Reduced increase of calcium scores using breath-hold in left-sided whole breast irradiation.

PURPOSE: In this prospective longitudinal study, Coronary Artery Calcium (CAC) scores determined before the start of whole breast irradiation were compared with those determined 7 years afterwards. The aim was to examine whether the use of a breath-hold (BH) technique is associated with less increase of CAC scores. METHODS AND MATERIALS: Changes in CAC scores were analysed in 87 breast cancer patients. The results of the following groups were compared: patients receiving right (R) or left-sided radiotherapy using free breathing (L-FB) with those receiving left-sided radiotherapy with BH (L-BH). We compared the changes of CAC scores between these groups over time, testing the hypothesis that a significantly reduced increase of calcium scores is observed when using BH. RESULTS: For L-BH cases, when compared with L-FB cases, for overall as well as for Left Anterior Descending coronary artery (LAD) CAC scores, we noted significantly less increased CAC scores (p < 0.01). This effect of BH was even more striking in the group with CAC scores >0 at baseline. The attenuated increase over time of CAC scores in the L-BH group was robust to correction for age and statin use (p < 0.05). CONCLUSION: After a median follow-up of 7.4 years, we found significantly less increased CAC scores when using BH. This is a relevant finding since higher levels of CAC scores are associated with higher probabilities of coronary artery events. Moreover, it underlines the rationale for the use of BH in left-sided whole breast irradiation.

Less increase of CT-based calcium scores of the coronary arteries : Effect three years after breast-conserving radiotherapy using breath-hold.

PURPOSE: The aim of this prospective longitudinal study was to compare coronary artery calcium (CAC) scores determined before the start of whole breast irradiation with those determined 3 years afterwards. PATIENTS AND METHODS: Changes in CAC scores were analysed in 99 breast cancer patients. Three groups were compared: patients receiving left- and right-sided radiotherapy, and those receiving left-sided radiotherapy with breath-hold. We analysed overall CAC scores and left anterior descending (LAD) and right coronary artery (RCA) CAC scores. Between the three groups, changes of the value of the LAD minus the RCA CAC scores of each individual patient were also compared. RESULTS: Three years after breath-hold-based whole breast irradiation, a less pronounced increase of CAC scores was noted. Furthermore, LAD minus RCA scores in patients treated for left-sided breast cancer without breath-hold were higher when compared to LAD minus RCA scores of patients with right-sided breast cancers and those with left-sided breast cancer treated with breath-hold. CONCLUSION: Breath-hold in breast-conserving radiotherapy leads to a less pronounced increase of CT-based CAC scores. Therefore, breath-hold probably prevents the development of radiation-induced coronary artery disease. However, the sample size of this study is limited and the follow-up period relatively short.

[Cardiac sarcoidosis: improved prognosis through new diagnostic tests and treatment]. / Cardiale sarcoïdose: betere prognose door nieuwe diagnostiek en behandeling.

Cardiac sarcoidosis was diagnosed in 3 patients: 2 men aged 52 and 51 years, respectively, and a woman aged 55 years. Both men had ventricular tachycardia. In the first man, a right-ventricle biopsy revealed a non-caseating granuloma. The second man had active granulomatous cardiac infiltration, according to a gallium scintigram. The first man recovered after receiving immunosuppression, heart-failure medication, and an implantable defibrillator; the second received the same plus radio-frequency catheter ablation, but experienced serious heart failure. The woman was being treated for pulmonary sarcoidosis but complained of progressive cardiac symptoms. She recovered after receiving heart-failure medication, immunosuppression, and a biventricular pacemaker. Sarcoidosis is a multi-system granulomatous disorder of unknown aetiology with cardiac involvement in 20 to 30% of patients, resulting in severe morbidity and mortality. With the help ofgadolinium MRI and positron emission tomography (PET), these conditions can be detected at an earlier stage, which allows for improved evaluation of the efficacy of available therapies. The use of resynchronisation therapy and implantable defibrillators has improved the prognosis of patients with cardiac sarcoidosis.

The left gastric artery as an in-situ conduit in coronary artery bypass grafting.

Unsuitability of the in-situ right gastroepiploic artery in coronary bypass grafting occurs. Sometimes free-grafting can be performed, although this should not be considered in patients with a diseased ascending aorta. We describe the successful use of the left gastric artery as an alternative in-situ arterial conduit in a patient with a severely atherosclerotic ascending aorta.

Both Na+-K+ ATPase and Na +-H+ exchanger are immediately active upon post-ischemic reperfusion in isolated rat hearts.

Limited time resolution has hampered proper evaluation of changes in intracellular Na+ (Na+i) in whole hearts upon post-ischemic reperfusion. In isolated rat hearts perfused at 37 degrees C, we studied the contribution of the Na+-K+ ATPase and the Na+-H+ exchanger to control of Na+i during reperfusion using 23Na NMR and the shift reagent Tm(DOTP)5- with a time resolution of 5 s. To assess activities of the Na +-K+ ATPase and the Na+-H+ exchanger, 250 micro mol/l ouabain and/or 3 micro mol/l EIPA, respectively, was added to the perfusate during the first 5 min of reperfusion, following 20 min of ischemia. When used, ouabain was also present for 2 min prior to ischemia. Na+i increased during ouabain perfusion prior to ischemia (132+/-5 and 133+/-4% of the pre-ischemic control value after 2 min, in ouabain and ouabain+EIPA hearts, respectively; mean+/-s.e.m.; n=6 per group) resulting in higher end-ischemic values in ouabain and ouabain+EIPA hearts (249+/-9 and 267+/-17% of the pre-ischemic control value, respectively) than in control and EIPA hearts (207+/-21 and 199+/-10% of the pre-ischemic control value, respectively). In ouabain, hearts Na+i started to rise directly upon reperfusion and amounted to 117+/-6% of the end-ischemic value after 60 s of reperfusion. In control hearts, however, Na+i dropped immediately and was 87+/-5% of the end-ischemic value after 60 s, indicating that the Na+-K+ ATPase resumed function directly upon reperfusion. The initial steep increase of Na+i upon reperfusion in ouabain hearts, which diminished after approximately 40 s to the rate of increase observed during ischemia, was absent in ouabain + EIPA hearts. This indicates the existence, although masked by Na+-K+ ATPase activity, of a Na+-H + exchange mediated Na+ influx upon reperfusion. If only EIPA was present during reperfusion the initial decrease in Na+i was faster than in control hearts, corroborating this finding.

Manipulation of intracellular sodium by extracellular divalent cations: a 23Na and 31P NMR study on intact rat hearts.

23Na and 31P NMR spectroscopy were used to follow intracellular [Na+] ([Na+]i) and energy metabolism in isolated, perfused rat hearts. During 30 min of Ca(2+)-free perfusion no significant change in [Na+]i could be detected, but during a subsequent 45 min period of ischemia [Na+]i rose significantly as expected, from 8.6 +/- 2.4 to 36.8 +/- 9.4 mM. In contrast, already during 30 min of Ca(2+)- and Mg(2+)-free perfusion [Na+]i rose significantly from 7.3 +/- 3.7 to 71.3 +/- 15.6 mM. During this period, the Na(+)-K+ ATPase was not limited by depletion of high energy phosphates, decrease of intracellular free Mg2+ or accumulation of inorganic phosphate. During the first 8 min of a subsequent period of ischemia, the rate of rise in [Na+]i even increased, suggesting that during the preceding period of Ca(2+)- and Mg(2+)-free perfusion, the Na(+)-K+ ATPase was indeed operative but apparently not coping with the large Na(+)-influx. Using verapamil, we could demonstrate that this large Na(+)-influx occurs through the L-type Ca2+ channels, and that both Mg2+ and verapamil can block this Na(+)-influx. Previously, we have demonstrated that [Na+]i does not play a role in the origin of the calcium paradox. The notion that an increased [Na+]i is a prerequisite for the calcium paradox to occur apparently results from experimental evidence obtained under conditions of low or absent Mg2+.

Thyroid hormone improves function and Ca2+ handling in pressure overload hypertrophy. Association with increased sarcoplasmic reticulum Ca2+-ATPase and alpha-myosin heavy chain in rat hearts.

We asked whether thyroid hormone (T4) would improve heart function in left ventricular hypertrophy (LVH) induced by pressure overload (aortic banding). After banding for 10-22 wk, rats were treated with T4 or saline for 10-14 d. Isovolumic LV pressure and cytosolic [Ca2+] (indo-1) were assessed in perfused hearts. Sarcoplasmic reticulum Ca2+-ATPase (SERCA), phospholamban, and alpha- and beta-myosin heavy chain (MHC) proteins were assayed in homogenates of myocytes isolated from the same hearts. Of 14 banded hearts treated with saline, 8 had compensated LVH with normal function (LVHcomp), whereas 6 had abnormal contraction, relaxation, and calcium handling (LVHdecomp). In contrast, banded animals treated with T4 had no myocardial dysfunction; these hearts had increased contractility, and faster relaxation and cytosolic [Ca2+] decline compared with LVHcomp and LVHdecomp. Myocytes from banded hearts treated with T4 were hypertrophied but had increased concentrations of alpha-MHC and SERCA proteins, similar to physiological hypertrophy induced by exercise. Thus thyroid hormone improves LV function and calcium handling in pressure overload hypertrophy, and these beneficial effects are related to changes in myocyte gene expression. Induction of physiological hypertrophy by thyroid hormone-like signaling might be a therapeutic strategy for treating cardiac dysfunction in pathological hypertrophy and heart failure.

Impaired Ca2+ handling is an early manifestation of pressure-overload hypertrophy in rat hearts.

Both cytosolic free Ca2+ ([Ca2+]i) decline and myocardial relaxation are slowed in severe hypertrophy and heart failure. However, it is not certain whether this occurs in mild to moderate hypertrophy. Therefore, we tested the hypotheses that slowing of [Ca2+]i decline 1) occurs in mild to moderate hypertrophy, 2) occurs in the absence of slowed relaxation, and 3) is related to the degree of hypertrophy. Experiments were performed on isolated rat hearts subjected to pressure overload. Indo 1 fluorescence was used as an index of [Ca2+]i. [Ca2+]i decline and myocardial relaxation were assessed by the time constant of exponential [Ca2+]i decline (tau Ca) and left ventricular (LV) pressure decline (tau p), respectively. Mean tau Ca was significantly increased in hearts from banded rats compared with sham-operated rats (59 +/- 13 vs. 45 +/- 5 ms, P = 0.03). In contrast, there was no difference in mean tau p (28 +/- 3 vs. 29 +/- 5 ms, P = not significant). There was a linear relationship between tau Ca and LV dry weight (r = 0.79). In summary, slowing of the [Ca2+]i transient decline occurred in mild to moderate hypertrophy. However, LV relaxation was unaffected. Furthermore, slowing of the [Ca2+]i transient decline was closely related to the degree of LV hypertrophy. These data suggest that slowing of [Ca2+]i decline is an early manifestation of pressure-overload hypertrophy that precedes slowing of relaxation.

Cytosolic and mitochondrial [Ca2+] in whole hearts using indo-1 acetoxymethyl ester: effects of high extracellular Ca2+.

Assessment of free cytosolic [Ca2+] ([Ca2+]c) using the acetoxymethyl ester (AM) form of indo-1 may be compromised by loading of indo-1 into noncytosolic compartments, primarily mitochondria. To determine the fraction of noncytosolic fluorescence in whole hearts loaded with indo-1 AM, Mn2+ was used to quench cytosolic fluorescence. Residual (i.e., noncytosolic) fluorescence was subtracted from the total fluorescence before calculating [Ca2+]c. Noncytosolic fluorescence was used to estimate mitochondrial [Ca2+]. In hearts paced at 5 Hz (N = 17), noncytosolic fluorescence was 0.61 +/- 0.06 and 0.56 +/- 0.07 of total fluorescence at lambda 385 and lambda 456, respectively. After taking into account noncytosolic fluorescence, systolic and diastolic [Ca2+]c was 673 +/- 72 and 132 +/- 9 nM, respectively, noncytosolic [Ca2+] was 183 +/- 36 nM and increased to 272 +/- 12 when extracellular Ca2+ was increased from 2 to 6 mM. This increase in noncytosolic [Ca2+] was inhibited by ruthenium red, a blocker of Ca2+ uptake by mitochondria. We conclude that cytosolic and mitochondrial [Ca2+] can be determined in whole hearts loaded with indo-1 AM by using Mn2+ to quench cytosolic fluorescence.

Protein and acidosis alter calcium-binding and fluorescence spectra of the calcium indicator indo-1.

The fluorescent indicator indo-1 is widely used to monitor intracellular calcium concentration. However, quantitation is limited by uncertain effects of the intracellular environment on indicator properties. The goal of this study was to determine the effects of protein and acidosis on the fluorescence spectra and calcium dissociation constant (Kd) of indo-1. With 350 nm excitation light, the ratio of indo-1 fluorescence in the absence versus the presence of saturating Ca2+ at wavelength lambda (S lambda) and Kd increased with [protein]. At pH 7.3, Kd, S400, and S470, which were 210 nM, 0.033, and 1.433 in the absence of protein, increased to 808 nM, 0.161, and 2.641, respectively, by adding proteins from frog muscle and to 638 nM, 0.304, and 3.039, respectively, by adding proteins from rat heart. Effects of protein on indo-1 fluorescence were reduced at higher [indo-1]. Acidosis (pH 6.3) had separate effects, which were additive to those of protein: in the absence of protein, acidosis increased Kd to 640 nM; frog muscle proteins further increased Kd to 1700 nM. Acidosis also changed S lambda slightly. In summary, interaction with protein or protons alters indo-1 calcium-binding and fluorescence. These findings are consistent with several previous studies and suggest that indo-1 calibration constants need to be derived in the presence of appropriate types of protein, ratio of [indo-1]/[protein], and pH.

Post-ischemic contractile dysfunction does not correlate with an elevated intracellular free [Mg2+]: a 31P-NMR study on isolated rat and rabbit hearts.

The aim of this study was to investigate whether intracellular free Mg2+ (Mgr), which increases during myocardial ischemia due to hydrolysis of ATP, remained elevated during reperfusion after a relatively short period of ischemia and thereby could account for temporary post-ischemic contractile dysfunction, often referred to as stunning. 31P-magnetic resonance (31P-NMR) spectroscopy was used to follow creatine phosphate, adenosine triphosphate, intracellular inorganic phosphate, intracellular pH and Mgr simultaneously with left ventricular developed pressure (LVDP) and coronary flow in isolated rat and rabbit hearts, which were perfused (37 degrees C) according to Langndorff. LVDP was measured in an isovolumic way by means of an intraventricular latex balloon. Rat hearts (300 beats/min) were made globally ischemic for 15 min and rabbit hearts (180 beats/min) for 15 or 20 min. All hearts were reperfused for 60 min. Control hearts were perfused for 75 min without being made ischemic. During ischemia Mgr (mmol/l) increased from 0.76 +/- 0.20 to 4.34 +2- 1.99 in the rat hearts, and from 0.72 +/- 0.22 to 2.18 +/- 1.06 (15 min) and 2.35 +/- 1.26 (20 min) in the rabbit hearts. During reperfusion Mgr in the three groups returned to the level of the control hearts within 7.5 min, and LVDP within 25 min. At the end of the reperfusion period ATP content amounted to 56 +/- 17% (rat hearts), 66 +/- 10% (rabbit hearts; 15 min ischemia group) and 61 +/- 7% (rabbit hearts; 20 min ischemia group) of the pre-ischemic levels. The results confirm that in vitro stunning is a short-lived phenomenon and indicate that an increased Mgr is not involved in this temporary mechanical dysfunction.

Postischaemic metabolic and functional recovery of rat heart after transient reperfusion with various low Ca2+ concentrations.

OBJECTIVE: The effects of transient low Ca2+ reperfusion after ischaemia on metabolic and functional recovery were studied in isolated rat hearts. METHODS: 31P nuclear magnetic resonance (NMR) was used to monitor creatine phosphate, ATP, intracellular inorganic phosphate (Pi), and intracellular pH during control perfusion (15 min), total ischaemia (30 min), and reperfusion (30 min). During early reperfusion (0-10 min) perfusate [Ca2+] amounted to 1.3 (control group), 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, or 0.7 mmol.litre-1. During late reperfusion (10-30 min) perfusate [Ca2+] was 1.3 mmol.litre-1. Isolated rat hearts were used and perfused according to Langendorff. RESULTS: Recovery of creatine phosphate during early reperfusion was partly abolished during late reperfusion in the 0.1-0.4 mmol.litre-1 groups (p < 0.01). In the 0.1 mmol.litre-1 group creatine phosphate content after 30 min reperfusion was lower (p < 0.05) than in the control group. Recovery of ATP during early reperfusion in the 0.3 mmol.litre-1 group was better than in the control group (p < 0.01). After 30 min reperfusion ATP recovery was better in the 0.3 mmol.litre-1 group (p < 0.01) and worse in the 0.1 mmol.litre-1 group (p = 0.05) than in the control group. Decline of Pi during early reperfusion was more pronounced in the 0.2 and 0.3 mmol.litre-1 groups (p < 0.01) and in the 0.5 and 0.6 mmol.litre-1 groups (p < 0.05) than in the control group. In the 0.3 and 0.4 mmol.litre-1 groups, Pi after 30 min reperfusion was higher (p < 0.05) than after 10 min reperfusion. After 30 min reperfusion left ventricular developed pressure, measured with an intraventricular balloon, was lower in the 0.1 mmol.litre-1 group (p < 0.01) than in the control group. CONCLUSIONS: The data show that under the experimental conditions used successive postischaemic reperfusion with 0.1 and 1.3 mmol.litre-1 Ca2+ resulted in poorer metabolic and functional recovery of the hearts than continuous reperfusion with 1.3 mmol.litre-1 Ca2+. Postischaemic reperfusion with 0.1 mmol.litre-1 Ca2+ may predispose the heart to a mild calcium paradox. Successive reperfusion with 0.3 and 1.3 mmol.litre-1 Ca2+ was optimal in terms of ATP recovery but did not result in an increased recovery of left ventricular developed pressure.

A phosphorus-31 nuclear magnetic resonance study of myocardial ATP content during postischemic low calcium reperfusion.

Postischemic reperfusion injury can be modified by transient low calcium (Ca2+) reperfusion, although the data on the optimal [Ca2+] are controversial. High-energy phosphates and contractile function of isolated perfused rat hearts (37 degrees C, 300 beats/min) were studied simultaneously during global ischemia (30 min) and reperfusion (10 min at [Ca2+] = 1.3, 0.05, 0.1, 0.3, 0.5 and 0.7 mmol/l, followed by 20 min at [Ca2+] = 1.3 mmol/l), using phosphorus-31 nuclear magnetic resonance (31P NMR) spectroscopy. Reperfusion with 1.3 mmol/l Ca2+ after 0.05 or 0.1 mmol/l Ca2+ largely abolished the recovery of ATP obtained during initial low Ca2+ reperfusion (calcium paradox effect). A [Ca2+] of 0.3 mmol/l was sufficiently high to prevent this detrimental effect; at the same time this concentration was sufficiently low to cause a substantial recovery of ATP, which was maintained upon switching to 1.3 mmol/l Ca2+. Recovery of ATP did not correlate with recovery of contractile function.