Fontan conversion to total cavopulmonary connection and arrhythmia ablation: clinical and functional results.
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OBJECTIVES: To assess the early results of conversion from atriopulmonary to total cavopulmonary connection in patients with failing Fontan operation. DESIGN: Early clinical and instrumental evaluation of patients undergoing conversion from atriopulmonary to total cavopulmonary connection from April 1999 to November 2000. SETTING: Tertiary referral centre for congenital heart disease. PATIENTS: 11 Fontan patients (mean (SD) age 20.9 (6.7) years) with refractory arrhythmias or ventricular dysfunction. INTERVENTIONS: Total cavopulmonary connection, intraoperative ablation, and AAIR pacemaker implantation. MAIN OUTCOME MEASURES: Holter monitoring, transoesophageal atrial stimulation, ergometric test, and myocardial scintigraphy at a mean (SD) follow up of 16.8 (5.6) months. RESULTS: One early postoperative death occurred. During follow up three patients had relapse of atrial tachycardia, controlled by medical treatment, and two were pacemaker dependent. Transoesophageal stimulation did not induce atrial tachycardia in any patient. Ergometric test showed a diminished exercise tolerance in all but one patient. Mean minute ventilation and maximum oxygen consumption were 62% and 40% of their respective predicted values. Myocardial scintigraphy showed reversal of rest or exercise dysfunction in five patients and improved systemic ventricular function in seven. Mean basal ejection fraction increased from 39.4% (95% confidence interval (CI) 32% to 46%) to 46.5% (95% CI 41.7% to 51.2%) and ejection fraction on effort from 42.3% (95% CI 33.9% to 50.7%) to 50.2% (95% CI 44.5% to 55.9%). CONCLUSIONS: Our data show that total cavopulmonary connection associated with intraoperative ablation and pacemaker implantation allows for better control of arrhythmias and improves ventricular function in the majority of patients with failing Fontan. (+info)
Tissue Doppler echocardiography in patients with thalassaemia detects early myocardial dysfunction related to myocardial iron overload.
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AIMS: To compare an echocardiographic method for detecting abnormal cardiac function before development of overt cardiomyopathy with a recently validated technique of quantifying myocardial iron load. METHODS AND RESULTS: We examined thalassaemia patients whose myocardial iron load had been evaluated with magnetic resonance imaging (MRI). By tissue Doppler echocardiography, myocardial velocities were sampled continuously from base to apex in the RV and LV free wall, and the septum in 52 patients aged 29.2 (14.2-43.1) years and 52 age-matched controls. Ninety-six percent of patients had normal LV ejection fraction by MRI. Thirty-eight (73%) had abnormal iron loading of the myocardium, and 33 of those had regional wall motion abnormalities detected in the septum (n=29), LV (n=2), RV (n=1), and septum plus LV (n=1). The incidence of wall motion abnormalities was significantly higher (P<0.04) in patients with myocardial iron overload (87%) than in the 14 without (35%). Furthermore, myocardial iron overload was suggested by a low T2(*)(15.1+/-15.8 ms) in patients with wall motion abnormalities vs those with normal wall motion (T2(*): 30+/-19 ms) (P<0.007). CONCLUSIONS: Wall motion abnormalities may represent an early sign of cardiac disease despite preserved global function. The regional abnormalities are related to iron overload and easily detectable with tissue Doppler echocardiography. (+info)
Identification of hibernating myocardium with quantitative intravenous myocardial contrast echocardiography: comparison with dobutamine echocardiography and thallium-201 scintigraphy.
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BACKGROUND: There are currently no data on the accuracy of intravenous myocardial contrast echocardiography (MCE) in detecting myocardial hibernation in man and its comparative accuracy to dobutamine echocardiography (DE) or thallium 201 (Tl(201)) scintigraphy. METHODS AND RESULTS: Twenty patients with coronary artery disease and ventricular dysfunction underwent MCE 1 to 5 days before bypass surgery and repeat echocardiography at 3 to 4 months. Patients also underwent DE (n=18) and rest-redistribution Tl(201) tomography (n=16) before revascularization. MCE was performed using continuous Optison infusion (12 to 16 cc/h) with intermittent pulse inversion harmonics and incremental triggering (1:1 to 1:8). Myocardial contrast intensity (MCI) replenishment curves were constructed to derive quantitative MCE indices of blood velocity and flow. Recovery of function occurred in 38% of dysfunctional segments. MCE parameters of perfusion in hibernating myocardium were similar to segments with normal function and higher than dysfunctional myocardium without recovery of function (P<0.001). The best MCE parameter for predicting functional recovery was Peak MCIxbeta, an index of myocardial blood flow (area under the curve, 0.83). MCE parameters were higher in segments with contractile reserve and Tl(201) uptake > or =60% (P<0.05) and identified viable segments without contractile reserve by DE. The sensitivity of Peak MCIxbeta >1.5 dB/s for recovery of function was 90% and was similar to Tl(201) scintigraphy (92%) and any contractile reserve (80%); specificity was higher than for Tl(201) and DE (63%, 45%, and 54%, respectively; P<0.05). CONCLUSIONS: MCE with intravenous contrast identifies myocardial hibernation in humans. Prediction of viable myocardium with MCE is best using quantification of myocardial blood flow and provides improved accuracy compared with DE and Tl(201) scintigraphy. (+info)
Combined ventricular systolic and arterial stiffening in patients with heart failure and preserved ejection fraction: implications for systolic and diastolic reserve limitations.
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BACKGROUND: Heart failure with preserved ejection fraction (HF-nlEF) is common in aged individuals with systolic hypertension and is frequently ascribed to diastolic dysfunction. We hypothesized that such patients also display combined ventricular-systolic and arterial stiffening that can exacerbate blood pressure lability and diastolic dysfunction under stress. METHODS AND RESULTS: Left ventricular pressure-volume relations were measured in patients with HF-nlEF (n=10) and contrasted with asymptomatic age-matched (n=9) and young (n=14) normotensives and age- and blood pressure-matched controls (n=25). End-systolic elastance (stiffness) was higher in patients with HF-nlEF (4.7+/-1.5 mm Hg/mL) than in controls (2.1+/-0.9 mm Hg/mL for normotensives and 3.3+/-1.0 mm Hg/mL for hypertensives; P<0.001). Effective arterial elastance was also higher (2.6+/-0.5 versus 1.9+/-0.5 mm Hg/mL) due to reduced total arterial compliance; the latter inversely correlated with end-systolic elastance (P=0.0001). Body size and stroke volumes were similar and could not explain differences in ventricular-arterial stiffening. HF-nlEF patients also displayed diastolic abnormalities, including higher left ventricular end-diastolic pressures (24.3+/-4.6 versus 12.9+/-5.5 mm Hg), caused by an upward-shifted diastolic pressure-volume curve. However, isovolumic relaxation and the early-to-late filling ratio were similar in age- and blood pressure-matched controls. Ventricular-arterial stiffening amplified stress-induced hypertension, which worsened diastolic function, and predicted higher cardiac energy costs to provide reserve output. CONCLUSION: Patients with HF-lnEF have systolic-ventricular and arterial stiffening beyond that associated with aging and/or hypertension. This may play an important pathophysiological role by exacerbating systemic load interaction with diastolic function, augmenting blood pressure lability, and elevating cardiac metabolic demand under stress. (+info)
Sudden death in noncoronary heart disease is associated with delayed paced ventricular activation.
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BACKGROUND: Slowed or delayed myocardial activation and dispersed refractoriness predispose to reentrant excitation that may lead to ventricular fibrillation (VF). Increased ventricular electrogram duration (DeltaED) in response to extrastimuli and increased S1S2 coupling intervals at which electrogram duration starts to increase (S1S2delay) are seen both in hypertrophic cardiomyopathy (HCM) in those at risk of VF and in patients with idiopathic VF (IVF). METHODS AND RESULTS: DeltaED and S1S2delay have been measured using paced electrogram fractionation analysis in 266 patients with noncoronary heart disease. Of these, one group of 61 patients had a history of VF and included 21 HCM, 17 IVF, 13 long-QT syndrome (LQTS), 5 dilated cardiomyopathy (DCM), and 5 others. These were compared with 205 patients with similar diseases with no VF history (non-VF group) and a control group (n=12) without heart disease. Results from HCM VF patients (DeltaED, 19+/-3.3 ms; S1S2delay, 350+/-9.7 ms) differed sharply from observations in HCM non-VF patients (DeltaED, 7.3+/-1.35 ms; S1S2delay, 312+/-6.7 ms; P<0.001). DCM VF patients had longer delays (DeltaED, 14.3+/-5.9; S1S2delay, 344+/-11.2) than DCM non-VF patients (DeltaED, 5.8+/-1.87 ms; S1S2delay, 311+/-5.7 ms; P<0.001), with major differences also seen comparing LQTS VF (DeltaED, 12.4+/-5.3 ms; S1S2delay, 343+/-13.8 ms) and LQTS non-VF patients (DeltaED, 11.0+/-2.7 ms; S1S2delay, 320+/-5.4 ms; P<0.001). IVF patients had both severely abnormal and normal areas of myocardium. CONCLUSIONS: Slowed or delayed myocardial activation is a common feature in patients with noncoronary heart disease with a history of VF, and its assessment may allow the prospective prediction of VF risk in these patients. (+info)
Cardiac autonomic characteristics in infants sleeping with their head covered by bedclothes.
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The risk of Sudden Infant Death Syndrome is increased in infants sleeping with their head covered by bedding items. This study was designed to evaluate cardiac autonomic nervous controls in infants sleeping with the head covered by bedclothes. Sixteen healthy infants with a median age of 12 weeks (range 9-13 weeks) were recorded polygraphically for one night. While they slept in their usual supine position, a bedsheet was placed over their head for about 45 min. All infants were challenged with the head covered and with the head free during both rapid eye movement (REM) and non-rapid eye movement (NREM) sleep. Sleep, breathing and heart rate (HR) characteristics were recorded simultaneously, together with rectal and pericephalic temperatures. In both head-free and head-covered conditions, autoregressive spectral analysis of HR was evaluated as a function of sleep stages. During the head-covered periods, parasympathetic tonus decreased and sympathetic activity increased in both REM and NREM sleep. Compared with the head-free periods, the head-covered sleep periods were characterized by greater rectal (P = 0.012) and pericephalic temperatures (P = 0.002). Covering the infant's head with a bedsheet was associated with significant changes in autonomic balance. The finding could be related to an elevation in temperatures within the infant's microenvironment. (+info)
Abnormal cardiac function in fetuses with increased nuchal translucency.
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OBJECTIVE: To evaluate cardiac function in structurally and chromosomally normal fetuses with increased nuchal translucency (NT). METHODS: Forty-two structurally and chromosomally normal fetuses with increased NT at 11-14 weeks of gestation underwent fetal echocardiographic examination at 20-23 weeks. Fifty fetuses with normal NT values were considered as controls. Pulmonary and aortic peak velocity and time to peak velocities were measured as indices of ventricular systolic function. The ratios between the E-wave and A-wave (E/A) and the ratios between the E-wave and time velocity integral (E/TVI) at the level of both atrioventricular valves were evaluated as indices of ventricular diastolic function. RESULTS: In fetuses with increased NT the E/A ratios were significantly decreased when compared to control fetuses at the level of both the mitral (0.52 +/- 0.09 vs. 0.60 +/- 0.10, P = 0.0002) and tricuspid (0.51 +/- 0.09 vs. 0.61 +/- 0.09, P < 0.0001) valves. Similar results were found for the E/TVI ratios (mitral valve 4.79 +/- 1.03 vs. 5.63 +/- 1.23, P = 0.0007 and tricuspid valve 4.40 +/- 0.88 vs. 5.19 +/- 0.82, P < 0.0001). No significant relationship was found between the degree of NT and the abnormalities in Doppler indices. There were no significant differences in Doppler systolic indices. CONCLUSION: Structurally and chromosomally normal fetuses with increased NT have low E/A and E/TVI ratios at 20-23 weeks of gestation. These findings might indicate cardiac diastolic dysfunction. (+info)
Inhibition of granulation tissue cell apoptosis during the subacute stage of myocardial infarction improves cardiac remodeling and dysfunction at the chronic stage.
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BACKGROUND: Granulation tissue cells at the subacute stage of myocardial infarction (MI) are eliminated by apoptosis to finally make a scar at the chronic stage. We hypothesized that postinfarct inhibition of apoptosis might preserve myofibroblasts and endothelial cells in granulation and modulate chronic left ventricular (LV) remodeling and heart failure. METHODS AND RESULTS: A pancaspase inhibitor, Boc-Asp-fmk (BAF, 10 micromol/kg per day), or vehicle (control) was given to rats with experimental large MI. The treatment was started on the third day after MI and continued until 4-week-old MI. Two weeks later, the apoptosis of granulation tissue cells was significantly reduced and conversely, the cell population was greater in BAF. Twelve weeks later, BAF showed significantly greater survival rates (84% versus 42%) with significantly smaller LV cavity, lower LV end-diastolic pressure and central venous pressure, and higher LV dP/dt, which indicated improvement of LV remodeling and dysfunction. A scar was established in old infarct of control subjects, but in BAF, the infarct wall was thicker because of greater old infarct area, which contained abundant myofibroblasts and vessels. Surprisingly, many of the alpha-smooth muscle actin-positive myofibroblast-like cells in BAF, making bundles and running parallel to the survived cardiomyocytes, were ultrastructurally mature smooth muscle cells with contractile phenotype. Cardiomyocyte apoptosis in the infarct area was equally rare in each group. CONCLUSIONS: The postinfarct treatment with BAF improved LV remodeling and dysfunction through inhibition of granulation tissue cell apoptosis. These findings imply a new therapeutic strategy against postinfarct heart failure. (+info)