Clinical significance of late potential in patients with duchenne muscular dystrophy

Summary The relationship between late ventricular potentials (LP) and myocardial ischemic changes or ventricular arrhythmias was investigated in patients with Duchenne muscular dystrophy (DMD). Twenty-six DMD patients aged 10–33 years (mean 18.2 years) and 27 agematched healthy volunteers were studied. Ventricular arrhythmias were detected by 24-h Holter ECGs and LPs were determined using signal-averaged ECGs. In DMD patients filtered QRS duration, late duration, and low-amplitude signal under 40 V were significantly prolonged compared with those of the controls. The root mean square voltage of the f-QRS complex in the last 40 ms was lower in DMD patients than in the controls. None of the control subjects had LP. However, LP was detected in 8 (31%) of the 26 DMD patients. The patients with LP had more frequent ST-T depression and ventricular arrhythmias than the patients without LP. LP had 60% sensitivity and 87% specificity for documented ventricular arrhythmias. It is concluded that LP in DMD patients indicates the presence of substrate for ventricular arrhythmias associated with local myocardial fibrosis, and is useful in identifying those at high risk for malignant ventricular arrhythmias.     

Later potentials on signal-averaged electrocardiograms in children after right ventriculotomy

After corrective surgery for congenital heart defects, scars may create fractionation and delay of the electrical signals in the heart muscle, providing a substrate for arrhythmias. Signalaveraged electrocardiograms (SAECGs) were obtained from 33 children after right ventriculotomy, on average 6 years after surgery, and from 38 healthy controls of the same age. The duration of the filtered QRS complex (fQRS), the duration of the low amplitude signal (<40V) in the terminal QRS complex (LAS40), and the root mean square amplitude of the terminal 40 ms of the QRS complex (RMS40) were determined. The values of fQRS 117 ms, RMS4025V, and LAS4035 ms, which were beyond the mean ±2 SD of the healthy controls, were considered abnormal. Most patients had right bundle branch block and therefore a prolonged fQRS. Late potentials were defined as present if both the RMS40 and LAS40 were abnormal. Altogether nine patients (27%) had late potentials. In the patients with late potentials the incidence of serious ventricular arrhythmias was 44% (4 of 9) and in the patients without late potentials 0% (0 of 24). In seven patients with enlargement of the right ventricle, the incidence of arrhythmias was 57% (4 of 7) when late potentials were present and 0% (0 of 7) when they were absent. In the present study late potentials were associated with a history of arrhythmias, especially when the right ventricle was enlarged. Therefore the SAECG may be useful for determining the risk of serious arrhythmia events in children operated for congenital heart defects.     

法洛四联症根治术后远期心律失常的随访

目的　了解法洛四联症 (TOF)根治术后远期心律失常的发生率以及影响心律失常发生的相关因素。方法　 54例法洛四联症根治术后患儿 ,男 3 5例 ,女 19例 ;年龄 5～ 14岁 [( 9 4± 2 5)岁 ]。术时年龄 17个月～ 117个月 ,随访年限 2 8～ 9 0年。进行了心电图、2 4小时Holter、二维超声心动图和活动平板运动试验检查。结果　 18例患儿存在不同程度的室性心律失常 ,室性心律失常的发生率为 3 3 % ,其中 1例患儿有短阵室性心动过速发生。 4例右室收缩压增高者均存在明显室性心律失常 ,右室收缩压正常者室性心律失常发生率为 2 8% ( 14 / 50例 ) ,两者差异有显著性 (P =0 0 1)。体外循环时间≥ 90min者室性心律失常发生率为 53 % ( 10 / 19例 ) ,体外循环时间 <90min的患儿室性心律失常发生率为 2 3 % ( 8/ 3 5例 ) ,两者差异有显著性 (P <0 0 5)。轻度肺动脉瓣返流组室性心律失常发生率为 2 1% ( 4 / 19例 ) ,中、重度肺动脉瓣返流组室性心律失常的发生率为 40 % ( 14 / 3 5例 ) ,两组差异无显著性 ( χ2 =1 989,P >0 0 5)。随访年限 5年以内室性心律失常发生率为 3 2 % ( 8/ 2 5例 ) ,5年以上患儿的室性心律失常发生率为 3 4 % ( 10 / 2 9例 ) ,两者差异无显著性 ( χ2 =0 0 3 7,P >0 0 5)。手术年龄     

Serial signal-averaged electrocardiography in children after cardiac transplantation

In patients with myocytolysis detected in endomyocardial biopsy, there is a tendency towards a shift of ventricular electrical axes from normal to strain pattern on surface ECG. Their 12-lead signal-averaged electrocardiogram (SAECG) show a significant increase in filtered QRS duration (QRSD) compared with those with specimens without myocytolysis. Late potentials were generally found more frequently in individual SAECG leads than in the vector magnitude. An increase in filtered QRSD and the presence of late potentials compared with a baseline study emphasizes the need for endomyocardial biopsy. Consequently, no change in these parameters may preclude the indication for endomyocardial biopsy.     

Correlation between QRS Duration,Pulmonary Insufficiency and Right Ventricle Performance in Totally Corrected Tetralogy of Fallot

Objective

Despite progresses in surgical correction of Tetralogy of Fallot, pulmonary insufficiency and progressive dysfunction of the right ventricle impress its long-term prognosis. In this study we examined the correlations between QRS duration, pulmonary insufficiency and right ventricular performance index.

Methods

We enrolled 57 repaired Tetralogy of Fallot patients. QRS duration on electrocardiogram, pulmonary regurgitation index (regurgitation time to diastolic time ratio), and right ventricular myocardial performance index were measured.

Findings

There was a strong inverse correlation between QRS duration and pulmonary regurgitation index. However, significant correlation did not exist between QRS duration and right ventricular myocardial performance index. QRS duration ≥160 ms predicted severe pulmonary regurgitation with 100% sensitivity and 87% specificity.

Conclusion

Increased QRS duration can predict severity of pulmonary regurgitation.     

Efficacy of Signal-Averaged Electrocardiography in the Young Orthotopic Heart Transplant Patient to Detect Allograft Rejection

Endomyocardial biopsy is the gold standard survey for cardiac graft rejection. Signal-averaged electrocardiography (SAECG) identifies slowly conducting, diseased myocardium. We sought to determine whether SAECG is a sensitive, noninvasive transplant surveillance method in the young. Ninety-four SAECGs recorded prior to biopsy in 20 young transplant (OHT) patients and those from 15 healthy age-matched controls (CTL) were analyzed. In the OHT group, 56 no-rejection (NOREJ) (ISHLT grades 0 or 1 A) and 37 acute rejection (REJ) (ISHLT grades IB, 2, and 3A) SAECGs were compared, SAECGs were filtered at 40–255 Hz. Total QRS duration (QRSd), duration of terminal low amplitude of QRS under 40 μV (LAS), and root mean square amplitude of terminal 40 msec of QRS (RMS40) were compared. SAECGs were significantly different in CTL vs NOREJ but not in NOREJ vs REJ: QRSd, 81.7 ± 8, 107.2 ± 18.4, and 112.3 ± 21.6 msec, respectively; LAS, (18 ± 5.8, 23.6 ± 10.7, and 27 ± 14.8 msec, respectively; and RMS40, (169.3 ± 100.4, 68 ± 48.8, and 57.5 ± 45.6 μV, respectively. Children following OHT exhibited significant differences in the SAECG compared to controls. Differences between the NOREJ and REJ groups were negligible. Therefore, SAECG may not be effective in detecting OHT rejection in the young.     

Signal-Averaged Electrocardiography in Children with Anthracycline-Induced Cardiomyopathy

The aim of the present study was to determine if signal-averaged ECG of patients with anthracycline-induced left ventricular dysfunction could differentiate between patients with anthracycline-induced cardiotoxicity and those without. Sixteen children with anthracycline-induced cardiomyopathy, aged 6.5 to 15.5 years (anthracycline dose = 198-737 mg/m2), and 31 patients aged 5.0 to 16.7 years, who received anthracyclines without evidence of left ventricular dysfunction (anthracycline dose = 120-517 mg/m2), were studied with signal averaged ECG. The two groups were comparable in age, body surface area, and time since completion of chemotherapy. Signal averaged ECG parameters of the patients were compared with data obtained from 530 healthy children. These parameters were converted to z-scores to account for growth-related changes in signal averaged ECG recordings. Z-scores for filtered QRS duration and low amplitude terminal signal < 40 microV were significantly lower (p = 0.002 and p = 0.015, respectively), and Z-score for root mean square voltage of the last -30 ms of filtered QRS tended to be higher (p = 0.06) in patients with left ventricular dysfunction. Filtered QRS duration lower than -1.5 SD was found in 4 of 16 patients with left ventricular dysfunction and in only 1 of 31 patients without (p < 0.05) yielding a sensitivity of 25% and a specificity of 97% to detect left ventricular dysfunction. Only 1 patient had late potentials; his left ventricular function was normal. Left ventricular mass index tended to be lower in patients with left ventricular dysfunction (p = 0.07), whereas left ventricular diastolic diameter was similar in the two groups. The mechanism that accounted for the difference in signal averaged-ECG between the two groups of patients could be linked with the decrease in left ventricular mass in patients with left ventricular dysfunction. In conclusion, children with left ventricular dysfunction following anthracycline therapy have a SA ECG different from those without left ventricular dysfunction, which is mainly characterized by a lower filtered QRS duration. A prospective study is needed in order to determine if this modification of SA ECG recordings precedes alteration of left ventricular function, and, therefore, if it could help in early detection of cardiac toxicity of anthracyclines.     

Electrophysiological Follow-Up of Tetralogy of Fallot

Arrhythmias and sudden death are well-recognized complications that occur late after correction of tetralogy of Fallot. This study, based on the literature and personal work, reviews the numerous investigations prompted by these complications and provides recommendations regarding follow-up. Conduction disturbances and ventricular arrhythmias are both common; although mostly asymptomatic, they are the likely cause of syncopy and sudden death. Supraventricular arrhythmias are less common but cause symptoms more frequently. Detecting patients at risk for life-threatening arrhythmias is an important task. The simple surface electrocardiogram (ECG) gives a host of information regarding patients at risk. Holter recordings, signal-averaged ECG, and invasive electrophysiological studies may all be helpful; the indications to perform these investigations are discussed and propositions are made for the follow-up of the postoperative patient. There is hope that a systematic approach along these lines, together with surgery done at an earlier age, will decrease the incidence of severe arrhythmias and sudden death in the future.     

Effects of cisapride on ventricular depolarization-repolarization and arrhythmia markers in infants

To study prospectively the effects of cisapride on ventricular repolarization, depolarization, and arrhythmia markers in neonates, we determined before and three days after starting cisapride (1 mg/kg/day): corrected QT interval (QTc) and QT dispersion (QTd) on standard ECGs, and duration of filtered QRS (fQRS) and of low amplitude (<40 microV) terminal signals (LAS40, ms) and root mean square of the last 40 ms (RMS40, microV) using high-gain signal-averaged ECG (SAECG). Twenty-four term and 11 preterm infants (gestational age 23-35 weeks) were studied at a median chronological age of 32 days. QTc and QTd were not different between term and preterm infants. Cisapride lengthened QTc (mean +/- SD; ms: 396.6 +/- 24.8 before vs. 417.0 +/- 35.2 after, p < 0.001). Three term and two preterm infants (5/35 = 14%; 95% CI: 5-30%) had a QTc >450 ms after cisapride. QTd after cisapride increased significantly in all infants with prolonged QTc. Filtered QRS, LAS40, and RMS40 before and after cisapride were within our normal values. We conclude that cisapride prolongs ventricular repolarization in neonates and infants without altering depolarization. Although no clinical arrhythmias were observed the dose of 0.8 mg/kg/day should not be exceeded.     

Signal-averaged electrocardiogram in children and adolescents with insulin-dependent diabetes mellitus

We report on the potential usefulness of the signal-averaged electrocardiogram (SA-ECG) in young patients with insulin-dependent diabetes mellitus (IDDM) to predict subclinical cardiovascular complications. Sixteen patients with IDDM and 18 age-matched healthy subjects were studied. The IDDM group included 4 males and 12 females, aged 7 to 20 y (mean 14.2 +/- 3.8 y, +/- SD). The duration from the onset of IDDM to the study ranged from 1.2 to 9.8 y (mean 5.4 +/- 3.8 y), and HbAlc value ranged from 6.6 to 12.4% (mean, 10.0 +/- 1.8%). SA-ECG was recorded and analyzed using the methods described by Simson. Values of filtered QRS duration (f-QRS), root mean square voltage (RMS), the duration of low amplitude signal (LAS) and late duration (LD) were calculated and compared between the groups. These parameters were not significantly different between the IDDM and control groups. However, in patients with poor glycemic control (HbAlc >10%), f-QRS was long and RMS was significantly low (p < 0.05, each) compared with the control group. Three patients with IDDM were positive for ventricular late potentials, although none had ventricular tachyarrhythmia. None of the control subjects showed ventricular late potentials. CONCLUSION: Certain parameters of SA-ECG showed abnormal values in IDDM patients with poor glycemic control. Thus, SA-ECG is a potentially useful and non-invasive method for the assessment of subclinical cardiac impairment in diabetic children and adolescents.     

The role of mechanical-electrical interaction in ventricular arrhythmia: evidence from a novel animal model for repaired tetralogy of Fallot

Pulmonary regurgitation and prolonged QRS duration of right bundle branch (RBB) block are common in repaired tetralogy of Fallot (TOF) and increase the risk of sudden death. We sought to establish an animal model to reflect both abnormalities. Twenty-one canines: group I (n = 7) received a surgical right ventricular outflow tract (RVOT) transannular patch plus pulmonary valve destruction; group II (n = 5) received RBB ablation and sham operation; and group III (n = 9) received combined interventions. Serial electrophysiological data were obtained up to 1 y. Procedure mortality was 27.6%. At 1 y, although severe pulmonary regurgitation was documented in most dogs in groups I (71%) and III (100%), progressive RVOT dilatation was noted in group III. RBB block was present in all dogs in groups II and III. However, the increments of QRS duration, QTc, JTc, and QT dispersion progression between 1 mo and 1 y were all greatest in group III. Ventricular arrhythmia events were frequent in group III (median 3.3/mo) but uncommon in groups I and II (median 1/mo). We have created a novel animal model that adequately reflects both the hemodynamic and electrophysiological characteristics of repaired TOF patients and can be applied to examine the risk of ventricular arrhythmias.     

Hemodynamic and Electrocardiographic Effects of Early Pulmonary Valve Replacement in Pediatric Patients After Transannular Complete Repair of Tetralogy of Fallot

In adults, pulmonary value replacement (PVR) shows improvement in right ventricular (RV) volume and function and reduces QRS duration. In addition, RV volume correlates with QRS duration and QRS change. This has not been shown in pediatric patients. The purpose of this study was to evaluate serial magnetic resonance imaging (MRI) and electrocardiogram measurements before and after early PVR in a pediatric population with repaired Tetralogy of Fallot and whether QRS duration and QRS change correlated with RV volume. A retrospective review of MRIs and electrocardiograms was conducted on 10 patients. Median age at repair was 2.1 ± 0.7 years, and median age at PVR was 11.5 ± 2.0 years. There were significant decreases in RV end diastolic volume (EDV)/body surface area (BSA) (p < 0.0004), end systolic volume (ESV)/BSA (p = 0.02), RVEDV/left ventricular (LV) EDV (p < 0.001), RV ejection fraction (p < 0.04), RV stroke volume (SV)/BSA (p < 0.0002), and (RVSV - LVSV)/BSA (p = 0.0007). No significant change in QRS duration occurred (p = 0.08). QRS duration (pre-r = 0.44, p = 0.20; post-r = 0.34, p = 0.33) and QRS change (r = −0.08, p = 0.83) did not correlate with RVEDV. We propose early consideration of PVR in pediatric patients. PVR improves RV volumes and function and may provide beneficial electromechanical effects by slowing the progression of QRS duration.     

Exercise-Induced Ventricular Arrhythmia after Repair of Tetralogy of Fallot

Treadmill exercise electrocardiography (TE) was recorded in 50 patients to evaluate the incidence of exercise-induced ventricular arrhythmias (VAs) in a group of patients who underwent corrective surgery of tetralogy of Fallot (TF) more than four years previously. The results of rhythm evaluation were correlated with cardiac catheterization data as well as clinical information such as the age at surgery and the interval from surgery. Of the 50 patients tested, ventricular premature contraction (VPC) was confirmed in 12 patients (24%) on TE, while five patients (10%) demonstrated VPC on the standard ECG. The interval from surgery was significantly longer in those patients with VA (Group 1) than those without VA (Group 11) on TE (p<0.05). There was no significant difference of the age at corrective surgery between the two groups. In group I, the preoperative hemoglobin level was higher (p<0.05) and the right ventricular ejection fraction was lower (p<0.01). Exercise-induced VAs are closely related to the length of period after surgery and the depressed right ventricular function.     

Recovery of High-Frequency QRS Potentials Following Cardioplegic Arrest in Pediatric Cardiac Surgery

We examined the hypothesis that recovery of high-frequency QRS potentials at reperfusion is influenced by the duration of myocardial ischemia during cardioplegic arrest in pediatric cardiac surgery. Signal-averaged electrocardiograms were recorded after induction of anesthesia (baseline data) and every 1 to 5 minutes after aortic declamping in 14 patients aged 2 months to 6 years. The signals were processed with a band-pass filter between 80 Hz and 300 Hz to obtain high-frequency potentials in the QRS complex. The high-frequency QRS potentials (80-300 Hz) were expressed as the root mean square voltage over the filtered QRS complex. The high-frequency QRS potentials at baseline were 33.9 +/- 4.4 microV. They decreased to 13.7 +/- 9.6 microV 1 minute after aortic declamping (p = 0.005). Subsequently they gradually increased and then returned to the baseline level. The time that the potentials were over 90% of baseline value ranged from 10 to 35 minutes after aortic declamping. The recovery time of this reduction in the high-frequency QRS potentials correlated with the duration of aortic cross-clamping (r = 0.80, p = 0.0009) and the value of postoperative MB isozyme of the creatine kinase (r = 0.81, p = 0.0042). This study demonstrated that the high-frequency QRS potentials decreased at early reperfusion following cardioplegic arrest and then returned to preischemic levels. The recovery time of the high-frequency QRS potentials significantly correlated with cardioplegic arrest time and postoperative MB isozyme of the creatine kinase values. Our results raise the possibility that changes in high-frequency electrocardiographic signals in the QRS complex may reflect myocardial ischemia during cardioplegic arrest.     

A Contemporary Assessment of the Risk for Sudden Cardiac Death in Patients With Congenital Heart Disease

Assessment of the risk for sudden cardiac death (SCD) after surgery for congenital heart disease (CHD) remains a difficult challenge. In the study of this problem, the focus has evolved from concern regarding late-onset heart block to a subsequent focus on ventricular and reentrant atrial arrhythmias, with the most recent emphasis on ventricular dysfunction and heart failure. Sudden cardiac death in CHD patients has been studied most extensively in tetralogy of Fallot. More than 30 risk factors have been proposed, with age at repair, QRS duration, right ventricular enlargement, and left ventricular dysfunction considered the most predictive risk factors. Additionally, SCD has been studied in patients with atrial repair for transposition of the great arteries, left heart obstructive lesions, and to a limited extent, patients with univentricular physiology. This review discusses current risk factors for SCD in CHD and the limited positive predictive value of any individual factor. The emphasis is on contemporary patients with CHD, who differ markedly from those who had repair of CHD decades earlier. This is characterized by complete repairs during the neonatal period, improved physiologic outcomes, and extended survival of patients with complex forms of CHD. Therefore, earlier data and conclusions may not be relevant to newer generations of patients with CHD. According to current perspectives, systemic ventricular dysfunction becomes a major risk factor beyond the age of 20 years. The first symptomatic arrhythmia may result in SCD, and defibrillators are increasingly implanted despite the lack of risk stratification criteria. The large number of potential risk factors and therapeutic options, in contrast to the low incidence of actual events, results in a difficult clinical challenge in the assessment of the risk for SCD in the individual patient with CHD.     

Value of the new Doppler-derived myocardial performance index for the evaluation of right and left ventricular function following repair of tetralogy of fallot

The systolic and diastolic function in both ventricles may be altered even after successful corrective surgery of tetralogy of Fallot. The aim of this study was to assess the combined diastolic and systolic function of both ventricles using the Doppler-derived myocardial performance index (MPI) in patients with operated tetralogy of Fallot (TOF). We performed a prospective analysis of 51 patients following corrective surgery of TOF: 21 had a subannular patch, 20 had a homograft implantation at initial operation, and 10 were reoperated with secondary homograft implantation. Patients were examined with Doppler echocardiography, and the MPI, which incorporates ejection and isovolumetric relaxation and contraction times and is an index of global ventricular function, was calculated 10.2 +/- 8.0 (0.89-36) years after surgery. In 86.4% of the examined patients the right ventricular isovolumetric relaxation time was shortened compared to the normal published range or even did not exist (negative value) (p <0.01). The right ventricular MPI was paradoxically below the normal published range in 76.5% of the examined patients. The left ventricle global function was impaired in 23.5% of the examined patients, mainly due to altered systolic function with a prolonged left ventricular isovolumetric contraction time. The z score of the comparison between patients' left ventricular isovolumetric contraction time and the normal published values was 3.03. Patients with severe pulmonary regurgitation also had a prolongation of the isovolumetric relaxation time compared to patients with mild to moderate pulmonary regurgitation. The noncompliant right ventricle may shorten the right ventricular isovolumetric relaxation time, resulting in a paradoxically low right MPI. This may reduce the sensitivity of the index in recognizing patients with right ventricular dysfunction following corrective surgery of TOF. Additional diastolic impairment occurs in patients with right ventricular volume overload.     

Quantitative Analysis of Paradoxical Interventricular Septal Motion Following Corrective Surgery of Tetralogy of Fallot

This study aimed to quantify paradoxical interventricular septal motion (PSM) among 20 patients following tetralogy of Fallot (TOF) repair without severe pulmonary regurgitation and 20 age-matched normal subjects. PSM was quantified using the echocardiography-derived paradox index. Tissue Doppler-derived strain rate was used to assess the longitudinal and radial systolic function of the interventricular septum (IVS). The tissue Doppler-derived Tei index was used to assess the global left ventricular function. Compared to the control group, the paradox index in patients after repair of TOF was significantly higher (p = 0.001), whereas the regional IVS longitudinal (p = 0.02) and radial (p = 0.001) systolic strain rate peaks were significantly reduced. The paradox index in the patient group correlated inversely with the IVS radial peak systolic strain rate (r = −0.64, p = 0.004) and positively with QRS duration (r = 0.50, p = 0.02). The left ventricular (LV) Tei-index correlated significantly with the paradox index (r = 0.71, p = 0.001) and with the septal radial systolic strain rate peak (r = 0.59, p = 0.004). We conclude that electrical delay and reduced regional septal systolic function were the main causes for paradoxical septal motion among patients following TOF repair without significant pulmonary regurgitation. The reduced LV systolic function among this group of patients is mainly secondary to diminished septal systolic function and the paradoxical septal motion.     

Right ventricular myocardial responses to chronic pulmonary regurgitation in lambs: disturbances of activation and conduction

Patients after repair of tetralogy of Fallot are at increased risk of arrhythmic death. Clinical data suggest that pulmonary regurgitation predisposes to these arrhythmias, although the cellular electrophysiologic effects of pulmonary regurgitation are unknown. We induced pulmonary regurgitation in lambs, and 3 mo later, having quantified the pulmonary regurgitant (PR) fraction, studied right ventricular mechanical and electrophysiologic properties in vivo and in vitro. The PR fraction was greater in PR (75 +/- 10%) than in sham-operated animals (8 +/- 4%; p < 0.01). In vivo, monophasic action potential duration and activation time, at rest and during acute right ventricular stretch, were similar in both groups. However, the dispersion of activation time was greater in PR animals at rest (13 +/- 1.1 versus 8 +/- 1.1 ms; p < 0.05). Furthermore, the dispersion of activation increased during right ventricular stretch in PR, but not in sham-operated animals. In vitro, myocardial force-frequency responses were similar in both groups, indicating preserved systolic performance, but mechanical restitution studies showed a prolonged refractory period (447 +/- 22 versus 370 +/- 26 ms; p < 0.05) and a decreased recovery time constant (184 +/- 19 versus 265 +/- 20 ms; p < 0.001) in PR animals, indicating altered calcium cycling. Furthermore, the myocardial conduction velocity was reduced in PR animals (31 +/- 3.58 versus 47.9 +/- 5.1 cm/s; p < 0.01), resulting from a 2-fold increase in intracellular resistance (437.25 +/- 125.93 versus 194 +/- 43.27 Omega. cm; p = 0.025). Chronic PR leads to inhomogeneity of right ventricular activation, alters myocardial calcium cycling, reduces conduction velocity, and increases intracellular resistivity. These may contribute to the development of arrhythmias associated with PR, including those in patients after tetralogy repair.     

Severe Pulmonary Regurgitation Late After Total Repair of Tetralogy of Fallot: Surgical Considerations

Background After total repair of tetralogy of Fallot (TOF-R) with transannular patching (TAP), severe pulmonary regurgitation (PR) is reported to develop in up to 30% of patients at a follow-up of 20 years, and 10–15% or more need pulmonary valve replacement (PVR). In this study, time-related progression of PR and right ventricular (RV) dilatation, and functional recovery of the RV after PVR are analyzed, and the possible causes of PR and timing of PVR are discussed.Methods Eighteen patients, who late after TOF-R with TAP underwent PVR for severe PR, were chosen for the study. NYHA class, QRS duration, RV dilatation index (RVDI = RVEDD/LVEDD), and RV–distal pulmonary artery (PA) peak systolic gradient were reviewed and retrospectively analyzed.Results TOF-R was performed at a mean age of 5.1 ± 3.9 years (range: 0.6–12.8 years); the mean time interval from TOF-R to PR grade 3 onset was 11.8 ± 7.0 years (range: 3.3–27.4 years), and from TOF-R to PVR was 18.5 ± 7.8 years (range: 8.7–37.1 years).At PVR, 11 patients were in NYHA class II–III, all patients had severe PR (grade 3/3) and severe RV enlargement, 4 patients had ventricular arrhythmias, 7 patients significant distal pulmonary artery stenosis, and 2 patients small nonrelevant residual VSD. The mean preoperative RVDI (normal: 0.5) was 0.99 ± 0.14 (range: 0.75–1.3), the mean QRS duration 170 ± 24 ms (140–220 ms), and the mean RV–distal PA peak systolic pressure gradient 33.3 ± 19.0 mmHg (range: 10–60 mmHg). Patients aged at TOF-R> 5 years had considerably longer redo-free intervals than their younger counterparts: mean 23.1 years (range 8.7–37.1 years) vs 14.8 years (range: 9.3–21.2 years), respectively. The redo-free intervals and the duration of severe PR correlated inversely with the RV-PA gradient.At a mean follow-up of 1.3 years (2 weeks–5 years), the mean RVDI decreased from 0.99 ± 0.14 to 0.69 ± 0.15, the mean validity class improved from 2.5 to 1.1. One patient died.Conclusions After TOF-R with TAP, the progression of PR has very individual dynamics, resulting in extremely varying redo-free intervals. Concomitant pulmonary stenosis seems to exaggerate progression of PR. PVR results in effective reduction of diastolic dimensions of severely dilated RV and in improvement of validity class. Referred PVR in no-risk cases seems to be justified.Presented at the 32nd Annual Meeting of the GSTCS, Leipzig, Germany, 24 February 2003.     

Biventricular Long Axis Function After Repair of Tetralogy of Fallot

Right ventricular restrictive physiology is common after repair of tetralogy of Fallot and relates to exercise performance and symptomatic arrhythmias. In this study, we examined biventricular long axis function in an attempt to clarify further the mechanical substrate of this phenomenon. We studied prospectively 95 patients with tetralogy of Fallot (age range 1–44.3 years) at a median of 4.3 years after repair with Doppler and M-mode echocardiography. Pulmonary arterial, tricuspid, and mitral Doppler spectrals and 2-D guided M-mode recordings of ventricular minor and long axes were obtained with simultaneous phonocardiogram and respirometer recordings. Right ventricular restriction was defined by the presence of antegrade pulmonary arterial flow during atrial systole throughout the respiratory cycle. Restrictive right ventricular physiology was demonstrated in 36 (39%) [group 1] of the 92 patients in whom the data were analyzed. Left ventricular function (FS, isovolumic relaxation time and transmitral E wave deceleration time) was not different in the two groups (p < 0.1, p < 0.6, and p < 0.8, respectively). The presence of antegrade diastolic flow shortened the pulmonary regurgitation in the restrictive group (PR duration/√RR 10.7 ± 2.1 vs 12.1 ± 2.1, p < 0.01). There was delayed onset of shortening (97.4 ± 24 vs 88.8 ± 24 ms, p= 0.01), and the amplitude of right atrioventricular ring excursion, corrected for body surface area, was significantly lower during atrial systole in the restrictive group (0.43 ± 0.15 vs 0.54 ± 0.2 cm/m², p < 0.01). There was also a tendency toward a smaller ratio of right to left total atrioventricular ring excursion in the same group (1.14 ± 0.19 vs 1.22 ± 0.23, p= 0.1). Impaired long axis function in patients with restrictive right ventricular physiology following repair of tetralogy of Fallot is associated with abnormal diastolic filling and may contribute to the long-term cardioprotective effect of restrictive physiology by limiting the degree of right ventricular dilatation.