Pregnancy in women with Fontan physiology

Advances in the care of patients with a univentricular heart have enabled the majority to survive well into adulthood. Consequently, an increasing number of women with Fontan palliation are contemplating pregnancy. This review summarizes physiologic modifications related to pregnancy in the setting of single-ventricle physiology, discusses potential maternal cardiovascular concerns and describes commonly encountered obstetrical and neonatal complications. Management issues are addressed, including counseling, anesthetic considerations and the need for multidisciplinary specialized care.     

Syncope--an unusual presentation of ventricle dysfunction in a patient with Fontan circulation

We report a case of recurrent syncope in association with moderate ventricular dysfunction and mild AV-valve regurgitation in an 18-year-old girl, 4 years after she underwent total cavopulmonary connection surgery. Cardiac catheterization revealed a transpulmonary gradient of 1-2 mmHg. During exercise, a dramatic fall in blood pressure and blood oxygenation was observed, paralleled by an increase in heart rate and central venous pressure. Although a slight increase in pulmonary vascular resistance could not be excluded, the reaction was interpreted in terms of an extremely low transpulmonary gradient in association with ventricular dysfunction. Five months after heart transplantation, the patient has been completely free from syncope. Fontan circulation usually involves a delicate haemodynamic situation which may necessitate haemodynamic re-evaluations, including dynamic measurements of the central venous pressure during exercise. Also a moderate ventricular dysfunction may result in compromised pulmonary circulation which in turn may lead to syncope during exercise as a result of insufficient systemic circulation.     

Permanent Pacing in Patients with Univentricular Heart

Patients with one of several varieties of malformation designated as "univentricular hearts" may be especially challenging when permanent pacing is required. Our objective was to review our experience in this subset of patients that had undergone permanent pacing and thus determine the optimal approach. A retrospective chart review was done of 32 patients with some variety of "univentricular" malformation who had required permanent pacing at our institution. Although technically challenging, permanent pacing in this group of patients can be successful through several approaches. The various approaches, as well as consideration of the differences that exist between patients undergoing septation and those undergoing a Fontan procedure are discussed. Although long-term permanent pacing is possible in this group of patients, before pacing begins, a thorough understanding of the anatomy and prior surgical procedures is necessary. Use of a combined atrial transvenous and ventricular epicardial pacing system may work well for some patients. With the development of newer and more reliable coronary sinus leads, dual chamber transvenous pacing with ventricular stimulation via the coronary sinus could become the approach of choice in some patients with "univentricular hearts."     

A new method to quantify postexercise ST‐deviation – the ST‐deficit. A study in men at high and low‐risk for coronary heart disease

Background Quantitative heart rate adjusted exercise ST criteria like μV/beats per minute (bpm) improve the diagnostic accuracy of the exercise ECG. However, there are few quantitative HR adjusted postexercise variables available. The aim of the present exercise study was to evaluate a new such variable from computerized averaging of the postexercise ECG. Methods The presence of possible myocardial ischaemia in a population based sample of 74 elderly male hypertensives at high‐risk of coronary heart disease, and in 42 age‐matched clinically healthy males (reference group) at low‐risk was assessed by exercise ECG. All men had a normal resting ECG without signs of ischaemia. Variables studied: standard ST‐criteria, ST/HR slope ≤–2·4 μV · bpm^–1, shape of the rate‐recovery loop, the latter also with a new quantitative variable, the ST‐deficit. Results In spite of a normal resting ECG many subjects showed an abnormal ST/HR slope during exercise, 43% in the hypertension group and 26% in the reference group. An abnormal rate‐recovery loop (ST‐deficit) also contributed substantially to identify patients with possible myocardial ischaemia, 30 vs. 10%, respectively (P<0·02); cumulatively for the two HR adjusted criteria 53% vs. 29%, respectively (P<0·02). Mean ST‐deficit was significantly lower in the high‐risk group. Conclusions Effort‐related myocardial ischaemia is frequently silent in elderly high‐risk hypertensives and necessitates testing, preferably with computerized exercise ECG and heart rate adjusted ST criteria. A new quantitative variable to assess the postexercise rate‐recovery loop in the time domain, the ST‐deficit is described. This variable seems to effectively discriminate between subjects with low and high‐risk for coronary heart disease and thus provides new information. Further studies are warranted to validate this variable against myocardial perfusion scintigraphy and coronary angiography.     

Transvenous Atrial Pacing in the Management of Sick Sinus Syndrome Following Surgical Treatment of the Univentricular Heart: Case Report and Review

An 11-year-old boy with univentricular heart type A-III underwent surgical treatment at age 10 with a modified Fontan operation. Six months postoperatively he developed intermittent periods of cyanosis and fatigue associated with profound sinus bradycardia and nodal escape. After demonstrating normal atrioventricular conduction, a transvenous atrial pacemaker was implanted. This produced a marked clinical improvement. Transvenous atrial pacing is a satisfactory method of treating sinus node dysfunction in patients with univentricular heart following the Fontan operation provided that there is normal AV conduction.     

Catheter ablation for atrial fibrillation and intervention for pulmonary vein stenosis in a patient with Fontan circulation

Incidence of atrial fibrillation (AF) is high in patients with congenial heart disease. However, management of AF is challenging in these patients. Although radiofrequency catheter ablation (RFCA) is effective therapeutic option for AF, RFCA for AF is not common in patients who underwent Fontan operation. We present a 24‐year‐old woman with paroxysmal AF, who underwent lateral tunnel Fontan operation for functional single ventricle. Circumferential pulmonary vein isolation was successfully performed. However, significant pulmonary vein stenosis developed after RFCA. Pulmonary vein stenosis was successfully treated by transcatheter intervention.     

急性下壁心肌梗塞时心前导联心电图ST段压低的临床意义

为评价急性下壁心肌梗塞(AIMI)时心前导联ST段压低的意义,对43例心电图示透壁急性心肌梗塞患者进行了研究。其中,31例有心前导联ST段压低(甲组),12例无心前导联ST段压低(乙组),两组临床表现无差异。研究结果表明,甲组患者血清酶平均峰值显著升高且左室衰竭的发生率升高;甲组室性心律紊乱、心肌再梗塞、心源性休克和房室传导阻滞的发生率亦显著高于乙组(P>0.01～0.05)。本研究资料提示,AIMI时心前导联ST段压低可能与广泛性心肌缺血和危重并发症的发生率高有关,从而认为,可将之用来预测AIMI的临床严重程度,治疗效果和预后。     

急性心肌梗死时心电图对应导联ST段压低的临床价值分析

目的 探讨急性心肌梗死（AMI）伴或不伴ST段压低（STD）临床意义.方法 纳入2009年9月到2012年9月AMI患者65例,其中AMI伴STD患者（STD组）29例,不伴STD患者（NSTD组）36例.分析两组患者冠脉受累支数、心肌损伤标志物水平及体内炎症水平差异.结果 STD组患者更多罹患冠脉多支病变;AMI伴STD患者心肌损伤标志物水平较NSTD患者高;同时,AMI伴STD患者红细胞沉降率（ESR）及C反应蛋白（CRP）水平均较NSTD患者为高.结论 AMI伴STD发生率高,可能提示更严重心肌病变及更强烈炎症反应.     

急性心肌梗塞早期和持续的心电图ST段对应改变的意义及与心功能的关系

分析104例急性心肌梗塞患者胸痛发作24h内心电图ST段对应性变化及与心功能的关系。发现:44/66例单一部位、8/29例复合部位梗塞和1/9例梗塞原位扩展者心电图有对应ST段改变;有或无对应改变者之间心功能无显著差异,而单一和复合梗塞者之间心功能变化有显著差异;33/51例无对应ST段改变者可找出使ST向量无变化的原因;26例急性下壁梗塞其前壁ST段压低可延伸至V(5～6)导联且发病72h后仍不回复至基线;单纯下壁梗塞者V_(1～4)ST段下降总和与下壁加正后壁者V_(1～4)ST段下降总和之间有显著差异。作者认为:急性心肌梗塞时ST段对应改变系心电向量力变化所致。唯一影响心功能因素是梗塞面积。动态监测ST段对应改变的过程对估计病情和判断预后均极有意义。     

Pulmonary and caval blood flow patterns in patients with intracardiac and extracardiac Fontan: a magnetic resonance study

Summary Aims We compared in vivo blood flow and pulsatility after different types of Fontan operation using magnetic resonance imaging. Material and methods A total of 37 consecutive patients (mean age 19±7.9 years, 7.3±3.2 years after Fontan operation), 7 with atriopulmonary anastomosis (APC), 18 with intra-atrial lateral tunnel (LTFO) and 12 with extracardiac Fontan (ECFO) were studied using magnetic resonance phase-contrast velocity mapping. Blood flow (volume flow) in the superior vena cava (SVC), inferior vena cava (IVC) and both pulmonary arteries were measured and a pulsatility index was calculated for each vessel. Results For all modifications, the blood flow distribution between the SVC and IVC was normal (1 : 2). Patients with APC had a normal pulsatility, a dilated right atrium, partial backward flow in the IVC and physiological blood flow distribution between the pulmonary arteries. LTFO and ECFO patients had no retrograde flow in the IVC, equal blood flow distribution between the pulmonary arteries and very low or absent pulsatility. Conclusions MRI allows hemodynamic quantification and characterization of various types of Fontan modifications and may be a valuable tool to predict Fontan failure. Despite showing normal pulsatility, patients with APC have right atrial dilatation and partial backward flow in the IVC, demonstrating suboptimal Fontan circulation. LTFO and ECFO both produce unidirectional antegrade flow in the IVC but pulsatility is very low or absent, which may promote poor pulmonary artery growth and increase of pulmonary vascular resistance contributing to late Fontan failure.     

运动中ST段下移程度不同的心肌梗死后患者的心血管反应

目的：对运动中ST段下移程度不同的心梗后患者（PMIP）的心血管反应进行探讨。方法：46名男性PMIP在跑台上进行递增负荷运动实验．其间测量每级负荷时的血压、心率并连续监测12导联心电图（ECG）。根据跑台第Ⅱ级负荷时的ST段下移程度将其分为两组．第一组ST段下移〈1．0mm．第二组ST段下移〉1．0mm。结果：定量负荷工作时ST段下移程度大的患者其心率-血压乘积（RPP）也高。结论：当不便进行ECG监测时．RPP可能是评价患者对运动的临床反应的特效指标。     

New Electrocardiographic Changes in Patients Diagnosed with Pulmonary Embolism

Background

The electronic medical record is a relatively new technology that allows quick review of patients' previous medical records, including previous electrocardiograms (ECGs). Previous studies have evaluated ECG patterns predictive of pulmonary embolism (PE) at the time of PE diagnosis, though none have examined ECG changes in these patients when compared with their previous ECGs.

Transvenous shock‐only implantable cardioverter defibrillator after an atrio‐pulmonary Fontan surgery

A 42‐year‐old woman with tricuspid atresia who underwent a Fontan surgery (atrio‐pulmonary connection) was admitted to our hospital due to symptomatic ventricular tachycardia (VT). A defibrillation lead was implanted in a distal site of a coronary vein since there was no usual entry to the ventricle. Ventricular pacing was impossible due to the high threshold, however, good sensing was obtained. Three years later, she felt palpitations and a subsequent shock therapy while climbing stairs. The cardioverter data showed that an appropriate cardioversion therapy successfully converted VT to normal rhythm.