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PubMed2006

[Successful surgical management of papillary muscle rupture following acute myocardial infarction in an elderly patient].

Papillary muscle rupture is rare but catastrophic complication of acute myocardial infarction. We report a 91-year-old woman who underwent successful management of papillary muscle rupture following acute myocardial infarction. She was transferred to our hospital because of severe pulmonary edema and cardiogenic shock. Echocardiography revealed severe mitral valve regurgitation due to total rupture of anterolateral papillary muscle. After intubation, intraaortic balloon pumping (IABP) and percutaneous cardiopulmonary support (PCPS) insertion, mitral valve replacement was successfully performed. She was discharged 134 days after operation. In papillary muscle rupture deteriorating hemodynamics, early diagnosis and immediate cardiopulmonary support are required before surgical treatment. She was, to the best of our knowledge, the oldest among the reported cases of successful surgical treatment of papillary muscle rupture in Japan.

Aged, 80 and over↗
PubMed1990

[A case of mitral regurgitation caused by necrosis and total rupture of the papillary muscle].

Mitral regurgitation (MR) caused by total rupture of the papillary muscle has so ominous prognosis that it is treated by surgery exceedingly rarely. We recently experienced a case of MR caused by total rupture of the posterior papillary muscle that had presumably occurred after myocardial infarction. The patient was a 52-year-old male who was admitted to a hospital with liver dysfunction where he was noticed for the first time of his having cardiac murmurs and was diagnosed as having MR on the basis of echocardiography. With this diagnosis he was transferred to our department. Examination on admission revealed the patient to have an NYHA class III mitral incompetence with ECG evidence of old posteroinferior myocardial infarction. Cardiac catheterization demonstrated total occlusion of the segment 1 of the right coronary artery and MR, Sellers III. Abnormal echoes were noted in the left ventricle that moved almost synchronously with the posterior leaflet of the mitral valve, a finding leading to a suspected diagnosis of rupture of the posterior papillary muscle or chordae tendineae. Intraoperative findings were confirmative of total rupture of the posterior papillary muscle and mitral valve replacement was performed using a SJM prosthetic valve. Histological examination of the ruptured muscle revealed presence of necrosis, but no other specific inflammatory changes. Documented cases of surgically treated total papillary muscle rupture are quite limited in number, the present case being the 4th to be reported in Japan.

Heart Rupture↗
PubMed1990

Clinical and pathologic factors contributing to acute papillary muscle ischemia.

Hearts from 110 consecutive adult autopsies were examined to determine the frequency and predisposing clinical and pathologic features of acute left ventricular papillary muscle ischemia. Acute infarcts of papillary muscles were present in 23% of the hearts and were more frequent than acute infarcts of their corresponding ventricular walls. Patients with acutely infarcted papillary muscles were more likely to have significant stenosis of the corresponding coronary artery than were patients with normal papillary muscles. Increasing heart weight was also associated with increased frequency of papillary muscle acute infarction. Patients with acutely infarcted papillary muscles were more likely to have had hypertension and to have suffered significant hypotension prior to death than were patients with normal papillary muscles.

Adult↗
PubMed1980

Some mechanical considerations in the selection and testing of papillary muscles.

Measurements of segmental deformation made on papillary muscles obtained from cat, rabbit, dog and pig hearts suggest that the deformational behavior in these specimens is appreciably nonuniform both in the resting (passive) state and in the stimulated (active) state. In view of this, in the mechanical testing of papillary muscles, it is necessary to establish a minimum size of segment "sufficiently" far from the disturbing influence of end fixtures generally used to hold the specimen in the testing machine. The segment size should be large enough to average out the nonuniform aspects of deformation. Thus, the shape and size of the specimen dictated by the nonuniformities in the mechanical response, the thinness of the specimen dictated by the viability considerations and aspects of the testing machines and method dictated by the visco-elastic features of the specimen should be given due consideration in the selection and testing of papillary muscles.

Animals↗
PubMed1984

Rabbit papillary muscle myosin isozymes and the velocity of muscle shortening.

Rabbits, ages 4-24 weeks, were injected with saline or thyroxine (150 micrograms/kg) for 7 days, and force-velocity curves were generated using papillary muscles from these hearts by a method described previously. In addition, the structure and relative amounts of myosin isozymes from papillary muscles and from 3- to 5-mg segments of the left and right ventricular free wall were analyzed by polyacrylamide gel electrophoresis under native and denatured conditions. We found that rabbit papillary muscles may contain up to three isozymic forms of myosin (V1, V2, and V3) and that their relative amounts change with age of the rabbit and with thyroxine treatment. There were no differences between papillary muscles and ventricular free wall in the molecular weight of light chain1 (27,000) and light chain2 (21,500) of heavy chain alpha or in the peptide map of heavy chain alpha nor were there any differences between papillary muscles and the ventricular free wall in the molecular weight of light chain1 (27,000) and light chain2 (21,500) of heavy chain beta or in the peptide map of heavy chain beta. However, the relative amounts of myosin isozymes in the ventricular free walls and papillary muscles may not be identical within the same heart. Analysis of the force-velocity curves indicated that the speed of papillary muscle shortening is correlated with the relative amount of V1 myosin present in each papillary muscle. Papillary muscles that contain 100% V1 myosin shorten, under zero load, approximately six times faster than papillary muscles that contain 100% V3 myosin. Our results indicate that changes in the relative amounts of myosin isozymes are responsible, at least in part, for sustained alterations in the speed of papillary muscle shortening.

Animals↗
PubMed1996

Effect of propionyl-L-carnitine on the mechanics of right and left papillary muscles from volume-overloaded rat hearts.

Propionyl-L-carnitine (PLC) was shown to improve global cardiac function in pressure overload hypertrophy by acting directly on muscle mechanics. We investigated whether PLC can effectively ameliorate papillary muscle mechanics in a volume overload (VO) model. We induced VO by constructing an aortocaval anastomosis in adult Wistar rats. Three experimental groups were studied: sham-operated controls and untreated and PLC-treated VO animals. Isometric function of right and left papillary muscle was studied 16-18 weeks later. PLC was administered in the drinking water at the dose of 180 mg/kg for the last 2 weeks before experiment. One-way analysis of variance (ANOVA) showed that in right papillary muscles from the untreated VO group the time course of the isometric contraction was significantly prolonged [time-to-peak tension (TPT, ms +/- SEM) from 126 +/- 4.9 to 156 +/- 7.1; time from peak tension to 30% relaxation (TRel) from 133 +/- 11.9 to 196 +/- 13.9; n = 11 and 8, respectively], and peak rates of contraction and relaxation normalized over developed tension were significantly decreased in comparison with sham [from (s-1 +/- SEM) 12.9 +/- 0.5 to 10.8 +/- 0.6, and from 7.2 +/- 0.6 to 5.2 +/- 0.4, respectively]. These parameters in the PLC VO group did not differ from sham (TPT, 140 +/- 5.7; TRel, 158 +/- 14.4; +dF/df/DT, 12.2 +/- 0.6; -dF/df/DT, 6.5 +/- 0.5; n = 8). Function of left papillary muscle was not modified by either VO or PLC treatment. Total carnitine levels in either ventricle free walls were unchanged by VO. PLC significantly increased total carnitine content of left ventricle free wall (from 5.4 +/- 0.28 to 7.0 +/- 0.50). The contraction changes observed in the right papillary muscle are likely to depend on the pressure overload occurring in the right chamber; moreover, they are unrelated to tissue carnitine depletion. PLC improved the altered right papillary muscle mechanics without exerting any apparent effect on the functionally normal left papillary muscle. PLC activity is independent of carnitine stores, but may presumably be ascribed to its anaplerotic properties.

Anastomosis, Surgical↗
PubMedDate not supplied

[Evaluation of elasticity by means of length-tension relationships in a model of isolated ventricular myocardium from rat and cat papillary muscle under conditions of contracture (author's transl)].

Increase of Ca2+ concentration to 7.5 mM in the presence of 10 mM or 20 mM caffeine shifted length-tension relationships of 5 rat trabecular muscles and 5 cat papillary muscles to higher tensions. At 1max diastolic tension was enhanced from (formula: see text), for all measured points of stress-strain relationships after the increase of diastolic tension by caffeine and Ca2+ as well as under control conditions. The function E = f (sigma) = b (sigma - c) was computed by linear regression analysis (0.99 greater than r2 greater than 0.96). The average value of constant b was 13.89 +/- 2.01 in control curves of rat trabecular muscles and 13.42 +/- 1.98 in curves with 10 mM caffeine and 7.5 mM Ca2+. Likewise, in cat papillary muscles 20 mM caffeine and 7.5 mM Ca2+ did not alter the stiffness constant b in a statistically significant manner (control: 16.63 +/- 3.03, caffeine: 16.43 +/- 3.02). The results demonstrate that the stiffness constant b cannot indicate acute variations of the length-tension relationships due to caffeine and Ca2+ and may result in overestimating of myocardial distensibility. However, if the tangent modulus (E) is related to strain (epsilon), the alterations of diastolic elasticity are detectable. Mathematical considerations of these experimental results imply a new base for evaluation of diastolic elasticity of the heart by means of the tangent modulus (E). These results are of substantial importance in clinical evaluation of distensibility of myocardial tissue, as the tangent modulus related to wall stress apparently is not appropriate to realize alterations in "passive" myocardial properties due to contracture.

Animals↗
PubMed1982

Stretch-induced increase in resting metabolism of isolated papillary muscle.

A mathematical model of oxygen diffusion into quiescent papillary muscles in vitro is developed. The model incorporates a continuous sigmoidal function relating the rate of oxygen consumption and the partial pressure of oxygen within the tissue. The behavior of the model is explored over a wide range of external oxygen partial pressures, oxygen consumption/partial pressure relations, oxygen diffusivities, muscle dimensions, and resting metabolic rates, while the muscle is subjected to stimulated stretches of various extents in order to test the assertion that the stretch-induced increase in basal metabolic rate observed experimentally implies the existence of an anoxic core region of papillary muscles in vitro. The model predicts the existence of an oxygen diffusion-mediated stretch response of resting papillary muscle metabolism, but one which is quantitatively insignificant compared with experimentally observed values. The classic Hill diffusion model which explicitly predicts an anoxic core, likewise predicts stretch effects of magnitudes smaller than those frequently observed. It is concluded that the increment in basal metabolism of papillary muscles subjected to stretch in vivo cannot be taken as evidence of oxygen diffusion limitation in unstretched preparations.

Animals↗
PubMed2004

Variations in the papillary muscles of normal tricuspid valve and their clinical relevance in medicolegal autopsies.

OBJECTIVE: In our study, tricuspid valves in cases of sudden death secondary to congenital differences of the tricuspid valve with significant papillary muscle anatomy were investigated. No studies of papillary muscle anatomy of the tricuspid valve have been found in medicolegal autopsies in literature. The purpose of our study is to investigate the relationship of papillary muscle in tricuspid valve in cases of sudden deaths, especially those resulting from cardiac disease, with the muscle structure, as well as the number of the muscle leading congenital changes. METHODS: The study was carried out in the Department of Anatomy, Faculty of Medicine, Ege, University, Izmir, Turkey and comprised of 400 human hearts obtained between 2000 and 2002 from 400 autopsy cases during a medicolegal autopsy with permission from the Council of Forensic Medicine, Izmir. Quantitative and morphological aspects of the papillary muscles of the right ventricle were evaluated. The criteria such as number, incidence, length and shape of the anterior, (APM) septal (SPM) and posterior papillary muscles (PPM) have been observed. RESULTS: Although the papillary muscle presented great variability in numbers, with a minimum of 2 and a maximum of 9 papillary muscles in the right ventricle, there were usually 3 papillary muscles in the right ventricle; APM, PPM and SPM. The one headed APM was found to be more often in cardiac deaths. However, observing more frequent conical and flat topped configurations in all PPM was striking. The absence or lower ratio, or both of attachment bridges of SPM and APM/PPM in deaths of cardiac origin is also significant. We have found that the presence of this attachment is higher in deaths of noncardiac origin. CONCLUSION: This anatomical study may explain the increased in incidence wide variations of papillary muscle tricuspid valve in deaths of cardiac origin. The verdict in legal affairs may change with this. The knowledge regarding wide variations and minor anatomical abnormalities of papillary muscle helps forensic examiners not to get confused at unexpected deaths.

Adolescent↗
PubMed1983

An ultrastructural morphometric study of the papillary muscle of the right ventricle of the cat.

The papillary muscle of the cat heart's right ventricle has not been studied previously with quantitative ultrastructural techniques despite its wide use for functional studies. This tissue was perfusion-fixed, processed for electron microscopy, and morphometric techniques were used to assess the ultrastructural characteristics of the papillary muscle as well as the working myocardial cells. The results of this study were that 73.5% of the papillary muscle was composed of muscle cells, 9.7% of blood vessels, and the remainder of interstitial connective tissue. In the muscle cell the volume fraction of mitochondria was 17.3%, that of myofibrils was 49.8%, and that of the nucleus was 2.0%. The mitochondria to myofibrils ratio was 0.36 and the surface to volume ratio was 0.309. In a quantitative ultrastructural comparison of perfusion and immersion fixed tissue it was found that significant differences in the volume density of the blood vessel lumen existed between the two groups. In addition, there were significant differences in the volume fraction of mitochondria and nucleus between perfusion-fixed and immersion-fixed muscle cells. A concurrent significant decrease between the two groups was also found for the ratio of mitochondria to myofibrils. The perfusion-fixed tissue can be considered to provide only normal baseline data for the papillary muscle of the right ventricle. These data are important as they can be used in future structure-function studies on normal and pathological heart tissue.

Animals↗
PubMedDate not supplied

Left ventricular papillary muscle mass: relationship to left ventricular mass and volumes by magnetic resonance imaging.

OBJECTIVE: To evaluate the effect of papillary muscle mass on the calculation of left ventricular (LV) function and mass and to determine the relationship between papillary muscle mass with body size and sex. METHODS: Cardiac magnetic resonance imaging examinations from 50 men and 50 women were randomly selected from the Multi-Ethnic Study of Atherosclerosis database. The contours of the papillary muscles were traced manually, and the LV wall contours were outlined semiautomatically based on short-axis images. Papillary muscle mass, LV mass, and volumes were calculated. RESULTS: Inclusion of the papillary muscles results in significantly higher total LV mass values (P<0.001) and lower end-diastolic volume values (P<0.001) compared with measurements excluding papillary muscles from the LV mass. Papillary muscle mass accounts for 8.9% of the total LV mass and is correlated with LV wall mass (r=0.81, P<0.001). CONCLUSION: Papillary muscle mass significantly affects LV volumes and mass determined by cine magnetic resonance imaging.

Aged↗
PubMed1994

Dynamics of normal and ischemic canine papillary muscles.

This investigation was designed to elucidate the dynamics of the left ventricular (LV) papillary muscles. Miniature tantalum myocardial markers were placed on the tip and base of each papillary muscle in six dogs. Markers were also implanted into the LV myocardium to define two orthogonal equatorial diameters and the long-axis dimension. Two weeks later, after recovery from thoracotomy, markers were visualized by biplane fluoroscopy, and video images were recorded during control conditions, after autonomic blockade, after inotropic stimulation with calcium, after methoxamine infusion (to increase afterload), and after blood volume augmentation (to increase preload). Two days later, radiographic recordings were made before and after occlusion of the left circumflex coronary artery. Computer-aided analysis of the video recordings was used to determine three-dimensional coordinates of the markers. It was found that before circumflex coronary occlusion, the dynamics of both papillary muscles closely mimicked the dynamics of the LV as a whole. The papillary muscles shortened during ejection and lengthened during diastole. Their lengths changed minimally during the isovolumic periods, and this behavior was not altered by any of the interventions except coronary occlusion. During circumflex coronary artery occlusion, the ischemic posterior papillary muscle lengthened during isovolumic contraction and most of ejection and shortened only when LV pressure began to fall. Hence, we believe that previous studies demonstrating papillary muscle lengthening during isovolumic contraction and shortening during isovolumic relaxation may have been confounded by coexistent myocardial ischemia or stunning.

Animals↗
PubMed1991

A comparison of contractile function between papillary muscles and isolated myocytes from the same human hearts.

The contractile function in response to increasing extracellular calcium and isoprenaline has been investigated using papillary muscles from seven human hearts (failing and non-failing) obtained at the time of transplant. Myocytes have been enzymatically isolated from adjacent myocardium, and their contractile characteristics measured in parallel to those of the intact papillary muscle. Similar experiments were performed on rabbit hearts, but in this case separate animals were used for the papillary muscles and cells. For human myocardium, the EC50 (concentration for half-maximal effect) for calcium, and the percentage increase in amplitude between basal (1.3mM) and maximally activating calcium, was similar between papillary muscle and cells. Variability of absolute responses was 4-5 times greater for papillary muscle than for myocytes. Isoprenaline accelerated the time to peak tension, time to 50% relaxation and time to 90% relaxation in papillary muscle; a similar effect on shortening was seen for time to peak tension and time to 50% relaxation in cells. Time to peak tension and time to 50% relaxation were not significantly different between the human preparations with isoprenaline, but the time to 50% relaxation with high calcium was faster for myocytes than for papillary muscle (p less than 0.05). Isoprenaline induced after-contractions in some cells, prolonging the time to 90% relaxation. This was not observed in papillary muscle preparations. Papillary muscles were less sensitive to the stimulatory effects of isoprenaline than cells taken from the same hearts. EC50 values were higher (p less than 0.05) and increases in contraction were lower (p less than 0.05) in whole tissue. This difference between cells and papillary muscle was not seen in rabbit hearts.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1999

Mitral annular dilatation and papillary muscle dislocation without mitral regurgitation in sheep.

BACKGROUND: Asymmetrical mitral annular (MA) dilatation and papillary muscle dislocation are implicated in the pathogenesis of functional mitral regurgitation (MR). METHODS AND RESULTS: To determine the mechanism by which annular and papillary muscle geometric alterations result in MR, we implanted radiopaque markers in the left ventricle, mitral annulus, anterior and posterior mitral leaflets, and papillary muscle tips and bases in 2 groups of sheep. One group served as controls (CTL, n=7); an experimental group (EXP, n=9) underwent topical phenol application to obliterate anterior annular and leaflet muscle (confirmed histologically ex vivo). After 1 week of recovery, markers were imaged with biplane videofluoroscopy, and hemodynamic data were recorded. MA area (computed from 3-dimensional marker coordinates) was 11% to 13% larger in the EXP group than in the CTL group (P<0.05 by ANOVA). This area increase resulted exclusively from intercommissural axis increase except in 1 heart with large (>1 cm) increases in both the intercommissural and septolateral annular axes. The anterior papillary muscle tip in EXP was displaced from CTL by 2.9+/-0.23 mm toward the anterolateral left ventricle and 2.5+/-0.12 mm toward the mitral annulus at end systole; the posterior papillary muscle geometry was unchanged. Transthoracic echocardiography revealed MR only in the heart exhibiting biaxial annular enlargement. CONCLUSIONS: MA dilatation in the intercommissural dimension with anterior papillary muscle tip displacement toward the annulus is insufficient to produce MR in sheep. Functional MR may require MA dilatation in the septolateral axis, as observed with proximal circumflex coronary occlusion.

Animals↗
PubMed1995

Partial papillary muscle rupture complicating acute myocardial infarction. diagnosis by multiplane transoesophageal echocardiography.

Papillary muscle rupture is a rare but generally fatal mechanical complication of acute myocardial infarction. In contrast to complete papillary muscle rupture, echocardiographic recognition of partial papillary muscle rupture has rarely been reported and seems to be more challenging. We describe a patient with partial papillary muscle rupture that could only be diagnosed by multiplane transoesophageal echocardiography, whereas transthoracic echocardiography and single plane transesophageal echocardiography showed only posterior mitral leaflet prolapse.

Echocardiography, Transesophageal↗
PubMed2006

The comparative investigation of left ventricle papillary muscle arteries in different species.

OBJECTIVE: To determine whether similar histologic findings exist in left ventricle papillary muscle arteries in different species and to elicit whether those animal hearts may be used as models for human heart in experimental studies related to papillary muscles. METHODS: We examined 360 samples taken from the tip, mid-portion and base of papillary muscles in 60 normal adult hearts (15 each from human, dog, sheep, goat). The samples were obtained from Dicle University and Kahramanmaras Sutcu Imam University, Turkey and the study was conducted in June-September 2004. Tissues were processed by routine histologic methods, stained with hematoxylin-eosin and van giesson, and later evaluated under a light microscope. RESULTS: While the values of human and dog heart resembled each other by means of left ventricle papillary muscle arteries, the hearts of sheep and goat were also found to be similar. The number of thin walled arteries increased from the tip (18%) to the base (48%), intermediate walled arteries decreased from the tip (56%) to the base (14%), thick walled arteries decreased from the tip (62%) to the mid-portion (38%). The differences among human and animals were not statistically significant in any group. We found that the thickness values of papillary muscle arterial walls at the tip, mid-portion and base varied from 4.86 microm to 107.7 microm in all species. The difference among values of human and animals was not significant statistically (p>0.05). CONCLUSION: The values for arterial walls of tip, mid-portion and base of papillary muscles were similar between human and dog, sheep and goat. These morphologic findings in human and animal hearts of different species prove that anatomists, cardiologists, experimental investigators, pathologists and physiologists may benefit from the hearts of those animals as a good model to imitate the human heart in experiments concerning papillary muscles.

Animals↗
PubMed1988

Protein synthesis assessed by ribosome analysis in human papillary muscle in relation to oxidative capacity: a comparison with skeletal muscle.

Protein synthesis as assessed by the concentration and size distribution of ribosomes was determined together with citrate synthase activity in papillary muscles obtained at open heart surgery from patients with mitral valve disease. The results were compared with corresponding data from the quadriceps femoris muscle of patients undergoing cholecystectomy. Citrate synthase activity was six times higher in papillary muscle than in skeletal muscle. The total ribosome concentration per mg DNA was similar in the two types of muscle. Compared with skeletal muscle, in papillary muscle polyribosomes constituted a higher proportion of the ribosomes (p less than 0.001), and there was a tendency towards larger polyribosome aggregates. It is proposed that the high concentration of polyribosomes in papillary muscle is related to the high oxidative capacity of that tissue.

Citrate (si)-Synthase↗
PubMed1997

Protection by hypoxic preconditioning against hypoxia-reoxygenation injury in guinea-pig papillary muscles.

OBJECTIVE: Developed tension in guinea-pig papillary muscles is depressed by prolonged hypoxia; subsequent reoxygenation leads to a partial recovery that stabilizes after an early period of arrhythmia. We have investigated whether hypoxic preconditioning in these muscles (1) improves the recovery of developed tension, (2) protects against arrhythmia, and (3) causes other significant electromechanical changes. METHODS: Papillary muscles stimulated at 1 Hz were superfused with oxygenated Krebs solution for 60 min and either preconditioned (5 min of 3 Hz pacing substrate-free hypoxic conditions, 10 min of normoxic recovery) or equilibrated for an extra 15 min. Muscles were subsequently challenged with substrate-free hypoxia (1 Hz), and reoxygenated (1 Hz) for 60 min. Contractile performance, action potential parameters, and indicators of arrhythmic activity were measured in 10 preconditioned and 10 non-preconditioned muscles. RESULTS: Developed tension in preconditioned muscles declined to the same level (10-15% control) as in non-preconditioned muscles after 60 min hypoxia. A notable difference was that developed tension in the preconditioned muscles failed to rebound during mid-hypoxia, a hallmark feature in non-preconditioned muscles. The action potential duration and overshoot collapsed at a significantly faster rate in hypoxic preconditioned muscles. Action potential recovery during reoxygenation was similar in the two groups of muscles, but recovery of developed tension was significantly stronger in preconditioned (76.7 +/- 5.4%) than in non-preconditioned (42.9 +/- 1.7%) muscles (P < 0.001). Reoxygenation provoked arrhythmic activity in all muscles, but the summed average duration was shorter (5.5 +/- 1.0 vs. 9.4 +/- 1.5 min) (P < 0.05) in the preconditioned muscles. CONCLUSION: Hypoxic preconditioning can significantly enhance post-hypoxia recovery of developed tension, and significantly attenuate arrhythmic activity, in guinea-pig papillary muscles.

Action Potentials↗