Filling patterns in left ventricular hypertrophy: a combined acoustic quantification and Doppler study.

OBJECTIVES: The purpose of this study was to evaluate the potential of acoustic quantification compared with Doppler echocardiography for assessment of left ventricular diastolic dysfunction. BACKGROUND: Diastolic dysfunction usually accompanies left ventricular hypertrophy. Although Doppler echocardiography is widely used, it has known limitations in the diagnosis of diastolic abnormalities. The ventricular area-change waveform obtained with acoustic quantification technology may provide an alternative to assess diastolic dysfunction. METHODS: Potential acoustic quantification variables (peak rate of area change and mean slope of area change rate during rapid filling, amount of relative area change during rapid filling and atrial contraction) were obtained and compared with widely used Doppler indexes of ventricular filling (isovolumetric relaxation time, pressure half-time, peak early diastolic velocity/peak late diastolic velocity ratio, rapid filling, atrial contribution to filling) in 16 healthy volunteers and 30 patients with left ventricular hypertrophy. RESULTS: Criteria for abnormal relaxation were present in 68% of patients by acoustic quantification and in 64% of patients by Doppler echocardiography. However, abnormal relaxation was identified in 80% of patients by one or both methods. Acoustic quantification indicated abnormal relaxation in the presence of completely normalized Doppler patterns and in patients with mitral regurgitation or abnormal rhythm with unreliable Doppler patterns. CONCLUSIONS: Acoustic quantification potentially presents a new way to assess diastolic dysfunction. This technique may be regarded as complementary to Doppler echocardiography. The combined use of the methods may improve the diagnosis of left ventricular relaxation abnormalities.

Balloon angioplasty results in increased segmental coronary distensibility: a likely mechanism of percutaneous transluminal coronary angioplasty.

OBJECTIVES: The purpose of this study was to evaluate the hypothesis that the increase in lumen area induced by percutaneous transluminal coronary angioplasty is secondary to a change in lesion (segmental) distensibility. BACKGROUND: Despite the widespread use of coronary angioplasty, the precise mechanism (or mechanisms) of lumen area improvement remains poorly understood. METHODS: Quantitative coronary angiography was used to measure the minimal (contrast agent filled) balloon diameters at 1 to 5 atm, inclusive, during the first and final balloon inflations in 24 lesions successfully treated with coronary angioplasty. To rule out possible confounding effects due to changes in balloon material distensibility during repeated inflations, five control balloons were studied ex vivo. In parallel, intravascular ultrasound imaging was utilized to compare the segmental distensibility (change in lumen area during the cardiac cycle) of eight disease-free and seven mildly diseased coronary segments and seven segments after successful balloon angioplasty. RESULTS: Minimal balloon diameters increased significantly between the first and final inflations (46%, 33%, 26%, 14% and 10% at 1, 2, 3, 4 and 5 atm, respectively, all p < 0.0001), demonstrating an increase in arterial distensibility after successful coronary angioplasty. No significant changes in balloon diameters were observed during sequential initial inflations at 1 and 2 atm (n = 5). Minimal increases in balloon diameters were observed during repeated balloon inflations in the ex vivo studies (4.9 +/- 1% [mean +/- SEM]). A distensibility index, derived from the intravascular ultrasound data, was not different between the balloon-dilated and the normal segments but was significantly lower in mildly diseased sites (14.7 +/- 2.2 vs. 12.9 +/- 1.2 vs. 6.9 +/- 1.9, respectively, p < 0.05) despite a smaller plaque area (7.3 +/- 1 vs. 11.3 +/- 1 mm2, proximal/nondilated vs. dilated segments, respectively, p < 0.05). CONCLUSIONS: Coronary distensibility is significantly impaired in atherosclerotically diseased coronary segments and increases significantly after balloon angioplasty. This increase in segmental coronary compliance after coronary angioplasty may create a larger lumen area by allowing the vessel to distend in response to normal intraarterial pressure.

Incidence and severity of transplant coronary artery disease early and up to 15 years after transplantation as detected by intravascular ultrasound.

OBJECTIVES: The purpose of this study was to quantify the severity of transplant coronary artery disease and to assess lesion characteristics early and up to 15 years after heart transplantation by using intracoronary ultrasound. BACKGROUND: Intravascular ultrasound has the ability to measure the components of the arterial wall and has been shown to be a sensitive method for detection of transplant coronary artery disease. METHODS: A total of 304 intracoronary ultrasound studies were performed in 174 heart transplant recipients at baseline and up to 15 (mean 3.3 +/- 0.2) years after transplantation. Mean intimal thickness and an intimal index were calculated, and lesion characteristics (eccentricity, calcification) were assessed for all coronary sites imaged (mean 3.0 +/- 0.1 sites/study). The Stanford classification was used to grade lesion severity. RESULTS: Compared with findings in patients studied at baseline (< 2 months after transplantation, n = 50), mean intimal thickness (0.09 +/- 0.02 vs. 0.16 +/- 0.02 mm, p < 0.01), intimal index (0.07 +/- 0.01 vs. 0.14 +/- 0.02, p < 0.01) and mean severity class (1.5 +/- 0.2 vs. 2.3 +/- 0.2, p < 0.01) were significantly higher at year 1 (n = 52) after transplantation. Thereafter, all three variables further increased over time and reached highest values between years 5 and 15. Calcification of lesions was detected in 2% to 12% of studies up to 5 years after transplantation, with a significant increase to 24% at years 6 to 10 (p < 0.05). CONCLUSIONS: Severity of transplant coronary artery disease appeared to progress with time after transplantation in this cross-sectional study. This characteristic was most prominent during the 1st 2 years after transplantation, whereas calcification of plaques occurred to a significant extent only later in the process. These data may serve as a reference for comparison of intravascular ultrasound findings in other studies of patients with transplant coronary artery disease.

Doppler echocardiographic patterns of left ventricular filling in patients early after acute myocardial infarction.

Diastolic function is routinely assessed using Doppler-derived left ventricular (LV) filling patterns. Ratios between peak flow velocities during early filling and atrial contraction (E/A) of less than 1 are considered pathologic and diagnostic of impaired relaxation. Myocardial stiffness can normalize the E/A ratio, and thus, in some clinical settings, a normal E/A ratio may identify patients with high filling pressures. LV filling patterns were studied with Doppler echocardiography in 15 healthy subjects and 38 patients with recent acute myocardial infarction. The results were correlated with clinical and hemodynamic variables. E/A ratio less than 1 was found in 14 patients (37%) and in only 1 control subject; E/A ratio greater than 2 found in 5 patients (13%) and in only 1 control subject; 19 patients (50%) had an apparently normal E/A ratio. No correlation was found between LV filling pattern and ejection fraction or presence of diabetes or arterial hypertension. LV end-diastolic pressures were low to normal in patients with an E/A ratio less than 1 and were usually greater than 15 mm Hg in those with normal or abnormally increased (greater than 2) E/A ratios. Thus, an apparently normal E/A ratio in patients after myocardial infarction may identify those with more severe LV diastolic dysfunction and increased LV filling pressure.

Reciprocal electrocardiographic changes in acute myocardial infarction.

If reciprocal electrocardiographic changes during acute myocardial infarction (AMI) are a result of ischemia of the wall opposite the AMI, a stress test is expected to induce similar changes in the corresponding electrocardiographic leads. Right atrial pacing was used as a myocardial stress method in 137 consecutive patients recovering from a transmural AMI, and the appearance of pacing-provoked ischemia before hospital discharge was correlated to the presence of absence of ST depression in the opposite wall during the initial 48 hours. Of the 137 patients, 83 (61%) had reciprocal changes; they were more common in inferior (87%) than in anterior (37%) AMI (p less than 0.01). Of 54 patients without reciprocal changes, only 5 (9%) had ST depression during predischarge pacing; however, of the 83 patients with reciprocal changes, 41 had pacing-induced ischemia (p less than 0.01) and 42 did not, indicating that in half of this group the reciprocal changes represent ischemia of the opposite wall. In the other half of the group, without ST depression during pacing, these changes may be a "mirror image" phenomenon. Follow-up showed that angina pectoris, positive treadmill test response 6 months later, or recurrent AMI all consequences of impaired myocardial blood supply, were significantly more frequent in patients with reciprocal changes. This group could be further separated according to the results of right atrial pacing, because angina pectoris or recurrent AMI were infrequent among those with reciprocal changes and negative pacing responses, but was frequent among those with reciprocal changes and positive pacing responses.(ABSTRACT TRUNCATED AT 250 WORDS)

Relation of coronary artery disease to atherosclerotic disease in the aorta, carotid, and femoral arteries evaluated by ultrasound.

This prospective study was conducted to correlate the presence of angiographically significant coronary artery disease (CAD) and atherosclerotic disease in the aorta, carotid, and femoral arteries as measured by ultrasound. One hundred two consecutive patients admitted for coronary angiography for suspected CAD participated in the study. All patients underwent transesophageal echocardiography for the evaluation of thoracic aortic atherosclerosis and B-mode ultrasound for evaluation of carotid and femoral atherosclerosis. Intimal-medial thickness > 1 mm in the thoracic aorta or peripheral vessels was considered as evidence of atherosclerosis. Patients with CAD (n = 64) had a significantly higher incidence of atherosclerotic plaques in the thoracic aorta, carotid, and femoral arteries than subjects with normal coronary arteries: 91%, 72%, 77% vs 31%, 47% and 42%, respectively. Extracoronary plaque was a stronger predictor of CAD than conventional risk factors. Evidence of plaque in patients younger than median age (64 years) had a higher specificity than in patients above median age (77% vs 40%, respectively, p <0.0001). Plaque score of the extracardiac vessels was significantly higher in patients with multivessel CAD than in patients with 1-vessel CAD disease and in subjects with normal coronary arteries (p <0.001). Thus, atherosclerotic plaques in the aortic and femoral arteries and, to a lesser extent, in the carotid arteries are strong predictors of CAD.

Early right atrial pacing after myocardial infarction. I. Comparison with early treadmill testing.

Right atrial (RA) pacing and modified treadmill testing (TT) were performed in 111 patients recovering from acute myocardial infarction (MI) before hospital discharge to determine whether ischemic responses are more common with RA pacing than with TT and whether the prognosis could be better determined by the results of 1 test compared with the other. Patients with predischarge congestive heart failure, chest pain, physical disability or age older than 70 years were excluded. Ischemic responses were significantly more frequent during RA pacing than during TT (41% vs 34%, p = 0.02). The results of the 2 tests were concordant in 102 patients (92%): Both were positive in 37 and both negative in 65. In 8 patients, results of RA pacing were positive and results of TT were negative; only 1 patient had positive TT and negative RA pacing responses. The higher percentage of positive responses during RA pacing than during TT can be attributed to the significantly higher pressure-rate product achieved during pacing (18,773 vs 16,831 mm Hg/min, p less than 0.001). The ischemic threshold, defined as the pressure-rate product at which an ischemic change was first noted in a particular patient, was almost identical in both tests. During a mean follow-up period of 16 months, 10 patients had recurrent MI; 8 had positive predischarge RA pacing but only 5 had positive TT responses (p = 0.008). Six patients died; in 3 RA pacing responses were positive and in 2 TT responses were positive.(ABSTRACT TRUNCATED AT 250 WORDS)

Early right atrial pacing after myocardial infarction. II. Results in 77 patients with predischarge angina pectoris, congestive heart failure, or age older than 70 years.

Seventy-seven consecutive postinfarction patients who had either predischarge angina pectoris or congestive heart failure, or who were older than 70 years of age, underwent right atrial (RA) pacing before hospital discharge. In 60% of these patients, ischemic changes developed during RA pacing; this high yield of positive response indicates advanced coronary arterial disease. During a mean follow-up of 15 months, these patients had a high mortality rate (18%) and a reinfarction rate of 9%. RA pacing separated this a priori high-risk group into lower- and higher-risk subsets. Of the 46 patients with a positive RA pacing response, 6 had reinfarction, while none of the 31 patients with a negative RA pacing response had reinfarction (p = 0.04); 10 of the 14 cardiac deaths were among the patients who had positive RA pacing responses at discharge (p = not significant). Thus, of the 20 major cardiac events, 16 occurred among those with positive RA pacing responses (p less than 0.05). Predischarge clinical symptoms, however, were not good predictors of subsequent major cardiac events. We conclude that RA pacing can be safely performed even in high-risk and elderly patients and a positive response can identify those who have a poorer prognosis. Therefore, for postinfarction patients who, according to the prevailing criteria, are excluded from treadmill testing, we advocate the use of RA pacing.

Magnesium therapy for torsades de pointes.

This is the first report of the successful use of magnesium sulfate (MgSO4) in 3 consecutive patients with torsades de pointes (TdP). In 1 patient, TdP was induced by a combination of quinidine and amiodarone, in the second by procainamide, and in the third by an overdose of imipramine. The QT intervals before TdP were 0.70, 0.64 and 0.56 second, respectively. A bolus of 1.0 to 2.0 g MgSO4 25% abolished the TdP in all 3 patients; but in the third patient, because of recurrent TdP, a second bolus of 1.0 g and a continuous 24-hour infusion of 1.0 mg/min were administered, preventing TdP. There was no immediate shortening in the QT interval in any patient after MgSO4. Magnesium can be given safely even in patients with acute myocardial infarction, angina pectoris or systemic hypertension, conditions in which isoproterenol is contraindicated; it can be applied faster than temporary cardiac pacing; and its use for TdP appears worthy of additional trials.

Biplane transesophageal echocardiography in the diagnosis of patent foramen ovale.

Patent foramen ovale is associated with unexplained systemic embolic events or persistent hypoxemia. The diagnosis of a patient foramen ovale is based on the existence of an interatrial right-to-left shunt. Biplane transesophageal echocardiography with its increased ability to provide accurate anatomic detail may allow the visualization of the actual opening of the patent foramen ovale. In 19 patients with transesophageal positive contrast studies, we assessed the value of the vertical versus the horizontal plane in the diagnosis of a patent foramen ovale. The patent foramen ovale opening could be seen and sized in the vertical plane in 10 studies (53%). In none of these 10 cases was the opening seen also in the horizontal plane. We conclude that in a significant number of cases, biplane transesophageal echocardiography adds morphological detail to the diagnosis of patent foramen ovale. The ability to size the actual opening may have therapeutic implications.

Distribution and morphologic features of coronary artery disease in cardiac allografts: an intracoronary ultrasound study.

The longitudinal distribution and circumferential pattern of coronary intimal proliferation were studied with intravascular ultrasonography in 135 patients after heart transplantation. Eighty-seven (64%) of 135 patients had significant intimal thickening, with most lesions (63%) concentric and free of fibrosis or calcification. Both diffuse and nonuniform longitudinal patterns of intimal thickening were found.

The significance of ST abnormalities in myocardial infarction.

During the acute phase of myocardial infarction, elevation of the ST segment represents one of the major criteria for location of the injury. Recent studies showed that changes in the ST segment in leads remote from the infarcted area or in right precordial leads may provide additional information on the extent of the infarction and right ventricular involvement.

Transesophageal echocardiography in the intensive care unit: impact on diagnosis and decision-making.

Transesophageal echocardiography (TEE) is widely used in the management of patients in intensive care units. The present study assesses the specific value of this technique in various categories of these patients. We reviewed 113 studies performed in 100 such patients for: suspected aortic dissection (25), suspected endocarditis (33), source of emboli assessment (19), hemodynamic instability (15), and miscellaneous (21). TEE provided diagnostic information in all patients with aortic dissection, in 53% of the cases with hemodynamic instability, in 50% of the cases with septic states with high likelihood of endocarditis, and in 29% of the cases where the question was the source of emboli. When the clinical probability for endocarditis was low, all transesophageal echocardiograms performed in septic patients were negative. The information provided by TEE was considered crucial in one-third of the positive cases; in about one-half of these special cases, the results were instrumental for further surgical management. There were no significant side effects related to the procedure. TEE is easily performed in the intensive care unit setting and yields useful information in almost half of the cases. Special benefit is expected in suspected aortic disease, hemodynamic instability, suspected endocarditis, and embolic events. The overall yield as screening procedure in febrile patients is low.

Age alone is not a risk factor for left atrial thrombus in atrial fibrillation.

OBJECTIVE: Advanced age is an indication for anticoagulation in patients with atrial fibrillation though it is not clear that elderly patients have a higher prevalence of left atrial thrombus. The purpose of this study was to clarify whether advanced age represents a risk for left atrial thrombus formation irrespective of other clinical variables. DESIGN: Observational study in patients with atrial fibrillation undergoing a transoesophageal echo scan for various clinical indications. SETTING: University-affiliated cardiology service in a general hospital. PATIENTS: Results are reported in 381 patients, 257 aged less than 75 years (Gr. A) and 124 aged 75 years or more (Gr. B). RESULTS: Thrombi were detected by TOE in 30 patients (7.9%), 21 from group A and nine from group B (8.1% vs 7.2%, p = NS). No thrombi were detected in patients with lone atrial fibrillation. Among patients with either valvular or nonvalvular atrial fibrillation, left atrial thrombus presence was not related to age or anticoagulation status. CONCLUSIONS: In patients with atrial fibrillation, age itself does not predict the presence of left atrial thrombus and the only identifiable risk factor seems to be the existing cardiac pathology.

Holter monitoring in the evaluation and rehabilitation of post-cerebrovascular accident patients.

Coronary artery disease, overt or silent, is frequently present in patients who have suffered a cerebrovascular accident (CVA). Rehabilitation therapy of CVA patients is based mostly on physical activity, which may be limited by fear of overloading the cardiovascular system. Therefore, assessment of the severity of coronary heart disease in CVA patients is of utmost importance. In this study we assessed the usefulness of 24-hour electrocardiographic Holter monitoring in the evaluation of post-CVA patients during daily activities and rehabilitation. Of the 43 post-CVA patients, 24 (55.8%) revealed pathological changes on Holter monitoring and 17 (71%) had a history of coronary artery disease prior to CVA. Holter monitoring revealed mainly ventricular and atrial arrhythmias and in three patients detected transient ischaemic episodes. Only six patients (14%) showed aggravation of arrhythmia during rehabilitation therapy, without aggravation of ST-T changes. The mean maximum heart rate during regular daily activities was 104 +/- 20 beats/min, which was significantly higher than the mean maximum heart rate during physical therapy (100 +/- 18 beats/min; p less than 0.01) and during occupational therapy (87 +/- 18 beats/min; p less than 0.001). These findings indicate that more vigorous physical and occupational therapy can be prescribed to these patients. The performance of Holter monitoring in post-CVA patients is a valuable substitute to exercise testing, and is useful for cardiovascular evaluation during daily activities and rehabilitation therapy.