Measuring the impact of known inotropes on rat papillary muscles via the force-clamped feedback work-loop

Abstract Introduction Ventricular arrhythmias from papillary muscles (PMs) often require extensive catheter ablation (CA). Not much is known about the mitral valve (MV) function after these extensive catheter ablations. Purpose The goal of this study was to determine the impact of papillary muscle CA on MV function. Methods We retrospectively examined echocardiographic measurements in 21 patients with frequent premature ventricular contractions (PVCs) originating from the mitral PMs who underwent CA, dating from October 2012 till November 2018. We assessed MV function at baseline, 6 month and last follow-up. Degree of mitral regurgitation (MR) was graded as mild (ERO <0,2 cm2, regurgitation volume (RV) <30ml), moderate (ERO 0,2-0,4cm2, RV 30-59ml) or severe (ERO ≥0,4cm2, RV ≥60ml). Significant MR was defined as a 2+ change. Results Mean age of the study population was 59,7 (27-80)years, 52,4% was female. 2 patients were known with ischemic heart disease. There was a family history of sudden cardiac death in 3 patients. Main symptoms at presentation were palpitations (66,7%), fatigue (33,3%), dyspnea (33,3%, all NYHA 2), dizziness (28,6%), angina pectoris (14,3%) and syncope (4,8%). Beta blocker (71,4%), flecaïnide (23,8%), amiodarone (9,5%), sotalol (4,8%) and propafenon (4,8%) were the most frequent medical therapies before CA. Mean burden of PVC before ablation was 15 574 (2000-39700)/24h. In 28,6% non sustained VT was documented, 1 patient suffered a sustained episode of VT. After ablation, mean burden of PVC was reduced to 1331 (0-14200)/24h. Redo ablation was necessary in 28,6% of patients. PVCs orginated from the anterolateral PM in 33,3% and from the posteromedial PM in 66,7%. Mean troponin release was 9.4 ± 5.3 µg/l, mean troponin hs (since 2016) was 1591.0 ±658.6ng/ml. CMR was done in 14/21 (66,7%) patients before CA. In 5 out of 14 patients (35,7%), delayed enhancement at the papillary muscles was noticed. In 5 patients without delayed enhancement, CMR was repeated after CA. In all these 5 patients, delayed enhancement was noticed at the level of the papillary muscles. At baseline, 15/21 had mild, 5/21 moderate and 1/21 severe MR. There was no significant chance in MR at 6m follow-up with 15/21 having mild and 6/21 moderate MR (p 0.58) with 1 patient having a significant MR 2+ change. At last follow-up (23.7 ± 22.6 months) there was also no significant chance in MR with 15/21 having mild and 6/21 moderate MR (p 0.58) without a significant MR 2+ change. Complications occurred in 1 patient (transient AV blok). No patients died during follow up. Conclusions Although PM ablation was associated with time extensive ablation, significant troponine release and documented delayed enhancement on post ablation MRI, there was no risk of additional valvular dysfunction after CA in this study. Larger studies will be necessary to confirm these findings.

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Abstract 2304: Impact of Papillary Muscle Relocation as Adjunct Procedure to Mitral Ring Annuloplasty in Functional Ischemic Mitral Regurgitation

Circulation ◽

10.1161/circ.118.suppl_18.s_702-c ◽

2008 ◽

Vol 118 (suppl_18) ◽

Author(s):

Henrik Jensen ◽

Morten O Jensen ◽

Morten H Smerup ◽

Stefan Vind-Kezunovic ◽

Steffen Ringgaard ◽

...

Keyword(s):

Mitral Regurgitation ◽

Papillary Muscle ◽

Ischemic Mitral Regurgitation ◽

Papillary Muscles ◽

Posterior Papillary Muscle ◽

Ring Annuloplasty ◽

Group A ◽

Leaflet Coaptation ◽

The Impact ◽

3D Magnetic Resonance Imaging

The optimal surgical treatment in functional ischemic mitral regurgitation (FIMR) remains controversial. Recently, a posterior papillary muscle relocation (PMR) technique as adjunct procedure to ring annuloplasty has been proposed to prevent recurrent FIMR. We assessed the hypothesis that relocating both papillary muscles as adjunct procedure to down-sized ring annuloplasty improves mitral leaflet coaptation geometry in FIMR pigs. Eleven FIMR pigs were randomized to down-sized ring annuloplasty (RA, N=6) or RA combined with PMR (RA+PMR, N=5). In the RA+PMR group a 2– 0 Goretex suture was attached to each trigone, exteriorized through the corresponding papillary muscle, mounted on an epicardial pad and tightened to relocate the myocardium adjacent to the anterior and posterior papillary muscles 5 and 15 mm, respectively. Using 3D magnetic resonance imaging the impact from these interventions on leaflet geometry was assessed. Statistically significant (p<0.05) differences in postoperative leaflet geometry were observed at end-systole (RA vs. RA+PMR, mean ±SEM): Occlusional leaflet area (877 ±36 vs. 666 ±52 mm 2 ), tenting volume (1620 ±132 vs. 1064 ±198 mm 3 ), mean tenting height (5.9 ±0.2 vs. 4.9 ±0.3 mm), mean coaptation length (6.5 ±0.2 vs. 7.6 ±0.3 mm). Figure 1 shows coaptation length and tenting height of leaflet segments A1-P1, A2-P2 and A3-P3 at end-systole. Adding papillary muscle relocation to down-sized ring annuloplasty reduced leaflet tethering and improved coaptation geometry and therefore holds promise for reducing the prevalence of recurrent FIMR in patients.

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Insights into diastolic function analyses using cardiac magnetic resonance imaging: impact of trabeculae and papillary muscles

Insights into Imaging ◽

10.1186/s13244-021-01104-4 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Bjoern P. Schoennagel ◽

Kai Müllerleile ◽

Enver Tahir ◽

Jitka Starekova ◽

Regine Grosse ◽

...

Keyword(s):

Magnetic Resonance ◽

Diastolic Function ◽

Blood Pool ◽

Precise Determination ◽

Papillary Muscles ◽

Third Phase ◽

Volume Curve ◽

Rate Ratios ◽

Age Range ◽

The Impact

Abstract Background This cardiovascular magnetic resonance (CMR) study investigates the impact of trabeculae and papillary muscles (TPM) on diastolic function parameters by differentiation of the time-volume curve. Differentiation causes additional problems, which is overcome by standardization. Methods Cine steady-state free-precession imaging at 1.5 T was performed in 40 healthy volunteers stratified for age (age range 7–78y). LV time-volume curves were assessed by software-assisted delineation of endocardial contours from short axis slices applying two different methods: (1) inclusion of TPM into the myocardium and (2) inclusion of TPM into the LV cavity blood volume. Diastolic function was assessed from the differentiated time-volume curves defining the early and atrial peaks, their filling rates, filling volumes, and further dedicated diastolic measures, respectively. Results Only inclusion of TPM into the myocardium allowed precise assessment of early and atrial peak filling rates (EPFR, APFR) with clear distinction of EPFR and APFR expressed by the minimum between the early and atrial peak (EAmin) (100% vs. 36% for EAmin < 0.8). Prediction of peak filling rate ratios (PFRR) and filling volume ratios (FVR) by age was superior with inclusion of TPM into the myocardium compared to inclusion into the blood pool (r2 = 0.85 vs. r2 = 0.56 and r2 = 0.89 vs. r2 = 0.66). Standardization problems were overcome by the introduction of a third phase (mid-diastole, apart from diastole and systole) and fitting of the early and atrial peaks in the differentiated time-volume curve. Conclusions Only LV volumetry with inclusion of TPM into the myocardium allows precise determination of diastolic measures and prevents methodological artifacts.

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Substrate dependence of myocardial response to hypoxia in the presence of theophylline

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1983.245.2.h363 ◽

1983 ◽

Vol 245 (2) ◽

pp. H363-H367

Author(s):

T. R. Snow ◽

T. Caspar

Keyword(s):

Mechanical Performance ◽

Pyridine Nucleotide ◽

Significant Loss ◽

Papillary Muscles ◽

Mechanical Function ◽

Dynamic Relation ◽

Oxidation Reduction ◽

Hypoxic Episode ◽

Substrate Dependence ◽

The Impact

The experiments reported here were designed to determine whether stimulating glycogenolysis with theophylline affects the ability of isolated rabbit papillary muscles to sustain and recover from a transient hypoxic episode (15 min). Different substrates [glucose (Glc), pyruvate (Pyr), and butyrate (BA)] were used to either support the glycogen levels or permit their depletion. To evaluate the metabolic consequences, the dynamic relation (coupling coefficient) between the oxidation-reduction level of the intramitochondrial pyridine nucleotide NADH and the mechanical power was determined using a microfluorometer. In the absence of theophylline, the presence of Glc was associated with a smaller decrease in developed tension (tau) during the hypoxic period (Glc 53 +/- 5%) when compared with the nonglycolytic substrates (Pyr 33 +/- 5% or BA 31 +/- 6%). The extent of the recovery was not dependent on the available substrate. The addition of theophylline was accompanied by a substrate-dependent increase in tau: Glc 153 +/- 9%, Pyr 134 +/- 9%, and BA 116 +/- 7%. Theophylline increased the impact of the hypoxic episode on mechanical performance: Glc 17 +/- 4%, Pyr 4 +/- 4%, and BA 6 +/- 5%. With Glc, recovery was comparable to control. For the nonglycolytic substrates, recovery of mechanical function was depressed (Pyr 69 +/- 7%, BA 71 +/- 6%), and there was a significant loss of metabolic sensitivity. These data show that the inotropic response to theophylline is in part determined by the available substrate; theophylline exacerbates the impact of a hypoxic episode, and this effect may be due to the metabolic consequences of its presence.

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Formation of Lunar Craters and Bright Rays as a Result of Meteorite Impacts

Symposium - International Astronomical Union ◽

10.1017/s0074180900178404 ◽

1962 ◽

Vol 14 ◽

pp. 415-418

Author(s):

K. P. Stanyukovich ◽

V. A. Bronshten

Keyword(s):

Explosive Charge ◽

The Moon ◽

Meteorite Impacts ◽

The Earth ◽

Lunar Craters ◽

The Impact

The phenomena accompanying the impact of large meteorites on the surface of the Moon or of the Earth can be examined on the basis of the theory of explosive phenomena if we assume that, instead of an exploding meteorite moving inside the rock, we have an explosive charge (equivalent in energy), situated at a certain distance under the surface.

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The Geosciences Applied to Lunar Exploration

Symposium - International Astronomical Union ◽

10.1017/s0074180900178222 ◽

1962 ◽

Vol 14 ◽

pp. 169-257 ◽

Cited By ~ 9

Author(s):

J. Green

Keyword(s):

Lunar Surface ◽

Probable Mechanism ◽

Point Of View ◽

Lunar Exploration ◽

Geological Model ◽

Apply Geophysics ◽

Surface Features ◽

The Impact

The term geo-sciences has been used here to include the disciplines geology, geophysics and geochemistry. However, in order to apply geophysics and geochemistry effectively one must begin with a geological model. Therefore, the science of geology should be used as the basis for lunar exploration. From an astronomical point of view, a lunar terrain heavily impacted with meteors appears the more reasonable; although from a geological standpoint, volcanism seems the more probable mechanism. A surface liberally marked with volcanic features has been advocated by such geologists as Bülow, Dana, Suess, von Wolff, Shaler, Spurr, and Kuno. In this paper, both the impact and volcanic hypotheses are considered in the application of the geo-sciences to manned lunar exploration. However, more emphasis is placed on the volcanic, or more correctly the defluidization, hypothesis to account for lunar surface features.

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Asteroid and Comet Impact Speeds upon Mars: Significance for Panspermia and the Supply of Organics

International Astronomical Union Colloquium ◽

10.1017/s0252921100014718 ◽

1997 ◽

Vol 161 ◽

pp. 197-201 ◽

Cited By ~ 1

Author(s):

Duncan Steel

Keyword(s):

Probability Distributions ◽

Regions Of Interest ◽

Significant Fraction ◽

Organic Chemicals ◽

Impact Speed ◽

The Mean ◽

The Impact

AbstractWhilst lithopanspermia depends upon massive impacts occurring at a speed above some limit, the intact delivery of organic chemicals or other volatiles to a planet requires the impact speed to be below some other limit such that a significant fraction of that material escapes destruction. Thus the two opposite ends of the impact speed distributions are the regions of interest in the bioastronomical context, whereas much modelling work on impacts delivers, or makes use of, only the mean speed. Here the probability distributions of impact speeds upon Mars are calculated for (i) the orbital distribution of known asteroids; and (ii) the expected distribution of near-parabolic cometary orbits. It is found that cometary impacts are far more likely to eject rocks from Mars (over 99 percent of the cometary impacts are at speeds above 20 km/sec, but at most 5 percent of the asteroidal impacts); paradoxically, the objects impacting at speeds low enough to make organic/volatile survival possible (the asteroids) are those which are depleted in such species.

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Organic Syntheses During the Impact of a Comet with a Gaseous Planet

International Astronomical Union Colloquium ◽

10.1017/s0252921100014706 ◽

1997 ◽

Vol 161 ◽

pp. 189-195

Author(s):

Cesare Guaita ◽

Roberto Crippa ◽

Federico Manzini

Keyword(s):

Polymeric Material ◽

Molecular Form ◽

Parent Compound ◽

Blue Filter ◽

Organic Syntheses ◽

The Impact

AbstractA large amount of CO has been detected above many SL9/Jupiter impacts. This gas was never detected before the collision. So, in our opinion, CO was released from a parent compound during the collision. We identify this compound as POM (polyoxymethylene), a formaldehyde (HCHO) polymer that, when suddenly heated, reformes monomeric HCHO. At temperatures higher than 1200°K HCHO cannot exist in molecular form and the most probable result of its decomposition is the formation of CO. At lower temperatures, HCHO can react with NH3 and/or HCN to form high UV-absorbing polymeric material. In our opinion, this kind of material has also to be taken in to account to explain the complex evolution of some SL9 impacts that we observed in CCD images taken with a blue filter.

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Hydrogen Cyanide Polymers from the Impact of Comet P/Shoemaker-Levy 9 on Jupiter

International Astronomical Union Colloquium ◽

10.1017/s025292110001469x ◽

1997 ◽

Vol 161 ◽

pp. 179-187

Author(s):

Clifford N. Matthews ◽

Rose A. Pesce-Rodriguez ◽

Shirley A. Liebman

Keyword(s):

Amino Acids ◽

Solar System ◽

Hydrogen Cyanide ◽

Nitrogen Heterocycles ◽

Laboratory Studies ◽

Heterogeneous Solids ◽

The Many ◽

Comet Halley ◽

The Impact ◽

By Products

AbstractHydrogen cyanide polymers – heterogeneous solids ranging in color from yellow to orange to brown to black – may be among the organic macromolecules most readily formed within the Solar System. The non-volatile black crust of comet Halley, for example, as well as the extensive orangebrown streaks in the atmosphere of Jupiter, might consist largely of such polymers synthesized from HCN formed by photolysis of methane and ammonia, the color observed depending on the concentration of HCN involved. Laboratory studies of these ubiquitous compounds point to the presence of polyamidine structures synthesized directly from hydrogen cyanide. These would be converted by water to polypeptides which can be further hydrolyzed to α-amino acids. Black polymers and multimers with conjugated ladder structures derived from HCN could also be formed and might well be the source of the many nitrogen heterocycles, adenine included, observed after pyrolysis. The dark brown color arising from the impacts of comet P/Shoemaker-Levy 9 on Jupiter might therefore be mainly caused by the presence of HCN polymers, whether originally present, deposited by the impactor or synthesized directly from HCN. Spectroscopic detection of these predicted macromolecules and their hydrolytic and pyrolytic by-products would strengthen significantly the hypothesis that cyanide polymerization is a preferred pathway for prebiotic and extraterrestrial chemistry.

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