Evaluation of Right Ventricular Volume and Systolic Function by Real-time Three-dimensional Echocardiography

The optimal plane for measurement of the right ventricular (RV) volumes by real-time three-dimensional echocardiography (RT3DE) was determined and the feasibility and accuracy of RT3DE in studying RV systolic function was assessed. RV “Full volume” images were acquired by RT3DE in 22 healthy subjects. RV end-diastolic volumes (RVEDV) and end-systolic volumes (RVESV) were outlined using apical biplane, 4-plane, 8-plane, 16-plane offline separately. RVSV and RVEF were calculated. Meanwhile tricuspid annual systolic excursion (TASE) was measured by M-mode echo. LVSV was outlined by 2-D echo according to the biplane Simpson's rule. The results showed: (1) There was a good correlation between RVSV measured from series planes and LVSV from 2-D echo (r=0.73; r=0.69; r=0.63; r=0.66, P<0.25—0.0025); (2) There were significant differences between RVEDV in biplane and those in 4-, 8-, 16-plane (P<0.001). There was also difference between RV volume in 4-plane and that in 8-plane (P<0.05), but there was no significant difference between RV volume in 8-plane and that in 16-plane (P>0.05); (3) Inter-observers and intro-observers variability analysis showed that there were close agreements and relations for RV volumes (r=0.986, P<0.001; r=0.93, P<0.001); (4) There was a significantly positive correlation of TASE to RVSV and RVEF from RT3DE (r=0.83; r=0.90). So RV volume measures with RT3DE are rapid, accurate and reproducible. In view of RV's complex shape, apical 8-plane method is better in clinical use. It may allow early detection of RV systolic function.

Validation of real-time three-dimensional echocardiography for quantifying left and right ventricular volumes:an experimental study

Background Assessment of the left ventricular (LV) and the right ventricular (RV) volumes and their functions is important for prognostic prediction and clinical decision making. We compared the accuracy for quantifying the LV and the RV volumes in vitro between conventional two-dimensional echocardiography (2DE) and real-time three-dimensional echocardiography (RT3DE) Methods The volumes of 37 rubber-models (10 regularly shaped to simulate normal LV, 7 shaped to simulate LV with symmetric aneurysm, 8 shaped to simulate LV with asymmetric aneurysm, and 12 irregularly shaped to simulate normal RV) and 10 excised canine hearts were measured by RT3DE and 2DE On RT3DE 'full volume' imaging, the inner-surfaces of the rubber-models and canine LV and RV were outlined and the volumes were measured using 2-, 4-, 8- and 16-plane methods with the RT3DE analysis software On 2DE imaging, the volumes were measured by the Simpson method The LV and RV volumes measured by drained water were served as reference values, with which we compared RT3DE and 2DE data Results In rubber models mimicking normal LV and LV with symmetric aneurysms, RT3DE results were strongly correlated with reference values ( r =0 795-0 998) and there was a good correlation between 2DE estimates and reference values ( r =0 715-0 729) There were no significant differences between RT3DE estimates, 2DE results and reference values ( P >0 05) In rubber models mimicking the RV and LV with asymmetric aneurysm, RT3DE strongly correlated with reference values ( r =0 765-0 988), but 2DE weakly correlated with reference values ( r =0 518-0 592) There were no differences between RT3DE and reference values ( P >0 05), but a significant difference between 2DE and reference values occurred ( P <0 05) For excised canine hearts, there was a strong correlation between RT3DE and reference values ( r =0 728-0 914), while 2DE showed a less obvious correlation ( r =0 502-0 615) Again, there were no significant differences between RT3DE and reference values ( P >0 05), but there was a significant difference between 2DE and reference values ( P <0 05) Conclusions RT3DE can accurately quantify LV and RV volumes and provides a new tool to evaluate LV and RV function For LV and RV measurements by RT3DE, 8-plane strategy is the optimum choice for accuracy and convenience

Right ventricular diverticulum following a pulmonary valve placement for correction of tetralogy of Fallot:A case report

BACKGROUND Ventricular diverticula are a rare congenital cardiac disorder presenting with an extremely low incidence.The presence of an apical diverticulum of the right ventricle has been associated with other congenital heart diseases such as tetralogy of Fallot.An important defining characteristic of ventricular diverticula that separates them from aneurysms through imaging techniques,is that they possess myocardial contraction synchronous to the adjacent walls,contributing to the ventricular stroke volume,so they do not usually require surgical treatment.CASE SUMMARY A 15-year-old male,currently asymptomatic,in follow up due to a pulmonary valve prosthesis placement and a history of corrected tetralogy of Fallot at 18 months old,underwent a cardiac magnetic resonance imaging in February 2024.A diverticulum was detected in the apical inferolateral wall of the right ventricle,which was not documented in the cardiac magnetic resonance imaging prior to valve prosthesis placement.CONCLUSION Right ventricular diverticula are a rare entity.To this date we could not find another case of a pulmonary valve placement,followed by a right ventricular diverticulum appearance.

Right Ventricular Outflow Tract Septal Pacing versus Apical Pacing: A Prospective, Randomized, Single-blind 5-Years Follow-up Study of Ventricular Lead Performance and Safety

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.

Arrhythmogenic right ventricular cardiomyopathy: From genetics to diagnostic and therapeutic challenges

Arrhythmogenic right ventricular cardiomyopathy(ARVC) is a genetic disease characterized by myocyte loss and fibro-fatty tissue replacement. Diagnosis of ARVC remains a clinical challenge mainly at its early stages and in patients with minimal echocardiographic right ventricular(RV) abnormalities. ARVC shares some common features with other cardiac diseases, such as RV outflow ventricular tachycardia, Brugada syndrome, and myocarditis, due to arrhythmic expressivity and biventricular involvement. The identification of ARVC can be often challenging, because of the heterogeneous clinical presentation, highly variable intra- and inter-family expressivity and incomplete penetrance. This genotypephenotype "plasticity" is largely unexplained. A familial history of ARVC is present in 30% to 50% of cases, and the disease is considered a genetic cardiomyopathy, usually inherited in an autosomal dominant pattern with variable penetrance and expressivity; in addition, autosomal recessive forms have been reported(Naxos disease and Carvajal syndrome). Diagnosis of ARVC relays on a scoring system, with major or minorcriteria on the Revised Task Force Criteria. Implantable cardioverter defibrillators(ICDs) are increasingly utilized in patients with ARVC who have survived sudden death(SD)(secondary prevention). However, there are few data available to help identifying ARVC patients in whom the prophylactic implantation of an ICD is truly warranted. Prevention of SD is the primary goal of management. Pharmacologic treatment of arrhythmias, catheter ablation of ventricular tachycardia, and ICD are the mainstay of treatment of ARVC.

Ablation strategies for arrhythmogenic right ventricular cardiomyopathy: a systematic review and meta-analysis

Background Catheter ablation for ventricular tachycardia(VT) in patients with arrhythmogenic right ventricular cardiomyopathy(ARVC) has significantly evolved over the past decade. However, different ablation strategies showed inconsistency in acute and long-term outcomes. Methods We searched the databases of Medline, Embase and Cochrane Library through October 17, 2019 for studies describing the clinical outcomes of VT ablation in ARVC. Data including VT recurrence, all-cause mortality, acute procedural efficacy and major procedural complications were extracted. A meta-analysis with trial sequential analysis was further performed in comparative studies of endo-epicardial versus endocardial-only ablation. Results A total of 24 studies with 717 participants were enrolled. The literatures of epicardial ablation were mainly published after 2010 with total ICD implantation of 73.7%, acute efficacy of 89.8%, major complication of 5.2%, follow-up of 28.9 months, VT freedom of 75.3%, all-cause mortality of 1.1% and heart transplantation of 0.6%. Meta-analysis of 10 comparative studies revealed that compared with endocardial-only approach, epicardial ablation significantly decreased VT recurrence(OR: 0.50;95% CI: 0.30–0.85;P = 0.010), but somehow increased major procedural complications(OR: 4.64;95% CI: 1.28–16.92;P = 0.02), with not evident improvement of acute efficacy(OR: 2.74;95% CI: 0.98–7.65;P = 0.051) or all-cause mortality(OR: 0.87;95% CI: 0.09–8.31;P = 0.90). Conclusion Catheter ablation for VT in ARVC is feasible and effective. Epicardial ablation is associated with better long-term VT freedom, but with more major complications and unremarkable survival or acute efficacy benefit.

Quantitative Assessment of Right Ventricular Systolic Function by the Analysis of Right Ventricular Contrast Time-intensity Curve

Summary: To study reliability and reliable indices of quantitative assessment of right ventricular systolic function by time-intensity curve (TIC) with right ventricular contrast, 5 % sonicated human albumin was injected intravenously at a does of 0.08 ml/kg into 10 dogs at baseline status and cardiac insufficiency. Apical four-chamber view was observed for washin and washout of contrast agent from right ventricle. The parameters of TIC were obtained by curve fitting. The differences of parameters were analyzed in different states of cardiac functions. Among the parameters derived from TIC, the time constant (k) was decreased significantly with decline of cardiac function (P<0.001). But half-time of decent of peak intensity (HT) and mean-transit-time (MTT) of washout were increased significantly (P<0.001). The k was strongly related to cardiac output of right ventricle (CO) and ejection fraction (EF) of left ventricle and fractional shortening (FS) of left ventricle. Right ventricular systolic function could be assessed reliably by the parameters derived from TIC with right ventricular contrast echocardiography. The k, HT and MTT are reliable indices for quantitative assessment of right ventricular systolic function.

Usefulness of myocardial performance index for assessing right ventricular function after percutaneous closure of atrial septal defect

Objective Assessment of right ventricular function in patients with atrial septal defect(ASD)is difficult.The Doppler myocardial performance index(MPI)may provide a method of assessing function in these patients.The purposes of this study were to evaluate the right ventricular function and its changes in patients with ASD after transcatheter closure of ASD.Methods MPI,defined as the sum of isovolumic relaxation time and isovolumic contraction time derived by ejection time,was measured from tricuspid inflow and right ventricular outflow;Doppler velocity profiles recorded during routine echocardiography.Twenty nine patients(13 men,16 women;mean age 25.28±12.69,range 6 to 57 years)were diagnosed to secundum ASD[the stretched diameters of ASD were from 9 To 36(24.91±7.98)mm],and had a successfully placed Amplatzer septal occluder(ASO)(the sizes of ASO were from 11 to 40 mm);there were 81 sex-matched,age-matched healthy people(control group 41men,40 women;mean age 29.02±14.22,range 4 to 45 years).MPI was measured again on 3 days and 1 month after closure of ASD.Change in the study group was assessed and compared to the control subjects with structurally normal hearts.A complete 2-dimensional and Doppler echocardiographic examination was performed in all study groups.Results 1)The isovolumic relaxation and isovolumic contraction times[respectively(77.59±14.39)ms vs(60.93±12.94)ms,P<0.0001;(28.28±10.88)ms vs(23.64±9.01)ms,P=0.027]were prolonged,and ejection time[(260.65±21.86)ms vs(271.85±21.92)ms,P=0.033]was shortened in patients with ASD compared with that in control subjects,resulting in a marked increase in the MPI(0.40±0.07 vs 0.31±0.05,P<0.0001)from normal values;2)by Pearson's correlations,the MPI had no correlation with heart rate and blood pressure in control subjects and patients with ASD,but it correlated positively with age in patients with ASD;3)by Pearson's correlations,the MPI correlated positively with the diameter of ASD and pulmonary artery pressure;4)after transcatheter closure of ASD,the MPI decreased markedly.Conclusions 1)MPI is a conceptually new,simple,and reproducible Doppler index in patients with ASD;2)MPI is free from the effect of age,heart rate and blood pressure;(3)MPI appears to be relatively dependent on changes in the diameter of ASD and pulmonary artery pressure;4)the right ventricular function was improved after transcatheter closure of ASD.

Correlation between ductus venosus spectrum and right ventricular diastolic function in isolated single-umbilical-artery foetus and normal foetus in third trimester

BACKGROUND Single umbilical artery(SUA)is the most common umbilical cord malformation in prenatal diagnosis.The presence of an SUA can cause blood circulation disorder in the foetus and functional changes of the foetal heart,affecting foetal circulation.The right ventricular diastolic functions in foetuses with isolated SUA and in normal foetuses in the third trimester were evaluated using the spectral Doppler of blood flow in the foetal ductus venosus(DV).AIM To evaluate the right ventricular diastolic functions in foetuses with isolated SUA and in normal foetuses in the third trimester.METHODS Colour Doppler was used to measure the spectrum of foetal DV and tricuspid orifice in 34 foetuses with isolated SUA aged 28-39 wk and in age-matched healthy controls.The DV flow velocities and velocity ratios were measured.The early passive/late active(E/A)ratio at the tricuspid orifice and tissue Doppler Tei index of the foetal right ventricular in the two groups were also measured.RESULTS During the third trimester,the isolated SUA group showed a lower‘a’-wave peak velocity in the DV than the control group(P<0.05).The correlations between the velocity ratios and E/A ratio at the tricuspid orifice in the two groups were analysed,and the correlation between the ventricular late diastolic velocity/ventricular diastolic peak flow velocity and E/A ratios was the best(R^2of the isolated SUA group:0.520;R2 of the control group:0.358).The correlations between the velocity ratios and tissue Doppler Tei index of foetal right ventricular in the two groups were analysed,and the correlation between the pulsatility index for veins(PIV)and tissue Doppler Tei index ratios was the best(R2 of the isolated SUA group:0.865;R2 of the control group:0.627).CONCLUSION In the isolated SUA group,the atrial systolic peak velocity‘a’decreased,and this finding might be related to the changes in foetal cardiac functions.The ratio of ventricular late diastolic velocity to ventricular diastolic peak flow velocity was closely related to the E/A ratio at the tricuspid valve and can be used to identify changes in the right ventricular diastolic functions of isolated SUA and healthy foetuses.PIV was closely related to the tissue Doppler Tei index of the foetal right ventricular and can be used to identify the right ventricular overall functions of isolated SUA and healthy foetuses.

EXPERIMENTAL STUDY OF RIGHT VENTRICULAR ASSIST IN ACUTE RIGHT VENTRICULAR FAILING

The efficacy of right atrial-pulmonary artery (RA-PA) bypass during acute right ventricular failure (RVF) produced by pulmonary artery constriction in dogs was examined in this study Control group (n=7) was supported with conventional volume loading and inotropic therapy. In the experimental animals (n=8) , RA-PA bypass was initiated 5 min. after the onset of severe RVF. Three control animals died from refractory ventricular fibrillation within one hour of RVF. No animals in the experimental group died within two hours of RA-PA bypass , but the histological study of the lungs in these animals demonstrated peribronchial , perivascular and intraalveolar hemorrhage. Light microscopic and electron microscopic examination of the myocardial specimens of the right ventricular free wall displayed the myocardial structures and ultrastructures were maintained effectively with RA-PA bypass while irreversible myocardial injuries occurred in the control animals after two hours of RVF with conventional therapy. During the 2 hours of RA-PA bypass, the hemodynamic indices were also maintained better when compared to the control animals. It may be concluded , a roller pump right ventricular assist device effectively unloads the acute failing right ventricle, maintains systemic cardiac output , and significantly reverses the myocardial ischemia during right ventricular failure, but RA-PA bypass may induce pulmonary hypertension due to increased pulmonary vascular resistance secondary to pulmonary edema and interstitial hemorrhage.

Fast rate （≥ 250 beats/min） right ventricular burst stimulation is useful for ventricular tachycardia induction in arrhythmogenic right ventricular cardiomyopathy

Background One of the major challenges in arrhythmogenic right ventricular cardiomyopathy （ARVC） ablation is ventricular tachy-cardia （VT） non-inducibility. The study aimed to assess whether fast rate （≥ 250 beats/min） right ventricular burst stimulation was useful for VT induction in patients with ARVC.Methods Ninety-one consecutive ARVC patients with clinical sustained VT that underwent electro-physiological study were enrolled. The stimulation protocol was implemented at both right ventricular apex and outflow tract as follows： Step A, up to double extra-stimuli; Step B, incremental stimulation with low rate （＆lt; 250 beats/min）; Step C, burst stimulation with fast rate （≥ 250 beats/min）; Step D, repeated all steps above with intravenous infusion of isoproterenol.Results A total of 76 patients had inducible VT （83.5%）, among which 49 were induced by Step C, 15 were induced by Step B, 8 and 4 by Step A and D, respectively. Clinical VTs were induced in 60 patients （65.9%）. Only two spontaneously ceased ventricular fibrillations were induced by Step C. Multivariate analysis showed that a narrower baseline QRS duration under sinus rhythm was independently associated with VT non-inducibility （OR： 1.1; 95% CI： 1.0-1.1;P = 0.019）.ConclusionFast rate （≥ 250 beats/min） right ventricular burst stimulation provides a useful supplemental method for VT induction in ARVC patients.

Primary angioplasty for infarction due to isolated right ventricular artery occlusion

We report an unusual case of an isolated right ventricular infarction with haemodynamic compromise caused by spontaneous isolated proximal occlusion of the right ventricular branch of the right coronary artery(RCA), successfully treated by balloon angioplasty. A 58-yearold gentleman presented with epigastric pain radiating into both arms. Electrocardiograph with right ventricular leads confirmed ST elevation in V4 R and a diagnosis of isolated right ventricular infarction was made. Urgent primary percutaneous intervention was performed which revealed occlusion of the right ventricular branch of the RCA. During the procedure, the patient's blood pressure dropped to 80/40 mm Hg, and echocardiography showed impaired right ventricular systolic function. Despite aggressive fluid resuscitation, the patient remained hypotensive, continued to have chest pain and persistent electrocardiograph changes, and hence balloon angioplasty was performed on the proximal right ventricular branch which restored flow to the vessel and revealed a severe ostial stenosis. This was treated with further balloon angioplasty which restored TIMI 3 flow with resolution of patient's symptoms. Repeat echocardiography showed complete resolution of theST-elevation in leads V4 R and V5 R and partial resolution in V1. Subsequent dobutamine-stress echocardiography at 4 wk showed good left and right ventricular contractions. The patient was discharged after a 3-d inpatient stay without any complications.

Hemodynamic improvement by right ventricular septal pacing in elderly patients with chronic atrial fibrillation and slow ventricular response

Background and objectives Right ventricular apical(RVA)pacing has been reported impairing left ventricular(LV)performance.Alternative pacing sites in right ventricle(RV)has been explored to obtain better cardiac function.Our study was designed to compare the hemodynamic effects of right ventricular septal(RVS)pacing with RVA pacing.Methods Ten elderly patients with chronic atrial fibrillation(AF)and long RR interval or slow ventricular response(VR)received VVI pacing.The hemodynamic difference between RVS and RVA pacing were examined by transthoracic echocardiography(TTE).Results Pacing leads were implanted successfully at the RVA and then RVS in all patients without complication.The left ventricular(LV)parameters,measured during RVA pacing including left ventricular ejection fraction(LVEF),FS,stroke volume(SV)and peak E wave velocity(EV)were decreased significantly compared to baseline data,while during RVS pacing,they were significantly better than those during RVA pacing.However,after 3-6 weeks there was no statistical significant difference between pre-and post-RVS pacing.Conclusions The LV hemodynamic parameters during RVA pacing were significantly worse than baseline data.The short term LV hemodynamic parameters of RVS pacing were significantly better than those of RVA pacing;RVS pacing could improve the hemodynamic effect through maintaining normal ventricular activation sequence and biventricular contraction synchrony in patients with chronic AF and slow ventricular response.

Long-term follow-up of right ventricular outflow tract septal pacing

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.

“I Dread the Heart Surgery but it Keeps My Child Alive”—Experiences of Parents of Children with Right Ventricular Outflow Tract Anomalies during the Assessment for Cardiac Reoperation

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.

Comparison of His-purkinje bundle pacing and right ventricular inflow tract septal pacing in the elderly

Objective To compare the short-term clinical effect and electrical parameters of His-purkinje bundle pacing(HPBP) and right ventricular inflow tract septal pacing(RVIP) in the elderly. Methods Between April 2017 and September 2019, sixty patients with indications for permanent cardiac pacing and resynchronization therapy in Beijing Anzhen Hospital were divided into the HPBP and RVIP groups, and were analyzed. A ventricular pacing lead was implanted in left ventricular septal sites with left bundle potentials or His potentials in the HPBP group. The lead was placed in right ventricular inflow tract septal sites close to distal His-bundle regions without potentials from the His-purkinje conduction system in the RVIP group. Lead impedance, R wave amplitude, pacing thresholds, QRS duration, left ventricular ejection fraction(LVEF), and left ventricular end-diastolic diameter(LVEDD), mitral regurgitation area reflux, QTc, T wave directivity, Tp-e and Tp-e/QT ratio were compared between the HPBP and RVIP groups during the procedure and the short-month follow-up. Results No significant differences were found in lead impedance, R wave amplitude, QRS duration, LVEF, LVEDD, mitral regurgitation area reflux, QTc, T wave directivity, Tp-e and Tp-e/QT ratio between the HPBP and RVIP groups. However, the pacing threshold was significantly lower in the HPBP group than in the RVIP group(0.7 ± 0.2 vs. 0.9 ± 0.3 V, P = 0.02). Conclusions The efficacy and electrical parameters of HPBP is comparable with RVIP during the procedure and the short-term follow-up.

Right ventricular pacing: the best site is yet to be defined

The right ventricular (RV) apex is the traditional site to provide stable and reliable chronic ventricular pacing. Interest in alternate site pacing has grown since RV apical pacing has been associated with increased mortality and morbidity compared to normal atrio-ventricular conduction. 1-4 Alternate pacing sites include the RV septum and outflow tract.

Intraoperative Right Ventricular Myocardial Infarction in a Geriatric Patient with Hip Fracture： a Case Report

HIP fracture is becoming a global public health issue due to increased longevity and the in-creased incidence of osteoporosis.1,2 Patients who underwent surgery experience high rates of mortality and disability, with approximately 5% death rate before discharge and 10% death rate within 30 days after discharge.3,4 Intraoperative cardiac arrest （IOCA） complicates up to 43 per 100,000 surgeries.5 Even with resuscitation by eligible professionals in a well-equipped operating room, IOCA is still associated with 35% imme-diate mortality and 65.5% in-hospital mortality.6,7 The main causes may be related to patient conditions, preoperative complications, anesthesia or surgical procedures.7,8 Age- associated changes in cardiovascular and other systems especially increase the risk of IOCA, which may explains why geriatric patients are the majority who experience asystole during surgery.

Implantation of Lumenless Pacing Leads at the Inter-atrial Septum and Right Ventricular Outflow Tract with Deflectable Catheter-sheath

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.