Chronotropic incompetence in adolescents and adults with congenital heart disease after cardiac surgery.

BACKGROUND: Chronotropic incompetence (CI) is one of the major problems in adults with congestive heart. Little is known about CI in adults with congenital heart disease (ACHD) after cardiac surgery. The purpose of our study was to investigate the presence and risk factors of CI in ACHD patients. METHODS AND RESULTS: Clinical and echocardiographic data, NT-pro brain natriuretic peptide (N-BNP), and peak oxygen uptake (VO2peak) during spiroergometry were obtained in 345 consecutive ACHD patients. CI was defined as the failure to achieve > or = 80% of the predicted maximal heart rate. A total of 117 (34%) of study patients fulfilled the CI criterion. These patients were in a higher New York Heart Association class (1.7 +/- 0.06 versus 1.4 +/- 0.03, P < .0001; mean +/- SEM), had significantly higher N-BNP levels (230 +/- 31 versus 121 +/- 10 pg/mL, P < .0001) and a more pronounced impairment of VO2peak (23.8 +/- 0.6 versus 28.4 +/- 0.5 mL x kg x min, P < .0001) than those without CI. Elevated odds ratios for CI were found in patients with a single ventricle (4.03), Mustard operation for transposition of the great arteries (3.11), and aortic coarctation (2.14). CONCLUSIONS: Our results indicate that CI in ACHD patients is a frequent problem and is related to the severity of the heart failure as measured by symptom assessment (New York Heart Association class), plasma N-BNP level and peak oxygen uptake.

Elevated brain natriuretic peptide and reduced exercise capacity in adult patients operated on for tetralogy of fallot is due to biventricular dysfunction as determined by the myocardial performance index.

Although tetralogy of Fallot (TOF) can be repaired surgically, residual lesions that cause abnormal ventricular load can eventually lead to heart failure. Subclinical biventricular dysfunction in these patients may be detected only by using suitably sensitive indexes. The Tei index determined by the pulsed Doppler method enables the measurement of left ventricular (LV) and right ventricular (RV) function. This study was designed to evaluate the biventricular Tei indexes in adults with operated congenital heart disease and to correlate these indexes with cardiopulmonary capacity and neurohormonal activation. Fifty-nine patients with surgically corrected TOF and 52 patients with operated left-to-right-shunt defects were included in the study. Patients with TOF showed significantly greater LV and RV Tei indexes than those with left-to-right-shunt defects (LV Tei index 0.50 +/- 0.09 vs 0.34 +/- 0.05, RV Tei index 0.37 +/- 0.1 vs 0.25 +/- 0.06; p <0.0001). Peak oxygen uptake was significantly reduced in the patients with TOF (25 +/- 6 vs 32 +/- 6 ml x kg(-1) x min(-1), p <0.0001) and was correlated inversely with the LV Tei index (r = -0.61, p <0.0001). N-terminal-pro-brain natriuretic peptide was significantly increased in patients with TOF (150 +/- 141 vs 57 +/- 39 pg/ml, p <0.0001). In conclusion, in asymptomatic or minimally symptomatic patients with TOF, biventricular dysfunction is detected by the Tei index. Further indexes for heart failure in these patients are increased circulating plasma N-terminal-pro-brain natriuretic peptide and impaired peak oxygen uptake. The combined determinations of these 3 variables enable the identification of congenital heart disease with impaired cardiac function before they become clinically symptomatic.

Relation of systemic ventricular function quantified by myocardial performance index (Tei) to cardiopulmonary exercise capacity in adults after Mustard procedure for transposition of the great arteries.

After Mustard repair for transposition of the great arteries, the right ventricle serves as a chronically overloaded systemic ventricle (SV). Thus, during long-term follow-up, dysfunction of the right ventricle with consecutive heart failure (HF) is not unusual. Early signs and symptoms of HF are depressed parameters of right ventricular (RV) function at rest and exercise intolerance. It was hypothesized that the measurement of RV function parameters, N-terminal pro-brain natriuretic peptide (NT-pro-BNP), and peak oxygen uptake (VO2max) during exercise testing were suitable for the early detection of subclinical HF. In 33 asymptomatic adolescents and adults who had undergone Mustard repair, RV function was analyzed by the myocardial performance index (Tei index). NT-pro-BNP and VO2max were also determined. The corresponding data from 52 patients operated on for left-to-right shunt defects without residual lesions served as reference data. In patients who underwent the Mustard procedure, the Tei index and NT-pro-BNP were elevated (mean Tei index of the SV 0.63 +/- 0.17 vs 0.34 +/- 0.05, p <0.002; mean NT-pro-BNP 240 +/- 230 vs 57 +/- 39 pg/ml, p <0.0001), and VO2max was reduced (27 +/- 6 vs 32 +/- 6 ml x kg(-1) x min(-1), p <0.002). A good correlation was found between the Tei index and VO2max (r = -0.83, p <0.0001). In conclusion, RV function is depressed in most patients with Mustard repair. Ventricular dysfunction in such asymptomatic or minimally symptomatic patients can be detected by measurement of the Tei index, NT-pro-BNP, and VO2max. These parameters are simple and reliable screening methods to stratify patients with impaired cardiac dysfunction before they become symptomatic.

Is the Ability index superior to the NYHA classification for assessing heart failure?: comparison of two classification scales in adolescents and adults with operated congenital heart defects.

BACKGROUND: Heart failure (HF) is a major problem in the long-term follow-up of adolescents and adults with congenital heart disease (ACHD) after cardiac surgery. The functional status of ACHD may be assessed in terms of the NYHA classification or the Ability index (ABILITY). OBJECTIVE: The purpose of our study was to examine which of the two classification systems is more closely related to objectively defined HF. METHODS: NT-pro brain natriuretic peptide (N-BNP) and maximal oxygen uptake (VO(2max)) were measured in 360 consecutive ACHD patients. HF was defined as an elevated N-BNP level > or =100 pg/ml combined with a reduced VO(2max) < or =25 ml/kg/min. RESULTS: There were no significant differences between the NYHA and ABILITY in grading HF in these patients. In both classifications, the risk of HF increases continuously over the classes and grades from odds ratio (OR) 1 in NYHA I/ABILITY 1 to an OR=3.4 in NYHA II/ ABILITY 2 up to 11.6 or 5.4 (ns) in NYHA III/ABILITY 3. Thus in the highest scores HF is found in 70-77% of the patients. The fact that in NYHA class I and ABILITY grade 1, 15% and 19% of the patients exhibited HF according to the measured indices underscores the discrepancy between subjective and objective assessment of the individual patients condition. CONCLUSION: The NYHA classification and the Ability index take different approaches to the patients with congenital heart defects but are equally suitable for the judgement of HF in post surgical ACHD.

A prospective, randomized, double-blind, placebo controlled trial of beta-blockade in patients who have undergone surgical correction of tetralogy of Fallot.

AIMS: Our purpose was to evaluate the effect of a treatment over six months with bisoprolol on the surrogate parameters of N-Terminal-pro brain natriuretic peptide, subsequently to be described as brain natriuretic peptide, peak uptake of oxygen, and ventricular function assessed by magnetic resonance imaging in grown ups and adults who had undergone surgical correction of tetralogy of Fallot. METHODS AND RESULTS: We designed a prospective, randomized, double-blind, placebo controlled trial. We enrolled 33 patients, aged 30.9 plus or minus 9.5 years in either class 1 or 2 of the grading of the New York Heart Association class with both levels of brain natriuretic peptide greater than 100 pg/ml and a reduced peak uptake of oxygen less than 25 ml/kg/min. During treatment with Bisoprolol, the levels of brain natriuretic peptide increased significantly from 206 plus or minus 95 to 341 plus or minus 250 pg/ml (p< 0.05), and those of atrial natriuretic peptide from 4117 plus or minus 1837 to 5340 plus or minus 2102 fmol/ml (p = 0.0005). These measures remained unchanged in the group of patients receiving the placebo. Peak uptake of oxygen did not differ significantly in either group, nor did treatment have any significant effect on right and left ventricular volumes and ejection fractions as determined by magnetic resonance imaging. The clinical state as judged within the grading system of the New York Heart Association was also unchanged by beta-blockade. CONCLUSION: Beta blockade with Bisoprolol seems to have no beneficial effect on asymptomatic or mildly symptomatic patients with right ventricular dysfunction secondary to repaired tetralogy of Fallot with residual pulmonary regurgitation and/or stenosis.

Pacemaker implantation as a risk factor for heart failure in young adults with congenital heart disease.

AIM: Complete postoperative heart block following open-heart surgery and sinus node dysfunction are indications for permanent cardiac pacing in children with congenital heart defects. The purpose of our study was to evaluate if cardiac pacing is a risk factor of heart failure during longtime follow-up of grown ups with congenital heart disease (GUCH). METHODS: For an objective assessment of heart failure, NT-Pro brain natriuretic peptide (BNP) and maximal oxygen uptake index (VO2max) during the cardiopulmonary exercise testing were measured in 346 consecutive GUCH patients during a longtime follow-up examination. RESULTS: Thirty-nine of these patients who had pacemaker implantation had significantly increased BNP levels (448.2 +/- 76.8 vs 123.8 +/- 9.7 pg/mL, P < 0.0001) and significantly decreased VO(2max) (22.5 +/- 0.9 vs 27.4 +/- 0.4, P < 0.0001). Heart failure in pacemaker patients was associated with significantly prolonged QRS complex durations (171.1 +/- 8.3 ms vs 108.7 +/- 1.8 ms, P < 0.0001), increased right ventricular end diastolic diameters (38.7 +/- 2.1 mm vs 27.8 +/- 0.5mm, P < 0.0001), lower heart rates at rest (69.5 +/- 1.9/min vs 82 +/- 1/min, P < 0.0001), and at exercise (140.3 +/- 5.8/min vs 163.5 +/- 1.2/min, P < 0.0001). Mean fractional shortening of the left ventricle was normal in both patient groups. CONCLUSION: Pacemaker implantation may be associated with heart failure during longtime follow-up of GUCH indicated by significantly elevated BNP levels and decreased VO2max. Possible explanations are prolongation of QRS complex duration, decreased maximal heart rates during exercise, and dilatation of the right ventricle.