Andrew M. Hauser

Sequence of mechanical, electrocardiographic and clinical effects of repeated coronary artery occlusion in human beings: Echocardiographic observations during coronary angioplasty

The direct manipulation of coronary blood flow to induce regional myocardial ischemia has been almost entirely limited to experimental animal models. Thus, the detection of ischemia-induced left ventricular dysfunction in human subjects has been generally limited to observations made under conditions of diagnostic loading or during spontaneous clinical events. Percutaneous coronary angioplasty requires repeated interruptions of coronary blood flow for periods as long as 1 minute. The resulting appearance of or increase in ischemia-produced changes in myocardial function were detected by two-dimensional echocardiography in 18 patients undergoing angioplasty of 22 coronary stenoses. Accordingly, left ventricular contraction was studied during 52 episodes of regional coronary blood flow interruption and reperfusion in the process of inflating and deflating the angioplasty balloon. Before angioplasty, left ventricular wall motion was normal in 14 patients. There was mild anteroapical hypokinesia in two patients, anteroapical akinesia in one and mild inferior hypokinesia in one. Balloon inflations repeatedly produced new or increased wall motion abnormalities in the distribution of the instrumented coronary artery in 19 (86.4%) of the 22 procedures, but did not alter wall motion during angioplasty of one left circumflex artery lesion, one highly collateralized left anterior descending artery stenosis and one left anterior descending stenosis that had already caused severe anteroapical dyssynergy. Hypokinesia, usually rapidly progressing to dyskinesia, began 19 +/- 8 seconds (mean +/- SD) after coronary occlusion. Wall motion began to normalize 17 +/- 8 seconds after reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Symmetric cardiac enlargement in highly trained endurance athletes: a two-dimensional echocardiographic study

Twelve highly trained male endurance athletes and 12 normally active matched control subjects were studied by two-dimensional and M-mode echocardiography to evaluate changes in the right and left heart chambers associated with intense aerobic training. Maximal oxygen uptake, a measure of cardiovascular fitness, ranged from 62.1 to 82.6 ml/kg/min in the athletes and from 33.0 to 49.3 ml/kg/min in the control subjects (p less than 0.001). The athletes had significantly greater left ventricular wall thickness (p less than 0.01), left ventricular chamber area (p less than 0.005), left atrial area (p less than 0.01), right ventricular chamber area (p less than 0.002), right ventricular wall thickness (p less than 0.05), and right atrial area (p less than 0.01). Proportionality of cardiac chamber enlargement in the athletes was shown by similar ratios of both right-to-left ventricular areas and right-to-left atrial areas in the two groups. Left ventricular contractility was not significantly different between groups. Cardiac enlargement in endurance athletes enables a greater stroke volume for the performance of sustained, intense exercise; hypertrophy of the chamber walls normalizes wall stress. These changes occur symmetrically in both right and left cardiac chambers in the endurance athlete, reflecting bilateral hemodynamic loading. The symmetry of the endurance athletes cardiac enlargement differs from most pathologic conditions which have heterogeneous effects on specific cardiac chambers.

Intracoronary streptokinase in clinical practice.

The candidacy for streptokinase (SK) infusion was studied in 95 patients displaying ECG evidence of acute or impending infarction who were catheterized within 5 hours of the onset of chest pain. Intracoronary SK was administered to 84 patients in whom occlusions of the infarct-related vessel were identified, with early recanalization having been achieved in 74 (88%). Because of completeness of studies, a data base of 72 patients was employed for further analysis. Recanalization was sustained at follow-up in 45 of 55 patients (82%). Spontaneous thrombolysis was demonstrated at follow-up in five patients (8%) initially resistant to SK, and rethrombosis occurred in 10 patients (18%). Preservation of R waves relative to Q wave depth was limited to patients with less than 90% residual stenosis. Eight of nine patients with continuing thrombolysis and patients with recanalized occlusions of the left anterior descending coronary artery displayed more impressive increases in mean (+/- SEM) ejection fraction (47% +/- 4% to 53% +/- 5% [p less than 0.05], and 47% +/- 3% to 52% +/- 5, respectively). The ejection fraction also increased significantly in 15 patients with pre-SK values of less than 50% (41% +/- 2% to 48% +/- 3%; p less than 0.05). Ventricular function deteriorated in SK failures. Reperfusion arrhythmias occurred in 28 of 62 recanalized patients (45%). Minor bleeding tendencies were displayed in 18 of 72 patients (25%). Major hemorrhages, one of which may have been fatal, occurred in four patients (5.6%). Of 84 patients, four (4.7%) died, two of whom were in cardiogenic shock when first seen. In contrast, there were 11 deaths (11.8%) in a consecutive simultaneously enrolled series of 93 control patients with similar entry criteria (p less than 0.05). Two additional SK-treated patients died, 16 and 30 days after treatment, both more than a week after surgical revascularization. It is concluded that SK recanalization is a promising new therapy that may decrease mortality and preserve myocardial function in certain circumstances. Its efficacy in a setting closer to the mainstream of cardiologic practice extends the favorable experience issuing from earlier clinical investigations.

The emerging role of echocardiography in the emergency department.

Cardiac ultrasound quickly provides both anatomic and physiologic assessment of the heart at the bedside, permitting rapid diagnosis and triage of patients presenting to the emergency department with chest pain, hypotension, or dyspnea. The identification and quantification of left ventricular dysfunction by ultrasound allows effective determination of prognosis and, thus, may supplant the ECG in patient triage. Transesophageal echocardiography definitively identifies the presence of thoracic aortic dissections, and this information may be obtained more immediately than by other imaging methods. Emergency physicians should have, at a minimum, sufficient knowledge of echocardiography to know when it is applicable to a patient problem. It may be feasible for noncardiologists to gain sufficient proficiency in echocardiography to use the technique as a screening procedure in the emergency department setting.

Aneurysm of the atrial septum as diagnosed by echocardiography: Analysis of 11 patients

Atrial septal aneurysm (ASA) is considered uncommon and, when discovered, has usually been found in association with other cardiac lesions.1-4 This association has led some observers to conclude that their occurrence is the result of an increased pressure gradient between the atria producing a bulging septal shift toward the low pressure side.1*2 In contrast, Silver and Dorsey5 detected clinically silent aneurysm of the septum primum in 16 of 1,578 serially autopsied adults. Only 1 of their 5 hemodynamically studied patients had elevated left ventricular end-diastolic pressure. Atrial septal aneurysm has been found by 2dimensional echocardiography (2-D echo) in association with various congenital and acquired valvular diseases.334 A patient who had a myocardial infarction and ASA with phasic inspiratory right-to-left motion of the aneurysm was reported.6 Isolated case reports of ASA associated with a midsystolic click,7 and with no associated lesions,” have also been recently reported. The subject of our report is 11 cases of ASA shown by 2-D echo to exist in the absence of other identifiable structural cardiac abnormalities.

Use of Two-Dimensional Echocardiography for the Diagnosis of Pulmonary Embolus

We investigated the diagnostic utility of transthoracic echocardiogram (2-D ECHO) in identifying acute right heart strain in patients with suspected pulmonary embolus (PE) undergoing a pulmonary angiogram during their hospitalization. A retrospective case control study was conducted over a 3-year period at a tertiary, community teaching hospital. Patients were eligible if they had a pulmonary angiogram and a transthoracic echocardiogram. Cases were defined as an angiogram positive for PE and controls were defined as an angiogram negative for PE. We excluded cases in which the time interval between 2-D ECHO and angiogram was greater than 2 days. The 2-D ECHO was considered positive for right heart strain if two of the following were present: enlarged right ventricle, moderate or severe tricuspid regurgitation, increased right ventricular pressures, or paradoxical septal wall motion. We were able to identify 71 patients, of whom 24 met our criteria for PE. Of these, 13 had an echocardiogram consistent with our definition of acute right heart strain, for a sensitivity of 0.54. Forty-six of the 47 patients without PE did not have findings of acute right heart strain. The echocardiogram was positive in 14 patients, for a positive predictive value of 0.93. In seven patients with systolic blood pressures of less than 100 mmHg, five had a PE, all of whom met our criteria for acute right heart strain. We conclude that 2-D ECHOs show promise in identifying PE and hemodynamic compromise as a result of PE, and that further studies are warranted.

Contribution of transesophageal echocardiography to patient diagnosis and treatment: A prospective analysis

The capability of transesophageal (TEE) versus transthoracic (TTE) echocardiography as a diagnostic tool in clinical practice was prospectively examined in 86 consecutive cases. A conclusive diagnosis was possible in 95% with TEE, whereas the same result was achieved in 48% by TTE. Specifically, TEE provided a conclusive diagnosis in 14 of 16 cases of infective endocarditis, while TTE gave this result in 4 of the 16 cases (p less than 0.001). Similarly, TEE allowed a conclusive diagnosis in 11 of 11 instances of aortic dissection, while TTE gave this indication in two cases (p less than 0.001). TEE was similarly effective in eight of eight cases of atrial thrombi, whereas TTE gave the diagnosis in three of eight cases (p less than 0.01). In five subjects with intracardiac masses, TEE gave a conclusive diagnosis in all five, whereas TTE was able to diagnose conclusively in one subject (p less than 0.02). In seven patients with mitral regurgitation, TEE gave the conclusive diagnosis in all seven and TTE was able to provide this information in four (p = NS). TEE was able to provide a conclusive diagnosis in four patients with aortic insufficiency, and TTE gave the same information in two of the four (p = NS). In 14 patients with prosthetic valve dysfunction, TEE gave the diagnosis in 12 and TTE gave it in eight patients (p = NS). Both methods gave a conclusive diagnosis in 13 out of 13 cases of mitral stenosis (p = NS). Also, TEE provided a conclusive diagnosis in eight of eight patients with adult congenital heart disease and TTE gave this information in four (p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of peripheral cardiopulmonary bypass on left ventricular size, afterload and myocardial function during elective supported coronary angioplasty

Although cardiopulmonary bypass support has been increasingly used for high risk coronary angioplasty, few data exist regarding its effects on left ventricular function. Accordingly, in 20 patients changes in left ventricular size, afterload and myocardial function were assessed by continuous hemodynamic monitoring and simultaneous two-dimensional echocardiography during cardiopulmonary bypass-supported high risk angioplasty. The cross-sectional left ventricular area during bypass support remained unchanged during diastole, whereas during systole it decreased (from 29.6 +/- 11.4 to 27.6 +/- 10.4 cm2, p less than 0.05). Global left ventricular function expressed as fractional area change remained unchanged from baseline to bypass support but decreased during balloon inflation (from 0.27 +/- 0.11 to 0.17 +/- 0.09, p less than 0.001). The end-systolic meridional wall stress decreased during bypass support (from 141 +/- 75 to 110 +/- 58 x 10(3) dynes/cm2, p less than 0.02). Regional myocardial function was assessed by a wall motion score (0 = normal, 1 = hypokinesia, 2 = akinesia and 3 = dyskinesia). Regions supplied by a stenotic (greater than or equal to 50% diameter) vessel deteriorated during bypass support (score from 0.9 +/- 0.8 to 1.06 +/- 0.8, p less than 0.01), whereas regions supplied by a nonstenotic vessel did not. Regions supplied by the target vessel deteriorated further during balloon inflation (score from 0.7 +/- 0.6 to 1.7 +/- 0.75, p less than 0.001). Thus, although left ventricular size and global function remain unchanged and afterload decreases during bypass support, myocardial dysfunction in regions supplied by a stenotic vessel may occur. Furthermore, regional and global left ventricular dysfunction still occur with angioplasty balloon inflation during cardiopulmonary bypass support.

Death with dipyridamole-thallium imaging.

Excerpt Dipyridamole-thallium 201 cardiac imaging is a sensitive and specific test for detecting coronary artery disease in patients unable to exercise effectively (1-3). Minor side effects from di...

Clinical, Hemodynamic, Electrocardiographic and Mechanical Events During Nonocclusive, Coronary Atherectomy and Comparison with Balloon Angioplasty

The periprocedural events and myocardial function during nonocclusive coronary atherectomy by Rotablator or transluminal extraction catheter (TEC) may differ from events during balloon angioplasty. This may have important clinical consequences and needs to be defined further. Therefore, 17 patients undergoing Rotablator and 18 undergoing TEC atherectomy were assessed by clinical, hemodynamic and electrocardiographic monitoring and simultaneous transesophageal echocardiography. The findings were compared with similar parameters during subsequent balloon angioplasty performed in 16 of 17 patients undergoing Rotablator and 14 of 18 undergoing TEC atherectomy. Chest pain occurred more frequently during balloon inflation than during either atherectomy (p less than 0.02), whereas ST-segment and T-wave electrocardiographic changes were equally frequent. Transient second- or third-degree atrioventricular block occurred in 6 patients during Rotablator but in none during TEC atherectomy or balloon inflation (p less than 0.01 for each). Hemodynamic parameters and global left ventricular function remained unchanged during atherectomy. Regional myocardial function in the distribution of the target coronary artery, assessed by a wall motion score, was not affected during Rotablator, but deteriorated slightly during TEC atherectomy and more significantly during balloon inflation (score from 0.3 +/- 0.5 to 1.0 +/- 0.7 during TEC and 2.0 +/- 0.6 during balloon inflation, p less than 0.005 for both). Thus, chest pain is infrequent, whereas hemodynamics and global left ventricular function are preserved during Rotablator and TEC atherectomy. Transient atrioventricular block during Rotablator and regional myocardial dysfunction during TEC atherectomy may occur without significant consequences. These data suggest that these techniques may be preferable to balloon angioplasty for preserving intraprocedural left ventricular function.