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Cardiac function and histological changes after non-dynamic cardiomyoplasty and preliminary study of dynamic cardiomyoplasty.

By means of histological method and ultrasound cardiographic (UCG) examination, the left-right ratio of transectional area of muscle fiber of latissimus dorsi muscle (LDM) after non-dynamic cardiomyoplasty was 77.4 +/- 11.7% in Group I (3 weeks after operation), and 78.4 +/- 11.6% atrophy and hyperplasia of LDM, but the basical structure was retained. The ejection fraction (EF) decreased significantly after operation (P < 0.05), but the difference between two groups was non- significant. Also, dynamic cardiomyoplasty was performed on a sheep. UCG showed the increased cardiac systolic function after operation. ATPase, succinodehydrogenase (SDH) and PAS examination implied the strengthening of fatigue-resistant ability in skeletal muscles after long-term electrical stimulation. So cardiomyoplasty is suggested to be a supplementary measure in treating end-stage heart failure.

Animals↗

Effects of long-term thyroid hormone suppressive treatment on the cardiac functions.

Long-term effects of thyroid hormone suppressive therapy on the heart were evaluated in 45 patients by non-invasive techniques. Fifteen patients were athyreotic after surgery for differentiated thyroid cancer and 30 had diffuse or nodular goiter. Mean age of the group was 42 +/- 12 years. Twenty-four age- and sex-matched subjects were taken as controls. Mean daily dose of levothyroxine was 158 +/- 36 micrograms. Plasma thyroid stimulating hormone (TSH) levels were within normal range. Mean serum T4 and free T4 were significantly higher (p < 0.001) whereas mean serum T3 and free T3 did not differ from the control levels. Non-invasive cardiac assessment was done by a standard 12 lead electrocardiogram (ECG), ambulatory electrocardiographic (Holter) monitoring and echocardiographic study. Six patients had left ventricular hypertrophy in ECG. Holter monitoring demonstrated a higher average heart rate in patients compared to controls (86 +/- 10 vs 72 +/- 6 beats/min; p < 0.001). Supraventricular premature beats were more frequent in patients than in the control group (98% vs 60%; p < 0.06). Echocardiogram showed an increased left ventricular (LV) mass index in patient group (98 +/- 28 vs 78 +/- 16 gm/m2; p < 0.02). LV systolic function was increased with higher values of fractional shortening (40 +/- 8% vs 34 +/- 6%; p < 0.05) and rate-adjusted velocity of shortening (1.4 +/- 0.12 vs 1.02 +/- 0.16 circumferences/sec; p < 0.01). It is concluded that long-term levothyroxine suppressive therapy has significant effects on the cardiac functions.

Adult↗

The relationship between left ventricular geometric remodeling and cardiac function in essential hypertension.

BACKGROUND: Abnormal left ventricular (LV) diastolic relaxation is an early sign of hypertensive heart disease. Whether diastolic dysfunction differs between LV geometric patterns remains controversial. METHODS AND RESULTS: We examined 220 hypertensive patients by echocardiography to assess the relationship between diastolic function and LV geometric pattern. We identified four LV geometric patterns: normal geometry, concentric remodeling, concentric hypertrophy, and eccentric hypertrophy. Diastolic function was evaluated by the E/A ratio, E wave deceleration time (Dct), and isovolumic relaxation time (IRT). The E/A ratio was below one and Dct was prolonged in each group. The duration of IRT in the concentric and eccentric hypertrophy groups was significantly longer than that in normal geometry and concentric remodeling groups (p < 0.05). CONCLUSIONS: Hypertensive patients may be possible to have diastolic dysfunction, regardless of the differences in their structural geometry. The degree of impairment of cardiac diastolic function differed between hypertensive patients with different LV geometric patterns.

Aged↗

Cardiac function after domino-donor heart transplantation.

A major limitation in cardiac transplantation is donor availability. A possible way to increase the supply of donor hearts is to use explanted hearts from patients undergoing heart-lung transplantation for primary lung disease. One potential advantage of this approach, termed domino-donor transplantation, is the existence of a donor right ventricle already adapted to pulmonary hypertension, which would therefore theoretically decrease the likelihood of acute donor right heart failure in recipients with preexisting elevation of pulmonary vascular resistance. Potential disadvantages include graft failure secondary to chronic effects of pulmonary hypertension on the right ventricle, arrhythmia and infections. Seven domino-donor transplants were performed at Stanford University Hospital; graft and patient survival to date are 100% at a mean follow-up of 20 months (range 1 to 26). Infection and rejection rates have been comparable to those of the current Stanford experience for conventional orthotopic transplantation. Right ventricular function and size have either improved or remained unchanged in all patients after transplantation. Transient early postoperative donor right ventricular dilation, a characteristic adaptive response seen in nondomino transplants, occurred in 4 patients with pulmonary hypertension before surgery. These data indicate that, with adequate assessment before surgery, domino-donor cardiac transplantation is an appropriate means of augmenting the donor pool.

Actuarial Analysis↗

Effect of low [CaCl2] and high [MgCl2] cardioplegia and moderate hypothermic ischemia on myoplasmic [Ca2+] and cardiac function in intact hearts.

OBJECTIVE: Cold cardioplegia (CP) protects against ischemic damage in part by reducing [Ca(2+)](i) overload on reperfusion. Hyperkalemic cardioplegic solutions are widely used in coronary artery bypass procedures, and the specific ionic composition of these solutions may contribute to their variable myocardial protective effects secondary to reduced Ca(2+)(i) loading. We reported previously that CP decreased the rise in cardiac diastolic (dia) [Ca(2+)](i) observed during 4 h cold storage at 3 degrees C in Krebs-Ringer's (KR) solution and decreased dia[Ca(2+)](i) and increased systolic (sys) [Ca(2+)](i) and function on reperfusion after cold storage. Our aim here was to determine if low Ca(2+)(o) and high Mg(2+)(o) adds to the protective effects of high K(+)(o) by decreasing [Ca(2+)](i) during ischemia and reperfusion. METHODS: We compared effects of 4.5 mM K(+)(o), 2.5 mM Ca(2+)(o) and 2.4 mM Mg(2+)(o) KR solution with a higher K(+)(o) (18 mM), a lower Ca(2+)(o) (1.25 mM) and/or higher Mg(2+)(o) (7.2 mM) CP solutions on cardiac mechanic function and sys and dia[Ca(2+)](i) during and after moderate hypothermic global ischemia (17 degrees C for 4 h) in guinea pig intact hearts isolated by the Langendorff technique. Isovolumetric left ventricular pressure (LVP) was measured with a transducer connected to a fluid-filled balloon placed in the LV and [Ca(2+)](i) was measured using indo-1 fluorescence and a fiberoptic cable placed on the LV free wall. RESULTS: For all CP groups compared to the KR control group after 60 min reperfusion, we observed significant lowering of dia[Ca(2+)](i) by 47%, left ventricular diastolic pressure (diaLVP) by 55%, and infarct size by 43%. We also found significant elevation of sys[Ca(2+)](i) by 25%, d[Ca(2+)](i)/dt(max) and d[Ca(2+)](i)/dt(min) by 33 and 34%, sys-diaLVP by 55%, dLVP/dt(max) and dLVP/dt(min) by 34 and 40%, coronary flow by 31%, cardiac efficiency by 21%, and MVO(2) by 25%. These results indicate that CP reduces myoplasmic Ca(2+) loading and improves mechanical and metabolic function on warm reperfusion compared to KR. However, there were no differences in these indices of Ca(2+)(i) cardiac function or metabolism among any CP group after warm reperfusion with KR solution. CONCLUSION: Increasing K(+)(o) to produce cardiac arrest was the most cardioprotective effect of CP against ischemia reperfusion injury; lowering Ca(2+)(o) or raising Mg(2+)(o) did not add to this protective effect or additionally alter [Ca(2+)](i).

Animals↗

Improvement of cardiac function after transplantation of autologous bone marrow mesenchymal stem cells in patients with acute myocardial infarction.

BACKGROUND: The infarct size determines the long-term prognosis of patients with acute myocardial infarction (AMI). There is a growing interest in repairing scar area by transplanting bone marrow stem cells. However, effectiveness of intracoronary injection of bone marrow mesenchymal stem cells (BMSCs) in patients with AMI still remains unclear. METHODS: Sixty-nine patients with AMI after percutaneous coronary intervention (PCI) were randomly divided into intracoronary injection of BMSCs (n = 34) and saline (control group, n = 35) groups. Serial single positron emission computer tomography (SPECT), cardiac echo and cardiac electromechanical mapping were done at the designed time intervals until six months after transplantation of BMSCs or injection of saline. RESULTS: The proportion with functional defect decreased significantly in the BMSCs patients after three months [(13 +/- 5)%] compared with that pre-transplantation [(32 +/- 11)%] and the control group [(28 +/- 10)%] at three month follow-up (P < 0.05, respectively). Wall movement velocity over the infracted region increased significantly in the BMSCs group [(4.2 +/- 2.5) cm/s vs (2.2 +/- 1.3) cm/s, P < 0.05], but not in the control group [(2.2 +/- 1.5) cm/s vs (2.7 +/- 1.7) cm/s, P > 0.05]. Left ventricular ejection fraction (LVEF) three months after transplantation in BMSCs group increased significantly compared with that pre-implantation and with that of the control group at three months post-injection [(67 +/- 11)% vs (49 +/- 9)% and (53 +/- 8)%, P < 0.05 respectively]. SPECT scan results showed that perfusion defect was improved significantly in BMSCs group at three-month follow-up compared with that in the control group [(134 +/- 66) cm(2) vs (185 +/- 87) cm(2), P < 0.01]. At the same time, left ventricular end-diastolic volume [(136 +/- 31) ml vs (162 +/- 27) ml, P < 0.05] and end-systolic volume [(63 +/- 20) ml vs (88 +/- 19) ml, P < 0.05] decreased synchronously. The ratio of end-systolic pressure to end-systolic volume [Psyst/ESV, (2.84 +/- 1.30) mmHg/ml vs (1.72 +/- 1.23) mmHg/ml, P < 0.05] increased significantly. Cardiac electromechanical mapping demonstrated significant improvement at three months after implantation of BMSCs compared with that pre-injection in both cardiac mechanical capability as left line local shorting [LLS, (11.29 +/- 1.64)% vs (7.32 +/- 1.86)%, P < 0.05] and electrical property as left ventricular endocardial unipolar voltage [UV, (10.38 +/- 1.12) mV vs (7.61 +/- 1.09) mV, P < 0.01]; perfusion defect decreased from (36.2 +/- 6.2)% to (20.3 +/- 5.31)% (P < 0.01). Twenty-four-hour electrocardiographic monitoring demonstrated no arrhythmias occurred at three-months follow-up. CONCLUSIONS: The transplantation of BMSCs might improve the cardiac function and it is safe and feasible with no deaths or malignant arrhythmias.

Adult↗

Low cholesterol and impaired cardiac function following heart transplantation.

1. During follow-up of 59 cardiac transplant recipients over 2 or more years, a small group of subjects was observed who displayed an unpredictable, relatively marked, reduction in plasma cholesterol. 2. A significant proportion of these subjects were subsequently observed as having experienced a marked decline in left ventricular function at the time of routine radionuclide ventriculography. 3. While the mechanism for this fall in cholesterol is unclear, the observation of such an unexpected reduction in total cholesterol, late after heart transplantation should be considered significant and prompt further investigation including an assessment of allograft function.

Cholesterol↗

Addition of calcium or other cations and of oxygen to ionic and non-ionic contrast media. Effects on cardiac function during coronary arteriography.

Metrizamide is a new non-ionic water soluble contrast agent. Isolated rabbit hearts were perfused with solutions of 1) metrizamide, 2) metrizamide with plasma equivalent amounts of cations, 3) oxygenated metrizamide, 4) oxygenated metrizamide with cations, 5) diatrizoate. Solutions of 1) metrizamide, 2) metrizamide with plasmaequivalent amounts of cations, 3) metrizamide with calcium ions, 4) metrizoate (ionic medium) with calcium ions, metrizoate with 5) low and 6) high sodium content and 7) diatrizoate were injected into the left coronary artery of dog hearts in vivo. Maximal change of myocardial contractile force was measured with a strain gauge arch. Changes in aortic blood pressures were also recorded. In both sets of experiments metrizamede affected these parameters less than the ionic contrast media. The addition of calcium ions to both ionic and non-ionic media reduced the adverse effects on the observed cardiac funcitons, while simultaneous addition of plasma equivalent amounts of four cations as metrizoate salts had no beneficial effects. Sodium ions had in high concentration deleterious effects on cardiac performance. Oxygen saturation of the contrast medium had no observable effect. The adverse effects on cardiac mechanical function of sodium ions and possibly other cations contained in a contrast medium solution might be counterbalanced by the addition of calcium ions to the solution.

Aminoglycosides↗

Abnormal cardiac function in diabetic patients with autonomic neuropathy in the absence of ischemic heart disease.

To determine if cardiac autonomic neuropathy (CAN) contributes to diabetic cardiomyopathy, left ventricular function was assessed by resting and exercise radionuclide ventriculography (RVG) in 30 patients with long-standing insulin-dependent diabetes mellitus who had no clinical, electrocardiographic, or tomographic thallium scan evidence of heart disease. In 11 of 30 patients (37%), RVG revealed abnormal left ventricular performance. CAN was found in 91% of these patients. RVG was abnormal in 59% of patients with CAN and in only 8% of patients without CAN (P less than 0.005). There were significant reductions in mean (+/- SE) ejection fractions (EF) in patients with CAN at rest (62.8 +/- 2.2% vs. 75.2 +/- 2.5%; P less than 0.001) and with maximal exercise (65.8 +/- 2.6% vs. 80.9 +/- 2.3%; P less than 0.001) compared to patients without CAN. There was an inverse correlation between the autonomic function score and both resting EF (r = -0.53; P less than 0.002) and exercise EF (r = -0.55; P less than 0.002). Systolic function did not correlate with age, sex, duration or control of diabetes, microvascular complications, or plasma norepinephrine levels. Thus, approximately one third of our study population had evidence for depressed left ventricular function in the absence of ischemic heart disease, and the cardiac dysfunction was related to the severity of CAN. CAN may be a contributor to cardiac dysfunction in diabetes mellitus.

Adult↗