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At least 163 records · Page 9Linked to original sources
PubMed2002

Isolated multiple bilateral echogenic papillary muscles: A unique sonographic feature of trisomy 13.

BACKGROUND: Echogenic papillary muscles are noted in 30% of fetuses with trisomy 13. All reported fetuses with trisomy 13 and echogenic papillary muscles have exhibited additional abnormal sonographic findings. CASE: A 21.7-week fetus demonstrated three papillary echogenicities in each cardiac ventricle during ultrasound examination. Chromosomal analysis of amniocytes showed the karyotype 47,XX,+13. CONCLUSION: Multiple bilateral papillary muscles may provide the only sonographic sign of fetal trisomy 13.

Adult↗
PubMed1996

Intramyocardial pressure measurements in the isolated perfused papillary muscle of rat heart.

The intramyocardial pressure (IMP) plays a role in the interaction between heart contraction and coronary flow. In order to measure IMP we developed the isolated perfused papillary muscle. The papillary muscle was suspended in a muscle bath with oxygenated Tyrode's solution. Perfusion with Tyrode's solution took place via the septal artery. Diastolic intramyocardial pressure was measured with micropipettes with a tipdiameter of 3 to 4 microns in combination with the servo-null technique. After an equilibration period of at least a half hour where the muscle was perfused with a perfusion pressure of 40 cmH2O and stimulated with 0.2 Hz the IMP measurements started. Pressure changes resulting from changes in perfusion pressure and injection of ink via the pipette made it possible to distinguish between interstitial and vascular localization. No leakage along the shaft of the pipette to the outside was found. Perfusion caused interstitial edema in the muscle so that the cross-sectional area (CSA) of myocytes relative to total muscle CSA decreased from 71% in non-perfused muscle to 51% in perfused muscle. Interstitial edema increased approximately from 10% to 30%. The amount of edema was reduced by rapid pacing (3.3 Hz) as judged from decreased muscle diameter and a lower IMP. It is concluded that reliable IMP measurements can be made in the isolated papillary muscle and that increased filling of the interstitium increases its pressure.

Animals↗
PubMed1992

Purkinje fibre-papillary muscle interaction in the genesis of triggered activity in a guinea pig model.

OBJECTIVE: Previous studies have attempted to characterise the genesis of triggered activity related to early afterdepolarisations. Little is known about their conduction behaviour. This study was designed to examine the origin and conduction behaviour of triggered activations to throw light on the pathogenesis of torsade de pointes. METHODS: Electrophysiological interactions related to triggered activations and early afterdepolarisations between papillary muscle and Purkinje fibres were studied in the guinea pig in a single chambered bath. EDTA (5 mM) in Tyrode's solution was used and microelectrodes were placed in both papillary muscle and Purkinje fibres. RESULTS: During early superfusion, marked prolongation of action potential duration and early afterdepolarisations occurred in Purkinje fibres but not in papillary muscle. In addition: (1) with prolongation of action potential duration and early afterdepolarisations in Purkinje fibres, triggered activations arose during phase 2 and were conducted to papillary muscle, where they induced activations; (2) the number of papillary muscle discharges increased with the increase in Purkinje fibre action potential duration in a linear correlation; (3) severing a segment of papillary muscle from Purkinje fibres eliminated these papillary muscle activations; (4) some triggered activations did not conduct to papillary muscle; these had smaller amplitude, slower rate of depolarisation (dV/dt), more positive activation voltage, and similar peak voltages compared to conducted triggered activations; (5) a low plateau resulting from electrotonic interaction was recorded at the Purkinje fibre-papillary muscle junction; this plateau may have facilitated conduction of triggered activations. CONCLUSIONS: In this preparation there was a disparity of effect on Purkinje fibre and papillary muscle. Prolongation of action potential duration and repetitive activations due to early afterdepolarisations originated in Purkinje fibres and were conducted to papillary muscle. Purkinje fibre-papillary muscle interactions are of interest in relation to torsade de pointes arrhythmias which are believed to arise from this mechanism.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1992

[A successful surgical repair of acute postinfarction mitral papillary muscle rupture].

We reviewed a case who underwent early operation for acute postinfarction papillary muscle rupture. The patient was a 75-year-old male who was admitted to our hospital with cardiogenic shock required endotracheal intubation and intraaortic balloon support. The period to operation was 6 days from the onset of inferior myocardial infarction, and 2 days from the onset of postinfarction papillary muscle rupture. The posterior papillary muscle of mitral valve was totally ruptured and the mitral valve was replaced with a mechanical prosthesis (SJM 27 mm). Postoperative clinical course was not smooth, but the patient was going well. We believe to get good results for early operations of postinfarction papillary muscle rupture unless operative chances were lost.

Aged↗
PubMed1996

Morphologic classification of the mitral papillary muscles.

BACKGROUND AND AIMS OF THE STUDY: Mitral homograft replacement requires a good knowledge of the anatomy of the papillary muscles. Clinical experience with mitral homografts has revealed an as yet unexplored aspect of the morphology of the mitral subvalvular apparatus, that is correspondence between papillary muscle sub-divisions and chordal attachment to the leaflets. METHODS: To further our understanding we subjected 65 normal hearts to close scrutiny which confirmed our perioperative observations. RESULTS: We could establish a classification based on the ways that the papillary muscles relate to the leaflets via the chordae. Four types are described. In type I the papillary muscle is single. In type II the papillary muscle has two heads, one of which sends chordae exclusively to the posterior leaflet. In type III the papillary muscle is also divided, one head supporting the commissural area exclusively. Type IV PM resembles type III but is distinguished from it in the way that the head supporting the commissure is very short. In this type the different heads also originate at different levels on the ventricular wall from the apex to the base.

Humans↗
PubMed1998

Papillary muscle rupture after chordal sparing mitral valve replacement.

Complete papillary muscle rupture is a catastrophic complication of acute myocardial infarction which usually leads to acute severe mitral regurgitation requiring urgent or emergent surgery. A case in which this complication occurred after chordal sparing mitral valve replacement is described. The severed papillary muscle was removed surgically. The incidence and natural history of papillary muscle rupture occurring after chordal sparing mitral valve replacement for ischemic mitral insufficiency is not known.

Aged↗
PubMed1990

The papillary muscles of the left ventricle and the cardiac segments.

The relationship between the arterial anatomicosurgical segments and the papillary muscles of the left ventricle was investigated in 38 human hearts of adult individuals of both sexes. The specimens were studied after (a) vinyl acetate injection and corrosion (28 hearts) or (b) formaldehyde fixation (10 hearts). In 4 of the corrosion casts, the cardiac chambers were not filled with the plastic substance and, prior to corrosion, the position of the papillary muscles was marked with threads or pins. The anterior papillary muscle was related to the (a) anterior interventricular segment (I SV); (b) lateral (II SV); and (c) left marginal segment (III SV). The medical portion of the anterior papillary muscle is supplied by the artery of the I SV whereas the lateral portion is supplied by the artery of the II or III SV. The posterior papillary muscle was related to the (a) anterior interventricular segment (I SV); (b) left marginal (III SV); (c) posterior interventricular segment (III DV) and (d) posterior ventricular (IV SV). As a rule, the papillary muscles are supplied by more than one segmental artery, therefore, anatomical variations may play an important role in functional alterations produced by ischemic lesions of the myocardium.

Adult↗
PubMed1999

[Electrophysiological effects of agmatine on guinea pig papillary muscles in vitro].

The cardiac electrophysiological effects of agmatine (AGM) were examined in guinea pig papillary muscle using intracellular microelectrode technique. The results obtained are as follows. (1) Duration of action potential (APD) in normal papillary muscles were decreased by AGM in a concentration-dependent manner. (2) In partially depolarized papillary muscles, amplitute of action potential, overshoot, maximal velocity of phase 0 depolarization and APD were depressed by AGM. (3) Pretreatment with NG-nitro-L-arginine methyl ester (L-NAME, 0.5 mmol/L) did not affect the above effects of AGM (1 mmol/L) on papillary muscles. (4) The effects of AGM (1 mmol/L) could be blocked completely by pretreatment with idazoxan (0.1 mmol/L), an alpha 2-adrenoceptor (alpha 2-AR) and imidazoline receptor (IR) antagonist. All these results indicate that the effects of AGM on papillary muscles are likely due to a decrease of intracellular calcium mediated by alpha 2-AR and IR.

Action Potentials↗
PubMed1981

Is it important to preserve the chordae tendinae and papillary muscles during mitral valve replacement?

To evaluate the importance of preserving chordae tendinae and papillary muscles to left ventricular function after mitral valve replacement, 12 dogs had Carpentier-Edwards or Björk-Shiley mitral valves inserted. Cardiopulmonary bypass, systemic hypothermia at 25 degrees C and cold cardioplegia were used. The period of anoxic arrest was 30 minutes. In six dogs, mitral valve replacement was performed after complete excision of the mitral valve. In the other six dogs the anterior leaflet was partially excised but all chordae tendinae and papillary muscles were left intact. Hemodynamic measurements, including left ventricular function following volume loading, were made preoperatively and postoperatively. Left ventricular angiograms were obtained postoperatively in all dogs. Preoperatively there was no significant difference in the left ventricular function curves in the two groups, but postoperatively the curves showed significant differences. In the group with preserved chordae tendinae, left ventricular function improved with volume loading to a left ventricular end-diastolic pressure of 20 mm Hg while in the group with divided chordae tendinae, function improved more slowly and ceased to improve after loading to an end-diastolic pressure of 15 mm Hg. The mean left ventricular ejection fraction following mitral valve replacement with preserved papillary muscles was 0.62 +/- 0.01 and with divided papillary muscles was 0.45 +/- 0.05 (P less than 0.05). The authors conclude that it is important to preserve chordae tendinae and papillary muscles when carrying out mitral valve replacement.

Animals↗
PubMed1997

[A surgical case of total anterior papillary muscle rupture after acute myocardial infarction].

Mitral regurgitation (MR) due to rupture of the papillary muscle is one of the most serious complications of acute myocardial infarction (AMI) as well as ventricular septal perforation and ventricular free wall rupture. We experienced a case of complete rupture of the anterior papillary muscle. A 68-year-old man experienced an episode of dyspnea. Electrocardiographic findings were consistent with postero-lateral infarction. Massive MR is present on color Doppler imaging. He was transferred to our hospital for urgent operative indication because of papillary muscle rupture due to AMI. Six hours after the onset, the operation was performed with intra-aortic balloon pump in place. The anterior papillary muscle was ruptured completely in the mid portion. He underwent a mitral valve replacement with a SJM prosthetic valve. There is a few cases with successful urgent surgery for a complete rupture of anterior papillary muscle.

Aged↗
PubMed1962

Cat heart muscle in vitro. II. The steady state restpotential in quiescent papillary muscles.

The steady state transmembrane resting potential difference (V(m)) has been measured in quiescent papillary muscles. V(m) was determined as a function of the external K concentration in Cl and SO(4) solutions and compared with the K equilibrium potential. Other measurements were made after replacement of external Na by choline, K by Rb and Cs, and Cl by SO(4), CH(3)SO(4), and NO(3). Effects on V(m) of albumin, temperature, and variation in internal K concentration are described.

Animals↗
PubMed1989

Abnormalities in position of left ventricular papillary muscles in congenital aortic stenosis.

Subclinical structural abnormalities may accompany some congenital cardiovascular abnormalities. Echocardiographic observations led us to hypothesize that the positions of the left ventricular papillary muscles are abnormal in hearts with aortic valvar stenosis. To test this hypothesis, we examined 6 normal heart specimens and hearts with congenital cardiovascular malformations, including 5 with pulmonary atresia and an intact ventricular septum, 6 with tetralogy of Fallot and 5 with aortic valvar stenosis. We marked the papillary muscles and the mitral commissures, X-rayed the hearts, and measured the angular positions of the papillary muscles using the midpoint of a chord drawn between the mitral commissures as a reference point. The direction from the midpoint to the lateral commissure was designated as 0 degrees. The data (mean +/- SEM) were analyzed using a computer program (ANOVA). In normal hearts, the anterolateral and posteromedial papillary muscles were positioned, respectively, at 43 +/- 19 degrees and 126 +/- 26 degrees. The positions of the papillary muscles were similar to normal in the hearts with pulmonary atresia (62 +/- 38 degrees and 128 +/- 27 degrees) and tetralogy of Fallot (40 +/- 13 degrees and 130 +/- 37 degrees). In aortic stenosis, the locations of the papillary muscles (-76 +/- 42 degrees and 71 +/- 25 degrees) were significantly different from normal (P less than 0.05). The arc between the papillary muscles was 83 +/- 16 degrees in normals and 147 +/- 45 degrees in aortic stenosis (P less than 0.05). The length of the arc was similar to normal in other heart specimens. Thus, the papillary muscles were abnormally positioned in aortic stenosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve Stenosis↗
PubMed1994

Comparative mechanical study of isolated papillary muscle from Wistar-Kyoto and Wistar rats.

Isolated papillary muscles have often been used in myocardial mechanical function studies. The objective of the present study was to compare the mechanical function of papillary muscle isolated from left ventricle between Wistar (W) and Wistar-Kyoto (WKY) rats of different ages (1, 3, 6 and 12 months), in order to examine whether there is a difference in intrinsic mechanical properties of muscle between the two rat strains. Muscles were perfused with Krebs-Henseleit solution at 28 degrees C and studied isometrically and isotonically at a stimulation rate of 0.2 Hz. The W and WKY showed statistically significant differences during both isometric and isotonic contractions. During isometric contraction, (1) the peak developed tension (DT) and +dT/dt were lower in WKY rats in the 1 mo groups, (2) the resting tension (RT) was greater in WKY at 3, 6 and 12 mo, (3) time to peak tension (TPT) was greater in WKY at 3 and 12 mo, (4) time for tension to fall from peak to 50% of peak tension (RT 1/2) was greater in WKY at 3 mo and (5)-dT/dt was lower in WKY at 1 and 3 mo. During isotonic contraction, (1) the peak shortening (PS) and--dL/dt were lower in WKY at 12 mo, (2) the time to peak shortening (TPS) was greater in WKY at 3 and 12 mo; (3) +dL/dt was lower in WKY at 3, 6, and 12 mo and (4) the relative variation of length (Lmax-PS)/Lmax was greater in WKY at 6 and 12 mo. These data showed a difference in mechanical behaviour of the papillary muscle between Wistar and Wistar-Kyoto rats of different age.

Aging↗
PubMed1982

[Positive inotropic action of plasma on the papillary muscle of rabbit heart].

Experiments on the papillary muscles of the rabbit heart were made to examine the effect of blood plasma on isometric contractions and intracellular rest potentials (RP) and action potentials (AP) of individual myocardial fibers. The replacement of the perfusate (Tyrode's solution) with plasma diluted with the solution (1:1) led to an increase in the amplitude of rhythmical contractions of the papillary muscles at stimulation frequencies of 0.1 to 2 Hz. The positive inotropic action of the plasma was accompanied by the shortening of the length of the intracellular AP. The increased amplitude of contractions does not appear to be associated with the action of catecholamines that might occur in the plasma, since the beta-adrenoblocker propranolol did not abolish the inotropic plasma effect. The removal (dialysis) of low-molecular plasma components with a molecular weight less than 50 000 daltons led to the elimination of the positive inotropic effect of the plasma. This allowed a suggestion that the factor that increases the contraction amplitude might occur in the low-molecular part of the plasma.

Animals↗
PubMed1993

Effects of bretylium tosylate on electrophysiologic properties of normal and digitalized papillary muscles of guinea pigs.

The effects of bretylium tosylate (BT) on the electrophysiologic properties of normal and digitalized papillary muscles isolated from guinea pigs were studied with regular glass microelectrode. BT prolonged effective refractory period (ERP) and action potential duration (APD) of normal papillary muscles. The ERP and APD of papillary muscles were shortened by perfusion with ouabain (Oua) 0.2 mumol.L-1. No recovery was seen in perfusion without drug for 30 min. In digitalized papillary muscles with Oua, ERP, APD90, and APD50 were prolonged by BT 120 mumol.L-1 form 175 +/- 20, 187 +/- 20, and 146 +/- 21 ms to 222 +/- 21, 220 +/- 19, and 190 +/- 19 ms, respectively. The results demonstrated that BT can prolong ERP and APD of papillary muscles digitalized with Oua.

Action Potentials↗
PubMed1977

In situ measurement of papillary muscle dynamics in the dog left ventricle.

In five open-chest dogs, pairs of ultrasonic dimension gauges were implanted in the anterior papillary muscle and in a circumferential subendocardial segment of the anterior left ventricular free wall, and simultaneous recordings were made with intracardiac pressure. The average shortening of the anterior segment in isovolumetric systole was 6% of end-diastolic length (EDL), with a total shortening of 19%. In the papillary muscles, isovolumetric shortening averaged 2%, total shortening was 10%, and shortening velocity was only 0.60 length/s. With acute pressure and volume overload, or inotropic interventions, changes in EDL were relatively less in papillary muscles than in the free wall. During acute occlusion of the anterior descending coronary artery, shortening of anterior segments and papillary muscles was replaced by holosystolic lengthening, and occlussion of the circumflex artery produced augmentation of shortening in both these regions, with lengthening of the posterior papillary muscle. The present study documents shortening of the anterior left ventricular papillary muscle throughout systole that is substantially less than that of the circumferential free wall, and demonstrates severe papillary muscle dysfunction with systolic elongation during regional ischemia.

Animals↗
PubMed1985

Length dependent potentiation and inhibition of post-rest twitch tension development in adult cat and kitten papillary muscles.

If a rest interval is applied to a regularly stimulated cardiac muscle, the first contraction after this interval (post-rest contraction) has either a greater (post-rest potentiation) or a smaller (post-rest inhibition) developed tension than the regular contraction. Positive inotropic interventions will augment the post-rest potentiation and reduce the post-rest inhibition. We examined the effects of muscle stretching on the post-rest contraction in papillary muscles isolated from adult cats and from kittens and compared the effects with those of two typical inotropic interventions: high frequency stimulation and high calcium concentration. We found that muscle stretching augmented the post-rest potentiation and reduced the post-rest inhibition in a manner similar to the two inotropic interventions in the adult cat papillary muscle, and that these effects were consistently reversed in the kitten papillary muscle. The similarity of the effect of muscle stretching to those of the two typical inotropic interventions in either adult cat or kitten papillary muscle suggests that the effect of muscle stretching is due to an inotropic effect of muscle length change.

Animals↗
PubMed2006

A morphological and morphometric study of the right ventricular papillary muscles of autopsied heart of Bangladeshi people.

Fifty formalin-fixed hearts from thirty nine male and eleven female Bangladeshis aged 20 to 70 years and without any known cardiac disorder were used in the present study. In right ventricle, there was a single anterior papillary muscle in 92% cases. The posterior papillary muscle was double in 32% and single in 28% cases. The septal papillary muscle was single in 46% cases while in 30% cases it was absent. The different between males and females in the total number of papillary muscles was statistically non significant. In the right ventricle, the anterior papillary muscles were the longest and the septal papillary muscles were the shortest.

Adult↗