Václav Chaloupecký

Predictors of left ventricular remodelling and failure in right ventricular pacing in the young.

Aims To identify risk factors for left ventricular (LV) dysfunction in right ventricular (RV) pacing in the young. Methods and results Left ventricular function was evaluated in 82 paediatric patients with either non-surgical (n = 41) or surgical (n= 41) complete atrioventricular block who have been 100% RV paced for a mean period of 7.4 years. Left ventricular shortening fraction (SF) decreased from a median (range) of 39 (24–62)% prior to implantation to 32 (8–49)% at last follow-up (P < 0.05). Prevalence of a combination of LV dilatation (LV end-diastolic diameter >+2z-values) and dysfunction (SF < 0.26) was found to increase from 1.3% prior to pacemaker implantation to 13.4% (11/82 patients) at last follow-up (P = 0.01). Ten of these 11 patients had progressive LV remodelling and 8 of 11 were symptomatic. The only significant risk factor for the development of LV dilatation and dysfunction was the presence of epicardial RV free wall pacing (OR = 14.3, P < 0.001). Other pre-implantation demographic, diagnostic, and haemodynamic factors including block aetiology, pacing variables, and pacing duration did not show independent significance. Conclusion Right ventricular pacing leads to pathologic LV remodelling in a significant proportion of paediatric patients. The major independent risk factor is the presence of epicardial RV free wall pacing, which should be avoided whenever possible.

Hemodynamically optimized temporary cardiac pacing after surgery for congenital heart defects.

Disturbance of normal AV synchrony and dyssynchronous ventricular contraction may be deleterious in patients with otherwise compromised hemodynamics. This study evaluated the effect of hemodynamically optimized temporary dual chamber pacing in patients after surgery for congenital heart disease. Pacing was performed in 23 children aged 5 days to 7.7 years (median 7.3 months) with various postoperative dysrhythmias, low cardiac output, and/or high inotropic support and optimized to achieve the highest systolic and mean arterial pressures. The following four pacing modes were used: (1) AV synchronous or AV sequential pacing with individually optimized AV delay in 11 patients with first‐to third‐degree AV block; (2) AV sequential pacing using transesophageal atrial pacing in combination with a temporary DDD pacemaker for atrial tracking and ventricular pacing in three patients with third‐degree A V block and junctional ectopic tachycardia, respectively, who had poor signal and exit block on atrial epicardial pacing wires; (3) R wave synchronized atrial pacing in eight patients with junctional ectopic tachycardia and impaired antegrade AV conduction precluding the use of atrial overdrive pacing; (4) Atrio‐biventricular sequential pacing in two patients. Pressures measured during optimized pacing were compared to baseline values at underlying rhythm (13 patients with first‐degree AV block or junctional ectopic tachycardia) or during pacing modes commonly used in the given clinical situation: AAI pacing (1 patient with slow junctional rhythm and first‐degree AV block during atrial pacing), WI pacing (2 patients with third‐degree A V block and exit block and poor sensing on epicardial atrial pacing wires) and dual‐chamber pacing with AV delays set to 100 ms (atrial tracking) or 150 rns (AV sequential pacing) in 7 patients with second‐ to third‐degree A V block and functional atrial pacing wires. Optimized pacing led to a significant increase in arterial systolic (mean) pressure from 71.5 ± 12.5 (52.3 ± 9.0) to 80.5 ± 12.2 (59.7 ± 9.1) mmHg (P < 0.001 for both) and a decrease in central venous (left atrial) pressure from 12.3 ± 3.4 (10.5 ± 3.2) to 11.0 ± 3.0 (9.2 ± 2.7) mmHg (P < 0.001 and < 0.005, respectively). In conclusion, several techniques of individually optimized temporary dual chamber pacing leading to optimal AV synchrony and/or synchronous ventricular contraction were successfully used to improve hemodynamics in patients with heart failure and selected dysrhythmias after congenital heart surgery.

Results of primary and two-stage repair of interrupted aortic arch

OBJECTIVE Early results of primary and two-stage repair of interrupted aortic arch have improved. Experience with different surgical approaches should be analysed and compared. METHODS Forty neonates and infants with interrupted aortic arch underwent primary repair (19 patients) or palliative operation (21 patients). Twenty (50%) patients were followed-up for 5.1+/-4.3 years. All patients were regularly examined with the aim of determining clinical development, presence of residual lesions or complications and need for re-intervention. Aortic arch and the left ventricular outflow tract growth were assessed by echocardiographic examination. Data from hospital and outpatient department records were analysed. RESULTS The early mortality was 61.9% after palliative operations and 36.8% after the primary repair. Presence of complications (P < 0.001), earlier year of surgery (P < 0.01), bad clinical condition and acidosis (P < 0.05) represented statistically significant risk factors for death in the whole series. In seven (87.5%) out of eight early survivors, after the initial palliative operation, closure of ventricular septal defect and debanding were done, and in three (37.5%) patients, re-operation for aortic arch obstruction was also required. Out of 12 patients, after the primary repair, one required early re-operation for persistent left ventricular outflow tract obstruction and two needed late re-intervention for left bronchus obstruction. In three (25%) patients, after the primary repair, left ventricular outflow tract obstruction with a maximal systolic pressure gradient higher than 30 mmHg developed. At present, all 20 early survivors are alive. Five patients, after palliative operation, are in NYHA class 1, but in three patients, who are in class III or IV, the outcome is influenced by severe complications. All patients after the primary repair are in class I or II. CONCLUSIONS Our experience confirmed better results after the primary repair of interrupted aortic arch, which was associated with lower mortality, prevalence of severe complications and need for re-intervention. Higher prevalence of subaortic stenosis after primary repair could be explained by patient selection early in our experience. We recommend the primary repair of interrupted aortic arch and associated heart lesions in neonates, however, in unfavourable conditions an individualised surgical approach with initial palliative surgery should be considered.

Long-term (up to 20 years) results of percutaneous balloon angioplasty of recurrent aortic coarctation without use of stents

AIMS To assess the efficacy, safety, and long-term results of the balloon angioplasty of recoarctation. METHODS AND RESULTS The angioplasty was performed in 99 consecutive patients aged 36 days to 32.6 years (median 268 days). Recoarctation to descending aorta diameter ratio increased from 0.44 (0.35/0.50) to 0.66 (0.57/0.77), P < 0.001. Systolic gradient was reduced from 34.0 (26.0/44.75) to 15.0 (8.25/27.0) mmHg, P < 0.001. In seven patients (7.1%) the procedure was ineffective. One patient (1%) with heart failure died within 24 h after a successful angioplasty and in another (1%) an intimal abruption necessitated surgical revision. The follow-up ranged up to 20.7 years (median 8.1 years). Actuarial probability of survival 20.7 years after the procedure was 0.91, and of reintervention-free survival was 0.44. Older age at the angioplasty was associated with a higher incidence of reinterventions (hazard ratio 1.057; 95% confidence interval 1.012-1.103; P = 0.010). The type of surgery and the recoarctation anatomy did not influence the outcome. In 69 patients aneurysm formation was studied by high-sensitive methods with only one positive finding per 462 patient-years. CONCLUSION Angioplasty is safe and effective regardless of the type of surgery used and the recoarctation anatomy. Older age at the angioplasty is associated with a higher incidence of reinterventions.

Nitrogen balance, 3-methylhistidine excretion, and plasma amino acid profile in infants after cardiac operations for congenital heart defects: The effect of early nutritional support☆☆☆★★★

OBJECTIVE The objective of this study was to evaluate the effect of nutritional support on proteolysis and plasma amino acid profile in infants early after cardiac operations for congenital heart defects. METHODS Thirty-seven patients, 2 to 12 months old, were randomized on postoperative day 1 for 24-hour isocaloric metabolic study. Group STANDARD (18 patients) received glucose as the maintenance fluid, and group PN (19 patients) received glucose and crystalloid amino acid solution at a dosage of 0.8 +/- 0.1 gm/kg per day. The nonprotein caloric intake in the two groups was 25 +/- 15 and 33 +/- 9 kcal/kg, respectively (p = not significant). RESULTS The nitrogen balance was markedly less negative in group PN than in group STANDARD (-114 +/- 81 vs -244 +/- 86 mg/kg, respectively, p = 0.001). There was a highly significant inverse correlation between the nitrogen balance and urinary 3-methylhistidine excretion in both groups, but the muscle proteolysis was blunted more effectively in patients receiving amino acids. Concentrations of the plasmatic branched-chain amino acids, alanine, glycine, and proline, decreased significantly in group STANDARD but not in group PN on postoperative day 2. Glutamine and threonine levels declined significantly on postoperative day 2 in both groups. Low levels of arginine were observed in our patients before operation and in the early postoperative period. The amino acid concentrations normalized on postoperative day 7 in all patients. CONCLUSION Significant proteolysis and hypoaminoacidemia were observed in infants early after cardiac operations. This hypercatabolic response was blunted by parenteral nutritional support.

Repair of tetralogy of Fallot associated with atrioventricular septal defect.

Tetralogy of Fallot, when associated with atrioventricular septal defect permitting shunting at ventricular level, represents a complex cyanotic congenital malformation. Experience with surgical repair is limited, and results vary considerably. Between 1984 and 1996, we repaired 14 consecutive patients with this combination seen in our center. Their ages ranged from 8 months to 21 years (median 7.4 years). Six (42.9%) had Downs syndrome. In eight patients the correct diagnosis was made using echocardiography alone. In the remaining six patients, who had previously-constructed arterial shunts and/or suspected pulmonary arterial stenosis, catheterization and angiocardiography were also performed. The repair consisted of double patch closure of the septal defect, reconstruction of two atrioventricular orifices, and relief of pulmonary stenosis at all levels. In five patients with a hypoplastic pulmonary trunk, a monocusp transannular patch (four patients) or an allograft (one patient) was used for restoration of continuity from the right ventricle to the pulmonary arteries. Patch enlargement of one or both pulmonary arteries was necessary in five patients. One patient (7.1%) died early, and another late. The twelve surviving (85.8%) patients have been followed for 1.2-12.5 years after surgery (median 4.9 years, mean 5.9+/-3.9 years). During the follow-up, reoperation was necessary for repair of residual ventricular septal defect and pulmonary regurgitation in two patients, and closure of an atrial septal defect and alteration to left atrioventricular valvar regurgitation in one patient. Seven patients are in class I of the New York Heart Association, four in class II, and one in class III. Tetralogy of Fallot associated with atrioventricular septal defect can be corrected with low mortality and good long-term results. Residual lesions, however, have a tendency to progress, especially when seen in combination. After surgery, all patients need long-term close follow-up.

Haemodynamic changes due to delayed sternal closure in newborns after surgery for congenital cardiac malformations.

BACKGROUND Delayed sternal closure is used to prevent low cardiac output syndrome in selected newborns shortly after cardiac surgery for congenital cardiac defects. Sternal closure itself often causes haemodynamic and ventilatory instability that cannot be entirely assessed by standard monitoring means. Therefore, we used transpulmonary thermodilution technique for an exact evaluation of the haemodynamic changes. PATIENTS AND METHODS Between April, 2006, and December, 2008, 23 neonates aged from 1 to 30 days, with a median of 7 days, and weighing from 1.9 to 4.2 kilograms, with a median of 3.25 kilograms, were studied after biventricular corrections. Residual intracardiac shunts were excluded by echocardiography. Haemodynamic and ventilatory parameters, along with those obtained by the transpulmonary thermodilution technique, were recorded before and immediately after the sternal closure, and then at 0.5, 1, 2, 6, 12, 24, and 48 hours. RESULTS Chest closure caused significant decrease in systolic arterial pressure from 80.04 +/- 11.48 to 69.48 +/- 9.63 mmHg (p < 0.001), cardiac index from [median (25th/75th centile)] 2.640 (2.355/2.950) to 2.070 (1.860/2.420) l/min/m2 (p < 0.001), stroke volume index from 18.50 (16.00/20.00) to 14.00 (11.00/17.00) ml/m2 (p < 0.001), and dynamic lung compliance from 2.45 (2.31/3.00) to 2.30 (2.14/2.77) ml/cmH2O (p = 0.007). Stroke volume variation increased from 14.00 (9.25/16.75) to 18.00 (15.00/21.00) % (p < 0.001). The oxygenation index transitorily increased from 2.50 (2.14/3.15) to 3.36 (2.63/4.29) (p < 0.001). Serum lactate decreased from 1.40 (1.12/2.27) to 1.0 (0.8/1.3)mmol/l, p < 0.001 in coincidence with a haemodynamic stabilisation at a later time after chest closure. Cardiopulmonary instability caused by the sternal closure necessitated therapeutic intervention in 18 of 23 patients (78.3%). CONCLUSION Delayed sternal closure causes a significant transitory decrease in stroke volume, cardiac output and arterial blood pressure. Also lung compliance and blood oxygenation are temporarily significantly compromised.