Noninvasive evaluation of pulmonary capillary wedge pressure in patients with acute myocardial infarction by deceleration time of pulmonary venous flow velocity in diastole.
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OBJECTIVES: This study investigates the correlation between deceleration time of diastolic pulmonary venous flow (PV-DT) and of early filling mitral flow (LV-DT), and pulmonary capillary wedge pressure (PCWP) in patients with acute myocardial infarction (AMI). BACKGROUND: An earlier study suggests that Doppler-derived LV-DT provides an accurate means of estimating PCWP in postinfarction patients with left ventricular systolic dysfunction. Furthermore, recent studies have suggested that PCWP correlates better with PV-DT than with LV-DT. However, the value of PV-DT and LV-DT for assessment of PCWP in patients with AMI has not been evaluated. METHODS: In 141 consecutive patients with AMI, we measured PV-DT and LV-DT by Doppler echocardiography, and compared these variables with PCWP measured using a Swan-Ganz catheter. RESULTS: There was a weak negative correlation between the LV-DT and PCWP (r = -0.54). Although the sensitivity of < or =130 ms in LV-DT in predicting > or =18 mm Hg in PCWP was high (86%), its specificity was low (59%). On the other hand, a very close negative correlation was found between PV-DT and PCWP (r = -0.89). The sensitivity and specificity of < or =160 ms in PV-DT in predicting > or =18 mm Hg in PCWP were 97% and 96%, respectively. CONCLUSIONS: In patients with AMI, Doppler-derived PV-DT showed a stronger correlation with PCWP than LV-DT. (+info)
Subunit expression of the cardiac L-type calcium channel is differentially regulated in diastolic heart failure of the cardiac allograft.
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BACKGROUND: Left ventricular diastolic dysfunction is a major cause of cardiac allograft failure. Multimeric L-type calcium channels (alpha1-, alpha2/delta-, and beta-subunits) are essential for excitation/contraction coupling in the heart. Their gene expression was studied in allografts that developed diastolic heart failure. METHODS AND RESULTS: mRNA levels of calcium channel subunits were measured by competitive reverse transcriptase-polymerase chain reaction in microbiopsy samples from the interventricular septum. Size and tissue variabilities between biopsy samples were assessed by determination of cardiac calsequestrin mRNA levels. In the cardiac allografts studied, mRNA levels in microbiopsy samples were considered to represent left ventricular gene expression, because septal and left ventricular gene expression in Northern blots was equivalent, and left ventricles contracted homogeneously. Biopsy samples (n=72) were taken from allografts with normal left ventricular end-diastolic pressure (LVEDP; 8 to 13 mm Hg; n=30), moderately elevated LVEDP (14 to 18 mm Hg; n=26), and elevated LVEDP (19 to 28 mm Hg; n=16). Increased LVEDP was related to slowed diastolic relaxation determined by the time constant tau (r2=0.86), whereas systolic performance (dP/dt; ejection fraction) was preserved. With increasing LVEDP, mRNA levels of the pore-forming alpha1c-subunit (n=15) and of the regulatory alpha2/delta-subunit (n=17) remained unchanged but decreased exponentially (r2=-0.83) for the regulatory beta-subunit (n=40). Compared with cardiac allografts with normal LVEDP (n=15), beta-subunit mRNA level was reduced by 75% at elevated LVEDP (n=9; P=0.012). In an explanted, diastolically failing cardiac allograft, beta-subunit expression was reduced correspondingly by 72% and 76% on the mRNA level in septal and left ventricular myocardium and by 80% on the protein level. CONCLUSIONS: The downregulated expression of the calcium channel beta-subunit might contribute to altered calcium handling in diastolically failing cardiac allografts. (+info)
Adenosine A(3)-receptor stimulation attenuates postischemic dysfunction through K(ATP) channels.
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We tested the hypothesis that selective adenosine A(3)-receptor stimulation reduces postischemic contractile dysfunction through activation of ATP-sensitive potassium (K(ATP)) channels. Isolated, buffer-perfused rat hearts (n = 8/group) were not drug pretreated (control) or were pretreated with adenosine (20 microM), 2-chloro-N(6)-(3-iodobenzyl)-adenosine-5'-N-methyluronamide (Cl-IB-MECA; A(3) agonist, 100 nM), Cl-IB-MECA + 8-(3-noradamantyl)-1,3-dipropylxanthine (KW-3902; A(1) antagonist, 5 microM), Cl-IB-MECA + glibenclamide (Glib; K(ATP)-channel blocker, 0. 3 microM), or Glib alone for 12 min before 30 min of global normothermic ischemia followed by 2 h of reperfusion. After 2 h of reperfusion, left ventricular developed pressure (LVDP, %baseline) in control hearts was depressed to 34 +/- 2%. In hearts pretreated with Cl-IB-MECA, there was a statistically significant increase in LVDP (50 +/- 6%), which was reversed with coadministration of Glib (37 +/- 1%). Control hearts also showed similar decreases in left ventricular peak positive rate of change in pressure (dP/dt). Therefore, the A(3) agonist significantly attenuated postischemic cardiodynamic injury compared with the control, which was reversed by Glib. Cumulative creatine kinase (CK in U/min) activity was most pronounced in the control group (10.4 +/- 0.6) and was significantly decreased by Cl-IB-MECA (7.5 +/- 0.4), which was reversed by coadministration of Glib (9.4 +/- 0.2). Coronary flow was increased during adenosine infusion (160% of baseline) but not during Cl-IB-MECA infusion. Effects of Cl-IB-MECA were not reversed by the specific A(1) antagonist KW-3902. We conclude that cardioprotection afforded by A(3)-receptor stimulation may be mediated in part by K(ATP) channels. Cl-IB-MECA may be an effective pretreatment agent that attenuates postischemic cardiodynamic dysfunction and CK release without the vasodilator liability of other adenosine agonists. (+info)
Effects of normal hematocrit on ambulatory blood pressure in epoetin-treated hemodialysis patients with cardiac disease.
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BACKGROUND: Hypertension is a recognized complication of partial correction of anemia with recombinant human erythropoietin (epoetin) in hemodialysis patients. We used interdialytic ambulatory blood pressure (ABP) monitoring to study the effects of partially corrected anemia versus normal hematocrit (hct) on BP in hemodialysis patients. METHODS: Repeated interdialytic ABP monitoring was performed for up to one year in 28 chronic hemodialysis patients with cardiac disease who were randomized to achieve and maintain normal hct levels (42 +/- 3%, group A) or anemic hct levels (30 +/- 3%, group B) with epoetin. Routine BP measurements obtained at dialysis treatments were also evaluated. RESULTS: Mean hct levels were 30.7 +/- 0.7% in group A and 30.6 +/- 0.7% in group B at baseline, then 39.3 +/- 1.2% (group A) and 33.5 +/- 0.6% (group B) at four months, and 42.0 +/- 1.1% (group A) and 30.4 +/- 1.0% (group B) at 12 months. Baseline ABP and routine dialysis unit BP levels were not different between the groups. At 2, 4, 8, and 12 months of follow-up, there were no statistically significant differences in any BP parameters between groups or increases in any BP parameters in either group A or group B patients compared with baseline. At 12 months, the mean nighttime diastolic BP (DBP) in group A patients was slightly but significantly lower than the mean daytime DBP (daytime DBP 76.6 +/- 1.9 mm Hg vs. nighttime DBP 72.9 +/- 2.1 mm Hg, P < 0.05). The mean daytime and nighttime BPs were not different from each other at two, four, and eight months in group A or at any time in group B, and in both groups, most patients had little diurnal change in BP. CONCLUSION: Correction of hct to normal with epoetin in chronic hemodialysis patients with cardiac disease did not cause increased BP as assessed by interdialytic ABP monitoring or by the measurement of routine predialysis and postdialysis BP. There was little diurnal change in systolic or diastolic BP at baseline or after correction of anemia to normal levels, and although mean nighttime DBP was lower than mean daytime DBP at 12 months in group A, the maintenance of normal hct levels did not affect the abnormal diurnal BP pattern seen at moderately anemic hct levels in most patients. (+info)
Assessment of myocardial metaiodobenzylguanidine uptake and its relation to left ventricular systolic and diastolic functional parameters in dilated cardiomyopathy.
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The purpose of this study was to assess the relation between myocardial metaiodobenzylguanidine (MIBG) uptake and left ventricular systolic and diastolic functional parameters, both of which are known as predictors of prognosis in patients with dilated cardiomyopathy. Echocardiography and iodine-123-MIBG myocardial scintigraphy were performed in 35 patients of dilated cardiomyopathy with normal sinus rhythm. Mean myocardial MIBG uptake in the patient group at early and delayed images were significantly lower than those in normal control subjects (10.6 +/- 1.1, 9.8 +/- 1.2 vs 12.4 +/- 1.0, 12.1 +/- 1.0, p < 0.01). There were, however, no significant differences of mean MIBG uptake in the lung and mediastinum between the two groups (p > 0.05). There were no significant correlations between myocardial MIBG uptake, expressed as the ratio of heart/mediastinum MIBG activity at delayed image, and left ventricular systolic and diastolic functional parameters [left ventricular ejection fraction, left ventricular end-diastolic dimension, peak velocity of early diastolic filling (E velocity), deceleration time of E wave, cardiac output, left ventricular end-diastolic pressure]. In conclusion, the myocardial uptake of MIBG is decreased in patients with dilated cardiomyopathy assessed by iodine-123-MIBG myocardial scintigraphy. There were, however, no significant correlations between myocardial MIBG uptake and left ventricular systolic and diastolic functional parameters derived from echocardiography. (+info)
A rational approach to the treatment of hypertension in special populations.
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Hypertension in blacks is usually characterized by low renin, expanded volume and sensitivity to salt. Diuretics are the preferred initial therapy, but response to calcium channel antagonists is also good. The blood pressure response to monotherapy with beta blockers or angiotensin-converting enzyme (ACE) inhibitors is blunted, but this effect is abolished with concomitant use of diuretics. The two major types of hypertension in older persons are isolated systolic hypertension and combined systolic and diastolic hypertension. Strong data support the treatment of combined hypertension in patients 60 to 79 years of age and isolated systolic hypertension in patients 60 to 96 years of age. Diuretics and long-acting dihydropyridine calcium channel antagonists are the recommended initial therapies for isolated systolic hypertension. More studies are necessary before recommendations can be made about the treatment of combined hypertension in patients 80 years of age and older. (+info)
Alterations in the local myocardial motion pattern in patients suffering from pressure overload due to aortic stenosis.
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BACKGROUND: MR tissue tagging allows the noninvasive assessment of the locally and temporally resolved motion pattern of the left ventricle. Alterations in cardiac torsion and diastolic relaxation of the left ventricle were studied in patients with aortic stenosis and were compared with those of healthy control subjects and championship rowers with physiological volume-overload hypertrophy. METHODS AND RESULTS: Twelve aortic stenosis patients, 11 healthy control subjects with normal left ventricular function, and 11 world-championship rowers were investigated for systolic and diastolic heart wall motion on a basal and an apical level of the myocardium. Systolic torsion and untwisting during diastole were examined by use of a novel tagging technique (CSPAMM) that provides access to systolic and diastolic motion data. In the healthy heart, the left ventricle performs a systolic wringing motion, with a counterclockwise rotation at the apex and a clockwise rotation at the base. Apical untwisting precedes diastolic filling. In the athlete's heart, torsion and untwisting remain unchanged compared with those of the control subjects. In aortic stenosis patients, torsion is significantly increased and diastolic apical untwisting is prolonged compared with those of control subjects or athletes. CONCLUSIONS: Torsional behavior as observed in pressure- and volume-overloaded hearts is consistent with current theoretical findings. A delayed diastolic untwisting in the pressure-overloaded hearts of the patients may contribute to a tendency toward diastolic dysfunction. (+info)
Modulation of left ventricular diastolic distensibility by collateral flow recruitment during balloon coronary occlusion.
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OBJECTIVES: The goals of this study were to elucidate the scaffolding effect of blood-filled coronary vasculature and to determine the functional role of recruited collateral flow in modulating left ventricular (LV) distensibility during balloon coronary occlusion (BCO). BACKGROUND: Although LV distensibility is an important factor affecting acute dilation after myocardial infarction, the response of LV diastolic pressure-volume (P-V) relations to coronary occlusion is inconsistent in humans. METHODS: Micromanometer and conductance derived LV P-V loops were serially obtained from 16 patients undergoing percutaneous transluminal coronary angioplasty. Coronary collateral flow recruitment was angiographically evaluated by contralateral and ipsilateral contrast injection during BCO. RESULTS: In the group with poor collateral flow (grades 0-I; n = 8), BCO resulted in a downward and rightward shift of the diastolic P-V relations, where end-diastolic volume (EDV) increased by 13% (p < 0.05) without appreciable change in end-diastolic pressure (EDP; 18 +/- 6 to 18 +/- 8 mm Hg). In contrast, BCO in the group with good collateral flow (grades II-III; n = 8) shifted the diastolic P-V relations upward to the right with a concomitant increase in minimal pressure (min-P; 6 +/- 4 to 10 +/- 5 mm Hg, p < 0.05), EDP (15 +/- 7 to 21 +/- 9 mm Hg, p < 0.05) and EDV (+/- 10%, p < 0.05). Reactive hyperemia after balloon deflation caused a rapid and parallel upward shift of the diastolic P-V relations with a marked increase in min-P and EDP, especially in the group with poor collateral flow, before any improvement in LV contraction or relaxation abnormalities. CONCLUSIONS: Grades of coronary filling, either retrograde or anterograde, abruptly modulate LV distensibility through the rapid scaffolding effect of coronary vascular turgor. (+info)