Reizo Kusukawa

Importance of left atrial function in patients with myocardial infarction.

Left atrial function was evaluated in patients with and without remote myocardial infarction. The simultaneous left atrial pressure recording and left atrial and left ventricular cineangiograms were obtained with a catheter-tip micromanometer. The pressure-volume curve of the left atrium was composed of an A-loop and a V-loop. The ratio of active atrial emptying to left ventricular stroke volume in patients with myocardial infarction was significantly larger than that in normal subjects (42 + 12% vs 29 + 10%, p < 0.05). The left atrial work was also significantly greater in patients with myocardial infarction (1690 + 717 mm Hgml) than in normal subjects (940 426 mm Hg-ml, p < 0.05). The ratio of active atrial emptying to left ventricular stroke volume and left atrial work were significantly related in both normal subjects and patients with myocardial infarction (y = 0.72, p < 0.01). The left ventricular ejection fraction correlated inversely with left atrial work (y = - 0.5, p < 0.05). Left atrial work also showed a significant linear correlation with left atrial volume before active atrial emptying (y = 0.82, p < 0.01). We conclude that the left atrial contribution to left ventricular function is increased in patients with remote myocardial infarction. This left atrial contribution to the left ventricle is attributed to the Frank- Starling mechanism in the left atrium.

Clinical applications of transesophageal echocardiography.

Standard transthoracic ultrasound examination of the heart has provided increasingly better images since it was clinically introduced approximately 25 years ago. Although two-dimensional echocardiography is an established tool in clinical cardiology, the image qualities of conventional transthoracic approaches are sometimes unsatisfactory for various reasons, such as obesity, chronic obstructive lung disease, and changes with age in the chest wall. In these patients, transesophageal echocardiography can provide important diagnostic information because chest wall interference and intrathoracic attenuation are eliminated. Furthermore, the close vicinity of the heart and thoracic aorta to the transducer allows the use of higher frequency, near-focused focused transducer, which produces better resolution and improved signal to noise ratio. In this brief review, We discuss the diagnostic possibilities and clinical advantages of transesophageal echocardiography based on its application in more than 1,500 awake patients since 1977 in our department.

Effects of the presence or absence of preceding angina pectoris on left ventricular function after acute myocardial infarction

Left ventricular (LV) function was evaluated in 31 patients, who had total occlusion of the left anterior descending coronary artery and less than 70% stenosis of the other two major coronary arteries or any branch. Fifteen of 31 patients had a history of angina pectoris before acute myocardial infarction (AMI) and 16 of 31 patients had no history of angina pectoris before AMI. The patients with angina pectoris before AMI had a significantly better ejection fraction, percentage of abnormally contracting segment, and regional wall motion than those without angina pectoris before AMI. These data suggest that the symptom of angina pectoris before AMI could be a favorable sign in preserving LV function when the patients subsequently had AMI.

Mechanism of augmented left atrial pump function in myocardial infarction and essential hypertension evaluated by left atrial pressure-dimension relation

To analyze left atrial (LA) pump function in normal subjects, in patients with essential hypertension and in patients with a healed myocardial infarction, LA dimension (aortic-root echogram) and pressure (catheter-tip manometer) were simultaneously recorded in 25 patients (8 normal subjects, 7 with hypertension and 10 with myocardial infarction). The pressure-dimension relation of the left atrium was composed of 2 loops: the A loop (expressing the pump function of the left atrium) and the V loop. LA dimension at the beginning of active LA shortening was significantly greater in hypertensive subjects (33 +/- 3 mm) and in those with myocardial infarction (32 +/- 4 mm) than in normal subjects (28 +/- 3 mm) (p less than 0.01, p less than 0.05, respectively). The area of the A loop significantly increased in subjects with hypertension (48 +/- 3 mm Hg.mm, p less than 0.01) and in subjects with myocardial infarction (29 +/- 10 mm Hg.mm, p less than 0.05), compared with normal subjects (20 +/- 8 mm Hg.mm). The mean fractional shortening velocity of the left atrium significantly increased in subjects with hypertension, compared with normal subjects and those with myocardial infarction (p less than 0.05 for both). LA peak wall tension during the LA active contraction period significantly increased with hypertension and with myocardial infarction, compared with normal subjects (p less than 0.01, p less than 0.05, respectively). The area of the A loop was directly proportional to the LA dimension at the beginning of active LA shortening (r = 0.53), p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnosis and quantitative evaluation of secundum-type atrial septal defect by transesophageal Doppler echocardiography.

Transesophageal echocardiography (horizontal sector scan) was performed in 11 patients with secundum atrial septal defect (ASD). In all 11 patients, transesophageal echocardiography presented the definite visualization of the defect and a clear laminar shunt flow that showed its 2 peaks in late systole and late diastole. We estimated the size of ASD and a shunt volume across the defect by using transesophageal echocardiography. The defect size determined by transesophageal echocardiography was correlated with the surgical measurement (horizontal width, r = 0.92, p less than 0.001; vertical length, r = 0.85, p less than 0.01). A significant high correlation was shown between the shunt volume measured by transesophageal echocardiography and that by Ficks method (r = 0.87, p less than 0.01). There was no significant correlation between the pulmonary to systemic flow volume (ratio) and the mean shunt flow velocity across ASD, although a high linear correlation was observed between the pulmonary to systemic flow ratio and the defect size in horizontal direction (r = 0.82, p less than 0.01). Transesophageal echocardiography used for diagnosis and quantitative evaluation of ASD could be performed easily and satisfactorily within 10 minutes. Thus, transesophageal echocardiography is a useful method in evaluation of the defect size and the shunt flow volume of ASD. The mean shunt flow velocity was not a reliable index for estimating the shunt flow volume. The defect size might be a valuable determinant of left-to-right shunt volume in ASD.

Coronary arteriography and left ventriculography during spontaneous and exercise-induced ST segment elevation in patients with variant angina

The present study is an angiographic demonstration of coronary artery spasm during both spontaneous and exercise-induced angina in three patients with variant angina. In each case, clinical, ECG, coronary angiographic, and left ventriculographic observations were made at rest, during spontaneous angina, and during exercise-induced angina. The character of chest pain was similar during spontaneous and exercise-induced episodes. ST segment elevation was present in the anterior ECG leads during both episodes. The left anterior descending coronary artery became partially or totally obstructed during both types of attacks. When coronary spasm was demonstrated during both types of attacks, left ventriculography disclosed akinetic or dyskinetic wall motion in the area supplied by the involved artery. In those patients with reproducible exercise-induced ST segment elevation and chest pain, thallium-201 scintigraphy showed areas of reversible anteroseptal hypoperfusion. Thus in selected patients exercise-induced attacks of angina were similar to spontaneous episodes.

Determination of atrial size by esophageal echocardiography.

The sizes of both left atrial (LA) and right atrial (RA) cavities were assessed in 16 patients by esophageal echocardiography and biplane cineangiography. The changes in echocardiographic dimension and cineangiographic volume during 1 cardiac cycle showed excellent correlations in both atria. In the left atrium, the relation between the echocardiographic dimension and the cineangiographic volume was significant (r = 0.83) and was fitted by the following power function: LA volume (ml) = 0.94 X LA dimension (mm) 1.24. In the right atrium, the relation between the dimension and the volume was significant; RA volume (ml) = 0.015 X RA dimension (mm) 2.34 (r = 0.95). Thus, esophageal echocardiography is a useful method for evaluating LA and RA size and simultaneously observing of both atria.

Esophageal echocardiographic left ventricular anterolateral wall motion in normal subjects and patients with coronary artery disease.

Esophageal echocardiography was developed for recording left ventricular anterolateral wall (LVAW) echocardiograms and was applied clinically to 14 normal subjects and 21 patients with coronary artery disease. LVAW echocardiograms were obtained satisfactorily in 11 of 14 normal subjects (75%) and 20 of 21 patients (95%) with coronary artery disease. LVAW echocardiograms were obtained by conventional anterior echocardiography in eight of 21 patients (38%) with coronary artery disease. In 11 normal subjects, LVAW excursion averaged 10.8 ± 1.7 mm (range 8–13 mm); mean systolic velocity ranged from 28–41 mm/sec (mean 34.3 ± 5.2 mm/sec); and diastolic wall thickness ranged from 9–12.5 mm (mean 11.2 ± 0.7 mm). In 20 patients with coronary artery disease, LVAW motion obtained by esophageal echocardiography was classified into five groups according to the excursion, and the findings were in good agreement (80%) with those obtained by left ventriculography. Classification of LVAW motion by conventional echocardiography agreed with that of left ventriculography in only three of eight patients, although all eight patients had abnormal LVAW motion by the conventional method. In all patients except one, whose LVAW echocardiograms were obtained by conventional echocardiography, excursion was much less than that obtained by esophageal echocardiography. We conclude that the projection of an ultrasonic beam from the intraesophageal transducer is a better approach for accurate measurement of LVAW motion.

Coronary angiography during exercise-induced angina with ECG changes

Coronary angiography was performed at rest and during bicycle exercise immediately after the onset of angina and significant ST segment elevation or depression in the ECG. Of 11 patients, six showed significant reduction of coronary lumen diameter at the site of organic stenosis; mean values of stenosis (range) before and during exercise were 55% (25% to 88%) and 98% (89% to 100%), respectively. Five patients did not have any diameter change of the organic lesion; mean values of stenosis (range) before and during exercise were 84% (74% to 89%) and 84% (73% to 92%), respectively. Excluding the areas of these stenoses, diameters of left main coronary artery, proximal, middle, and distal left anterior descending, circumflex, and right coronary artery segments were measured before and during exercise. Diameter in each coronary artery segment during exercise was not significantly changed from that before exercise, both in the groups with and without diameter reduction. Exercise provoked a localized worsening of coronary artery stenosis without changing the diameter in the remaining artery. These findings suggest that the worsening of stenosis might be caused by a regional abnormality of the coronary artery that is not necessarily related to the degree of organic stenosis.

Angina pectoris before and during acute myocardial infarction: Relation to degree of physical activity

One hundred ninety-seven patients with a history of acute myocardial infarction (AMI) were interviewed to evaluate the character of angina pectoris relative to physical activity before AMI and at the onset of AMI. Ninety-two patients had no angina before AMI and 105 had angina. Among the 105 patients with angina, 58 had chronic stable angina that did not change before AMI, 22 noted worsening of symptoms within 2 weeks before AMI, and 25 had onset of angina within 2 weeks before AMI. In the 92 patients without angina before AMI, AMI occurred during heavy exertion in 10 (11%), mild exertion in 43 (47%), at rest in 28 (30%), and during sleep in 11 (12%). In the 58 patients with chronic stable angina, 47 had angina during exertion, 7 during rest and 4 during both. However, subsequent AMI occurred during heavy exertion in 9 (15%), during mild exertion in 16 (28%), at rest in 25 (43%), and during sleep in 8 (14%). In the patients without angina, or with chronic stable angina without worsening of symptoms, AMI occurred unpredictably or differently from the mode of physical activity precipitating angina before AMI.