Survival After Intervention for Single-Ventricle Heart Disease Over 15 Years at a Single Institution.

BACKGROUND: Children with single-ventricle (SV) heart disease possess a spectrum of heart malformations, yet progress through similar hemodynamic states, suggesting differences in outcomes are related to fundamental morphologic differences, patient characteristics, or procedural pathways. We sought to provide a holistic overview of survival after intervention for SV heart disease at our institution. METHODS: SV heart disease was defined as patients born with a hypoplastic or dysfunctional ventricle with uncertain or unacceptable candidacy for a 2-ventricle circulation. Patients were stratified into 8 diagnostic groups and 11 procedural categories based on the initial interventional procedure. RESULTS: Between 2005 and 2020, 381 patients born with SV heart disease underwent intervention at our institution. Ten-year survival was highest for patients with double inlet left ventricle (89% ± 7%) and lowest for patients with hypoplastic left heart syndrome (55% ± 5%). Initial palliation with less invasive procedures, such as ductal stent (4-year: 100%) or pulmonary artery banding (10-year: 95% ± 5%), demonstrated superior survival compared with more invasive procedures such as the Norwood procedure (10-year: 59% ± 4%). Survival of patients who achieved a biventricular circulation was superior to patients who remained with SV physiology (10-year: 87% ± 5% vs 63% ± 3%, P = .04). In a multivariable analysis, chromosomal/syndromic abnormality, lower weight, hybrid Norwood procedure, nonleft ventricular dominance, and earlier year of operation were risk factors for death. CONCLUSIONS: Survival differences in patients with SV heart disease were related primarily to underlying cardiac anatomy, patient characteristics, and procedural complexity. Left ventricular dominance, more recent intervention, and attainment of a 2-ventricle circulation were associated with improved survival.

Chimney reconstruction provides a wider subaortic space and reduces the risk of pulmonary artery compression in the Norwood-type aortic arch reconstruction without patch supplementation.

OBJECTIVES: Pulmonary artery (PA) compression by the neoaorta is a serious complication after the Norwood-type palliation (NP) for hypoplastic left heart syndrome. Either excess patch tailoring or limited use of autologous tissue may cause narrowing of the subaortic space. The chimney technique could theoretically provide a wide subaortic space. METHODS: Twenty-nine patients with both pre- and post-NP computed tomography data available of the 37 consecutive patients who underwent NP in our institution were reviewed. Arch height, arch width, sinus of Valsalva diameter, area under the neoaortic arch and arch angle were measured. These patients were divided according to the neo-arch reconstruction technique, chimney reconstruction technique (CR) or conventional direct reconstruction technique (DR). RESULTS: Median age and weight at NP were 2.1 months and 3.5 kg, respectively. Twenty-two patients underwent previous bilateral PA banding. During NP, 17 CR and 12 DR were performed. Four patients in the DR group developed PA compression. No neoaortic arch dilatation was found in either group. Post-NP arch width, area under the neo-arch and the arch angle were significantly larger in the CR group. Pre-NP arch height was significantly smaller in DR patients with PA compression than in those without. CONCLUSIONS: The chimney technique decreased the risk of PA compression and provided a wider subaortic space and a less acute arch angle. This technique had no short-term effect on the neoaortic root. Small preoperative arch height is a potential risk factor for PA compression in DR, and the chimney technique could be an effective solution.

The role of balloon pulmonary angioplasty and pulmonary endarterectomy: Is chronic thromboembolic pulmonary hypertension still a life-threatening disease?

BACKGROUND: The management of non-operable chronic thromboembolic pulmonary hypertension (CTEPH) has evolved with the availability of balloon pulmonary angioplasty (BPA) and pulmonary vasodilators. We launched the BPA program in 2011. The aim was to analyze the survival and treatment efficacy of our CTEPH treatment program in the modern management era. METHODS AND RESULTS: We retrospectively reviewed data from 143 consecutive CTEPH patients diagnosed from January 2011 (i.e. after the availability of BPA) to December 2019. Of forty-one patients who underwent pulmonary endarterectomy (PEA), 25 underwent additional BPA (Combination group) and the others were treated with only PEA (PEA group). Ninety patients underwent BPA (BPA group). The remaining 12 patients did not undergo any interventional treatments. The 1- and 5-year survival rates of operated patients (n = 41) were 97.4% and 90.0%, compared to 96.9% and 86.9% in not-operated patients (n = 102), respectively (p = 0.579). There was no mortality in the Combination group. Mean pulmonary artery pressure after treatments in the PEA only, Combination, and BPA only groups was 20.5 ± 6.7, 17.9 ± 4.9, and 20.7 ± 4.6 mmHg, respectively (p = 0.067, one-way ANOVA). Percent decrease of pulmonary vascular resistance in each treatment groups was -73.7 ± 11.3%, -74.3 ± 11.8%, and - 54.9 ± 22.5%, respectively (p < 0.01, one-way ANOVA). CONCLUSION: There was no significant difference in long-term survival between operated and not-operated CTEPH. Moreover, the Combination approach might have the potential to introduce notable improvements in the prognosis of CTEPH. BPA and PEA appear to be mutually complementary therapies in the modern management era.

Electrical Stimulation-Guided Approach to Pulmonary Artery Catheter Ablation in Patients with Idiopathic Pulmonary Arterial Hypertension: A Pilot Feasibility Study with a 12-Month Follow-Up.

BACKGROUND: Recently, transcatheter pulmonary artery (PA) ablation aiming at sympathetic denervation has been proposed in pulmonary arterial hypertension (PAH). This pilot feasibility study aimed to assess the feasibility of selective radiofrequency PA ablation based on response to high-frequency stimulation mapping. METHODS: The study comprised 3 female patients with idiopathic PAH (IPAH). The following reactions to PA stimulation were noted and marked by color points on the three-dimensional map: sinus bradycardia (heart rate decrease ≥15%), tachycardia (heart rate increase ≥15%), phrenic nerve capture, and cough. Since the most appropriate ablation strategy was unknown, two approaches were suggested, according to stimulation results: ablation at points with any heart rate response (either bradycardia or tachycardia)-this approach was applied in patient #1 (IPAH long-term responder to calcium channel blockers); segmental ablation at points with no response and with tachycardia response (one IPAH long-term responder to calcium channel blockers patient and one-IPAH with negative vasoreactive testing). Hemodynamic measurements were performed before and after denervation. Follow-up visits were scheduled at 6 and 12 months. RESULTS: Six-months follow-up was uneventful for patients #1 and 3; patient #2 had one syncope and reduced 6-minute walk test distance and peak VO2 consumption. At 12 months, there was a normalization of mean PA pressure and pulmonary vascular resistance (PVR) in patient #1. Patient #2 had no change in PA pressure and PVR at 12 months. Patient #3 remained in II functional class; however, there was an increase in mean PA pressure and loss of vasoreactivity. CONCLUSIONS: Electrical high-frequency stimulation of the PA identifies several types of evoked reactions: heart rate slowing, acceleration, phrenic nerve capture, and cough. The improvement in clinical and hemodynamic parameters following targeted PA ablation in the IPAH patient with positive vasoreactive testing should be confirmed in larger studies.

Mapping and Ablation of Arrhythmias from Uncommon Sites (Aortic Cusp, Pulmonary Artery, and Left Ventricular Summit).

Despite advances in our understanding of the relevant anatomy and mapping and catheter ablation techniques of idiopathic outflow tract ventricular arrhythmias, challenging sites for catheter ablation remain the aortic cusps, pulmonary artery, and notably the left ventricular summit. A systematic approach should be used to direct mapping efforts efficiently between endocardial, coronary venous, and epicardial sites. Foci at the left ventricular summit, particularly intraseptal and at the inaccessible epicardial region, remain difficult to reach and when percutaneous techniques fail, surgical ablation remains an option but with risk of late coronary artery stenosis.

Pulmonary artery: A pivotal site for catheter ablation in idiopathic RVOT ventricular arrhythmias.

In patients without associated myocardial diseases, characterized by left bundle branch block and inferior axis morphologies, repetitive idiopathic right ventricular tachycardias and ventricular premature contractions typically arise from right ventricular outflow tract (RVOT). Accumulated evidences have shown that radiofrequency catheter ablation is a useful treatment for patients with RVOT ventricular arrhythmias (VAs). Interestingly, several medical centers have shown that pulmonary artery (PA) is a potential novel site for catheter ablation in RVOT-like VAs, particularly in patients where termination of RVOT VAs at the usual site fails. In this review, we comprehensively demonstrated that RVOT VAs were successfully terminated at the site of PA, analyzed the characteristics of surface electrocardiogram and endocardial potentials, and explored the underlying mechanisms for these cases.

Mapping and ablation of anteroseptal atrial tachycardia in patients with congenitally corrected transposition of the great arteries: implication of pulmonary sinus cusps.

AIMS: We sought to investigate focal atrial tachycardias (ATs) in patients with congenitally corrected transposition of the great arteries (ccTGA). METHODS AND RESULTS: We identified three cases of focal ATs with ccTGA from 2007 to 2015. The clinical findings, electrocardiography, electrophysiological features, and ablation were reported. All three cases had {S,L,L}-type ccTGA. The AT P waves shared the following features: narrow in width, positive in leads I and aVL, and negative/positive in lead V1. All ATs had focal activation pattern with early activation at the anteroseptal area, and further mapping demonstrated earliest atrial activation (EAA) inside the pulmonary sinus cusps (PSCs), especially the right PSC. In Cases 1 and 2, double potentials were recorded at the EAA sites. Conduction delay between the two potentials during atrial extrastimulus was observed. After successful ablation, the second potential during sinus rhythm was further delayed in Case 1 and was eliminated in Case 2. However, only one potential was recorded in Case 3. All three cases were successfully managed by ablating the sites with EAA, which preceded the P-wave onset by 60, 80, and 42 ms, respectively. During ablation, no junctional rhythm was observed. Incomplete left bundle branch block was induced during mapping in Case 1, but no other complications occurred. All patients were free from tachycardia during follow-up periods of 36, 7, and 5 months, respectively. CONCLUSION: Anteroseptal AT in patients with ccTGA could be eliminated by ablation inside the PSC.

Hybrid therapy for hypoplastic left heart syndrome: Myth, alternative, or standard?

OBJECTIVE: This retrospective study presents our operative results, mortality, and morbidity with regard to pulmonary artery growth and reinterventions on the pulmonary artery and aortic arch, including key features of our institutional standards for the 3-stage hybrid palliation of patients with hypoplastic left heart syndrome. METHODS: Between June 1998 and February 2015, 182 patients with hypoplastic left heart structures underwent the Giessen hybrid stage I procedure. Among these, 126 patients with hypoplastic left heart syndrome who received a univentricular palliation or heart transplantation were included in the main analysis. Median age and body weight of patients at hybrid stage I were 6 days (0-237) and 3.2 kg (1.2-7), respectively. Comprehensive stage II operation was performed at 4.5 months (2.9-39.5), and Fontan completion was established at 33.7 months (21.1-108.2). Operative and interstage mortality, morbidity, growth and reinterventions on the pulmonary arteries, and long-term operative results of the aortic arch reconstruction were assessed. RESULTS: Median follow-up time after Giessen hybrid stage I palliation was 4.6 years (0-16.8). Operative mortality at hybrid stage I, comprehensive stage II, and Fontan completion was 2.5%, 4.9%, and 0%, respectively. Cumulative interstage mortality was 14.2%. At 10 years, the probability of survival is 77.8%. Body weight (<2.5 kg) and aortic atresia had no significant impact on survival. McGoon ratio did not differ at comprehensive stage II and Fontan completion (P = .991). Freedom from pulmonary artery intervention was estimated to be 32.2% at 10 years. Aortic arch reinterventions were needed in 16.7% of patients; 2 reoperations on the aortic arch were necessary. CONCLUSIONS: In view of the early results and long-term outcome, the hybrid approach has become an alternative to the conventional strategy to treat neonates with hypoplastic left heart syndrome and variants. Further refinements are warranted to decrease patient morbidity.

Pulmonary artery mapping for differential diagnosis of left-sided atrial tachycardia.

BACKGROUND: Distinguishing left-and right-sided atrial tachycardia (AT) is often challenging. The coronary sinus (CS) provides information only concerning the anterior left atrium (LA). Potentials recorded in the pulmonary artery (PA) have been substituted for those of the upper posterior LA because of their anatomical relationship. METHODS AND RESULTS: Three patterns were designed, using potentials in the PA, right atrium (RA) and CS, to predict the side of AT. Two patterns were for left-sided AT and 1 pattern was for right-sided AT. Ten left-sided and 11 right-sided ATs were investigated regardless of mechanism. Electrode catheters were inserted in the RA, His bundle region, and CS, and an ablation catheter was inserted into the left and/or right PA. The sequences from these catheters were analyzed before detailed electroanatomical mapping. Patterns were obtained for 20 of 21 ATs. The mechanism was focal in 16 ATs and macroreentry in 5. The method predicted left-sided AT with a sensitivity of 78%, a specificity of 100%, a positive predictive value of 100%, a negative predictive value of 84%, and an accuracy of 90%. CONCLUSIONS: The use of potentials in PA combined with conventional RA and CS electrograms is useful for distinguishing left-sided AT from right-sided AT, regardless of mechanism.

Landiolol for junctional ectopic tachycardia refractory to amiodarone after pediatric cardiac surgery.

Postoperative junctional ectopic tachycardia (JET) in children undergoing cardiac surgery is a serious arrhythmia that is associated with considerable morbidity and mortality. We present here a case of successful landiolol therapy for postoperative JET in a 3-month-old infant who underwent ventricular septal defect closure and right pulmonary artery plasty. His left ventricular function was poor postoperatively. The JET was refractory to amiodarone and caused severe hypotension, which was required cardiac massage. Continuous intravenous infusion of low-dose landiolol reduced the persistent JET rate immediately, and restored to sinus rhythm with stable hemodynamics.

[Treatment of superior lobe central lung cancer with lung replantation].

BACKGROUND: Patients suffering from lung cancer often have poor quality of life after pneumonectomy. It has clinical significances to preserve maximum lobes of the "healthy" lung. The aim of this study is to report the applications of lung replantation in treatment of superior lobe central lung cancer. METHODS: Three lung cancer cases were included and analysed. The bronchus and margin of lower lung lobe were encroached by cancer. Pulmonary artery was invaded and surrounded by metastatic lymph node. Complete pneumonectomy, antegrade perfusion and retroperfusion with low-potassium dextran (LPD) solution in vitro were performed. The retainable lower pulmonary lobe was selected from the isolated lung and superior pulmonary vein was replaced with inferior pulmonary veins. The bronchus and pulmonary artery were inosculated by turns. RESULTS: The operative cumulative time ranged from 220 min to 250 min. The isolated time of lobus inferior pulmonary ranged from 120 min to 150 min. The chest tube was pulled out after chest X-ray confirmed the reimplant lung full re-expansion. The patients were followed up for 4 months to 8 months and accomplished adjuvant chemotherapy for 3 or 4 periodicities. The patients had a sound quality of life. CONCLUSIONS: Lung replantation removing the extensive tumor tissue and retaining the maximum pulmonary normal tissue is an useful method for treatment of lung cancer.

Predonation of autologous blood reduces perioperative allogenic transfusion requirement in grown-up patients with congenital heart disease.

BACKGROUND: Adults with congenital heart diseases have a substantial risk for bleeding upon re-operations. Due to the detrimental effects of allogeneic blood transfusion, reduction of transfusion requirement is a major concern. To investigate the efficacy of autologous blood predonation (ABP), we focussed on a homogeneous subgroup of patients, with right ventricular outflow tract reconstruction. METHODS: Prospectively collected data included 76 patients older than 16 years with repeated right ventricular outflow tract reconstruction from May 1995 to November 2006. In 27 patients, ABP was performed without any complication. RESULTS: Primary diagnoses included Tetralogy of Fallot in 50 patients and others in 26 patients. All patients had at least one previous operation, 62% had more than one. All patients received a homograft conduit between the right ventricle and the pulmonary artery. Preoperative haemoglobin was 123+/-15 g l(-1) in patients with ABP and 134+/-22 g l(-1) in the remainder (p=0.037), but was not significantly different after cardiopulmonary bypass until discharge from the intensive care unit. Significantly more patients without ABP required transfusion of allogeneic packed red cells (PRCs) (26 of 49 patients (53%) vs 4 of 27 patients (15%), p=0.001) and allogeneic fresh frozen plasma (FFP) (30 of 49 patients (61%) vs 6 of 27 patients (22%), p=0.002) than patients with ABP. Of 27 patients, 23 (85%) and 25 (93%) with ABP received their predonated PRC and FFP, respectively. Logistic regression analysis identified no ABP (p=0.005, odds ratio (OR) 5.4, 95% confidence interval (CI) 1.7-17.7) and time on extracorporeal circulation >83 min (p=0.009, OR 5.0, 95% CI 1.5-16.8) to be predictive for allogeneic blood transfusion. CONCLUSION: ABP can be safely performed in grown-up patients with congenital heart disease without complications. Patients without predonation of autologous blood exhibit a fivefold increased risk for requiring allogeneic blood transfusion.

Postoperative management of pulmonary endarterectomy and outcome.

Pulmonary artery thromboendarterectomy (PTE) has been regarded as a promising, potentially curative surgical procedure. However, PTE is associated with specific postoperative complications, such as reperfusion pulmonary edema and right heart failure leading to a considerable mortality of 7-24%. Despite its limitations PTE is a better surgical alternative to lung transplantation which carries high morbidity and mortality. The aim of the study is to analyze the efficacy, safety, morbidity and survival associated in the postoperative period and quality of life after six months of PTE in Indian patients. Forty-one patients with surgically correctable chronic thromboembolic pulmonary hypertension underwent pulmonary endarterectomy. All patients were in New York Heart Association (NYHA) Class II, III or IV. Preoperative mean pulmonary artery pressure was 40.98 +/- 9.29 mmHg and mean pulmonary vascular resistance was 418.39 +/- 95.88 dynes/sec/cm(-5). All patients were followed up to six months and a telephonic survey was conducted using a standard questionnaire. They were assessed and classified as per NYHA grading. There was a significant reduction in the mean pulmonary artery pressure (from 40.98 +/- 9.29 mmHg to 24.13 +/- 7.36 mmHg, P < 0.001) and pulmonary vascular resistance (from 418.39 +/- 95.88 dynes/sec/cm(-5) to 142.45 +/- 36.27 dynes/sec/cm(-5), P < 0.001) with a concomitant increase in the cardiac index (from 1.99 +/- 0.20 L/min/m 2 to 3.28 +/- 0.56 L/min/m 2 , P < 0.001) during the postoperative period. The mortality rate in our study was 12.19% (five patients). Ninety per cent of the patients reported a significant improvement in the quality of life and exercise tolerance after surgery compared to the preoperative state. Pulmonary endarterectomy is an effective and potentially curative surgical treatment for patients with severe chronic thromboembolic pulmonary hypertension. The current techniques of operation make the procedure relatively safe and long-term survival, NYHA functional status and exercise capacity improve significantly.

Spatiotemporal organization of the left atrial substrate after circumferential pulmonary vein isolation of atrial fibrillation.

BACKGROUND: There is a paucity of data regarding the mechanism of maintaining atrial fibrillation (AF) after pulmonary vein isolation (PVI) in patients with AF. The aim of this study was to examine the impact of circumferential PVI on the left atrial (LA) substrate characteristics. METHODS AND RESULTS: Seventy-two AF patients (age, 53+/-11 years) underwent mapping and catheter ablation using an NavX system. The biatrial characteristics such as the complex fractionated atrial electrograms (CFEs; based on fractionated intervals) and frequency analysis (based on dominant frequencies) were mapped before and after PVI. PVI with electric isolation was performed in all patients. In the 45 patients who did not respond to PVI, the continuous CFEs (>8 seconds, 18+/-18% and 12+/-17% of the LA sites, before and after PVI, respectively, P=0.02), degree of LA fractionation (mean fractionated interval: 75.6+/-14.3 msec versus 87.3+/-16.7 msec, P=0.001), and mean LA dominant frequencies (6.92+/-0.88 Hz versus 6.58+/-0.91 Hz, P=0.001) decreased after PVI. Complete PVI altered the distribution of the CFEs toward the LA anteroseptum, mitral annulus, and LA appendage regions. A persistent presence of continuous CFEs in the vicinity of the dominant frequencies sites (observed in 53% patients) correlated with a higher procedural AF termination rate for the CFE ablation (63% versus 23%, P<0.05). CONCLUSIONS: Complete PVI eliminated some CFEs in the LA and altered the distribution of the CFEs. The persistent presence of CFEs before and after PVI in the vicinity of the high frequency sites is important for AF maintenance after PVI.

Supravalvular arrhythmia: identifying and ablating the substrate.

Supravalvar ablation has now been well documented to be the ideal mode for ablating specific forms of ventricular tachycardia, atrial tachycardia, and accessory pathways. A studied appreciation of the anatomy of the supravalvar region is a prerequisite for electrophysiologists to safely and effectively approach these arrhythmias. In addition, the consistent ability to correlate the recorded electrograms with fluoroscopic anatomy and intracardiac ultrasound images enhances the chance of successful elimination of supravalvar arrhythmias.

Mechanisms and utility of discrete great arterial potentials in the ablation of outflow tract ventricular arrhythmias.

BACKGROUND: Outflow tract ventricular tachycardia originating above the semilunar valves has been reported in a small number of studies. Discrete potentials in the great arteries (above the semilunar valves) have been rarely described in patients undergoing electrophysiology evaluation and radiofrequency ablation for ventricular arrhythmias. The mechanisms of these discrete potentials in the great arteries and the utility of such potentials in guiding radiofrequency ablation are unknown. METHODS AND RESULTS: Twelve patients with outflow tract ventricular arrhythmia originating above the semilunar valves with discrete arterial potentials were studied. The clinical characteristics, properties of the arterial potentials, electrophysiological evaluation and ablation, and short- and long-term outcomes were reviewed. Of the twelve patients, 8 (67%) were women. The patients' average age was 41+/-14 years. The average ejection fraction was 0.52+/-0.16 (range: 0.16 to 0.75). Contact mapping in the great artery demonstrated discrete near-field electrograms that were separate from far-field ventricular electrograms in all patients (8 above the pulmonary valve and in 4 the aortic valve). One or more of the following electrophysiological characteristics, supportive of an arrhythmogenic substrate, were observed in 10 of 12 patients: (1) A fixed or reproducibly variable pattern of discrete potential-ventricular arrhythmia relationship was present at baseline or during pacing; (2) the discrete potential-ventricular electrogram relationship during sinus rhythm was the reverse of that during the ventricular arrhythmia; (3) during sustained ventricular tachycardia, spontaneous variation of the ventricular (V-V) cycle length was preceded by a similar variation of arterial spike potential-spike potential cycle length; and (4) ablation guided by the discrete arterial potential successfully eliminated the clinical arrhythmia. Ablation was successful in these patients. In the remaining 2 patients, the potentials were believed to be bystanders. Over 10+/-4 months (range: 5 to 32 months) of follow-up, there have been no recurrences of the premature ventricular complex or ventricular arrhythmia. CONCLUSIONS: Discrete potentials are present in the great arteries of a select group of patients with outflow tract ventricular tachycardia originating above the semilunar valves. When an arrhythmogenic relationship can be demonstrated, discrete potentials are useful in guiding ablation within the great vessels, despite significant anatomic complexity.

Long-term palliation of tetralogy of Fallot in dogs by use of a modified Blalock-Taussig shunt.

OBJECTIVE: To describe a modified Blalock-Taussig shunt (mBT) procedure and assess its use in dogs with clinical signs associated with tetralogy of Fallot (TOF). DESIGN: Descriptive report. ANIMALS: 6 dogs with severe TOF-associated clinical signs. PROCEDURES: Each dog had TOF (confirmed echocardiographically or angiographically) and underwent an mBT shunt procedure for surgical palliation of signs. The surgery was performed through a left fourth rib resection or a left fifth intercostal thoracotomy. The left subclavian artery was dissected free from surrounding mediastinal tissue. The main pulmonary artery trunk was exposed through an incision in the overlying pericardium. A shunt comprised of a 6-mm-diameter tube of expanded polytetrafluoroethylene (5 dogs) or a segment of carotid artery (1 dog) was sutured end to side between the left subclavian artery and pulmonary artery trunk. RESULTS: 5 of the 6 dogs survived the immediate postoperative period. The dog that died shortly after surgery was the smallest of the dogs (weight, 2.9 kg [6.38 lb]) and had received the carotid artery autograft. Three dogs survived long term and 2 dogs died of unknown causes 6 years after undergoing the mBT shunt procedure. In all dogs that survived the mBT procedure, shunt patency was confirmed and quality of life appeared improved. CONCLUSIONS AND CLINICAL RELEVANCE: These findings have suggested that the mBT shunt procedure safely provides long-term palliation of TOF-associated clinical signs in dogs. In addition, it may offer an effective low-risk and lower-cost alternative to open heart repair of TOF.

Persistence of bilateral arterial ducts in pulmonary atresia despite confluent branch pulmonary arteries: opportunity for two percutaneous therapeutic alternatives.

We present a case of a newborn infant with double inlet left ventricle, pulmonary atresia, confluent pulmonary arteries, and bilateral arterial ducts (AD), to discuss the therapeutic alternatives offered by interventional catheterization techniques in this anatomic arrangement. The infant initially underwent stenting of the right AD to stabilize pulmonary blood flow off of prostaglandin infusion. Three weeks later, she developed left pulmonary artery isolation upon closure of the left arterial duct. An additional stent was placed in the pulmonary artery confluence, restoring blood flow to the left lung and significantly improving her oxygen saturations. At 6 months of age she underwent her first surgical procedure, a successful bidirectional cavopulmonary anastomosis with removal of the left pulmonary artery stent and patch enlargement of the pulmonary artery confluence. She continues to do well in clinical follow-up at 16 months of age.

Electrocardiographic and electrophysiologic characteristics of ventricular tachycardia originating within the pulmonary artery.

OBJECTIVES: We investigated the electrocardiographic (ECG) and electrophysiologic characteristics of ventricular tachycardia (VT) originating within the pulmonary artery (PA). BACKGROUND: Radiofrequency catheter ablation (RFCA) is routinely applied to the endocardial surface of the right ventricular outflow tract (RVOT) in patients with idiopathic VT of left bundle branch block morphology. It was recently reported that this arrhythmia may originate within the PA. METHODS: Activation mapping and ECG analysis were performed in 24 patients whose VTs or ventricular premature contractions (VPCs) were successfully ablated within the PA (PA group) and in 48 patients whose VTs or VPCs were successfully ablated from the endocardial surface of the RVOT (RV-end-OT group). RESULTS: R-wave amplitudes on inferior ECG leads, aVL/aVR ratio of Q-wave amplitude, and R/S ratio on lead V(2) were significantly larger in the PA group than in the RV-end-OT group. On intracardiac electrograms, atrial potentials were more frequently recorded in the PA group than in the RV-end-OT group (58% vs. 12%; p < 0.01). The amplitude of local ventricular potentials recorded during sinus rhythm within the PA was significantly lower than that recorded from the RV-end-OT (0.62 +/- 0.56 mV vs. 1.55 +/- 0.88 mV; p < 0.01). CONCLUSIONS: Ventricular tachycardia originating within the PA has different electrocardiographic and electrophysiologic characteristics from that originating from the RV-end-OT. When mapping the RVOT area, the catheter may be located within the PA if a low-voltage atrial or local ventricular potential of <1-mV amplitude is recorded. Heightened attention must be paid if RFCA is required within the PA.

Moderate and chronic hemodynamic overload of sheep atria induces reversible cellular electrophysiologic abnormalities and atrial vulnerability.

OBJECTIVES: The aim of this study was to evaluate the myocardial consequences of a chronic volume overload of the left atrium (LA). BACKGROUND: Atrial dilation is a major risk factor for atrial fibrillation (AF), but the underlying mechanisms are poorly understood. METHODS: A left-right aorto-pulmonary artery shunt (APS) was created in sheep. The cardiopathy was characterized by echocardiography, electrophysiologic testing, and histologic analysis. Cellular action potential (AP) and calcium current (I(Ca)) were recorded by means of microelectrode and patch clamp techniques. RESULTS: Three to four months after surgery, all animals in the APS state had a dilated LA (146.2 +/- 35.4 cm(2)/m(2) vs. 91.7 +/- 10.4 cm(2)/m(2) in the control state; p = 0.0024) but remained in sinus rhythm. Repetitive atrial firing was triggered by a single extra beat in five of six animals in the APS state and in two of six animals in the control state. Moreover, in two animals in the APS state, a single extra beat triggered sustained AF. Myocytes were enlarged and 39.8% showed some degree of myolysis. In animals in the APS state, the AP had no plateau phase or small amplitude and numerous myocytes were unexcitable. The I(Ca) density was 45.2% lower in APS animals than in control animals. Beta-adrenergic stimulation normalized I(Ca) and restored the plateau phase of the AP. After shunt suppression, the electrophysiologic properties of the atria returned to normal. CONCLUSIONS: The APS induced moderate, isolated LA dilation, which was sufficient to cause major changes in cellular electrophysiologic properties and to render the atria vulnerable to fibrillation. These effects were reversed by shunt suppression.