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At least 19 recordsLinked to original sources

PubMed1977

Effects of stroke volume and velocity of ejection on end-systolic pressure of canine left ventricle. End-systolic volume clamping.

To study the effects of contraction mode on ventricular end-systolic pressure-volume relationship, we compared the end-systolic pressure of isovolumic contraction with that of ejecting contraction at an identical end-systolic volume. The left ventricle of excised cross-circulated canine hearts was fitted with a water-filled balloon. The balloon was connected to a hydraulic pump that allowed the ventricle to contract to a preset constant end-systolic volume (19-37 ml) from a variable end-diastolic volume. At each of control, enhanced, and depressed levels of contractility, differences of end-systolic pressures of steady state isovolumic and ejecting contractions were evaluated while stroke volume and velocity of ejection were widely varied. The end-systolic pressure in the ejecting contraction tended to decrease by 5-15% from that of the isovolumic beat with increases in either stroke volume to 20-25 ml or peak velocity of ejection to about 800 ml/sec. There was no obvious difference in the results at different levels of contractility. The magnitude of the end-systolic pressure depression due to ejection was, however, relatively small as compared to 4-fold changes in end-systolic pressure due to the changes in contracility. We, therefore, conclude that the ventricular end-systolic pressure-volume relationship is affected slightly by ejection, and that this effect is much smaller than the maximal effect of changing contractility on the end-systolic pressure-volume relationship.

Animals↗

PubMed1976

Non-ejection systolic clicks and mitral systolic murmurs in black schoolchildren of Soweto, Johannesburg.

A survey was conducted on 12 050 Black schoolchildren, aged 2 to 18 years, in the South Western Townships of Johannesburg (Soweto), and the prevalence of non-ejection systolic clicks and late systolic murmurs was determined. One or both of these auscultatory findings were detected in 168 children, yielding a prevalence rate of 13-99 per 1000 in the school population. A female preponderance of 1-9:1 was present and there was a strong linear increase in prevalence with age, with a peak rate of 29-41 per 1000 in 17-year-old children. A non-ejection click was the only abnormal auscultatory finding in 123 children (73%) and a mitral systolic murmur in 8 (5%), whereas in 37 (22%) both these findings were present. Of the latter 37 children, the murmur was late systolic in 32; in 5 it was early systolic. Auscultation in different postures was important in the detection of both non-ejection clicks and mitral systolic murmurs. Experience in the detection of these auscultatory findings influenced the frequency with which they were heard. Electrocardiographic abnormalities compatible with those previously described in the billowing mitral leaflet syndrome were present in 11 of 158 children. The aetiology of these auscultatory findings in this community remains unknown. In the same survey, a high prevalence rate of rheumatic heart disease was recorded and the epidemiology of the non-ejection clicks and these mitral systolic murmurs showed similarties to that of rheumatic heart disease. Though the specific billowing mitral leaflet syndrome almost certainly accounts for some of these auscultatory findings, a significant proportion may have early rheumatic heart disease. Further elucidation of this problem is necessary.

Adolescent↗

PubMed1975

Postural changes in left ventricular and mitral valvular dynamics in the systolic click - late systolic murmur syndrome.

Marked changes in the auscultatory pattern with posture have been noted in patients with mid-systolic clicks and/or late systolic murmurs (MSC-LSM). MSC tend to move earlier in systole and LSM become longer and often louder when patients assume upright posture. Systolic prolapse of the mitral leaflets with mild regurgitation account for MSC-LSM; earlier and greater prolapse with more and prolonged regurgitation associated with a reduced left ventricular volume (LVV) in the upright position would explain the auscultatory changes. Twenty-two patients with MSC-LSM were studied supine and at 45 degrees head-up tilt, recording intracardiac pressures, cardiac outputs, systolic time intervals, and performing LV cineangiography. Systolic prolapse of one or both mitral leaflets was demonstrated in all patients. Left ventricular end-diastolic and end-systolic volumes both decreased significantly at 45 degrees in all sixteen technically satisfactory studies. Greater mitral prolapse was noted upright in 12 of 14 studies with enough sinus beats to judge. The amount of mitral regurgitation was mild in all, and changes in amount from supine to upright posture could not be discerned angiographically. THE FINDINGS, SUGGEST THAT THE AUSCULTATORY CHANGES OCCURRING WITH UPRIGHT POSTURE IN PATIENTS WITH MSC-LSM are related to greater prolapse of the mitral leaflets which is associated with a small LVV in the upright position.

Angiocardiography↗

PubMed1975

Radiographic appearance of the thorax in systolic click-late systolic murmur syndrome.

The posteroanterior and lateral chest X-ray films of 64 consecutive patients with an isolated systolic click (55 patients) or a systolic click with a late systolic murmur (9 patients) showed a striking frequency of thoracic skeletal abnormalities. There were 50 female and 14 male subjects. The average age of the female subjects was 36.7 years (range 13 to 67), that of the male subjects 39.7 years (range 17 to 56). Seventy-two percent of the female and 78 percent of the male subjects had an anteroposterior/transverse thoracic ratio less than the mean ratio in a small population. Bony abnormalities such as pectus excavatum, straight thoracic spine and scoliosis occurred alone or in a combination in 31 of the 50 female patients (62 percent) and in 8 of the 14 male patients (57 percent). Overall, 39 of the 64 patients (61 percent) had at least one of the skeletal abnormalities. Scoliosis occurred in 25 subjects (39 percent) and was mild in 19. A "straight back" was found in 15 (23 percent) and pectus excavatum in 7 patients (11 percent). The explanation for these findings is not apparent. Thoracic cage abnormalities should be included as one of the nonauscultatory features of the systolic click-late systolic murmur syndrome.

Adolescent↗

PubMed1976

The determinants of onset of mitral valve prolapse in the systolic click-late systolic murmur syndrome.

The onset of mitral valve prolapse and its close correlate, the time of systolic click, vary considerably with different physiologic and pharmacologic interventions. In order to explain the mechanism responsible for these alterations, the effects of tilt and amyl nitrite inhalation on left ventricular dynamics and the time of the systolic click were studied by analyzing echocardiograms and simultaneously recorded phonocardiograms in 14 patients with mitral valve prolapse and mid-systolic click. The patients were studied in the supine position, with 40-60 degrees head-up tilt and after amyl nitrite inhalation. Computer analysis of the recordings was used to measure the left ventricular end-diastolic diameter, the click diameter (left ventricular diameter at the time of mid-systolic click), the maximal velocity of circumferential fiber shortening (max VCF), and the time interval between the first heart sound and systolic click (S1-X). With tilt and amyl nitrite, shortening of the S1-X interval b y an average of 44 and 87 msec, respectively, was observed. The click diameter, however, remained virtually constant with both maneuvers. Earlier prolapse after tilt was due to a decrease in the end-diastolic diameter from 5.03 +/- 0.74 to 4.50 +/- 0.68 cm (P less than 0.001) with no change in max VCF. Immediately after amyl nitrite, earlier prolapse was due to an increase of VCF in the preprolapse period, with max VCF increasing from 2.15 +/- 0.27 to 3.06 +/- 0.40 circ/sec (P less than 0.001), there being no change in the end-diastolic diameter up to this time. The constant click diameter indicates that the abnormal valve motion in this syndrome occurs at a critical left ventricular chamber size. Variations in the onset of prolapse are caused by changes in left ventricular end-diastolic dimensions and the velocity of circumferential fiber shortening in the preprolapse period.

Adult↗

PubMed1977

Abnormal left ventricular contraction pattern in the systolic click-late systolic murmur syndrome.

A contraction abnormality of the left ventricle has previously been described in patients with systolic click-late systolic murmur syndrome. To determine if the contraction abnormality is present in the preprolapse period, LV dimensions and the instantaneous velocity of circumferential fiber shortening (VCF) were studied in 18 patients with the mitral valve prolapse and 16 normal subjects using computer analysis of echocardiograms. VCF attained its maximum (max VCF) during the preprolapse period an average of 94 msec before the mid-systolic click. Max VCF was significantly reduced in patients with mitral valve prolapse (2.06 vs 2.55 circ/sec in normal subjects, P less than 0.001). Despite the reduction in max VCF, no difference in the extent and percentage of diameter shortening was found between patients and normal subjects. This discrepancy is explained by a sustained rate of mid-to-late systolic diameter shortening in the presence of mitral valve prolapse as manifested by a typical VCF profile (P less than 0.001) and a longer duration of diameter shortening (353 vs 306 msec in normal subjects, P less than 0.01). The decrease of max VCF in patients with mitral valve prolapse suggests a reduction in LV contractility. Since the abnormality is present in the preprolapse period, it is unrelated to a direct mechanical effect of the prolapse itself. Additional fiber shortening in mid-to-late systole indicates that the sudden displacement of the mitral leaflets may have an unloading effect on the left ventricle.

Adult↗

PubMed1975

Mid-systolic click, late systolic murmur syndrome associated with complete heart block.

A 60 year old woman is presented who had the mid-systolic click, late systolic murmur syndrome, documented by phonocardiogram and left ventricular angiography. During an episode of non-anginal chest pain, advanced heart block was demonstrated and permanent transvenous pacemaker therapy was subsequently instituted. The association of the mid-systolic click, late systolic murmur syndrome and heart block is reviewed. It is suggested that 24-hour continuous electrocardiographic monitoring, as well as exercise stress testing, be included in the evaluation of patients with this syndrome.

Angiocardiography↗

PubMed1977

Systolic time intervals in the syndrome of midsystolic click and late systolic murmur.

Left ventricular function, as measured by systolic time intervals, was studied in 30 subjects with the syndrome of midsystolic click and late systolic murmur (ages, 20 to 53 years; mean, 34 +/- 9 years). Twenty-one were asymptomatic, six had chest pain, two had palpitations, one had shortness of breath, and one had hypotensive episodes. Each patient had the typical auscultatory and echocardiographic findings of the syndrome of midsystolic click and late systolic murmur. In the study the values for the interval between the onset of the QRS complex (Q) and the aortic component of the second heart sound (A2) (377 +/- 42 msec), the Q-A2 index (532 +/- 39 msec), the preejection period (PEP) (97 +/- 17 MSEC), THE PEP index (127 +/- 16 msec), the left ventricular ejection time index (403 +/- 26 msec) and the ratio of PEP to left ventricular ejection time (0.35 +/- 0.01) were not significantly different from the values in 17 controls matched for age. Out study, then, supports the contention that left ventricular function remains well preserved in most patients with the syndrome of midsystolic click and late systolic murmur.

Adult↗

PubMed1976

Assessment of the mid systolic click late systolic murmur syndrome by noninvasive methods.

In patients with the mid systolic click/late systolic murmur syndrome (MSC/LSM Sy) a ballooning, billowing or aneurysmal protrusion of one or both mitral leaflets has previously been described in angiographic studies. It is accepted that besides angiography noninvasive methods such as dynamic electrocardiography, phonocardiography, apexcardiography and echocardiography can provide valuable information in the diagnosis of this syndrome. Little is known however about diagnostic value and sensitivity of these methods. The dynamic Ecg, recorded during an average of 10 hours, showed in 8/20 patients (40%) one or several significant arrhythmias such as frequent ventricular premature contractions (VPCs) (greater than 12/min), multifocal VPCs, VPCs in a row or ventricular tachycardia, or 2 degrees SA-block. 12/20 patients (60%) showed in the phonocardiogram a movement of the click toward the first heart sound when the patients' position was changed from supine to sitting. In 40% of the patients a double or triple click was recorded. A late systolic bulge in the apexcardiogram was seen in 13/20 patients (65%). In one patient the recording was not successful. Echocardiographic signs of abnormal posterior movement (prolapse) of one or both mitral leaflets were recorded in 15/20 patients (75%). Five echocardiograms did not show any abnormality, but all these cases demonstrated in their apexcardiogram a late systolic bulge. We believe that in patients with the MSC/LSM Sy a mitral valve abnormality can be documented adequately by noninvasive methods.

Adolescent↗

PubMed1978

Four year follow-up of black schoolchildren with non-ejection systolic clicks and mitral systolic murmurs.

In 1972 we conducted a survey of 12,050 urban Black schoolchildren and detected 168 (prevalence rate of 14 per 1,000) with a non-ejection systolic click (NESC), a late systolic murmur, or both. The etiology of the mitral valve abnormality was unknown but we considered that a significant proportion might have early rheumatic heart disease. The auscultatory features four years later of 139 of the original 168 subjects as well as those of 139 age- and sex-matched controls are presented in this study. No cardiac abnormality was detected in as many as 55 of the subjects. Five children now had pansystolic murmurs but the mitral regurgitation was assessed as mild in four. Twenty-five (17.9 per cent) of the controls, 23 of whom had NESCs, had auscultatory features compatible with mitral valve prolapse. These findings do not support our earlier suggestion that a large number of the 1972 subjects have mild rheumatic heart disease. The results are in accord with other studies which have indicated that auscultatory features compatible with mitral valve prolapse are common in "normals" and also that the prognosis of the specific "billowing mitral leaflet syndrome" is generally benign.

Adolescent↗

PubMed1978

Apex-carotid diagram in systolic click-late systolic murmur syndrome.

A new non-invasive method based on mechanographic cycles has been developed for the study of heart function. It integrates synchronously recorded indirect carotid tracing and left apex cardiogram into an apex-carotid diagram. In 25 patients with systolic click-late systolic murmur syndrome, the diagram showed an elongation with a curvature of the segment of slow ventricular ejection to the right and a decrease in the area of ventricular ejection. It is concluded that apex-carotid diagram is an additional tool in diagnosis of the mitral valve prolapse syndrome.

Adolescent↗

PubMed1976

[Study of systolic time by external phonomechanocardiography in myocardial infarction. 1. Value of systolic times and their course during the 1st 3 weeks].

A phonomechanographic study was carried out on 38 patients with recent myocardial infarction both during the initial phase of necrosis (between the 5th and 7th day) and at the end of the third week. The parameters studied were electromechanical systole (QB2), systolic ejection time corrected for heart rate (CET), the OBl interval, isometric contraction (IC), the pre-ejection periode (PEP), and the haemodynamic coefficient (PEP/ET). The results were compared with the values found in a similar control series. A tendency towards lengthening of the pre-ejection times and shortening of the corrected ejection time was noted. These changes were significant for the second measurement of CET, and for the ratio PEP/ET during the initial phase and on second measurement. The pre-ejection times were generally increased more markedly in the group of patients with left ventricular failure; the ejection time was also markedly shorter in this group, and the haemodynamic coefficient was larger. There was a tendency for the various measurements studied to return to normal by the third week.

Heart Rate↗

PubMed1975

The problem of nonejection systolic clicks and associated mitral systolic murmurs: emphasis on the billowing mitral leaflet syndrome.

Nonejection clicks and associated mitral systolic murmurs are common in routine cardiologic practice and can result from multiple etiologic factors affecting the complex mitral valve mechanism. Such factors include a specific syndrome the essential feature of which is that the mitral leaflets or part thereof, primarily the posterior one, are voluminous. The syndrome has stimulated widespread interest and study during the last decade and various descriptive terms, including the "billowing mitral leaflet syndrome" (BMLS), have been applied to it. A familial occurrence of the BMLS may be detected and symptoms include chest pain, palpitations, syncope, and anxiety. Arrhythmias, conduction defects, and ECG abnormalities which mimic occlusive coronary artery disease are important features which remain ill understood. It is suggested that there is a possible relationship between the so-called "athlete's heart" and the BMLS. We also postulate that the entity of acute myocardial infarction without demonstrable occlusive coronary artery disease is, in at least some instances, a complication of the BMLS-possibly on the basis of coronary spasm. More severe mitral regurgitation, infective endocarditis, or, rarely, sudden death may supervene in the BMLS but we conclude, from published data and our own experience, that the prognosis is generally good.

Adolescent↗

PubMed1992

Comparison between end-systolic pressure-volume and end-systolic wall stress in determining left ventricular contractility with increased afterload.

This study compared end-systolic pressure-volume relationship (P/V) versus wall stress index (WS) as a tool for the evaluation of ventricular contractile state during upright isometric exercise. Both indices of contractility exhibit significant (p < 0.001) increase during exercise compared to resting values. The correlation coefficients for the two indices of contractility were r = -0.45 for exercise and r = -0.70 for rest. Both were significant at the p < 0.01 level. The correlation of the difference scores between rest and exercise as computed by both indices was low (-0.20) and insignificant. These data suggest that changes in contractility from rest to exercise as measured by one index do not reflect the pattern of individual differences that are measured by means of the other index. However, from a reliability point of view, it seems appropriate to prefer the use of P/V index over the WS index in order to determine contractile state.

Adult↗

PubMed1976