SEARCH · PubMed Health

Results for “Papillary Muscles”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 541 records · Page 30Linked to original sources

PubMed2001

Metoprolol attenuates postischemic depressed myocardial function in papillary muscles isolated from normal and postinfarction rat hearts.

The present study was designed to test the hypothesis that metoprolol treatment may enhance tolerance to ischemia in normal and postinfarction rat myocardium. Myocardial infarction was induced by permanent ligation of the left coronary artery in adult rats. Animals were divided into sham-operated and infarction groups with or without metoprolol treatment. Metoprolol treatment (60 mg/kg/day via gastric gavage) was started on the second day after surgery and continued until sacrifice at 6 weeks after myocardial infarction. Isometric force and intracellular Ca(2+) ([Ca(2+)](i)) transients were simultaneously recorded in isolated left ventricular papillary muscles. Ischemia was simulated by immersing the muscles into fluorocarbon with hypoxia. Metoprolol treatment induced a significant improvement of isometric force and ameliorated diastolic [Ca(2+)](i) overload in postinfarction rat myocardium at baseline. Metoprolol treatment also reduced diastolic [Ca(2+)](i), ameliorated the depression of developed tension during ischemia, and enhanced recovery of postischemic depressed myocardial function in sham-operated and postinfarction rat papillary muscles. Protein levels of the sarcoplasmic reticulum Ca(2+) ATPase of left ventricles and postischemic papillary muscles from metoprolol-treated rats were higher than those in placebo-treated animals. We concluded, therefore, that metoprolol treatment produced appreciable improvement of intracellular Ca(2+) handling during ischemia-reoxygenation cycles, and enhanced recovery of postischemic depressed myocardial function in both normal and postinfarction rat myocardium.

Adrenergic beta-Antagonists↗

PubMed2002

Cardiac pseudoaneurysm coupled with a rupture of the papillary muscle complicating myocardial infarction.

As a complication of myocardial infarction, dual rupture of the left ventricular myocardium and the papillary muscle is a rare condition. In such a case, the heart is predisposed to reduced output because of unloading of the ventricle during systole, resulting in the patient being in danger of deteriorating into a severe state or dying suddenly from cardiogenic shock. We report a rescued case of a 65-year-old woman, who had cardiogenic shock due to left ventricular pseudoaneurysm, coupled with partial rupture of the posteromedial papillary muscle three weeks after posterior myocardial infarction. Emergent left ventriculography revealed a large aneurysmal cavity and regurgitation towards the left atrium. The patient underwent emergent aneurysmectomy with mitral valve replacement.

Aged↗

PubMed1990

Effect of pinacidil on the electrophysiological properties in guinea-pig papillary muscle and rabbit sino-atrial node.

The electrophysiological effect of the antihypertensive drug pinacidil has been examined in preparations of guinea-pig papillary muscle and rabbit sino-atrial node using a standard microelectrode method. In papillary muscle preparations, pinacidil (greater than 30 microM) shortened the action potential duration (APD), whereas it did not affect the maximum rate of rise (Vmax). Pinacidil (greater than 1 microM) also decreased APD of slow action potentials evoked by high K+ (27 mM) solution containing 0.2 mM Ba2+. At 30 microM, the drug reduced the Vmax of slow action potentials. In the spontaneously beating sino-atrial node, pinacidil (greater than 30 microM) shortened APD. At 100 microM, it also decreased the heart rate, Vmax, action potential amplitude and the rate of diastolic depolarization. It is concluded that pinacidil modifies the electrical activity of myocardial cells probably due to an increase in the potassium conductance although in high concentrations the compound might also reduce Ca2+ influx through the cell membrane, which would contribute to an obvious negative chronotropic action.

Action Potentials↗

PubMed1983

Anomalous papillary muscle insertion contributing to obstruction in discrete subaortic stenosis.

A case of discrete subvalvular aortic stenosis with anomalous insertion of a papillary muscle to the base of the anterior mitral valve leaflet and continuous with the discrete subaortic stenosis is described. Two-dimensional echocardiographic and pathologic data showing the contribution of the anomalous papillary muscle to left ventricular outflow tract obstruction are presented.

Adult↗

PubMed1988

Papillary muscle rupture as a first event in acute myocardial infarction.

Cardiogenic shock caused by papillary muscle rupture in acute myocardial infarction is potentially reversible by surgical treatment. A case of inferior myocardial infarction in a 56-year-old previously healthy man is reported, in which the first event was papillary muscle rupture. The patient was in shock and had a mitral insufficiency murmur. The diagnosis was made by echocardiography and ventriculography. A St. Jude valve was implanted, and the patient was discharged in good health. It is suggested that routine echocardiography be carried out on patients with sudden cardiogenic shock, when a mitral murmur is present.

Heart Rupture↗

PubMed1975

Enhanced contractility during relaxation of cat papillary muscle.

Contractility during relaxation of isometric tension was studied in isolated, electrically driven cat papillary muscle by interpolation of test extrasystoles, all of whichpartially fused with their antecedent (control) contractions, were separated by computer from the fused contractions and then analyzed. The time course of the restitutionof contractility during relaxation was defined by plotting maximal positive dT/dt andtime-to-peak tension of the computer-separated extrasystole versus delay preceding the extrasystole. The dT/dt and time-to-peak tension, which steadily decline with progressive prematurity between contractions, both increase again during late relaxation, become progressively greater still earlier in relaxation, peak shortly after peak isometric tension, and then again decline. This phase of an apparently enhanced contractilityduring relaxation is depressed in low Ca'++ and is transmitted into the postextrasystolic period (in which it is superimposed on the usual postextrasystolic potentiation). The possible contributions of variations in series-elastic component and contractile-element lengths, actionpotential characteristics, and other factors on contractility during relaxation are discussed. It is suggested that enhanced contractility during relaxation may also be related in part to the decay of the intracellular free Ca'++ transient.

Action Potentials↗

PubMed1976

[Morphology, topography and nomenclature of the human papillary muscles compared with mammalian].

On the internal or parietal surface of the left ventricle in man and in mammals are two papillary muscles, which are almost identical and well developed. In man, these muscles are known as the m. papillaris parietalis anterior sinister and the m. papillaris parietalis posterior dexter, in mammals, the m. papillaris parietalis cranialis sinister and caudalis dexter, or, in shorter form, mm. papillaris parietalis sinister et dexter. In the right ventricle in man, there are two papillary parietal muscles: the mm. papillares anteriores et posteriores. On the septum of this ventricle there is, as in mammals, a muscle called the m. papillaris septalis medialis seu subarteriosus. Beside it are one or several smaller muscles, varying from one individual to another: the mm. papillares septales accessorii seu parvi. In the right ventricle of the mammalian heart is found, in addition to the m. parietalis septalis subarteriosus, already mentioned, a m. papillaris caudalis, more or less well developed in some species and, in the majority of mammals, the m. papillaris septalis cranials, which is always well developed. In certain mammals, there is, in rare cases, a m. papillaris septomarginalis seu parietalis. It may be said, in conclusion, that, in a large number of mammals, there is, on the internal surface of the external wall of the right ventricle, a reasonably well developed m. papillaris parietalis.

Anatomy, Comparative↗

PubMed2002

Mechanical activity and force-frequency relationship of isolated mouse papillary muscle: effects of extracellular calcium concentration, temperature and contraction type.

Cardiac physiology of the mouse is becoming increasingly important because the mouse is the mammalian model animal of choice for genetic modifications. However, mouse cardiac muscle is still poorly characterized under physiological conditions and inconsistent results have been published in the literature regarding mechanical activity especially the force-frequency relationship in isolated mouse muscle preparations. In this study we investigated systematically several mechanical parameters of isolated mouse papillary muscle such as force-frequency relation, twitch force, time to peak tension, relaxation time and post-rest potentiation at different experimental conditions. Extracellular calcium concentration ([Ca2+]) was varied between 1.0 and 5.0 mM, temperature between 27 degrees C and 37 degrees C and force measurements were performed under isometric as well as auxotonic conditions. The mechanical activity of muscle preparations was found to be strongly dependent on [Ca2+] and temperature and slightly on contraction type. At low temperature and low [Ca2+] the force-frequency relation was strongly positive whereas at high temperature and high calcium it turned negative. The results of this study demonstrate a flat force-frequency relation in mouse papillary muscle at physiological conditions (37 degrees C, [Ca2+] of 1.5 mM) and provide a reliable experimental basis for comparative studies with genetically altered mice.

Animals↗

PubMedDate not supplied

The relationship between the papillary muscles and the anatomicosurgical segments of the left ventricle of the human heart.

The relationship between the blood supply of the papillary muscles of the left ventricle of 90 adult human Caucasian hearts and the arteries of the cardiac anatomicosurgical segments was studied after arterial injection of Vinyl acetate and partial or total corrosion. The anterior papillary muscle belongs in most cases to the I SV segment whereas the posterior muscle belongs to the III DV segment, the former pertaining to the left coronary a. and the latter to the right a.

Adolescent↗

PubMed1990

[Effect of a new positive inotropic agent (OPC-8212) on intracellular potential of isolated canine ventricular papillary muscle].

This study adopted intracellular microelectrode technic to observe the effect of OPC-8212 (Vesnarinone) on intracellular potential of isolated canine ventricular papillary muscle. The record and data processing were completed by computerized intellective instrument designed by ourselves. The results of intracellular record in 14 canine ventricular papillary muscle showed no significant change in the resting potential (RP), amplitude of action potential (APA) and maximum depolarize velocity of 0 phase (Vmax). But significantly increased whole duration of action potential (APT). The duration of repolarization to 1/3 (APD 1/3) and to 2/3 (APD 2/3) significantly increased too. The plateau phase raised. These results suggest that K+ permeability at resting myocardiac cell membrane may have not been effected by OPC-8212. Activation of the fast sodium channel may have not been effected too. The results of our studies also suggest that inward flow of Ca2+ increased. The delayed outward K+ (Ik) and the inward, rectifying K+ current (Ik1) possible decreased. Thus, the OPC-8212 might become a nonglucoside and noncatecholamine new positive inotropic drug.

Action Potentials↗

PubMed1973

Triglycerides, cholesterol, and phospholipids in normal heart papillary muscle and in patients suffering from diabetes, cholelithiasis, hypertension, and coronary atheroma.

The triglyceride, cholesterol, and phospholipid contents of heart papillary muscle were measured in groups of obviously healthy and diseased females and males on whom either routine or forensic necropsies were performed. In healthy men the triglyceride content was 1.77 +/- 1.30 mg/g of wet weight and in women 1.25 +/- 0.48 mg/g wet weight. The corresponding values for cholesterol were 1.07 +/- 0.24 mg/g and 1.21 +/- 0.22 mg/g and those for phospholipids 17.70 +/- 5.15 mg/g and 19.65 +/- 10.21 mg/g. The differences between the sexes were not significant. The hypertensive or cardiac hypertrophy group had about the same or slightly lower means for lipid content. In the cholelithiasis group, women had significantly high triglyceride values (3.38 +/- 2.36 mg/g). The cholesterol values were not significantly elevated in either men or women. In the diabetic group, triglycerides were significantly increased both in men (mean 8.12 +/- 0.54 mg/g) and in women (6.85 +/- 5.66 mg/g). The cholesterol mean values were also high in both sexes, but the rise was not significant because of the great variation. In the coronary atheroma group, both male and female hospital cases had high triglyceride contents (mean 4.48 +/- 4.25 mg/g and 3.65 +/- 3.94 mg/g) whereas the forensic cases had only slightly elevated or normal values. Cholesterol assays paralleled the triglyceride ones, but phospholipids showed an inverse trend. The results showed that the lipid content of papillary muscle was increased in diseases where disturbances of lipid metabolism are evident, as in diabetes and cholelithiasis. In coronary atheroma only those cases with advanced obstruction of the arteries were associated with abnormal values of papillary lipids. No increase of the lipid content with age alone was found, nor was there any correlation with obesity.

Age Factors↗

PubMed1997

Hybrid logistic characterization of isometric twitch force-time curve of intact blood-perfused canine right ventricular papillary muscle.

We previously found that a ventricular isovolumic pressure-time curve could be well fitted by the difference between two S-shaped logistic curves for the pressure rising and falling components, and called it "hybrid logistic" function: P(t)=A/[1+exp[-(4B/A)(t-C)]]-D/[1+exp[-(4E/D)(t-F)]]+G. We reported that the parameters of this hybrid logistic function are useful to characterize left ventricular contraction and relaxation comprehensively. In this study, we investigated how well this hybrid logistic function could fit the isometric twitch force-time curves of cross-circulated right ventricular papillary muscles of 7 dogs. This function precisely fitted the isometric force curves with correlation coefficients above 0.9996, much better than another fitting function (F(t)=C(t/A)(B)exp[1-(t/A)(B)]) proposed by Nwasokwa. The present results indicate that our hybrid logistic function can also reasonably express the canine right ventricular papillary muscle isometric twitch force-time curve. We suggest the possibility that the parameters of this hybrid logistic function are also useful to comprehensively characterize right ventricular papillary muscle twitch contraction and relaxation.

Animals↗

PubMedDate not supplied

Anomalous papillary muscle producing dynamic left ventricular outflow tract obstruction.

A patient with a dynamic left ventricular outflow murmur was shown to have an anomalous anterolateral papillary muscle by transthoracic and transesophageal two-dimensional Doppler echocardiography. High late systolic outflow velocity and systolic anterior motion were demonstrated in the lateral outflow tract near the anomalous muscle, suggesting a role for the Venturi effect. This is the first confirmation by Doppler echocardiography of an anomalous papillary muscle contributing to abnormal left ventricular hemodynamics.

Adult↗

PubMed2004

Extended septal myectomy for hypertrophic obstructive cardiomyopathy with anomalous mitral papillary muscles or chordae.

OBJECTIVES: Transaortic left ventricular septal myectomy yields excellent results for most severely symptomatic patients with hypertrophic obstructive cardiomyopathy. However, associated anomalies of the mitral subvalvular apparatus may prevent complete relief of obstruction, and mitral valve replacement has been advocated. We reviewed our results of procedures designed to relieve obstruction with preservation of the mitral valve. METHODS: Among 291 patients undergoing septal myectomy from 1975 to 2002, 56 (ages 2-77 years) had anomalous mitral subvalvular apparatus including anomalous chordae (n = 28) and papillary muscles with direct insertion into mitral leaflets (n = 13) or fusion to septum (n = 31) or free wall (n = 12); 82% of patients were in New York Heart Association class III or IV. Operation included resection of anomalous chordae (28 patients), relief of papillary muscle fusion (36 patients), and extended septal myectomy, wider at the apex than the base. RESULTS: There were no early deaths and no patients required mitral valve replacement. Mean peak pressure gradients decreased from 70 +/- 28 to 4.9 +/- 8.4 mm Hg and mean mitral regurgitation grade decreased from 2.3 to 1.0 (P <.001). Mean follow-up was 2.8 +/- 2.6 years. Freedom from reoperation at 4 years was 95%. There were 3 late noncardiac deaths; 98% of patients were in New York Heart Association class I or II. CONCLUSIONS: Hypertrophic obstructive cardiomyopathy associated with anomalous mitral papillary muscles or chordae can be successfully treated without mitral valve replacement by surgical relief of the anomalies and an extended septal myectomy; early mortality is low, obstruction and mitral regurgitation are significantly reduced, and late results are excellent.

Adolescent↗

PubMed1991

Acceleration of H+ extrusion via Na(+)-H+ exchange in guinea-pig ventricular papillary muscle under intracellular acidic condition.

We investigated mechanisms by which intracellular pH was regulated under intracellular acidic condition in resting guinea-pig ventricular papillary muscles in vitro. Intracellular sodium ion activity (aiNa), intracellular and surface pH (pHi and pHs) were measured with Na(+)- and H(+)-selective microelectrodes and resting tension was measured. By exposure to 0 mM K solution aiNa and resting tension increased progressively while pHi decreased but reached the steady level of pH 6.95. pHs which was lower than external bulk pH (pHo) decreased progressively by exposure to 0 mM K solution. In 4 mM K solution, amiloride (1 mM), an inhibitor of Na(+)-H+ exchange, induced a reversible decrease in both aiNa and pHi, and an increase in pHs. Changes in pHi and pHs induced by application of amiloride in 0 mM K solution were larger than those in 4 mM K solution. The rate of decrease in pHi induced by amiloride became larger at longer exposure to 0 mM K solution. Lowering pHo from 7.4 to 6.4 induced a larger decrease in pHi in 0 mM K solution than that in 4 mM K solution. Lowering pHo from 7.4 to 5.4 reversed the difference between pHs and pHo. These results suggest that in guinea-pig papillary muscle, Na(+)-H+ exchange is active to regulate intracellular H+ under resting condition and under intracellular acidic condition, H+ extrusion via the Na(+)-H+ exchange would be accelerated not only by the net thermodynamic driving force for Na+ and H+ but also by other factors.

Acids↗

PubMed2003

Left ventricular myxoma originating from the papillary muscle.

A rare case of left ventricular myxoma presenting embolization into the brachial artery is reported. The sessile tumor originated from the posteromedial papillary muscle and involved the chorda supporting the posterior mitral leaflet. Complete excision of the tumor with the posterior head of the posteromedial papillary muscle, with the chorda and with the posterior mitral leaflet necessitated valve replacement. The tumor was well visualized by the superior-septal and transaortic approaches. These enabled exploration of all four cardiac chambers so as not to overlook any multifocal myxoma. The left ventricular myxoma should be completely resected with the surrounding endocardium in order to avoid recurrence of the disease.

Cardiomyopathies↗

PubMedDate not supplied

Comparative studies on the pharmacological actions of antiarrhythmic drugs in isolated rate papillary muscle.

1. The effects of ajmaline, cocaine, phenytoin, lignocaine, procainamide, propranolol, quinidine and trimetazidine on the contractility and the refractory period of isolated rat papillary muscles were compared. 2. At the higher concentrations used, all drugs suppressed the contractile tension of the rat papillary muscles. 3. The effects of these drugs on the refractory period were compared at concentrations at which the contractile tension was suppressed by 30% of the control. At this point, lignocaine, procainamide, ajmaline and quinidine prolonged the refractory period more than two-fold while the effects of propranolol and phenytoin were slight, cocaine and trimetazidine had little or no effect.

Animals↗

PubMed1980

Effect of substrates on the mechanical performance of rhesus monkey papillary muscle.

This study examines the effect of different substrates on mechanical performance of excised papillary muscles from rhesus monkeys which had been divided into a control group and an experimental group fed a high fat diet for 5 months prior to sacrifice. The results show that performance is affected by availabel substrate for both groups. The performance of the experimental group was depressed relative to control with the short chain fatty acid, butyrate (C4), producing a monotonically decreasing force-frequency response. Relative to the other mammals, isolated rhesus papillary muscles exhibited a protracted treppe which was sensitive to beta-adrenergic blockade with propranolol.

Animals↗