PubMed Health⌕ Search

Biomedical subjects

Michael A Gatzoulis

Publications and source records attributed to Michael A Gatzoulis.

At least 19 recordsLinked to original sources
PubMed2007

Arrhythmia and reduced heart rate variability during pregnancy in women with congenital heart disease and previous reparative surgery.

OBJECTIVES: Tachyarrhythmia during pregnancy may have an adverse effect on the mother and the fetus. Heart rate variability (HRV) is a significant marker of autonomic nervous function and may predict tachyarrhythmia. HRV and incidence of arrhythmia in women with repaired congenital heart disease (CHD) during pregnancy were examined. METHODS: Twenty-eight patients with repaired CHD (35 pregnancies, age: 26+/-3.5 years at their first pregnancy, 22+/-6.2 years post-repair) and 19 healthy pregnant volunteers (controls, 19 pregnancies, age: 28+/-5.5 years) were enrolled. Holter monitoring and laboratory tests were examined at 28+/-4 weeks of gestation and 22+/-13 weeks postpartum in patients and 28+/-3 weeks of gestation in controls. Time and frequency variables of HRV were analyzed. RESULTS: Compared with controls and postpartum, there was a significantly higher incidence of tachyarrhythmia during pregnancy in women with CHD (4 episodes of supraventricular tachyarrhythmia (SVT) and 5 of non-sustained ventricular tachycardia, P=0.02). HR response in tetralogy of Fallot was impaired (781+/-50 ms, P=0.02). Most of HRV variables were significantly suppressed (average RR 740+/-64 ms, SDRR 99+/-22 ms, low and high frequency domains (341+/-165 ms2 and 256+/-181 ms2) (P<0.05). Reduced SDRR and high frequency domains were observed in patients with tachyarrhythmia. Furthermore, there were increased left ventricular end-diastolic dimensions 48+/-5 mm (P=0.001) and atrial natriuretic peptide levels 33+/-13 pg/ml (P=0.01) in the CHD patients compared with postpartum levels. CONCLUSIONS: Impaired autonomic nervous activity, volume overload of the heart and operative scar all play a contributory role in higher incidence of tachyarrhythmia during pregnancy in patients with repaired CHD compared to healthy pregnant controls. Close monitoring of patients with CHD for tachyarrhythmia during pregnancy is, thus, warranted.

Adult↗
PubMed2006

Pulmonary arterial hypertension in adults born with a heart septal defect: the Euro Heart Survey on adult congenital heart disease.

AIM: To investigate the role of pulmonary arterial hypertension (PAH) in adult patients born with a cardiac septal defect, by assessing its prevalence and its relation with patient characteristics and outcome. METHODS AND RESULTS: From the database of the Euro Heart Survey on adult congenital heart disease (a retrospective cohort study with a 5-year follow-up), the relevant data on all 1877 patients with an atrial septal defect (ASD), a ventricular septal defect (VSD), or a cyanotic defect were analysed. Most patients (83%) attended a specialised centre. There were 896 patients with an ASD (377 closed, 504 open without and 15 with Eisenmenger's syndrome), 710 with a VSD (275, 352 and 83, respectively), 133 with Eisenmenger's syndrome owing to another defect and 138 remaining patients with cyanosis. PAH was present in 531 (28%) patients, or in 34% of patients with an open ASD and 28% of patients with an open VSD, and 12% and 13% of patients with a closed defect, respectively. Mortality was highest in patients with Eisenmenger's syndrome (20.6%). In case of an open defect, PAH entailed an eightfold increased probability of functional limitations (New York Heart Association class >1), with a further sixfold increase when Eisenmenger's syndrome was present. Also, in patients with persisting PAH despite defect closure, functional limitations were more common. In patients with ASD, the prevalence of right ventricular dysfunction increased with systolic pulmonary artery pressure (OR = 1.073 per mm Hg; p<0.001). Major bleeding events were more prevalent in patients with cyanosis with than without Eisenmenger's syndrome (17% vs 3%; p<0.001). CONCLUSION: In this selected population of adults with congenital heart disease, PAH was common and predisposed to more symptoms and further clinical deterioration, even among patients with previous defect closure and patients who had not developed Eisenmenger's physiology.

Adult↗
PubMed2006

Adult patients with Eisenmenger syndrome report flying safely on commercial airlines.

BACKGROUND: Despite fears of compromised oxygen delivery in patients with Eisenmenger syndrome during flight on commercial aircraft, a clinical study has shown no adverse effects, and many patients travel frequently. METHODS: The air travel history over the past decade of 53 patients with Eisenmenger syndrome and 48 acyanotic patients was obtained. Patients listed all flights and destinations, and any major adverse event or symptoms, including, specifically, headache, palpitations, oedema or need for supplemental oxygen. For the patients with Eisenmenger syndrome, a full blood count, 6-minute walk test and p50 of the oxygen-haemoglobin dissociation curve were also obtained. RESULTS: 1157 flights were reported evenly between the two groups. Thirteen patients with Eisenmenger syndrome reported no travel in the past 10 years (vs 4/48 acyanotic patients, p = 0.03), six of whom were told not to fly by healthcare providers. Of those who flew, the number and distance of flights was similar in both groups. No major adverse events were reported. One patient with Eisenmenger syndrome possibly had a transient ischaemic attack and a second patient needed supplemental oxygen when exposed to ambient cigarette smoke in flight. Other symptoms such as headache, palpitations and lower extremity oedema at the travel destination were reported with similar frequency in both groups. Patients with Eisenmenger syndrome had a raised p50 of the oxygen-haemoglobin dissociation curve (mean (SD) 29.4 (2.6) mm Hg vs 27 (3) mm Hg in laboratory controls, p<0.01). CONCLUSIONS: Patients with Eisenmenger syndrome report travelling frequently and safely on commercial airlines. Shifts in the oxygen-haemoglobin dissociation curve are likely to attenuate the effects of low oxygen tension. Patients with Eisenmenger syndrome should, nevertheless, be advised to avoid inactivity and dehydration as usual, but there is no justification for limiting air travel.

Adult↗
PubMed2006

Analytical identification of ideal pulmonary-systemic flow balance in patients with bidirectional cavopulmonary shunt and univentricular circulation: oxygen delivery or tissue oxygenation?

BACKGROUND: In the present study, we extended previous mathematical modeling work on patients with bidirectional cavopulmonary ("bidirectional Glenn") anastomosis to assess the potential utility of several descriptors of oxygen status. We set out to determine which of these descriptors best represents the overall tissue oxygenation. We also introduce a new descriptor, SO2min, defined as the lower of the superior and inferior vena cava oxygen saturations. METHODS AND RESULTS: The application of differential calculus to a model of oxygen physiology of patients with bidirectional Glenn allowed simultaneous assessment of all possible distributions of blood flow and metabolic rate between upper and lower body, across all cardiac outputs, total metabolic rates, and oxygen-carrying capacities. When total cardiac output is fixed, although it may intuitively seem best to distribute flow to maximize oxygen delivery (total, upper body, or lower body), we found that for each variable, there are situations in which its maximization seriously deprives flow to the upper or lower circulation. In contrast, maximizing SO2min always gives physiologically sensible results. If the majority of metabolism is in the upper body (typical of infancy), then oxygenation is optimized when flow distribution matches metabolic distribution. In contrast, if the majority of metabolism is in the lower body (typical of older children and during exercise), oxygenation is optimal when flows are equal. CONCLUSIONS: In patients with bidirectional cavopulmonary anastomosis, because there is a tradeoff between flow distribution and saturation, it is unwise to concentrate on maximizing oxygen delivery. Maximizing systemic venous saturations (especially SO2min) is conceptually different and physiologically preferable for tissue oxygenation.

Blood Circulation↗
PubMed2006

Heart rate response during exercise predicts survival in adults with congenital heart disease.

OBJECTIVES: To assess the prognostic value of heart rate response to exercise in adult congenital heart disease (ACHD) patients. BACKGROUND: An abnormal heart rate response to exercise is related to autonomic dysfunction and may have prognostic implications in ACHD. METHODS: We identified 727 consecutive ACHD patients (mean age [+/- SD] 33 +/- 13 years) with varying diagnoses and without pacemakers. Peak oxygen consumption (peak VO2), resting heart rate, and the increase in heart rate from resting level to peak exercise ("heart rate reserve") were measured. We also quantified the decrease in heart rate ("heart rate recovery") after cessation of exercise. RESULTS: During a median follow-up of 28 months, 38 patients died. Lower values of heart rate reserve, peak heart rate, heart rate recovery, and peak VO2 (p < 0.01 for each) were associated with increased mortality in univariate analysis. Furthermore, heart rate reserve predicted mortality independently of antiarrhythmic therapy, functional class, and peak VO2. Stratifying patients by diagnostic groups revealed that a lower heart rate reserve was also associated with a greater risk of death in patients with complex anatomy, Fontan circulation, and tetralogy of Fallot (p < 0.05 for each). CONCLUSIONS: An abnormal heart rate response to exercise identifies ACHD patients with a higher risk of mortality in the midterm, even after accounting for antiarrhythmic medication and exercise capacity. Heart rate reserve is a simple and inexpensive way to identify ACHD patients at higher mortality risk.

Adult↗
PubMed2006

"Isolated" diastolic dysfunction in left ventricular outflow tract obstruction.

We sought to investigate the prescence of "isolated" diastolic disease, defined as reduced long-axis early diastolic velocity with normal systolic velocity, in 21 young patients with left outflow tract obstruction. Most patients had depressed systolic velocities despite normal ejection fractions. The close relations amond long-axis velocities suggest isolated diastolic disease is unlikely.

Adult↗
PubMed2006

Bosentan therapy in patients with Eisenmenger syndrome: a multicenter, double-blind, randomized, placebo-controlled study.

BACKGROUND: Eisenmenger syndrome is characterized by the development of pulmonary arterial hypertension with consequent intracardiac right-to-left shunt and hypoxemia in patients with preexisting congenital heart disease. Because Eisenmenger syndrome is associated with increased endothelin expression, patients may benefit from endothelin receptor antagonism. Theoretically, interventions that have some effect on the systemic vascular bed could worsen the shunt and increase hypoxemia. METHODS AND RESULTS: The Bosentan Randomized Trial of Endothelin Antagonist Therapy-5 (BREATHE-5) was a 16-week, multicenter, randomized, double-blind, placebo-controlled study evaluating the effect of bosentan, a dual endothelin receptor antagonist, on systemic pulse oximetry (primary safety end point) and pulmonary vascular resistance (primary efficacy end point) in patients with World Health Organization functional class III Eisenmenger syndrome. Hemodynamics were assessed by right- and left-heart catheterization. Secondary end points included exercise capacity assessed by 6-minute walk distance, additional hemodynamic parameters, functional capacity, and safety. Fifty-four patients were randomized 2:1 to bosentan (n=37) or placebo (n=17) for 16 weeks. The placebo-corrected effect on systemic pulse oximetry was 1.0% (95% confidence interval, -0.7 to 2.8), demonstrating that bosentan did not worsen oxygen saturation. Compared with placebo, bosentan reduced pulmonary vascular resistance index (-472.0 dyne.s.cm(-5); P=0.0383). The mean pulmonary arterial pressure decreased (-5.5 mm Hg; P=0.0363), and the exercise capacity increased (53.1 m; P=0.0079). Four patients discontinued as a result of adverse events, 2 (5%) in the bosentan group and 2 (12%) in the placebo group. CONCLUSIONS: In this first placebo-controlled trial in patients with Eisenmenger syndrome, bosentan was well tolerated and improved exercise capacity and hemodynamics without compromising peripheral oxygen saturation.

Adult↗
PubMed2006

Blood viscosity and its relationship to iron deficiency, symptoms, and exercise capacity in adults with cyanotic congenital heart disease.

OBJECTIVES: This study sought to determine the relationship between blood viscosity and iron deficiency and their impact on symptoms and exercise function in adults with cyanotic congenital heart disease. BACKGROUND: Iron deficiency is believed to raise whole blood viscosity in cyanotic congenital heart disease, although available data are inconsistent. METHODS: Thirty-nine cyanotic adults were prospectively assessed for iron deficiency (transferrin saturation < or =5%), hyperviscosity symptoms, and exercise capacity. Same-day measurement of whole blood viscosity and hematocrit (Hct) adjusted viscosity (cells resuspended in autologous plasma to Hct of 45%) was performed at shear rates ranging from 0.277 s(-1) to 128.5 s(-1). RESULTS: Viscosity did not differ between patients with iron deficiency (n = 14) and those without (n = 25). Whole blood viscosity correlated with Hct (r = 0.63, p < 0.001 at low shear and r = 0.84, p < 0.001 at high shear) but not with red blood cell size or iron indices. Hyperviscosity symptoms were independent of iron indices but directly correlated with increased Hct-adjusted viscosity (r = 0.41, p = 0.01). Exercise capacity did not differ in iron-deficient patients. However, peak oxygen consumption was higher in those with Hct > or = 65% (12.6 +/- 3.4 ml/kg/m2 vs. 9.8 +/- 2.6 ml/kg/m2, mean +/- SD, p = 0.036) despite higher whole blood viscosity in these same individuals (p < 0.01 for all shear rates). CONCLUSIONS: Iron deficiency is common in cyanotic adults but does not alter viscosity. Hyperviscosity symptoms are associated with a higher Hct-adjusted viscosity independent of cell size or iron stores. Higher Hct is associated with better exercise capacity. Further work to understand the origin of hyperviscosity symptoms is warranted.

Adult↗
PubMed2006

Presentation, survival prospects, and predictors of death in Eisenmenger syndrome: a combined retrospective and case-control study.

AIMS: To characterize contemporary Eisenmenger patients at a large centre for adult congenital heart disease, assess survival prospects, and identify predictors of death in this population. METHODS AND RESULTS: All Eisenmenger patients under follow-up at our centre since 2000 (n=171, mean age 37+/-12 years) were included. To identify predictors of mortality, a case-control study was performed. Data including symptoms, functional class, medication, laboratory, and electrocardiographic and echocardiographic parameters are presented. Iron deficiency was common and strongly related to phlebotomy (relative risk 4.1, P<0.0001). Haemoglobin concentration was inversely related to arterial oxygen saturations in iron-replete patients (P<0.001) but not in iron-deficient patients. During a median follow-up of 67 months, 20 patients died. Survival at 40, 50, and 60 years of age was 94, 74, and 52%, respectively. When compared with healthy individuals, median survival was reduced by approximately 20 years in Eisenmenger patients and was worst in those with complex lesions. Predictors of mortality included functional class, signs of heart failure, history of clinical arrhythmia, QRS duration and QTc interval, and low serum albumin and potassium levels. CONCLUSION: Despite good short-term prognosis, life expectancy is markedly reduced in Eisenmenger patients. Markers of heart failure and parameters associated with arrhythmia are of prognostic value in terms of mortality and may guide clinicians caring for Eisenmenger patients.

Adolescent↗
PubMed2006

Abnormal ventilatory response to exercise in adults with congenital heart disease relates to cyanosis and predicts survival.

BACKGROUND: Limited data exist with which to stratify risk in adult congenital heart disease (ACHD). An increased ventilatory response to exercise, expressed as ventilation per unit of carbon dioxide production (V(E)/V(CO2) slope), is an established predictor of impaired survival in acquired heart disease. We sought to establish the distribution, relation to cyanosis, and prognostic value of the V(E)/V(CO2) slope across a wide spectrum of ACHD patients. METHODS AND RESULTS: Five hundred sixty ACHD patients of varying diagnoses and 50 healthy controls underwent cardiopulmonary exercise testing at a single laboratory between 2001 and 2004. Patient age was 33.2 +/- 12.9 years (mean +/- SD). Peak oxygen consumption was 23.5 +/- 9.0 mL.kg(-1).min(-1).V(E)/V(CO2) slope for all patients was 36.3 +/-15.3. The slope was raised in all ACHD groups compared with controls and was 73% higher in cyanotic patients. Cyanosis, with or without pulmonary arterial hypertension, was the strongest predictor of abnormal V(E)/V(CO2) slope. The V(E)/V(CO2) slope was the most powerful univariate predictor of mortality in the noncyanotic group and the only independent predictor of mortality among exercise parameters on multivariate analysis. In cyanotic patients, no parameter was predictive of death. CONCLUSIONS: Ventilatory response to exercise is abnormal across the spectrum of ACHD. Cyanosis is a powerful stimulus for such exaggerated ventilatory patterns irrespective of the presence of pulmonary arterial hypertension. Increased V(E)/V(CO2) slope is the strongest exercise predictor of death in noncyanotic ACHD patients.

Adult↗
PubMed2006

Transvenous pacing leads and systemic thromboemboli in patients with intracardiac shunts: a multicenter study.

BACKGROUND: The risk of systemic thromboemboli associated with transvenous leads in the presence of an intracardiac shunt is currently unknown. METHODS AND RESULTS: To define this risk, we conducted a multicenter, retrospective cohort study of 202 patients with intracardiac shunts: Sixty-four had transvenous leads (group 1), 56 had epicardial leads (group 2), and 82 had right-to-left shunts but no pacemaker or implantable cardioverter defibrillator leads (group 3). Patient-years were accrued until the occurrence of systemic thromboemboli or study termination. Censoring occurred in the event of complete shunt closure, death, or loss to follow-up. Mean ages for groups 1, 2, and 3 were 33.9+/-18.0, 22.2+/-12.6, and 22.9+/-15.0 years, respectively. Respective oxygen saturations were 91.2+/-9.1%, 88.1+/-8.1%, and 79.7+/-6.7%. During respective median follow-ups of 7.3, 9.3, and 17.0 years, 24 patients had at least 1 systemic thromboembolus: 10 (15.6%), 5 (8.9%), and 9 (11.0%) in groups 1, 2, and 3, respectively. Univariate risk factors were older age (hazard ratio [HR], 1.05; P=0.0001), ongoing phlebotomy (HR, 3.1; P=0.0415), and an transvenous lead (HR, 2.4; P=0.0421). In multivariate, stepwise regression analyses, transvenous leads remained an independent predictor of systemic thromboemboli (HR, 2.6; P=0.0265). In patients with transvenous leads, independent risk factors were older age (HR, 1.05; P=0.0080), atrial fibrillation or flutter (HR, 6.7; P=0.0214), and ongoing phlebotomy (HR, 14.4; P=0.0349). Having had aspirin or warfarin prescribed was not protective. Epicardial leads were, however, associated with higher atrial (P=0.0407) and ventricular (P=0.0270) thresholds and shorter generator longevity (HR, 1.9; P=0.0176). CONCLUSIONS: Transvenous leads incur a >2-fold increased risk of systemic thromboemboli in patients with intracardiac shunts.

Arteriovenous Shunt, Surgical↗
PubMed2006

Cardiac resynchronization therapy for adult congenital heart disease patients with a systemic right ventricle: analysis of feasibility and review of early experience.

AIMS: Patients with a systemic right ventricle (RV) frequently develop heart failure and may benefit from cardiac resynchronization therapy (CRT). We aimed to assess the proportion of unselected patients with a systemic RV eligible for CRT and to review available data on the effect of CRT in congenital heart disease patients. METHODS AND RESULTS: Adhering to criteria derived from landmark CRT trials, we determined the eligibility of patients with a systemic RV for CRT. Seventy-five transposition of the great arteries (TGA) patients (age 29.5+/-10.2 years) and 49 patients with congenitally corrected (cc) TGA (age 36.2+/-12.8 years) were studied. Full criteria for CRT were met in 4.0% of the TGA patients and 4.1% of the ccTGA patients. Including New York Heart Association class 2 patients, 9.3% of TGA and 6.1% of ccTGA patients were eligible for CRT. CONCLUSION: Four to 9% of unselected patients with a systemic RV appear to be potential candidates for CRT. Although large clinical studies are currently lacking, available data consistently demonstrate that CRT improves haemodynamics in congenital heart disease patients and warrants further investigation.

Adult↗
PubMed2006

Risk factors for arrhythmia and late death in patients with right ventricle to pulmonary artery conduit repair--Japanese multicenter study.

BACKGROUND: Arrhythmia and late cardiac deaths are thought to be major complications in patients after right ventricle (RV) to pulmonary artery (PA) conduit repair, although the incidence and predictors of these complications remain unknown. The aim of this study was to clarify the incidence and risk factors for arrhythmia and late deaths in patients with the RV to PA conduit repair through a Japanese multicenter study. METHODS: Three hundred fifty-one hospital survivors who underwent the RV to PA conduit repair before 1995 were studied. RESULTS: Survival rate after repair was 92% at 10 years, 88% at 20 and 25 years, respectively. Late death was observed in 30 (8.5%) including 4 patients with sudden death (SD). Higher right ventricular pressure (p = 0.02), larger cardio-thoracic ratio after repair (p = 0.02) and higher incidence of brady- or tachy-arrhythmia and SD (9/30) were associated with late death. Six (1.7%) patients developed ventricular tachycardia or ventricular fibrillation (VT/Vf). There were 22 patients who had 23 new-onset supraventricular tachy-arrhythmia (SVT). Right ventricular hypertension (p = 0.04) was associated with VT/Vf or SD. Male sex (p < 0.01), absence of previously aorto-pulmonary shunt (p < 0.05), older age at repair (p < 0.01) or longer length of follow-up (p < 0.01) were associated with SVT. CONCLUSION: Arrhythmia and late sudden death are relatively common late after the RV to PA conduit repair. Our data support recent surgical strategies of earlier primary operation and timely reoperation for progressive right ventricular outflow stenosis that may reduce the incidence of late arrhythmias and SD.

Adolescent↗
PubMed2006

Ventricular fibrosis suggested by cardiovascular magnetic resonance in adults with repaired tetralogy of fallot and its relationship to adverse markers of clinical outcome.

BACKGROUND: Late morbidity and mortality remain problematic after repair of tetralogy of Fallot (TOF). We hypothesized that fibrosis detected by late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) would be present in adults with repaired TOF and would be related to adverse markers of outcome. METHOD AND RESULTS: LGE was scored in the right and left ventricles (RV and LV) of 92 adult patients who had undergone TOF repair. RV LGE was seen in all patients at surgical sites located in the outflow tract (99%) or the site of ventricular septal defect patching (98%) and in the inferior RV insertion point (79%) and trabeculated myocardium (24%). LV LGE (53%) was located at the apex consistent with apical vent insertion (49%), in the inferior or lateral wall consistent with infarction (5%), or in other areas (8%). Patients with supramedian RV LGE score were older (38 versus 27 years, P<0.001) and more symptomatic (38% versus 8% in New York Heart Association class II or greater, P=0.001), had increased levels of atrial natriuretic peptide (7.3 versus 4.9 pmol/L, P=0.041), and had a trend to higher brain natriuretic peptide (12.3 versus 7.2 pmol/L, P=0.086), exercise intolerance (maximum VO2 24 versus 28 mL.min(-1).kg(-1), P=0.021), RV dysfunction (RV end-systolic volume 61 versus 55 mL/m2, P=0.018; RV ejection fraction 50% versus 56%, P=0.007), and clinical arrhythmia (26% versus 10%, P=0.039). Non-apical vent LV LGE also correlated with markers of adverse outcome. In a multivariate model, RV LGE remained a predictor of arrhythmia. CONCLUSIONS: RV and LV LGE were common after TOF repair and were related to adverse clinical markers, including ventricular dysfunction, exercise intolerance, and neurohormonal activation. Furthermore, RV LGE was significantly associated with clinical arrhythmia.

Adolescent↗
PubMed2006

Adherence to guidelines in the clinical care for adults with congenital heart disease: the Euro Heart Survey on adult congenital heart disease.

AIMS: To investigate the role of guidelines in structuring the clinical care for adult patients with congenital heart disease (CHD), and to assess adherence to the guidelines in Europe. METHODS AND RESULTS: A selected number of current guidelines were chosen pertaining to operative procedures, investigations, and the use of medication ('interventions'). The source for this analysis was the database of the Euro Heart Survey on adult CHD, which contains retrospectively collected data on 4110 patients followed-up for a median of 5.1 years. For each guideline investigated, patients were selected from the database for whom the particular guideline was relevant. The selected cases were classified according to two criteria: was there an indication for the particular intervention and did the intervention take place? In this manner, cases of 'undue treatment' and 'insufficient treatment' were identified. Adherence to guidelines was found to be good in the case of operative procedures and prophylactic drug treatment. However, regarding diagnostic procedures there had been adherence to guidelines in only slightly more than half of the cases. CONCLUSION: Guidelines have an important role in the actual clinical care of adults with CHD. However, large outcome studies are needed to develop more precise guidelines.

Adolescent↗