Past and current cause-specific mortality in Eisenmenger syndrome.

AIMS: Eisenmenger syndrome (ES) is associated with considerable morbidity and mortality. Therapeutic strategies have changed during the 2000s in conjunction with an emphasis on specialist follow-up. The aim of this study was to determine the cause-specific mortality in ES and evaluate any relevant changes between 1977 and 2015. METHODS AND RESULTS: This is a retrospective, descriptive multicentre study. A total of 1546 patients (mean age 38.7 ± 15.4 years; 36% male) from 13 countries were included. Cause-specific mortality was examined before and after July 2006, 'early' and 'late', respectively. Over a median follow-up of 6.1 years (interquartile range 2.1-21.5 years) 558 deaths were recorded; cause-specific mortality was identified in 411 (74%) cases. Leading causes of death were heart failure (34%), infection (26%), sudden cardiac death (10%), thromboembolism (8%), haemorrhage (7%), and peri-procedural (7%). Heart failure deaths increased in the 'late' relative to the 'early' era (P = 0.032), whereas death from thromboembolic events and death in relation to cardiac and non-cardiac procedures decreased (P = 0.014, P = 0.014, P = 0.004, respectively). There was an increase in longevity in the 'late' vs. 'early' era (median survival 52.3 vs. 35.2 years, P < 0.001). CONCLUSION: The study shows that despite changes in therapy, care, and follow-up of ES in tertiary care centres, all-cause mortality including cardiac remains high. Patients from the 'late' era, however, die later and from chronic rather than acute cardiac causes, primarily heart failure, whereas peri-procedural and deaths due to haemoptysis have become less common. Lifelong vigilance in tertiary centres and further research for ES are clearly needed.

Long-Term Outcome of Mustard/Senning Correction for Transposition of the Great Arteries in Sweden and Denmark.

BACKGROUND: The atrial switch operation, the Mustard or Senning operation, for the transposition of the great arteries (TGA) was introduced in the late 1950s and was the preferred surgery for TGA until the early 1990s. The Mustard and Senning operation involves extensive surgery in the atria and leaves the right ventricle as the systemic ventricle. The Mustard and Senning cohort is now well into adulthood and we begin to see the long-term outcome. METHODS AND RESULTS: All the 6 surgical centers that performed Mustard and Senning operations in Sweden and Denmark identified all operated TGA patients. Information about death was obtained in late 2007 and early 2008 from the Danish and Swedish Centralised Civil Register by using the patients' unique national Civil Registration Numbers. Four hundred sixty-eight patients undergoing the atrial switch operation were identified. Perioperative 30-day mortality was 20%, and 60% were alive after 30 years of follow-up. Perioperative mortality was significantly increased by the presence of a ventricular septal defect, left ventricular outflow obstruction, surgery early in the Mustard and Senning era. However, only pacemaker implantation is predictive of long-term outcome (hazard ratio, 1.90; 95% confidence interval, 1.05-3.46, P=0.04), once the TGA patient has survived the perioperative period. The risk of reoperation was correlated to the presence of associated defects and where the first Mustard/Senning operation was performed. CONCLUSIONS: The long-term survival of patients with Mustard and Senning correction for TGA appears to be primarily determined by factors in the right ventricle and tricuspid valve and not the timing of or the type of surgery in childhood. Cardiac function necessitating the implantation of a pacemaker is associated with an increase in mortality.

Bosentan improves exercise capacity in adolescents and adults after Fontan operation: the TEMPO (Treatment With Endothelin Receptor Antagonist in Fontan Patients, a Randomized, Placebo-Controlled, Double-Blind Study Measuring Peak Oxygen Consumption) study.

BACKGROUND: The Fontan procedure has improved survival in children with functionally univentricular hearts. With time, however, complications such as reduced exercise capacity are seen more frequently. Exercise intolerance is multifactorial, but pulmonary vascular resistance probably plays a crucial role. Elevated pulmonary vascular resistance has been associated with raised levels of endothelin-1, which are common both before and after Fontan operations. Treatment with endothelin-1 receptor antagonists could theoretically improve cardiopulmonary hemodynamics and exercise capacity. The aim of this study was therefore to examine the efficacy and safety of bosentan in Fontan patients. METHODS AND RESULTS: Seventy-five adolescents and adults were randomized 1:1 to 14 weeks of treatment with bosentan or placebo. Cardiopulmonary exercise test, functional class, blood samples, and quality-of-life questionnaires were evaluated at baseline and at the end of treatment. Sixty-nine patients (92%) completed the study. Peak oxygen consumption increased 2.0 mL·kg(-1)·min(-1) (from 28.7 to 30.7 mL·kg(-1)·min(-1)) in the bosentan group compared with 0.6 mL·kg(-1)·min(-1) (from 28.4 to 29.0 mL·kg(-1)·min(-1)) in the placebo group (P=0.02). Cardiopulmonary exercise test time increased by 0.48 minute (from 6.79 to 7.27 minutes) versus 0.08 minute (from 6.94 to 7.02 minutes; P=0.04). Nine bosentan-treated patients improved 1 functional class, whereas none improved in the placebo group (P=0.0085). Side effects were mild and occurred equally in both groups. No serious adverse effects were seen, and no patients had liver enzyme levels above the 3-fold upper limit. CONCLUSIONS: Bosentan improves exercise capacity, exercise time, and functional class in Fontan patients without serious adverse events or hepatotoxicity. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT01292551.

The effect of bosentan on exercise capacity in Fontan patients; rationale and design for the TEMPO study.

BACKGROUND: Palliative treatment with the Fontan procedure has greatly improved survival for children with functionally univentricular heart. Since Fontan performed the first successful operation, the procedure has evolved and is now performed as Total Cavo-Pulmonary Connection (TCPC).An increasing prevalence and longer life expectancy of TCPC patients have raised new challenges. The survivors are often suffering complications such as arrhythmias, myocardial dysfunction, thromboembolic events, neuropsychological deficit, protein-losing enteropathy and reduced exercise capacity. Several causes for the reduced exercise capacity may be present e.g. impaired function of the single ventricle, valve dysfunction and chronotropic impairment, and perhaps also increased pulmonary vascular resistance. Thus, plasma endothelin-1 has been shown to correlate with increased pulmonary vascular resistance and the risk of failing Fontan circulation. This has raised the question of the role for pulmonary vasodilation therapy, especially endothelin receptor antagonist in the management of TCPC patients. METHODS/DESIGN: The TEMPO trial aims to investigate whether Bosentan, an endothelin receptor antagonist, can be administered safely and improve exercise capacity in TCPC patients. The trial design is randomized, double-blind and placebo-controlled. Bosentan/placebo is administered for 14 weeks with control visits every four weeks. The primary endpoint is change in maximal oxygen consumption as assessed on bicycle ergometer test. Secondary endpoints include changes in pulmonary blood flow during exercise test, pro brain natriuretic peptide and quality of life. DISCUSSION: We hypothesize that treatment with Bosentan, an endothelin receptor antagonist, can be administered safely and improve exercise capacity in TCPC patients.

Dilation of the ascending aorta in Turner syndrome - a prospective cardiovascular magnetic resonance study.

BACKGROUND: The risk of aortic dissection is 100-fold increased in Turner syndrome (TS). Unfortunately, risk stratification is inadequate due to a lack of insight into the natural course of the syndrome-associated aortopathy. Therefore, this study aimed to prospectively assess aortic dimensions in TS. METHODS: Eighty adult TS patients were examined twice with a mean follow-up of 2.4 ± 0.4 years, and 67 healthy age and gender-matched controls were examined once. Aortic dimensions were measured at nine predefined positions using 3D, non-contrast and free-breathing cardiovascular magnetic resonance. Transthoracic echocardiography and 24-hour ambulatory blood pressure were also performed. RESULTS: At baseline, aortic diameters (body surface area indexed) were larger at all positions in TS. Aortic dilation was more prevalent at all positions excluding the distal transverse aortic arch. Aortic diameter increased in the aortic sinus, at the sinotubular junction and in the mid-ascending aorta with growth rates of 0.1 - 0.4 mm/year. Aortic diameters at all other positions were unchanged. The bicuspid aortic valve conferred higher aortic sinus growth rates (p < 0.05). No other predictors of aortic growth were identified. CONCLUSION: A general aortopathy is present in TS with enlargement of the ascending aorta, which is accelerated in the presence of a bicuspid aortic valve.

Thoracic aortopathy in Turner syndrome and the influence of bicuspid aortic valves and blood pressure: a CMR study.

BACKGROUND: To investigate aortic dimensions in women with Turner syndrome (TS) in relation to aortic valve morphology, blood pressure, karyotype, and clinical characteristics. METHODS AND RESULTS: A cross sectional study of 102 women with TS (mean age 37.7; 18-62 years) examined by cardiovascular magnetic resonance (CMR- successful in 95), echocardiography, and 24-hour ambulatory blood pressure. Aortic diameters were measured by CMR at 8 positions along the thoracic aorta. Twenty-four healthy females were recruited as controls. In TS, aortic dilatation was present at one or more positions in 22 (23%). Aortic diameter in women with TS and bicuspid aortic valve was significantly larger than in TS with tricuspid valves in both the ascending (32.4 +/- 6.7 vs. 26.0 +/- 4.4 mm; p < 0.001) and descending (21.4 +/- 3.5 vs. 18.8 +/- 2.4 mm; p < 0.001) aorta. Aortic diameter correlated to age (R = 0.2 - 0.5; p < 0.01), blood pressure (R = 0.4; p < 0.05), a history of coarctation (R = 0.3; p = 0.01) and bicuspid aortic valve (R = 0.2-0.5; p < 0.05). Body surface area only correlated with descending aortic diameter (R = 0.23; p = 0.024). CONCLUSIONS: Aortic dilatation was present in 23% of adult TS women, where aortic valve morphology, age and blood pressure were major determinants of the aortic diameter.

Abnormalities of the major intrathoracic arteries in Turner syndrome as revealed by magnetic resonance imaging.

BACKGROUND: Ectatic aortopathy and arterial abnormalities cause excess morbidity and mortality in Turner syndrome, where a state of vasculopathy seemingly extends into the major head and neck branch arteries. OBJECTIVE: We investigated the prevalence of abnormalities of the major intrathoracic arteries, their interaction with arterial dimensions, and their association with karyotype. DESIGN: Magnetic resonance imaging scans determined the arterial abnormalities as well as head and neck branch artery and aortic dimensions in 99 adult women with Turner syndrome compared with 33 healthy female controls. Echocardiography determined aortic valve morphology. RESULTS: In Turner syndrome, the relative risk of any congenital abnormality was 7.7 (p = 0.003) and 6.7 of ascending aortic dilation (p = 0.02). A bovine aortic arch was seen in both Turner syndrome and controls. Other abnormalities were only encountered in Turner syndrome: elongated transverse aortic arch (47%), bicuspid aortic valve (27%), aortic coarctation (13%), aberrant right subclavian artery (8%), and aortic arch hypoplasia (2%). The innominate and left common carotid arteries were enlarged in Turner syndrome (p < 0.001). Significant associations were first, bicuspid aortic valve with aortic coarctation, elongated transverse aortic arch, and ascending aortic dilation; second, aortic coarctation with elongated aortic arch and descending aortic dilation; third, 45,X with aortic coarctation, elongated transverse aortic arch and ascending aortic dilation; and fourth, branch artery dilation with bicuspid aortic valve, aortic coarctation, elongated transverse aortic arch and 45,X. CONCLUSION: An increased risk of arterial abnormalities, aortic dilation, and enlargement of the branch arteries was found in Turner syndrome without distinct patterns of co-segregation.

Vascular function in adults with cyanotic congenital heart disease.

BACKGROUND: Patients with cyanotic congenital heart disease (CCHD) may have a low burden of atherosclerosis. Endothelial dysfunction is an early stage of atherosclerosis and endothelial function is previously studied in smaller CCHD groups with different techniques and variable results. We aimed to examine endothelial function and carotid atherosclerosis in a larger group of CCHD patients. METHODS: This multicentre study assessed endothelial function in adults with CCHD and controls by measuring the dilatory response of the brachial artery to post-ischemic hyperaemia (endothelium-dependent flow-mediated-vasodilatation (FMD)), and to nitroglycerin (endothelium-independent nitroglycerin-induced dilatation (NID)). Flow was measured at baseline and after ischaemia (reactive hyperaemia). Carotid-intima-media-thickness (CIMT), prevalence of carotid plaque and plaque thickness (cPT-max) were evaluated ultrasonographically. Lipoproteins, inflammatory and vascular markers, including sphingosine-1-phosphate (S1P) were measured. RESULTS: Forty-five patients with CCHD (median age 50 years) and 45 matched controls (median age 52 years) were included. The patients presented with lower reactive hyperaemia (409 ± 114% vs. 611 ± 248%, p < 0.0001), however preserved FMD response compared to controls (106.5 ± 8.3% vs. 106.4 ± 6.1%, p = 0.95). In contrast, NID was lower in the patients (110.5 ± 6.1% vs. 115.1 ± 7.4%, p = 0.053). There was no difference in CIMT, carotid plaque or cPT-max. The patients presented with lower high-density-lipoprotein cholesterol, and higher level of inflammatory markers and S1P. CONCLUSION: Adults with CCHD had preserved FMD in the brachial artery, but impaired NID response and lower reactive hyperaemia than controls. The preserved FMD and the comparable prevalence of carotid atherosclerosis indicate that CCHD patients have the same risk of atherosclerosis as controls.

Preserved flow-mediated dilation in adults with cyanotic congenital heart disease.

Adults with cyanotic congenital heart disease (CCHD) have been shown to have endothelial dysfunction in the forearm resistance vessels as assessed with venous occlusion plethysmography. Whether these abnormalities are confined to the microvasculature or reflect generalized endothelial dysfunction remain unknown. We used high-resolution ultrasound to compare flow responses and endothelial-dependent flow-mediated dilation (FMD) in the brachial artery of 13 adult patients with CCHD and 14 healthy controls. High-dose vitamin C was infused to evaluate the possible role of reactive oxygen species on endothelial vasomotor function. FMD was measured both prior to and after vitamin C infusion. Sublingual glyceryl nitrate was given to assess endothelium-independent responses. FMD did not differ among patients with CCHD and controls either before (6.2 +/- 4.1, 5.1 +/- 2.6%, p = 0.44) or after (5.1 +/- 2.8, 5.2 +/- 3.1%, p = 0.90) vitamin C infusion. Endothelium-independent vasodilatation was similar in both groups (14.3 +/- 3.7, 13.2 +/- 4.4%). There were no differences in baseline flow or in measures of reactive hyperemia. Adults with CCHD appear to have preserved endothelial function in their conduit arteries. This suggests that these patients are not at an increased risk of premature atherosclerotic cardiovascular events.

Intravascular assessment of coronary arteries in patients with cyanotic congenital heart disease.

AIMS: Patients with cyanotic congenital heart disease (CCHD) have been suggested to develop less atherosclerosis than the general population. This study aimed to evaluate the extent of coronary atherosclerosis in patients with CCHD using intravascular ultrasound (IVUS) and near-infrared spectroscopy (NIRS). METHODS AND RESULTS: Fifteen patients with CCHD (women, 9; median age, 53 years) and 14 acyanotic controls (women, 6; median age, 53 years) were examined with IVUS-NIRS of the right coronary artery (RCA). The patients with CCHD presented with a larger RCA diameter than the controls (external elastic membrane diameter, 6.1 [4.8-6.7] vs. 4.7 [4.1-5.1] mm, respectively; p=0.01). No difference in area stenosis was found between the patients and the controls (15.8% [12.3-19.7] vs. 15.2% [9.5-18.8]; p=0.87). The presence of lipid by NIRS was noted in 43% of patients with CCHD and in 92% of the controls; however, no differences in total or max 4 mm lipid core burden index (LCBI) or in plasma lipid profile were found. CONCLUSIONS: Patients with CCHD presented with larger coronary arteries than acyanotic controls. No difference in the degree of area stenosis in the coronary arteries was found between the cyanotic and acyanotic patients; however, a lower proportion of patients with CCHD showed a positive LCBI.

Everolimus for the prevention of allograft rejection and vasculopathy in cardiac-transplant recipients.

BACKGROUND: Everolimus, a novel proliferation inhibitor and immunosuppressive agent, may suppress cardiac-allograft vasculopathy. We conducted a randomized, double-blind, clinical trial comparing everolimus with azathioprine in recipients of a first heart transplant. METHODS: A total of 634 patients were randomly assigned to receive 1.5 mg of everolimus per day (209 patients), 3.0 mg of everolimus per day (211 patients), or 1.0 to 3.0 mg of azathioprine per kilogram of body weight per day (214 patients), in combination with cyclosporine, corticosteroids, and statins. The primary efficacy end point was a composite of death, graft loss or retransplantation, loss to follow-up, biopsy-proved acute rejection of grade 3A, or rejection with hemodynamic compromise. RESULTS: At six months, the percentage of patients who had reached the primary efficacy end point was significantly smaller in the group given 3.0 mg of everolimus (27.0 percent, P<0.001) and the group given 1.5 mg of everolimus (36.4 percent, P=0.03) than in the azathioprine group (46.7 percent). Intravascular ultrasonography showed that the average increase in maximal intimal thickness 12 months after transplantation was significantly smaller in the two everolimus groups than in the azathioprine group. The incidence of vasculopathy was also significantly lower in the 1.5-mg group (35.7 percent, P=0.045) and the 3.0-mg group (30.4 percent, P=0.01) than in the azathioprine group (52.8 percent). The rates of cytomegalovirus infection were significantly lower in the 1.5-mg group (7.7 percent, P<0.001) and the 3.0-mg group (7.6 percent, P<0.001) than in the azathioprine group (21.5 percent). Rates of bacterial infection were significantly higher in the 3.0-mg group than in the azathioprine group. Serum creatinine levels were also significantly higher in the two everolimus groups than in the azathioprine group. CONCLUSIONS: Everolimus was more efficacious than azathioprine in reducing the severity and incidence of cardiac-allograft vasculopathy, suggesting that everolimus therapy may alleviate this serious problem.

Epidemiological changes in Eisenmenger syndrome in the Nordic region in 1977-2012.

OBJECTIVE: Improved diagnostic tools, timely closure of the shunt and a better understanding of the complexity of Eisenmenger syndrome (ES) have led to improved care and treatment in tertiary centres. These may have decreased the incidence of ES and improved survival of patients with ES, although evidence is still lacking. The aim of this study was to investigate temporal changes in incidence, prevalence and mortality in patients with ES for 35 years in the Nordic region. METHODS: This was a retrospective population-based study including 714 patients with ES. Survival analysis was performed based on all-cause mortality and accounting for immortal time bias. RESULTS: The incidence of ES decreased from 2.5/million inhabitants/year in 1977 to 0.2/million inhabitants/year in 2012. Correspondingly, prevalence decreased from 24.6 to 11.9/million inhabitants. The median survival was 38.4 years, with 20-year, 40-year and 60-year survival of 72.5%, 48.4%, and 21.3%, respectively. Complex lesions and Down syndrome were independently associated with worse survival (HR 2.2, p<0.001 and HR 1.8, p<0.001, respectively). Age at death increased from 27.7 years in the period from 1977 to 1992, to 46.3 years from July 2006 to 2012 (p<0.001). CONCLUSIONS: The incidence and prevalence of ES in the Nordic region have decreased markedly during the last decades. Furthermore, the median age at death increased throughout the study period, indicating prolonged life expectancy in the ES population. However, increasing age represents decreased incidence, rather than improved survival. Nonetheless, longevity with ES is still shorter than in the background population.

Endothelial function and biochemical vascular markers in first-degree relatives of type 2 diabetic patients: the effect of exercise training.

Endothelial dysfunction (ED) is associated with the presence of atherosclerosis. However, ED is also considered a sign of the early vascular changes preceding atherosclerosis. By measuring flow-mediated vasodilation (FMD) and circulating markers of endothelial function we sought to explore whether impaired endothelial function is already present in healthy subjects at increased risk of developing type 2 diabetes mellitus. Furthermore, we aimed to assess the impact of short-term lifestyle intervention (10 weeks endurance exercise) on the potentially primary defects of endothelial function. Twenty-nine healthy but insulin-resistant first-degree relatives of patients diagnosed with type 2 diabetes mellitus (33 +/- 5 years; body mass index, 26.3 +/- 1.6 kg/m2) were compared with 19 control subjects without a family history of diabetes mellitus (31 +/- 5 years; body mass index, 25.8 +/- 3.0 kg/m2). At baseline the von Willebrand factor was significantly increased in the relatives (P < .05). Furthermore, mannose-binding lectin (P = .06), soluble intercellular adhesion molecule 1 (P = .08), and osteoprotegerin (P = .08) tended to be increased in relatives. The following markers of endothelial function were comparable at baseline: FMD, C-reactive protein, plasminogen activator inhibitor 1, and soluble vascular cell adhesion molecule 1. Exercise training resulted in a decrease in mannose-binding lectin (P = .02) and osteoprotegerin (P < .01) in relatives only, whereas other biochemical markers were unaffected in both groups. Moreover, the relatively high-intensity exercise training tended weakly to reduce FMD in the relatives (P = .15). In conclusion, healthy subjects predisposed for type 2 diabetes mellitus show only minor signs of endothelial dysfunction. Under these almost normal vascular conditions, exercise training has little effect on endothelial function.

A mutation in the glutamate-rich region of RNA-binding motif protein 20 causes dilated cardiomyopathy through missplicing of titin and impaired Frank-Starling mechanism.

AIM: Mutations in the RS-domain of RNA-binding motif protein 20 (RBM20) have recently been identified to segregate with aggressive forms of familial dilated cardiomyopathy (DCM). Loss of RBM20 in rats results in missplicing of the sarcomeric gene titin (TTN). The functional and physiological consequences of RBM20 mutations outside the mutational hotspot of RBM20 have not been explored to date. In this study, we investigated the pathomechanism of DCM caused by a novel RBM20 mutation in human cardiomyocytes. METHODS AND RESULTS: We identified a family with DCM carrying a mutation (RBM20(E913K/+)) in a glutamate-rich region of RBM20. Western blot analysis of endogenous RBM20 protein revealed strongly reduced protein levels in the heart of an RBM20(E913K/+ )carrier. RNA deep-sequencing demonstrated massive inclusion of exons coding for the spring region of titin in the RBM20(E913K/+ )carrier. Titin isoform analysis revealed a dramatic shift from the less compliant N2B towards the highly compliant N2BA isoforms in RBM20(E913K/+ )heart. Moreover, an increased sarcomere resting-length was observed in single cardiomyocytes and isometric force measurements revealed an attenuated Frank-Starling mechanism (FSM), which was rescued by protein kinase A treatment. CONCLUSION: A mutation outside the mutational hotspot of RBM20 results in haploinsufficiency of RBM20. This leads to disturbed alternative splicing of TTN, resulting in a dramatic shift to highly compliant titin isoforms and an impaired FSM. These effects may contribute to the early onset, and malignant course of DCM caused by RBM20 mutations. Altogether, our results demonstrate that heterozygous loss of RBM20 suffices to profoundly impair myocyte biomechanics by its disturbance of TTN splicing.

Validation of myocardial acceleration during isovolumic contraction as a novel noninvasive index of right ventricular contractility: comparison with ventricular pressure-volume relations in an animal model.

BACKGROUND: We have demonstrated that myocardial acceleration during isovolumic contraction (IVA) is a sensitive index of left ventricular contractile function. In this study, we assessed the utility of IVA to measure right ventricular (RV) contractile function. METHODS AND RESULTS: We examined 8 pigs by using tissue Doppler imaging of the RV free wall and simultaneous measurements of intraventricular pressure, volume, maximal elastance (e(max)), preload recruitable stroke work, and dP/dt(max) by conductance catheterization. Animals were paced in the right atrium at a rate of 130 beats per minute (bpm). IVA was compared with elastance during contractility modulation by esmolol and dobutamine and during preload reduction and afterload increase by transient balloon occlusion of the inferior vena cava and pulmonary artery, respectively. Data were also obtained during incremental atrial pacing from 110 to 210 bpm. Esmolol led to a decrease in IVA and dP/dt(max). During dobutamine infusion, IVA, dP/dt(max), preload recruitable stroke work, and e(max) all increased significantly. During preload reduction and afterload increase, IVA remained constant up to a reduction of RV volume by 54% and an RV systolic pressure increase of 58%. Pacing up to a rate of 190 bpm led to a stepwise increase in IVA and dP/dt(max), with a subsequent fall at a pacing rate of 210 bpm. CONCLUSIONS: IVA is a measurement of RV contractile function that is unaffected by preload and afterload changes in a physiological range and is able to measure the force-frequency relation. This novel index may be ideally suited to the assessment of acute changes of RV function in clinical studies.

Noninvasive assessment of left ventricular force-frequency relationships using tissue Doppler-derived isovolumic acceleration: validation in an animal model.

BACKGROUND: We have demonstrated that myocardial acceleration during isovolumic contraction (IVA) is a sensitive index of right ventricular contractile function. In this study, we assessed the usefulness of IVA to measure left ventricular (LV) contractile function and force-frequency relationships in an experimental preparation. METHODS AND RESULTS: In study 1, we examined 6 pigs by use of tissue Doppler imaging of LV free wall and simultaneous measurements of intraventricular pressure, volume, maximal elastance (Emax), and dP/dtmax by conductance catheterization. Animals were paced via the right atrium at a rate of 130 bpm. IVA was compared with elastance during contractility modulation by esmolol and dobutamine and assessed during preload reduction and afterload increase. In study 2, in 6 more pigs, force-frequency data were obtained during incremental atrial pacing from 120 to 180 bpm. Study 1: Esmolol led to a decrease in IVA and Emax (P<0.03 and <0.02, respectively), both of which increased during dobutamine infusion (P<0.02 and <0.03, respectively). IVA was unaffected by significant (P<0.001) acute reduction of LV volume and a significantly increased LV afterload (systolic pressure increase, P<0.001). Study 2: There was a positive correlation between IVA and dP/dtmax (r2=0.92, P<0.05). As heart rate was increased from 120 to 160 bpm, there were significant increases in both IVA and dP/dtmax (P<0.0004 and P=0.02, respectively). Over the same range of heart rates, there was no significant change in Emax (P=0.22). CONCLUSIONS: IVA is a measurement of LV contractile function that is unaffected by preload and afterload changes within a physiological range and can be used noninvasively to measure LV force-frequency relationships.

Glucose-insulin infusion improves cardiac function during fetal tachycardia.

OBJECTIVES: The aim of this work was to study the effects of substrate deficiency and supplementation on cardiac function during fetal tachycardia. BACKGROUND: Although sustained fetal tachycardia may lead to cardiac failure and intrauterine death, neonatal tachycardia is generally better tolerated. Fetal myocardial energy production relies almost solely on glucose as substrate. We hypothesized that increased substrate availability by glucose-insulin (GI) infusion would improve fetal myocardial responses to tachycardia. METHODS: We used three porcine models: 1) an isolated fetal heart model; 2) an in vivo fetal model; and 3) an in vivo closed-chest neonatal model. Each animal was randomized to control or GI treatment during tachycardia. In model 1, the controls were perfused with conventional Krebs-Henseleit solution containing a glucose concentration of 5.5 mmol/l; the GI hearts received double glucose concentration and added insulin. In models 2 and 3, the GI animals received insulin in a 20% glucose solution. All hearts were exposed to 90 min of pacing at 250 to 330 beats/min. RESULTS: The isolated fetal hearts in the GI group showed no decline in dP/dt(max) during pacing, while the controls declined. In the in vivo fetal hearts, dP/dt(max) remained unchanged in the GI group and decreased significantly in the control group. Myocardial glycogen content was higher in the GI group than in controls. Functional indexes remained unchanged among both neonatal groups despite a higher glycogen content in the GI group. CONCLUSIONS: Glucose-insulin infusion during fetal tachycardia has a beneficial effect on myocardial metabolism and cardiac function. These observations may have direct clinical relevance to the management of fetal arrhythmia.

Effect of oral nitroglycerin and cold stress on myocardial perfusion in areas subtended by stenosed and nonstenosed coronary arteries.

Physical obstruction and coronary vasoconstriction mediated by adrenergic stress are believed to be responsible for episodes of myocardial hypoperfusion and angina. Nitroglycerin relieves symptoms by reducing preload and dilating epicardial vessels. The net perfusion change and relation to stenosis severity of nitroglycerin and adrenergic stress have been debated. This study aimed to evaluate whether oral nitroglycerin and adrenergic stress alters perfusion in myocardial segments subtended by stenosed and nonstenosed coronary arteries. Myocardial perfusion was quantified (using N-13-ammonia positron emission tomography [PET]) at rest, after oral nitroglycerin 400 microg, and after cold stress in 25 patients with coronary artery disease (62 +/- 9 years, 21 men) and in 30 controls (34 +/- 9 years, 22 men). Myocardial perfusion was quantified in areas supplied by stenosed (>70%) and nonstenosed (<30%) coronary arteries. The cold pressor test did not significantly alter myocardial perfusion in any of the groups. However, when normalized for rate-pressure product, the response in stenosed areas showed a significantly more pronounced reduction compared with nonstenosed areas (0.78 +/- 0.18 vs 0.64 +/- 0.19 ml/g/min, p <0.005 and 0.86 +/- 0.19 vs 0.73 +/- 0.24 ml/g/min, p <0.05, p <0.05) for intergroup comparison. In both stenosed areas and nonstenosed areas nitroglycerin increased perfusion (0.51 +/- 0.14 vs 0.60 +/- 0.17 ml/g/min, p <0.05 and 0.56 +/- 0.14 vs 0.61 +/- 0.17 ml/g/min, p <0.05). Nitroglycerin did not alter myocardial perfusion in the control group. There was a negative correlation between the cold pressor test response and stenosis severity (r(2) = 0.17, p <0.046), whereas this was not the case for nitroglycerin. In patients with coronary artery disease, myocardial segments supplied by stenosed coronary arteries showed an altered perfusion response to adrenergic stress. Oral nitroglycerin increased myocardial perfusion irrespective of the presence of a stenosis.

[Transcatheter closure of atrial septal defects]. / Kateterbaseret lukning af atrieseptumdefekter.

INTRODUCTION: Transcatheter based device closure of secundum atrial septal defects (ASD) have been offered at our institution since September 1997. During the first three years, closure was attempted in 56 patients aged 3 to 71 years (median 15). MATERIAL AND METHODS: Hospital notes on all patients undergoing device closure of atrial septal defects between September 1997 and September 2000 were reviewed. Indications for attempted closure were significant arteriovenous shunting (n = 49), venoarterial shunting (n = 3), and suspected paradoxical embolism (n = 4). RESULTS: Device delivery was achieved in 51 (91%) patients. In five patients, the procedure was abandoned, owing to the unsatisfactory position of the device. In one patient, embolisation occurred within 24 hours. At three months follow-up, 44 of the 46 patients investigated had completely closed defects. Residual flow was seen in two patients, including one (with three defects) who subsequently underwent elective surgical closure. There were no other complications. DISCUSSION: Device closure of ASD is a realistic alternative to surgical treatment.