Allen D. Johnson

Temporal response of left ventricular performance to mitral valve surgery.

We separated MR patients into two subgroups. In 12 subjects (group 1) with preoperative EDD = 5.94 0.42 cm, ESD = 3.55 ± 0.43 cm, and EF = 0.70 ± 0.05, EF fell slightly by 6 months after surgery to 0.59 ± 0.10 (p < 0.01), but remained within the normal range. Concomitantly, left ventricular hypertrophy regressed, as CSA was 24.2 6.5 cm2 before and 18.6 ± 2.4 cm2 after surgery (p < 0.01). contrast, in four subjects (group 2) with preoperative EDD = 8.07 ± 0.35 cm, ESD = 5.69 ± 0.70 cm, and EF = 0.57 ± 0.05, left ventricular function progressively deteriorated after surgery, with EF falling 0.26 ± 0.06 (p < 0.01). In the latter group left ventricular hypertrophy did not regress (CSA = 31.5 ± 4.5 cm2 before and 31.9 ± 3.4 cm2 after surgery, NS). Techniques for myocardial preservation during mitral valve surgery did not differ between the MR and MS groups. In group 2 MR subjects, there was no evidence of intraoperative myocardial infarction.

Nontraumatic determination of left ventricular ejection fraction by radionuclide angiocardiography.

Previous reports have suggested that left ventricular ejection fraction can be assessed by recording the passage of peripherally administered radioactive bolus through the heart. The accuracy and validity of this technique were examined in 20 patients undergoing diagnostic cardiac catheterization. 99m-Tc-human serum albumin was injected via a central venous catheter into the superior vena cava and precordial activity recorded with a gamma scintillation camera interfaced to a small digital computer. A computer program was designed to generate time-activity curves from the left ventricular blood pool and to calculate left ventricular ejection fractions from the cyclic fluctuations of the left ventricular time-activity curve which correspond to left ventricular volume changes during each cardiac cycle. The results correlated well with those obtained by biplane cineangiocardiography (r equals 0.94) and indicated that the technique should allow accurate and reproducible determination of left ventricular ejection fraction. The findings, however, demonstrated that the time-activity curve must be generated from a region-of-interest which fits the left ventricular blood pool precisely and must be corrected for contributions arising from noncardiac background structures. This nontraumatic and potentially noninvasive technique appears particularly useful for serial evaluation of the acutely ill patient and for follow-up studies in nonhospitalized patients.

Measurement of left ventricular ejection fraction by mechanical cross-sectional echocardiography.

Cross-sectional echocardiography is a new noninvasive technique for imaging the heart. We developed a method for using mechanical cross-sectional echocardiograms (sector scans) to determine left ventricular volumes and ejection fraction. Using left ventricular cineangiography as a standard, sector scan ejection fraction correlated better (r = 0.93) than M-mode echocardiography by any of three established methods, and the sector scan regression line did not differ from the line of identity (p > 0.33). Interobserver variability for sector scan ejection fraction was 2.3 i 1.2% (mean ± SD). Variation between two studies performed within 24 hours and analyzed by the same observer was 1.4 ± 1.5%. However, the sector scans consistently underestimated left ventricular end-diastolic volume. We conclude that sector scan echocardiography is more reliable than conventional M-mode techniques for estimating left ventricular ejection fraction, but estimation of left ventricular end-diastolic volume is unreliable with the methods currently available.

Serial noninvasive assessment of left ventricular hypertrophy and function after surgical correction of aortic regurgitation

Serial echocardiographic analyses of left ventricular hypertrophy and function, with validation of extent of shortening by first pass radionuclide angiography, was performed in 16 patients before and after surgical correction of severe aortic valve regurgitation. All patients were symptomatic (predominantly in New York Heart Association functional class III or IV) before operation but were in class I or II after operation. The preoperative pattern of eccentric hypertrophy (increased mass with normal ratio of left ventricular cross-sectional wall area to cavity area) changed immediately after operation to a pattern of concentric hypertrophy (increased mass with increased ratio of left ventricular cross-sectional wall area to cavity area) because of a significant reduction in chamber size and increase in wall thickness. On late follow-up (9 to 35 months, average 15 months after operation), the hypertrophy lessened significantly, the cross-sectional area of the ventricular wall decreasing to 21.1 ± 5.4 (mean ± standard deviation) cm2 from a preoperative average of 31.6 ± 4.8 cm2 (P < 0.01), and the ratio of wall area to cavity area was once again normal. In the same period, left ventricular enddiastolic diameter decreased from 6.52 ± 0.68 to 4.64 ± 0.52 cm (P < 0.01). Preoperatively, ejection phase indexes were normal or only marginally depressed in 12 of 16 patients but were moderately depressed in the remaining 4. At early follow-up (average 4 months) ventricular shortening tended to increase; and at late follow-up the fractional shortening of the minor axis, the ejection fraction and the mean velocity of circumferential fiber shortening increased to 0.39 ± 0.07, 0.68 ± 0.10 and 1.26 ± 0.22 circumference/sec, respectively, from preoperative values of 0.33 ± 0.09, 0.60 ± 0.14 and 1.05 ± 0.31 circumferences/sec (P < 0.05 for each index). In the four subjects with preoperative depression of left ventricular function, the extent and speed of myocardial shortening at late follow-up became normal in three subjects and remained moderately depressed in one patient. Paradoxical septal motion was observed immediately postoperatively and in the early follow-up studies, but it was noted in only 3 of 16 cases by the late follow-up period. Provided septal dyskinesia was not present, echocardiographic and first pass radionuclide determinations of ejection fraction correlated highly (r = 0.92). It is concluded that when aortic valve replacement for symptomatic aortic regurgitation is undertaken prior to severe myocardial decompensation, improvement in clinical status is associated with significant regression of myocardial hypertrophy, reduction in left ventricular size, evolution of a normal massvolume ratio, recovery of septal dyskinesia as revealed on echocardiography, and improvement in left ventricular function. These data do not define the type and degree of left ventricular dysfunction which is irreversible.

False aneurysms of the left ventricle. Identification of distinctive clinical, radiographic, and angiographic features.

False aneurysms of the left ventricle were observed in 14 patients. They were caused by obstructive coronary arterial disease with resultant myocardial infarction in 11, bacterial endocarditis in 1, a knife wound in 1, and disruption of a ventriculotomy in 1. Most of them extended posteriorly on the lateral radiograph, as opposed to the usual anterior position of true aneurysms. Enlargement was frequently observed on sequential studies. Angiography usually demonstrated involvement of the diaphragmatic or posterolateral segment due to occlusion of the right coronary artery; in contrast, true aneurysms are apical or anterolateral and are due to occlusion of the left anterior descending artery. The frequency of rupture of false aneurysms points up the importance of dinstinguishing them from true aneurysms.

An echocardiographic study of interventricular septal motion in the Wolff-Parkinson-White syndrome.

SUMMARY Echocardiographic studies of interventricular septal motion were performed in 26 consecutive patients with the Wolff- Parkinson-White (WPW) syndrome and in ten normal subjects. All patients with types A or B pre-excitation were subclassified into groups I to IV on the basis of their electrocardiogram utilizing the method of Boineau and associates. In all 14 patients with type A (Group III or IV) pre-excitation, the motion of the interventricular septum and posterior left ventricular wall motion were normal. However, in 11 patients with type B (Group 1) WPW an abnormal septal movement was noted. This was characterized in ten patients by an early systolic posterior motion, a subsequent anterior movement in mid systole, and the usual posterior septal motion beginning in late systole. In eight patients, including the one without early systolic posterior movement of the septum, the late systolic posterior movement was interrupted by a prominent septal notch. One patient with type B (Group II) WPW was studied and exhibited normal septal and posterior wall motion. In one patient with a spontaneous change in the QRS complex from normal to a type B (Group I) WPW pattern, the septal motion was initially normal and abruptly changed following the first WPW beat. The onset of abnormal interventricular septal motion with type B pre-excitation QRS complexes strongly suggests that abnormal septal movement may be related to an altered sequence of ventricular depolarization during right ventricular pre-excitation.

Assessment of left ventricular function in severe aortic regurgitation

SUMMARY Echocardiographic (echo) measurements of left ventricular ejection phase indices — ejection fraction, percent shortening of the minor diameter (%ΔD), and velocity of circumferential fiber shortening (Vcf) — are said to be accurate reflections of their angiographic (angio) counterparts. Most studies correlating echo and angio left ventricular function parameters have induded relatively few patients with aortic regurgitation. Echo and angio measurements of left ventricular ejection phase indices thus might not correlate in these patients in whom left ventricular geometry may have been altered due to the volume overload. To test this hypothesis, left ventricular ejection phase indices were determined by angiography and echocardiography and compared in 20 patients with isolated, symptomatic, severe aortic regurgitation. Ejection fraction, %ΔD, and Vcf by LAO cineangiograms and echo were uniformly higher than corresponding meaurements from RAO angio, and were often normal in the presence of other indicators of significant left ventricular dysfunction. We conclude that the usual, linear echocardiographic measurement of left ventricular wall motion may not reflect sigpificant myocardial dysfunction in patients with severe aortic regurgitation.

Swallowing-Induced Paroxysmal Supraventricular Tachycardia

This report describes an unusual case of swallowing-induced paroxysmal supraventricular (atrial or junctional) tachycardia in a young man without evidence of organic cardiac or esophageal disease. The arrhythmia was apparently potentiated by excessive coffee ingestion. Unlike swallowing-induced brady-arrhythmias which are due to vago-vagal mechanisms, the supraventricular tachycardia in the present case may have been related to an adrenergic reflex.

Noninvasive diagnosis of ischemic cardiomyopathy by fluoroscopic detection of coronary arterial calcification

Twenty-four patients with severe congestive heart failure and cardiomegaly in whom the presence or absence of significant coronary disease could not be ascertained clinically underwent fluoroscopy for coronary artery calcification prior to cardiac catheterization. Ten of the patients were found to have significant coronary artery disease, and 14 had normal coronary arteriograms. Coronary artery calcification was found in all ten patients with significant coronary disease, and was absent in all of those patients with normal coronary arteriograms. We conclude that fluoroscopy for coronary artery calcification provides a reliable noninvasive method for differentiating ischemic from nonischemic cardiomyopathy.