Background:Parents of children with complex right ventricular outflow tract(RVOT)anomalies are confronted with their child’s need for heart surgery early in life and repeated reoperations later on.Preoperative assess...Background:Parents of children with complex right ventricular outflow tract(RVOT)anomalies are confronted with their child’s need for heart surgery early in life and repeated reoperations later on.Preoperative assessment needs to be performed whenever an indication for reoperation is suspected.The aim was to illuminate the experiences of parents of children diagnosed with RVOT anomalies,in particular,how they experience their child’s heart disease and everyday life during the assessment and after the decision on whether to perform a reoperation.Method:Individual interviews(n=27)were conducted with nine parents on three occasions between 2014 and 2016 and analyzed using reflexive thematic analysis.Results:The analysis resulted in the following five main coexisting themes:The heart surgery keeps my child alive illuminates parents’experiences during and after the assessment and emphasizes that heart surgery,although dreaded,is central for their child’s survival;Everyday struggles illuminates the different struggles parents had to face to ensure that their child would be in the best possible condition;the remaining three themes,Unconditional love,Trust in life,and Togetherness,illuminate the ways in which the parents gained inner strength and confidence in their everyday lives.Conclusion:Although the parents were grateful for the assessment and had learned to navigate among the fears it aroused,they experienced several distressing situations during the assessment process that should be addressed.By inviting both the parents and their child to participate in the child’s care,individualized support can take into account the needs of both parents and child.展开更多
Summary: Lead placement for ventricular pacing variably impacts the physiological benefit of the pa- tient. This study evaluated the ventricular lead performance and safety of right ventricular outflow tract septal p...Summary: Lead placement for ventricular pacing variably impacts the physiological benefit of the pa- tient. This study evaluated the ventricular lead performance and safety of right ventricular outflow tract septal pacing in patients with bradyarrhythmia in South China over 60-month follow-up. Totally, 192 patients (108 males, and 84 females, 63-4-21 years old) with bradyarrhythmia were randomly divided into two groups. The right ventricular outflow tract septum (RVOTs) group had lead placement near the sep- tum (n=97), while the right ventricular apex (RVA) group had a traditional apical placement (n=95). RV septal lead positioning was achieved with a specialized stylet and confirmed using fluoroscopic projec- tion. All patients were followed up for 60 months. Follow-up assessment included stimulation threshold, R-wave sensing, lead impedance and lead complications. The time of electrode implantation in both the ROVTs and RVA groups were significantly different (4.29±0.61 vs. 2.16±0.22 min; P=0.009). No dif- ferences were identified in threshold, impedance or R-wave sensing between the two groups at 1 st, 12th, 36th and 60th month during the follow-up period. No occurrence of electrode displacement, increased pacing threshold or inadequate sensing was found. The long-term active fixation ventricular electrode performance in RVOTs group was similar to that in RVA group. RVOTs pacing near the septum using active fixation electrodes may provide stability during long-term follow-up period.展开更多
Current permanent right ventricular and right atrial endocardial pacing leads are implanted utilizing a central lumen stylet. Right ventricular apex pacing initiates an abnormal asynchronous electrical activation patt...Current permanent right ventricular and right atrial endocardial pacing leads are implanted utilizing a central lumen stylet. Right ventricular apex pacing initiates an abnormal asynchronous electrical activation pattern, which results in asynchronous ventricular contraction and relaxation. When pacing from right atrial appendage, the conduction time between two atria will be prolonged, which results in heterogeneity for both depolarization and repolarization. Six patients with Class Ⅰ indication for permanent pacing were implanted with either single chamber or dual chamber pacemaker. The SelectSecure 3830 4-French (Fr) lumenless lead and the SelectSite C304 8.5-Fr steerable catheter-sheath (Medtronic Inc., USA) were used. Pre-selected pacing sites included inter-atrial septum and right ventricular outflow tract, which were defined by ECG and fluoroscopic criteria. All the implanting procedures were successful without complication. Testing results (mean atrial pacing threshold: 0.87 V; mean P wave amplitude: 2.28 mV; mean ventricular pacing threshold: 0.53V; mean R wave amplitude: 8.75 mV) were satisfactory. It is concluded that implantation of a 4-Fr lumenless pacing lead by using a streerable catheter-sheath to achieve inter-atrial septum or right ventricular outflow tract pacing is safe and feasible.展开更多
Objective Right ventricular outflow tract septum has become widely used us an electrode placement site. However, data concerning lead performances and complications for lead repositioning with this technique were scan...Objective Right ventricular outflow tract septum has become widely used us an electrode placement site. However, data concerning lead performances and complications for lead repositioning with this technique were scant. The purpose of this study was to observe long- term lead performances and complications of right ventricular outflow tract septal pacing and provide evidences for choosing an optimal electrode implantation site. Methods Thirty-six patients with septal active electrode implantation and 39 with apical passive electrode implantation were enrolled in this study. Pacing threshold, R-wave sensing, lead impedance, pacing QRS width and pacing-related compli- cations for two groups at implantation and follow-up were compared. Results There were higher pacing threshold and shorter pacing QRS width at implantation in the septal group compared with the apical group. There were no differences between the septal and the apical groups in pacing threshold, R-wave sensitivity, lead impedance and pace-related complication during a follow-up. Conclusions Right ventricular outflow tract septum could be used as a first choice for implantation site because it had long-term stable lead performances and no serious complications compared with the traditional apical site.展开更多
Background:Mechanisms and clinical manifestations of coronary artery complications after right ventricular outflow tract reconstruction surgery are not well known.Methods:Patients who had coronary artery complications...Background:Mechanisms and clinical manifestations of coronary artery complications after right ventricular outflow tract reconstruction surgery are not well known.Methods:Patients who had coronary artery complications after pulmonary valve replacement or the Rastelli procedure at a single tertiary centre were retrospectively analysed.Results:Coronary artery complications were identified in 20 patients who underwent right ventricular outflow tract reconstruction surgery.The median age at diagnosis of coronary artery complication was 21 years(interquartile range:13–25 years).Mechanisms of coronary artery complications were compression by adjacent materials in 12 patients,dynamic compression of intramural course of coronary artery in two patients,and intraoperative injury in six patients.Congenital coronary artery anomalies were identified in 50%(10/20)of patients.Four patients presented with early postoperative haemodynamic instability.Fourteen patients showed late onset symptoms or signs of coronary insufficiency,including chest pain,ventricular dysfunction,or ventricular arrhythmias.Coronary artery stenosis was incidentally found on cardiac computed tomography angiography in two asymptomatic patients.Four patients underwent surgical interventions,and one patient underwent percutaneous coronary intervention for coronary stenosis.One patient with recurrent ventricular tachycardia required an implantable cardioverter-defibrillator.There were two deaths in patients with intraoperative coronary injury.Conclusion:Preoperative coronary evaluation and long-term follow-up for the development of coronary artery complications are required in patients undergoing right ventricular outflow tract reconstruction surgery to prevent ventricular dysfunction,arrhythmias,and death,especially among those with congenital coronary anomalies.展开更多
A 63-year-old patient presented with dyspnea and chest distress. A computerized tomography and echocardiogram showed a cardiac mass in the right ventricle, which caused obstruction of the right ventricular outflow tra...A 63-year-old patient presented with dyspnea and chest distress. A computerized tomography and echocardiogram showed a cardiac mass in the right ventricle, which caused obstruction of the right ventricular outflow tract. Coronary angiography revealed a dense meshwork of the abnomorly capillary vessels originating from right coronary artery. The mass was completely excised under cardiopulmonary bypass. The mass attached right ventricle lateral wall and posterior triscupid leaflet. Histology was typical myomatous tissue.展开更多
Objective: For patients of TOF with pulmonary annular hypoplasia, reconstruction of right ventricular outflow tract (RVOT) often requires a trans annular patch (TAP). The present study aims to compare the outcomes of ...Objective: For patients of TOF with pulmonary annular hypoplasia, reconstruction of right ventricular outflow tract (RVOT) often requires a trans annular patch (TAP). The present study aims to compare the outcomes of TOF repair using Polytetrafluoroethylene (PTFE) patch versus autologous glutaraldehyde fixed pericardial patch for RVOT reconstruction. Materials and methods: 103 consecutive patients undergoing TOF repair in whom TAP was required were randomized into two groups: Group I (pericardial patch), Group II (PTFE patch). Postoperative outcomes in terms of postoperative heart rhythm, duration of mechanical ventilation, mediastinal and pleural drainage, length of stay in intensive care unit (ICU) and hospital mortality were assessed. A separate team of cardiologists independently evaluated pre- and post-operative gradients across the RVOT, degree of pulmonary insufficiency, right ventricular systolic function. Results: There were no significant differences between the two groups in terms of the incidence of postoperative arrhythmias, duration of mechanical ventilation, length of intensive care unit or hospital stay. The requirement of inotropes was no different in the PTFE patch group as compared with the pericardial patch group (16.84 ± 7.04 vs. 17.90 ± 6.71, median 19 vs. 20, p = 0.825). The re-exploration rate was higher in the PTFE group as compared with the pericardial patch group (6 vs. 1). Postoperative Echocar-diography revealed no differences in the RV systolic function between the two groups before discharge. Conclusion: In patients undergoing TOF repair, using a PTFE patch yields comparable results. However, the efficacy of PTFE will only be established once;mid-term and long-term results are available.展开更多
Background Frequent premature ventricular complexes from the right ventricular outflow tract (RVOT-PVCs) are associated with left ventricular dysfunction.This study adopted two-dimensional speckle tracking imaging t...Background Frequent premature ventricular complexes from the right ventricular outflow tract (RVOT-PVCs) are associated with left ventricular dysfunction.This study adopted two-dimensional speckle tracking imaging to evaluate global and regional left ventricular myocardial function in patients with frequent RVOT-PVCs.Methods This study included 30 patients with frequent RVOT-PVCs and 30 healthy subjects.Aortic systolic velocity-time integral (AoVTI) and myocardium strain in circumferential (CS),radial (RS) and longitudinal (LS) directions were evaluated by conventional echocardiography and speckle tracking imaging.All values of patients with RVOT-PVCs were recorded during sinus (PVC-S) and PVC beats (PVC-V).Results Significant differences were demonstrated in global CS,RS and LS between the control subjects and the PVC-V (CS:(17.46±2.48)% vs.(11.52±3.28)%,RS:(48.26±10.20)% vs.(20.92±9.78)%,LS:(19.89±2.62)% vs.(11.79±3.66)%,P 〈0.01),and in segmental RS and LS of nearly all the left ventricular segments.Statistical differences in segmental CS between the PVC-V and the control subjects were only observed in anterior,anteroseptal and septal segments (only seen in anteroseptal and septal segments at apex).Furthermore,V/S AoVTI (AoVTI during the PVC beat divided by AoVTI during the sinus beat,then multiplied by 100%) correlated with coupling interval (r=0.67,P 〈0.001) and global strain (CS:r=0.48,P=0.007; RS:r=0.65,P 〈0.001; LS:r=0.65,P 〈0.001).Conclusions Frequent RVOT-PVCs can induce global and regional left ventricular systolic dysfunction.The reduction of hemodynamic parameters relates to the coupling interval and the global systolic function.展开更多
The mechanism of idiopathic ventricular tachycardia originating from the right ventricular outflow tract (RVOT) is not clear. Many clinical reports have suggested a mechanism of triggered activity. However, there ar...The mechanism of idiopathic ventricular tachycardia originating from the right ventricular outflow tract (RVOT) is not clear. Many clinical reports have suggested a mechanism of triggered activity. However, there are few studies investigating this be- cause of the technical difficulties associated with examining this theory. The L-type calcium current (/Ca-L), an important in- ward current of the action potential (AP), plays an important role in arrhythmogenesis. The aim of this study was to explore differences in the APs of right ventricular (RV) and RVOT cardiomyocytes, and differences in electrophysiological character- istics of the ICa-L in these myocytes. Rabbit RVOT and RV myocytes were isolated and their AP and Ic,-L were investigated us- ing the patch-clamp technique. RVOT cardiomyocytes had a wider range of AP duration (APD) than RV cardiomyocytes, with some markedly prolonged APDs and markedly shortened APDs. The markedly shortened APDs in RVOT myocytes were abolished by treatment with 4-AP, an inhibitor of the transient outward potassium current, but the markedly prolonged APDs remained, with some myocytes with a long AP plateau not repolarizing to resting potential. In addition, early afterdepolariza- tion (EAD) and second plateau responses were seen in RVOT myocytes but not in RV myocytes. RVOT myocytes had a high- er current density for/Ca-L than RV myocytes (RVOT (13.16±0.87) pA pF-1, RV (8.59±1.97) pA pF-1; P〈0.05). The ICa-L and the prolonged APD were reduced, and the EAD and second plateau response disappeared, after treatment with nifedipine (10 μmol L^-1), which blocks the Ica-L. In conclusion, there was a wider range of APDs in RVOT myocytes than in RV myocytes, which is one of the basic factors involved in arrhythmogenesis. The higher current density for ICa-L is one of the factors causing prolongation of the APD in RVOT myocytes. The combination of EAD with prolonged APD may be one of the mechanisms of RVOT-VT generation.展开更多
Background This study aimed to investigate the performance of handmade tri-leaflet expanded polytetrafluoroethylene(ePTFE)conduits in the absence of a suitable homograft.Methods Patients who underwent right ventricula...Background This study aimed to investigate the performance of handmade tri-leaflet expanded polytetrafluoroethylene(ePTFE)conduits in the absence of a suitable homograft.Methods Patients who underwent right ventricular outflow tract reconstruction with tri-leaflet ePTFE conduits or homografts between December 2016 and August 2020 were included.The primary endpoint was the incidence of moderate or severe conduit stenosis(>36 mmHg)and/or moderate or severe insufficiency.The secondary endpoint was the incidence of severe conduit stenosis(>64 mmHg)and/or severe insufficiency.Results There were 102 patients in the ePTFE group and 52 patients in the homograft group.The median age was younger[34.5(interquartile range:20.8-62.8)vs.60.0(interquartile range:39.3-81.0)months,P=0.001]and the median weight was lower[13.5(10.0-19.0)vs.17.8(13.6-25.8)kg,P=0.003]in the ePTFE group.The conduit size was smaller(17.9±2.2 vs.20.5±3.0 mm,P<0.001)and the conduit Z score was lower(1.48±1.04 vs.1.83±1.05,P—0.048)in the ePTFE group.There was no significant difference in the primary endpoints(log rank,T3=0.33)and secondary endpoints(log rank,P=0.35).Multivariate analysis identified lower weight at surgery[P=0.01;hazard ratio:0.75;95%confidence interval(CI)0.59-0.94]and homograft conduit use(P=0.04;hazard ratio:8.43;95%CI 1.14—62.29)to be risk factors for moderate or severe conduit insufficiency.No risk factors were found for moderate or severe conduit stenosis or conduit dysfunction on multivariate analysis.Conclusion Handmade tri-leaflet ePTFE conduits showed acceptable early and midterm outcomes in the absence of a suitable homograft,but a longer follow-up is needed.展开更多
Ventricular fibrillation (VF) is a malignant arrhythmia, usually initiated by a ventricular premature contraction (VPC) during the vulnerable period of cardiac repolarization. Ablation therapy for VF has been desc...Ventricular fibrillation (VF) is a malignant arrhythmia, usually initiated by a ventricular premature contraction (VPC) during the vulnerable period of cardiac repolarization. Ablation therapy for VF has been described and increasingly reported. Targets for VF triggers are VPCs preceded by Purkinje potentials or from the right ventricular outflow tract (RVOT) in structurally normal hearts, and VPC triggers preceded by Purkinje potentials in ischemic cardiomyopathy. During the session, mapping should be focused on the earliest activation and determining the earliest potential is the key to a successful ablation. However, suppression of VF can be achieved by not only the elimination of triggering VPCs, but also by substrate modification of possible reentry circuits in the Purkinje network, or between the PA and RVOT. The most important issue before the ablation session is the recording of the 12-lead ECG of the triggering event, which can prove invaluable in regionalizing the origin of the triggering VPC for more detailed mapping. In cases where the VPC is not spontaneous or inducible, ablation may be performed by pace mapping. Further studies are needed to evaluate the precise mechanisms of this arrhythmia.展开更多
基金This study was supported by the Pediatric Heart Center at Skåne University Hospital Lund and Lund University,and by the Swedish Children’s Heart Association.
文摘Background:Parents of children with complex right ventricular outflow tract(RVOT)anomalies are confronted with their child’s need for heart surgery early in life and repeated reoperations later on.Preoperative assessment needs to be performed whenever an indication for reoperation is suspected.The aim was to illuminate the experiences of parents of children diagnosed with RVOT anomalies,in particular,how they experience their child’s heart disease and everyday life during the assessment and after the decision on whether to perform a reoperation.Method:Individual interviews(n=27)were conducted with nine parents on three occasions between 2014 and 2016 and analyzed using reflexive thematic analysis.Results:The analysis resulted in the following five main coexisting themes:The heart surgery keeps my child alive illuminates parents’experiences during and after the assessment and emphasizes that heart surgery,although dreaded,is central for their child’s survival;Everyday struggles illuminates the different struggles parents had to face to ensure that their child would be in the best possible condition;the remaining three themes,Unconditional love,Trust in life,and Togetherness,illuminate the ways in which the parents gained inner strength and confidence in their everyday lives.Conclusion:Although the parents were grateful for the assessment and had learned to navigate among the fears it aroused,they experienced several distressing situations during the assessment process that should be addressed.By inviting both the parents and their child to participate in the child’s care,individualized support can take into account the needs of both parents and child.
基金supported in part by grants from the Science and Technology Key Foundation of Guangdong Province(No.2010B031600166)the Science and Technology Foundation of Guangdong Province(No.2011B061300072)
文摘Summary: Lead placement for ventricular pacing variably impacts the physiological benefit of the pa- tient. This study evaluated the ventricular lead performance and safety of right ventricular outflow tract septal pacing in patients with bradyarrhythmia in South China over 60-month follow-up. Totally, 192 patients (108 males, and 84 females, 63-4-21 years old) with bradyarrhythmia were randomly divided into two groups. The right ventricular outflow tract septum (RVOTs) group had lead placement near the sep- tum (n=97), while the right ventricular apex (RVA) group had a traditional apical placement (n=95). RV septal lead positioning was achieved with a specialized stylet and confirmed using fluoroscopic projec- tion. All patients were followed up for 60 months. Follow-up assessment included stimulation threshold, R-wave sensing, lead impedance and lead complications. The time of electrode implantation in both the ROVTs and RVA groups were significantly different (4.29±0.61 vs. 2.16±0.22 min; P=0.009). No dif- ferences were identified in threshold, impedance or R-wave sensing between the two groups at 1 st, 12th, 36th and 60th month during the follow-up period. No occurrence of electrode displacement, increased pacing threshold or inadequate sensing was found. The long-term active fixation ventricular electrode performance in RVOTs group was similar to that in RVA group. RVOTs pacing near the septum using active fixation electrodes may provide stability during long-term follow-up period.
基金supported by a grant form a Program of Science and Technology Development of Hubei Province (2004AA304B09).
文摘Current permanent right ventricular and right atrial endocardial pacing leads are implanted utilizing a central lumen stylet. Right ventricular apex pacing initiates an abnormal asynchronous electrical activation pattern, which results in asynchronous ventricular contraction and relaxation. When pacing from right atrial appendage, the conduction time between two atria will be prolonged, which results in heterogeneity for both depolarization and repolarization. Six patients with Class Ⅰ indication for permanent pacing were implanted with either single chamber or dual chamber pacemaker. The SelectSecure 3830 4-French (Fr) lumenless lead and the SelectSite C304 8.5-Fr steerable catheter-sheath (Medtronic Inc., USA) were used. Pre-selected pacing sites included inter-atrial septum and right ventricular outflow tract, which were defined by ECG and fluoroscopic criteria. All the implanting procedures were successful without complication. Testing results (mean atrial pacing threshold: 0.87 V; mean P wave amplitude: 2.28 mV; mean ventricular pacing threshold: 0.53V; mean R wave amplitude: 8.75 mV) were satisfactory. It is concluded that implantation of a 4-Fr lumenless pacing lead by using a streerable catheter-sheath to achieve inter-atrial septum or right ventricular outflow tract pacing is safe and feasible.
文摘Objective Right ventricular outflow tract septum has become widely used us an electrode placement site. However, data concerning lead performances and complications for lead repositioning with this technique were scant. The purpose of this study was to observe long- term lead performances and complications of right ventricular outflow tract septal pacing and provide evidences for choosing an optimal electrode implantation site. Methods Thirty-six patients with septal active electrode implantation and 39 with apical passive electrode implantation were enrolled in this study. Pacing threshold, R-wave sensing, lead impedance, pacing QRS width and pacing-related compli- cations for two groups at implantation and follow-up were compared. Results There were higher pacing threshold and shorter pacing QRS width at implantation in the septal group compared with the apical group. There were no differences between the septal and the apical groups in pacing threshold, R-wave sensitivity, lead impedance and pace-related complication during a follow-up. Conclusions Right ventricular outflow tract septum could be used as a first choice for implantation site because it had long-term stable lead performances and no serious complications compared with the traditional apical site.
文摘Background:Mechanisms and clinical manifestations of coronary artery complications after right ventricular outflow tract reconstruction surgery are not well known.Methods:Patients who had coronary artery complications after pulmonary valve replacement or the Rastelli procedure at a single tertiary centre were retrospectively analysed.Results:Coronary artery complications were identified in 20 patients who underwent right ventricular outflow tract reconstruction surgery.The median age at diagnosis of coronary artery complication was 21 years(interquartile range:13–25 years).Mechanisms of coronary artery complications were compression by adjacent materials in 12 patients,dynamic compression of intramural course of coronary artery in two patients,and intraoperative injury in six patients.Congenital coronary artery anomalies were identified in 50%(10/20)of patients.Four patients presented with early postoperative haemodynamic instability.Fourteen patients showed late onset symptoms or signs of coronary insufficiency,including chest pain,ventricular dysfunction,or ventricular arrhythmias.Coronary artery stenosis was incidentally found on cardiac computed tomography angiography in two asymptomatic patients.Four patients underwent surgical interventions,and one patient underwent percutaneous coronary intervention for coronary stenosis.One patient with recurrent ventricular tachycardia required an implantable cardioverter-defibrillator.There were two deaths in patients with intraoperative coronary injury.Conclusion:Preoperative coronary evaluation and long-term follow-up for the development of coronary artery complications are required in patients undergoing right ventricular outflow tract reconstruction surgery to prevent ventricular dysfunction,arrhythmias,and death,especially among those with congenital coronary anomalies.
文摘A 63-year-old patient presented with dyspnea and chest distress. A computerized tomography and echocardiogram showed a cardiac mass in the right ventricle, which caused obstruction of the right ventricular outflow tract. Coronary angiography revealed a dense meshwork of the abnomorly capillary vessels originating from right coronary artery. The mass was completely excised under cardiopulmonary bypass. The mass attached right ventricle lateral wall and posterior triscupid leaflet. Histology was typical myomatous tissue.
文摘Objective: For patients of TOF with pulmonary annular hypoplasia, reconstruction of right ventricular outflow tract (RVOT) often requires a trans annular patch (TAP). The present study aims to compare the outcomes of TOF repair using Polytetrafluoroethylene (PTFE) patch versus autologous glutaraldehyde fixed pericardial patch for RVOT reconstruction. Materials and methods: 103 consecutive patients undergoing TOF repair in whom TAP was required were randomized into two groups: Group I (pericardial patch), Group II (PTFE patch). Postoperative outcomes in terms of postoperative heart rhythm, duration of mechanical ventilation, mediastinal and pleural drainage, length of stay in intensive care unit (ICU) and hospital mortality were assessed. A separate team of cardiologists independently evaluated pre- and post-operative gradients across the RVOT, degree of pulmonary insufficiency, right ventricular systolic function. Results: There were no significant differences between the two groups in terms of the incidence of postoperative arrhythmias, duration of mechanical ventilation, length of intensive care unit or hospital stay. The requirement of inotropes was no different in the PTFE patch group as compared with the pericardial patch group (16.84 ± 7.04 vs. 17.90 ± 6.71, median 19 vs. 20, p = 0.825). The re-exploration rate was higher in the PTFE group as compared with the pericardial patch group (6 vs. 1). Postoperative Echocar-diography revealed no differences in the RV systolic function between the two groups before discharge. Conclusion: In patients undergoing TOF repair, using a PTFE patch yields comparable results. However, the efficacy of PTFE will only be established once;mid-term and long-term results are available.
文摘Background Frequent premature ventricular complexes from the right ventricular outflow tract (RVOT-PVCs) are associated with left ventricular dysfunction.This study adopted two-dimensional speckle tracking imaging to evaluate global and regional left ventricular myocardial function in patients with frequent RVOT-PVCs.Methods This study included 30 patients with frequent RVOT-PVCs and 30 healthy subjects.Aortic systolic velocity-time integral (AoVTI) and myocardium strain in circumferential (CS),radial (RS) and longitudinal (LS) directions were evaluated by conventional echocardiography and speckle tracking imaging.All values of patients with RVOT-PVCs were recorded during sinus (PVC-S) and PVC beats (PVC-V).Results Significant differences were demonstrated in global CS,RS and LS between the control subjects and the PVC-V (CS:(17.46±2.48)% vs.(11.52±3.28)%,RS:(48.26±10.20)% vs.(20.92±9.78)%,LS:(19.89±2.62)% vs.(11.79±3.66)%,P 〈0.01),and in segmental RS and LS of nearly all the left ventricular segments.Statistical differences in segmental CS between the PVC-V and the control subjects were only observed in anterior,anteroseptal and septal segments (only seen in anteroseptal and septal segments at apex).Furthermore,V/S AoVTI (AoVTI during the PVC beat divided by AoVTI during the sinus beat,then multiplied by 100%) correlated with coupling interval (r=0.67,P 〈0.001) and global strain (CS:r=0.48,P=0.007; RS:r=0.65,P 〈0.001; LS:r=0.65,P 〈0.001).Conclusions Frequent RVOT-PVCs can induce global and regional left ventricular systolic dysfunction.The reduction of hemodynamic parameters relates to the coupling interval and the global systolic function.
文摘The mechanism of idiopathic ventricular tachycardia originating from the right ventricular outflow tract (RVOT) is not clear. Many clinical reports have suggested a mechanism of triggered activity. However, there are few studies investigating this be- cause of the technical difficulties associated with examining this theory. The L-type calcium current (/Ca-L), an important in- ward current of the action potential (AP), plays an important role in arrhythmogenesis. The aim of this study was to explore differences in the APs of right ventricular (RV) and RVOT cardiomyocytes, and differences in electrophysiological character- istics of the ICa-L in these myocytes. Rabbit RVOT and RV myocytes were isolated and their AP and Ic,-L were investigated us- ing the patch-clamp technique. RVOT cardiomyocytes had a wider range of AP duration (APD) than RV cardiomyocytes, with some markedly prolonged APDs and markedly shortened APDs. The markedly shortened APDs in RVOT myocytes were abolished by treatment with 4-AP, an inhibitor of the transient outward potassium current, but the markedly prolonged APDs remained, with some myocytes with a long AP plateau not repolarizing to resting potential. In addition, early afterdepolariza- tion (EAD) and second plateau responses were seen in RVOT myocytes but not in RV myocytes. RVOT myocytes had a high- er current density for/Ca-L than RV myocytes (RVOT (13.16±0.87) pA pF-1, RV (8.59±1.97) pA pF-1; P〈0.05). The ICa-L and the prolonged APD were reduced, and the EAD and second plateau response disappeared, after treatment with nifedipine (10 μmol L^-1), which blocks the Ica-L. In conclusion, there was a wider range of APDs in RVOT myocytes than in RV myocytes, which is one of the basic factors involved in arrhythmogenesis. The higher current density for ICa-L is one of the factors causing prolongation of the APD in RVOT myocytes. The combination of EAD with prolonged APD may be one of the mechanisms of RVOT-VT generation.
基金This work was supported by National Key R&D Program of China(No.2017YFC1308100)Beijing Municipal Science and Technology Commission(No.Z201100005520001).
文摘Background This study aimed to investigate the performance of handmade tri-leaflet expanded polytetrafluoroethylene(ePTFE)conduits in the absence of a suitable homograft.Methods Patients who underwent right ventricular outflow tract reconstruction with tri-leaflet ePTFE conduits or homografts between December 2016 and August 2020 were included.The primary endpoint was the incidence of moderate or severe conduit stenosis(>36 mmHg)and/or moderate or severe insufficiency.The secondary endpoint was the incidence of severe conduit stenosis(>64 mmHg)and/or severe insufficiency.Results There were 102 patients in the ePTFE group and 52 patients in the homograft group.The median age was younger[34.5(interquartile range:20.8-62.8)vs.60.0(interquartile range:39.3-81.0)months,P=0.001]and the median weight was lower[13.5(10.0-19.0)vs.17.8(13.6-25.8)kg,P=0.003]in the ePTFE group.The conduit size was smaller(17.9±2.2 vs.20.5±3.0 mm,P<0.001)and the conduit Z score was lower(1.48±1.04 vs.1.83±1.05,P—0.048)in the ePTFE group.There was no significant difference in the primary endpoints(log rank,T3=0.33)and secondary endpoints(log rank,P=0.35).Multivariate analysis identified lower weight at surgery[P=0.01;hazard ratio:0.75;95%confidence interval(CI)0.59-0.94]and homograft conduit use(P=0.04;hazard ratio:8.43;95%CI 1.14—62.29)to be risk factors for moderate or severe conduit insufficiency.No risk factors were found for moderate or severe conduit stenosis or conduit dysfunction on multivariate analysis.Conclusion Handmade tri-leaflet ePTFE conduits showed acceptable early and midterm outcomes in the absence of a suitable homograft,but a longer follow-up is needed.
文摘Ventricular fibrillation (VF) is a malignant arrhythmia, usually initiated by a ventricular premature contraction (VPC) during the vulnerable period of cardiac repolarization. Ablation therapy for VF has been described and increasingly reported. Targets for VF triggers are VPCs preceded by Purkinje potentials or from the right ventricular outflow tract (RVOT) in structurally normal hearts, and VPC triggers preceded by Purkinje potentials in ischemic cardiomyopathy. During the session, mapping should be focused on the earliest activation and determining the earliest potential is the key to a successful ablation. However, suppression of VF can be achieved by not only the elimination of triggering VPCs, but also by substrate modification of possible reentry circuits in the Purkinje network, or between the PA and RVOT. The most important issue before the ablation session is the recording of the 12-lead ECG of the triggering event, which can prove invaluable in regionalizing the origin of the triggering VPC for more detailed mapping. In cases where the VPC is not spontaneous or inducible, ablation may be performed by pace mapping. Further studies are needed to evaluate the precise mechanisms of this arrhythmia.