients with acute myocardial infarction. In the present study this method was used to verify whether thrombolytic therapy performed late (6 to 24 hours) after symptoms onset was still able to produce significant salvage of jeopardized myocardial tissue., Methods: Fifteen patients (mean age 60.9 +/- 9 years) admitted to CCU 8-23 hours (mean 13.2 +/- 4 hours) after symptoms onset of their first acute myocardial infarction were studied. Both myocardial perfusion and left ventricular function were assessed before and after thrombolysis. Myocardial perfusion was studied using Tc-99m-sestamibi Single Photon Emission Tomography (SPET) before (pre-lysis SPET), 4.4 +/- 0.9 days (post-lysis SPET A) and 32 +/- 6 days (post-lysis SPET B) after thrombolysis. Uptake defects were graded from 0 to 4 using a 20-segment scheme. Regional ventricular function was evaluated using two-dimensional echocardiography before (pre-lysis ECHO), simultaneously with post-lysis SPET A (post-lysis ECHO A) and 32 +/- 4 days after treatment (post-lysis ECHO B); asynergy was graded from 1 to 4. Global left ventricular function was estimated using gated blood pool imaging and measuring the ejection fraction (EF) 5.3 +/- 1 (GBP 1) and 32 +/- 4 days after treatment (GBP 2). Within 6-9 days of admission all patients underwent coronary angiography., Results: In pre-lysis SPET all patients had uptaken defects (score range 17-52, mean 34.6 +/- 12). According to the comparison between pre-lysis SPET and post-lysis SPET A, patients were divided into two groups: 7 patients with perfusion recovery (Group I) and 8 patients with absent or minimal perfusion recovery (Group II). In Group I the mean uptaken score decreased significantly (from pre-lysis SPET 34.2 +/- 12 to post-lysis SPET A 21.7 +/- 7, p < 0.05); in Group II the uptaken score remained unchanged (from pre-lysis SPET 34.8 +/- 12 to post-lysis SPET A 33.6 +/- 12, ns). In post-lysis SPET B both groups showed a defect reduction compared to post-lysis SPET A; however, the defect score of SPET B in Group I was significantly lower than that in Group II (18.7 +/- 16 vs 30.1 +/- 10, p < 0.05). The asynergic score in pre-lysis ECHO was the same in the two groups (19.5 +/- 4); in post-lysis ECHO A no significant decrease was observed in the two groups. In post-lysis ECHO B a significant decrease was seen in Group I (14.8 +/- 5, p < 0.05 vs pre-lysis ECHO and vs post-lysis ECHO A), but not in Group II (19.8 +/- 5, ns); the asynergic score in post-lysis ECHO B was significantly lower in Group I than in Group II (p < 0.05). In GBP 1 the EF was 38% +/- 6 in Group I and 40% +/- 6 in Group II (ns). In GBP 2 a significant increase was registered in Group I (47% +/- 10, p < 0.05), whereas in Group II the EF remained unchanged (40% +/- 6, ns). Coronary angiography showed a patent infarct related vessel in all Group I patients and in 2 Group II patients (p < 0.05)., Conclusions: These results show that in patients with acute myocardial infarction treated with thrombolysis late after symptoms onset it is still possible to obtain an effective reperfusion and the consequent salvage of jeopardized tissue, as demonstrated by the recovery of both regional and global left ventricular function.

Objectives: This study was conducted to establish whether changes in myocardial texture can be observed in humans by transthoracic echocardiography during ischemic episodes of different severity and duration induced by various pathogenetic mechanisms., Background: Increased echo-reflectivity of ischemic myocardium has been detected in experimental animals by epicardial echocardiography and by backscatter evaluation., Methods: Transthoracic two-dimensional echocardiographic monitoring with a commercially available electronic sector scanner (2.25- or 3.5-MHz transducer) was performed during 35 episodes of transient myocardial ischemia induced by ergonovine in patients with vasospastic angina (n = 9), by dipyridamole in patients with angiographically assessed coronary artery disease (n = 11) and by balloon occlusion during coronary angioplasty (n = 15). Quantitative texture analysis of gray levels was performed off-line on digitized images during rest conditions, ischemia and the recovery phase in regions showing normal contraction at rest, obvious dyssynergy during ischemia and normal contraction in the recovery phase. In each condition, a control region with normal contraction throughout the study was also evaluated., Results: Chest pain occurred in 23 of the 35 episodes; electrocardiographic (ECG) changes were present in 26 episodes, and consisted of ST segment elevation in 13, ST segment depression in 10 and pseudonormalization of a basally negative T wave in 3. The duration of ischemic episodes was 67 +/- 53 s by symptomatic criteria and 91 +/- 52 s by ECG criteria. The risk region showed an increased end-diastolic mean gray level amplitude in a.u. (arbitrary units) during ischemia (57 +/- 19) compared with rest (38 +/- 15) and recovery (38 +/- 18, p < 0.01). No significant changes were detected in the control region (rest 36 +/- 16 vs. ischemia 34 +/- 18 vs. recovery 31 +/- 13, p = NS). The percent increase in mean gray level was similar in the various types of stress employed (ergonovine, dipyridamole or angioplasty) and was not significantly correlated with either the duration of ST segment shift (r = 0.05, p = NS) or the severity of dyssynergy evaluated semiquantitatively by means of the wall motion score (r = 0.28, p = NS). In the 15 balloon occlusions performed in six patients during coronary angioplasty, the increased echoreflectivity of the risk zone was already evident during echocardiographic sampling performed after 10 +/- 4 s of occlusion (rest 35 +/- 9 vs. 53 +/- 10 a.u., p < 0.01) when no dyssynergy could be detected by quantitative wall motion analysis (percent area change by fixed center of mass reference system 31 +/- 10% at rest vs. 32 +/- 11% after 10 s of occlusion, p = NS)., Conclusions: Transient short-lasting myocardial ischemia is associated with an abrupt increase in myocardial echodensity detectable by videodensitometric analysis applied to standard transthoracic echocardiographic images and is largely independent of the underlying pathogenetic mechanism (reduced blood supply or flow maldistribution with coronary stenosis). During controlled coronary occlusion, increased echodensity precedes the onset of regional dyssynergy.

Propafenone efficacy in conversion of atrial fibrillation to sinus rhythm has been well documented. In this study we considered propafenone efficacy according to a graduated protocol of administration. Forty-two patients with recent-onset atrial fibrillation, without left ventricular failure, ischemic symptoms and in absence of antiarrhythmical treatment, were treated according to the following protocol: propafenone 1 mg/kg i.v. (5 min) followed, in the non-responder patient group, by a second dose, 0.5 mg/kg i.v. (15 min). Patients with persistent atrial fibrillation received 900 mg/daily of propafenone per os, at home for two days. Thereafter, patients still not restored to sinus rhythm were considered non-responders. Patients who were converted to sinus rhythm received 450 mg daily of the drug (oral administration), at home, as antiarrhythmical prophylaxis, for three months. Thirty-nine patients were converted to sinus rhythm (92.8%), 24 of them after intravenous propafenone (57.2%), and the other 15 (35.6%) after oral administration of the drug. The average heart rate in patients not converted to sinus rhythm with intravenous propafenone was significantly reduced after drug administration, compared to basal values (from 136.4 +/- 18.1 to 107.1 +/- 17.6, p < 0.01), allowing home treatment. No major cardiac effects were observed after infusion, nor after oral administration of propafenone. During a three-month follow-up we observed 3 cases of relapsed atrial fibrillation and 2 discontinued treatments due to minor gastroenteric side effects. In conclusion, propafenone therapy in ambulatory regimen is safe and effective in patients with recent-onset atrial fibrillation. In many patients refractory to IV treatment, further therapeutic success may be achieved following oral propafenone administration.

The use of a single-day protocol for 99mTc MIBI myocardial scintigraphy is particularly well-suited for the nuclear medicine departments that are the referral centres for the cardiology departments of several community hospitals. The aim of the study was to compare, in the same patient population, the diagnostic accuracy of planar and SPECT imaging with 99mTc MIBI using a single-day protocol. Thirty-nine patients (31 males and 8 females, age range 32-69 years) were studied because of effort chest pain. Of them, 7 had a pre-test probability of coronary artery disease less than 2.5%; coronary angiography demonstrated significant coronary obstructions in the remaining 32 subjects and 21 of them also had a history of previous myocardial infarction. All patients underwent 99mTc MIBI myocardial scintigraphy with acquisition of planar and SPECT images after injection of a low dose (370 MBq) at rest and after a second higher dose (1110 MBq), injected approximately four hours later during exercise stress testing. The normalcy rate in the 7 patients with low pre-test probability was 100% using both imaging techniques. For the diagnosis of previous infarction, the sensitivities of planar and SPECT images were 71% and 96% respectively. For the diagnosis of effort ischemia the sensitivity values were 34% and 88%, respectively, using planar and SPECT imaging. With regard to the classification of the diseased coronary arteries, the sensitivities of planar and SPECT studies were 42% and 79% respectively, and the related specificities were 91% and 77%. We may conclude that using a single-day protocol planar imaging seems to allow lower levels of diagnostic accuracy both for the diagnosis of effort ischemia and the classification of the diseased vessels as compared to SPECT, which appears therefore in a similar setting the imaging technique of choice.

In order to determinate the incidence, predictivity and prognosis of ventricular fibrillation in the early phase of acute myocardial infarction a series of 301 patients with acute myocardial infarction consecutively assisted by the Mobile Coronary Care Unit of Florence was analyzed. 151 patients (50.2%) received intensive care within 2 hours from the onset of the symptoms, 75 patients (24.9%) received intensive care between the second and sixth hour. 38 patients (12.6%) had at least one episode of ventricular fibrillation. 30% of the episodes of ventricular fibrillation happened within 1 hours from the onset of the symptoms, 47.4% within 2 hours, 74% within 6 hours. Serious arrhythmias complicated the early phase of acute myocardial infarction, but only sinus bradycardia seems to have a significant predicativity of ventricular fibrillation (P less than 0.05). We found that hospital survival resuscitated patients is strictly related to the time between early symptoms and the episode of ventricular fibrillation: 91% of the patients with ventricular fibrillation within 1 hour were discharged alive from hospital, 71% of those with ventricular fibrillation within 6 hours, 20% of those with ventricular fibrillation beyond 6 hours (P less than 0.01). The high rate and the favourable prognosis of ventricular fibrillation in the early phase of acute myocardial infarction must lead to a widespread implementation of rapid response emergency care systems away from hospital.