Diagnosis of anthracycline-induced late cardiomyopathy by exercise-spiroergometry and stress-echocardiography

Anthracyclines are used in the therapy of several of the most common paediatric oncological disorders. The usefulness of these agents is limited by cardiotoxicity, with congestive heart failure developing in up to 20% of patients. To stratify possible risk factors, we investigated 38 children with acute lymphoblastic leukaemia for signs of late cardiomyopathy. Exercise-spiroergometry and stress-echocardiography with measurement of fractional shortening (FS) and ejection fraction (EF) as indicators of left ventricular function were performed. ECG, 24 h Holter monitoring, chest X-ray, virus serology and carnitine were analysed. Control subjects were 38 healthy children matched for age and body surface area. All 38 patients had normal echocardiographic findings at rest (EF: 0.73 +/- 0.06; FS: 0.35 +/- 0.05). ten patients had a significant attenuation of left ventricular function after exercise assessed by stress-echocardiography compared to the remaining 28 patients and 38 healthy control subjects (EF: 0.52 +/- 0.08 versus 0.77 +/- 0.06 and 0.80 +/- 0.08; FS: 0.29 +/- 0.06 versus 0.39 +/- 0.05 and 0.41 +/- 0.02); patients with reduced ventricular function after exercise had significant low anaerobic threshold, subnormal maximal oxygen uptake and decreased carnitine levels. The findings were not related to the dosage of administered doxorubicin. There exists no correlation between ECG, 24 h ECG, chest X-ray, virology and left ventricular dysfunction. The benefit of angiotensin converting enzyme inhibitors and the administration of carnitine remains speculative. Conclusion: exercise-spiroergometry and stress-echocardiography are sensitive investigations for diagnosing subclinical cardiomyopathy late after completion of chemotherapy. Investigative findings of cardiomyopathy are not dose related and may provide information for therapeutic prevention before clinical symptoms of cardiomyopathy appear.     

Late cardiotoxicity after treatment for a malignant bone tumor

Cardiac function was assessed in long-term survivors of malignant bone tumors who were treated according to Rosen's T₅ or T₁₀ protocol, both including doxorubicin. Thirty-one patients, ages 10–45 years (median age 17.8 years) were evaluated 2.3–14.1 years (median 8.9 years) following completion of treatment. Cumulative doses of doxorubicin were 225–550 mg/m² (median dose 360). The evaluation consisted of a history, physical examination, electrocardiogram (ECG), signal averaged ECG, 24-hour ambulatory ECG, echocardiography and radionuclide angiography. Eighteen of 31 (58%) patients showed cardiac toxicity, defined as having one or more of the following abnormalities: late potentials, complex ventricular arrhythmias, left ventricular dilatation, decreased shortening fraction, or decreased ejection fraction. The incidence of cardiac abnormalities increased with length of follow-up (P ≤ .05). No correlation could be demonstrated between cumulative dose of doxorubicin and cardiac status, except for heart rate variability. When adjusted to body surface area, the left ventricular posterior wall thickness (LVPW index) was decreased in all patients. The incidence of doxorubicin-induced cardiotoxicity is high and increases with follow-up, irrespective of cumulative dose. Life-long cardiac follow-up in these patients is warranted. The results of our study suggest that heart rate variability and LVPW index could be sensitive indicators for cardiotoxicity. © 1996 Wiley-Liss, Inc.     

Signal-Averaged Electrocardiography in Children with Anthracycline-Induced Cardiomyopathy

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

Cardiomyopathy of Duchenne muscular dystrophy

Summary A total of 18 male patients with Duchenne muscular dystrophy (DMD), aged 8–29 years (mean, 15.7 years), were prospectively studied to assess the cardiomyopathy associated with DMD, using clinical parameters and noninvasive cardiovascular investigations: electrocardiogram (ECG), Holter monitoring, and echocardiography. In addition, five clinical tests of cardiovascular autonomic function were used to assess the role of the autonomic nervous system in the pathogenesis of dysrhythmias.The majority of subjects were asymptomatic, but four had abnormal physical findings. All had abnormal ECG, the commonest abnormality (in 16) being tall R waves or increased R/S ratios in the right precordial leads; 14 had abnormal findings on echocardiography, including three with poor left ventricular function and five with mitral valve prolapse (MVP). Labile abrupt sinus tachycardia was present in 11, and four had high-grade ventricular ectopy. None had definite clinical evidence of autonomic dysfunction.The cardiomyopathy of DMD appears to be unrelated to disease severity. However, abnormal Q waves or Q/R ratios in ECG leads I, a V_L, and V₅–V₆ are significantly related to young age (p<0.05), and high-grade ventricular ectopy occurred significantly more frequently (p<0.05) in older subjects (>15 years). Dysrhythmias were not related to the presence of MVP, poor left ventricular function, or autonomic dysfunction.     

Electrocardiographic signs of hypertrophy in fabry disease-associated hypertrophic cardiomyopathy

AIMS: Fabry disease results from deficient activity of the lysosomal enzyme alpha-galactosidase A. Progressive accumulation of the major substrates leads, in both men and women, to progressive hypertrophic cardiomyopathy. We aimed to evaluate the utility of different electrocardiographic (ECG) parameters for assessing the degree and severity of hypertrophic cardiomyopathy in patients with Fabry disease. METHODS: A total of 166 ECGs of 94 hemi- and heterozygous patients with Fabry disease were analysed and compared with echocardiographic-estimated left ventricular mass (LVM). RESULTS: There was a significant (p < 0.0001) correlation between QRS duration (R2 = 0.59), 12-lead amplitude/duration product (R2 = 0.61), Sokolow-Lyon voltage/duration product (R2 = 0.52) and LVM. Analysis of receiver operating characteristics revealed that the 12-lead amplitude/duration product had the highest sensitivity-specificity relationship (p < 0.01 compared with the Cornell index). CONCLUSION: In general, ECG signs of left ventricular hypertrophy correlated well with LVM as revealed by echocardiography. Of the parameters studied, the 12-lead amplitude/duration product was the most successful at describing the severity of cardiac involvement in Fabry disease. These data suggest that ECG parameters have potential for use as a simple and cost-effective means of screening for hypertrophic cardiomyopathy in patients with Fabry disease.     

Electrocardiographic signs of hypertrophy in Fabry disease-associated hypertrophic cardiomyopathy

Aims : Fabry disease results from deficient activity of the lysosomal enzyme α-galactosidase A. Progressive accumulation of the major substrates leads, in both men and women, to progressive hypertrophic cardiomyopathy. We aimed to evaluate the utility of different electrocardiographic (ECG) parameters for assessing the degree and severity of hypertrophic cardiomyopathy in patients with Fabry disease. Methods : A total of 166 ECGs of 94 hemi- and heterozygous patients with Fabry disease were analysed and compared with echocardiographic-estimated left ventricular mass (LVM). Results : There was a significant ( p > 0.0001) correlation between QRS duration (R²= 0.59), 12-lead amplitude/duration product (R²= 0.61), Sokolow-Lyon voltage/duration product (R²= 0.52) and LVM. Analysis of receiver operating characteristics revealed that the 12-lead amplitude/duration product had the highest sensitivity-specificity relationship ( p > 0.01 compared with the Cornell index).
Conclusion : In general, ECG signs of left ventricular hypertrophy correlated well with LVM as revealed by echocardiography. Of the parameters studied, the 12-lead amplitude/duration product was the most successful at describing the severity of cardiac involvement in Fabry disease. These data suggest that ECG parameters have potential for use as a simple and cost-effective means of screening for hypertrophic cardiomyopathy in patients with Fabry disease.     

慢性心力衰竭患儿血清卵泡抑素样蛋白1的变化及临床意义

目的 探讨卵泡抑素样蛋白1(FSTL1)在慢性心力衰竭(CHF)患儿血清中的变化及与左心室重构的相关性。方法 选取2014年5月至2015年5月CHF患儿45例为心衰组,其中心内膜弹力纤维增生症21例,扩张型心肌病24例;另选取门诊健康儿童30例为健康对照组。采用酶联免疫吸附法测定血清FSTL1水平;采用放射免疫分析法测定氨基末端脑利钠肽前体;超声心动图测定左心室重构指标;Pearson相关或Spearman秩相关分析血清FSTL1与左心室重构指标的相关性。结果 心衰组治疗前血清FSTL1水平高于健康对照组(PPP=0.176)。血清FSTL1与左心室舒张末径(r=0.485,P=0.001)、左心室质量(r=0.322,P=0.031)、左心室质量分数(r=0.353,P=0.017)、氨基末端脑利钠肽前体(r=0.562,Pr=-0.436,P=0.003)、左室短轴缩短率(r=-0.436,P=0.003)呈负相关。结论 FSTL1可能参与CHF患儿左心室重构,血清FSTL1可以作为儿童CHF临床诊断、病情评估的客观指标之一。     

Distinguishing Cardiac Features of a Novel Form of Congenital Muscular Dystrophy (Salih CMD)

The cardiac features of a novel form of congenital muscular dystrophy (Salih CMD) are described in two adolescent siblings. The patients presented with severe hypotonia at birth, associated with delayed development. They could walk independently and managed to maintain walking after 13 years of age. Their muscle immunohistochemistry differed from that seen in Duchenne and Becher muscular dystrophy (DMD and BMD), severe childhood autosomal recessive muscular dystrophy (SCARMD) due to sarcoglycan deficiency (sarcoglycanopathies), and lamininα2 (merosin)-deficient CMD. However, both patients had associated cardiomyopathy. Electrocardiography (ECG) in Salih CMD was characterized by delayed atrioventricular (AV) conduction, left anterior fascicular block (left axis deviation), and left atrial enlargement without evidence of atrial dysarrhythmia. Echocardiography showed features of severe left ventricular dysfunction with estimated left ventricle ejection fraction (LVEF) of 25% at 16 years-of-age in the older patient. A year later, multigated aquisition MUGA scan showed LVEF of 21% and dilatation of the right ventricle. Echocardiography and MUGA scan were normal in the younger patient at 15 years-of-age. ECG, echocardiography, and MUGA scan are effective techniques for diagnosing and monitoring the cardiomyopathy in Salih CMD. They can also distinguish it from features seen in the other common forms of MD, including DMD, BMD, and sarcoglycanopathies.     

Isolated cardiac manifestations in Fabry disease: the UK experience

Cardiac abnormalities are common in patients with Fabry disease, and may be the only clinical manifestation of the disease in some patients. At St George's Hospital Medical School, a national referral centre for hypertrophic cardiomyopathy in the UK, a study of 153 consecutively referred male patients revealed that 4% had Fabry disease. This increased to 6% in patients over 40 years of age. All these patients had electrocardiographic (ECG) abnormalities, most of which were consistent with those found in patients with classic Fabry disease: left ventricular hypertrophy, repolarization abnormalities and a prolonged QRS complex. A study of heterozygote females with Fabry disease also showed ECG and echocardiographic abnormalities in most patients. CONCLUSIONS: Fabry disease should be considered in the differential diagnosis of otherwise unexplained cardiac disease.     

伴有左心室扩大的儿童肥厚型心肌病临床特征及预后

目的 总结伴有左心室扩大的儿童肥厚型心肌病(HCM)的临床特征及预后.方法 回顾分析2008年7月至2020年3月住院HCM患儿的临床资料,随访至2020年4月.根据首次住院超声心动图左心室舒张末期内径(LVEDD)-Z值,将患儿分为左心室扩大组(LVEDD-Z>2)和对照组(LVEDD-Z≤2),比较两组临床特征及预...     

Isolated cardiac manifestations in Fabry disease: the UK experience

Cardiac abnormalities are common in patients with Fabry disease, and may be the only clinical manifestation of the disease in some patients. At St George's Hospital Medical School, a national referral centre for hypertrophic cardiomyopathy in the UK, a study of 153 consecutively referred male patients revealed that 4% had Fabry disease. This increased to 6% in patients over 40 years of age. All these patients had electrocardiographic (ECG) abnormalities, most of which were consistent with those found in patients with classic Fabry disease: left ventricular hypertrophy, repolarization abnormalities and a prolonged QRS complex. A study of heterozygote females with Fabry disease also showed ECG and echocardiographic abnormalities in most patients.
Conclusions : Fabry disease should be considered in the differential diagnosis of otherwise unexplained cardiac disease.     

血清嗜铬粒蛋白A、尾加压素Ⅱ在小儿慢性心力衰竭中的变化及意义

目的探讨嗜铬粒蛋白A(CgA)、尾加压素Ⅱ(UⅡ)在慢性心力衰竭(CHF)患儿血清中的变化及意义。方法选取58例CHF患儿为心衰组,其中心内膜弹力纤维增生症17例,扩张型心肌病41例;另选取门诊健康体检儿童20例为对照组。采用酶联免疫吸附法(ELISA法)测定血清CgA及UⅡ水平;采用双向侧流免疫法测定氨基末端脑钠肽前体(NT-proBNP)水平;超声心动图测定心室重塑指标;Pearson相关或Spearman秩相关分析血清CgA、UⅡ与心室重塑的相关性。结果心功能Ⅱ级患儿的血清CgA、NT-proBNP水平与对照组的差异无统计学意义(P0.05);CgA、NT-proBNP水平在心功能Ⅲ级、Ⅳ级患儿中高于对照组,并且随着心功能损害加重而升高(P0.05)。UⅡ浓度在心功能Ⅱ级、Ⅲ级、Ⅳ级患儿中均低于对照组,并且随着心功能损害加重而逐渐降低,差异有统计学意义(P0.05)。心内膜弹力纤维增生症与扩张型心肌病患儿间血清CgA、UⅡ水平的差异无统计学意义(P0.05)。血清CgA浓度分别与左心室质量分数(LVMI)、NT-proBNP、心功能分级成正相关(r分别为0.279、0.649及0.778,P0.05),与左室射血分数(LVEF)、左室短轴缩短率(LVFS)、UⅡ成负相关(r分别为-0.369、-0.322及-0.718,P0.05)。血清UⅡ分别与NT-proBNP、心功能分级成负相关(r=-0.472、-0.591,P0.05),而与LVMI、LVEF、LVFS无明显相关性(P0.05)。结论 CgA可能参与CHF患儿心室重塑,血清CgA和UⅡ有可能为心衰的诊断和心功能判断提供参考。     

Endocardial fibroelastosis with coronary artery thromboembolus and myocardial infarction

We report a case of an 18-month-old male, born to a woman with third trimester febrile illness, who had a history of congestive heart failure and respiratory distress, cardiomegaly, and electrocardiographic (ECG) findings suggestive of cardiomyopathy and myocarditis. After gradual improvement in heart size and function with pharmacologic therapy, he developed a terminal episode of respiratory distress and cardiogenic shock, with ECG findings of an anterolateral infarct. At autopsy it was found that endocardial fibroelastosis with mural thrombi in the left ventricle had been complicated by thromboembolism to the left anterior descending coronary artery, resulting in transmural infarction of the anteroseptal region of the left ventricle. Myocardial infarction is a potential but unusual thromboembolic complication of endocardial fibroelastosis. A high index of suspicion for coronary artery thromboemboli should be maintained in pediatric patients with cardiomyopathy and suspected myocardial infarction.     

慢性心力衰竭患儿血清半乳糖凝集素-3变化及临床意义

目的探讨慢性心力衰竭(CHF)患儿血清半乳糖凝集素-3(galectin-3)变化及其与左心室重构的相关性。方法选取CHF患儿45例,按心衰严重程度分为心功能Ⅱ级组、Ⅲ级组和Ⅳ级组;按原发疾病分为心内膜弹力纤维增生症(EFE)组和扩张型心肌病(DCM)组;30例健康体检儿童为对照组。采用酶联免疫吸附法(ELISA)测定血清galectin-3水平,放射免疫分析法测定NT-pro BNP,超声心动图测定左心室重构指标。分析血清galectin-3与左心室重构和NT-pro BNP的相关性。结果 45例CHF患儿中,男19例、女26例,年龄(3.42±1.89)岁。心功能Ⅱ级组10例,Ⅲ级组18例和Ⅳ级组17例;EFE组21例,DCM组24例。心功能Ⅱ级、Ⅲ级、Ⅳ级组患儿的血清galectin-3及NT-pro BNP水平均高于对照组,差异有统计学意义(P均0.05),不同心功能分级组两两比较差异均有统计学意义(P?0.05)。EFE和DCM两组间血清galectin-3水平差异无统计学意义(P?0.05)。Spearman秩相关分析结果显示,CHF患儿的血清galectin-3水平与左心室舒张末径、左心质量、左心质量分数及血清NT-pro BNP水平呈正相关(P均0.05),与左室射血分数、左室短轴缩短率均呈负相关(P均0.05)。结论血清galectin-3有助于对儿童CHF的临床诊断和病情评估。     

Anthracycline—Induced Congestive Heart Failure in two Pediatric Leukemia Cases and Long Term Follow—Up

Endomyocardial biopsy was performed on two leukemia patients who had recovered from severe congestive heart failure (CHF) due to anthracycline cardiomyopathy at 41 months and 47 months after CHF. Microscopic myocardial findings in both patients revealed that myocytes were hypertrophic, but interstitial fibrosis was not observed, suggesting a compensatory mechanism for the damaged heart muscle during the acute episode of CHF. The improvement of clinical symptoms and the normalization of cardiac function, including fractional shortening and ECG changes, is thought to have been associated with this myocardial repairing process.     

Reliability of Left Ventricular Hypertrophy by ECG Criteria in Children with Syncope: Do the Criteria Need to be Revised?

In the outpatient setting, children who present with syncope routinely undergo electrocardiograms (ECG). Because of concerns for hypertrophic cardiomyopathy, children with syncope meeting ECG criteria for left ventricular hypertrophy (LVH) will frequently undergo an echocardiogram. Our objectives were to determine whether Davignon criteria for ECG waves overestimate LVH in children presenting with syncope, and to study the usefulness of echocardiography in these children. We hypothesize that the Davignon criteria presently used for interpretation of ECGs overestimate LVH, resulting in unnecessary echocardiography in this clinical setting. The clinical database of The Children’s Hospital of Philadelphia was evaluated from 2002 to 2012 to identify children between 9 and 16 years of age, who presented with non-exercise-induced, isolated syncope. From this group of patients, only those with clear-cut evidence of LVH (by Davignon criteria), who also underwent an echocardiogram, were selected. A total of 136 children with syncope were identified as having LVH by Davignon ECG criteria. None of these patients manifested any evidence of hypertrophic cardiomyopathy, with normal ventricular septum (average Z-score ?0.68 ± 0.84), LV posterior wall (average Z-score ?0.66 ± 1.18) and LV mass (average Z-score 0.52 ± 1.29). No significant correlation was found between summed RV6 plus SV1 and LV mass. Correlations between additional ECG parameters and measures of LVH by echocardiography were similarly poor. In children presenting with syncope and LVH by ECG, there was no evidence of true LVH by echocardiography. We propose that the Davignon ECG criteria for interpreting LVH in children overestimate the degree of hypertrophy in these children and the yield of echocardiography is extremely low.     

儿童肥厚型心肌病临床分析

目的探讨儿童肥厚型心肌病的临床特点、诊治方法及预后。方法对2000年10月至2013年9月在北京儿童医院确诊为肥厚型心肌病的25例患儿的临床表现、实验室检查、治疗方法及预后进行回顾性分析。结果肥厚型心肌病以年长儿童多见,平均年龄8岁9个月,男女比例3．1：1。临床表现：气促乏力5例,胸闷长出气4例,心前区不适3例,因咳喘就诊发现心脏异常5例,无症状发现心脏杂音来诊治8例,伴晕厥发作2例,6例有明确的肥厚型心肌病家族史,3例家族史中有幼年死亡病例（具体疾病不详）。心电图：18例提示左室和（或）右室肥厚伴ST—T改变,3例伴有异常Q波,2例有I。房室传导阻滞,1例有左前分支阻滞,1例有完全性左束支阻滞。心肌酶升高5例。X线胸片心影扩大17例。心脏彩超提示非梗阻型肥厚型心肌病23例;梗阻型肥厚型心肌病2例。收缩功能减低2例,舒张功能减低3例。21例患儿口服美托洛尔治疗,1例异搏定,1例心得安,未用药2例。随访2个月～13年,2例患儿死亡,其余23例生存。结论 小儿肥厚型心肌病临床表现缺乏特异性,病情重,呈进行性发展,是青少年猝死的主要原因之一,预后差。     

心电图T波振幅与儿童扩张性心肌病左室射血分数的关系

目的 探讨心电图T波振幅与儿童扩张性心肌病左室射血分数（LVEF）的关系。方法 回顾性分析2009年5月至2018年6月诊断为扩张性心肌病的44例儿童的临床资料。根据LVEF分为LVEF ≥ 50%组（n=26）和LVEF<50%组（n=18）,且对治疗后25例进行3~42个月（平均14±9个月）的随访。采用广东中山SR-1000A心电综合自动分析仪描记仰卧位12导联体表心电图,程序自动分析结合人工干预测量12导联心电图T波振幅。结果 （1）T波振幅比较：LVEF<50%组较LVEF ≥ 50%组Ⅱ、V₄、V₅、V₆导联T波振幅明显降低（P < 0.05）。LVEF增高组（治疗后较治疗前LVEF增加>5%）治疗后aVR、V₅、V₆导联T波振幅明显增高（P < 0.05）;LVEF不变组（治疗后较治疗前LVEF增加≤ 5%）治疗后aVR导联T波振幅明显降低（P < 0.05）。（2）受试者工作特征曲线评价：Ⅱ、V₄、V₅、V₆导联T波振幅对扩张性心肌病患儿LVEF<50%具有预测价值（P < 0.05）。当同时出现Ⅱ导联T波振幅≤ 0.20 mV、V₄导联T波振幅≤ 0.40 mV、V₅导联T波振幅≤ 0.3 mV、V₆导联T波振幅≤ 0.30 mV时,预测扩张性心肌病患儿LVEF<50%的灵敏度为88.2%,特异度为76.0%。结论 心电图T波振幅可作为评估儿童扩张性心肌病左室收缩功能的指标。     

Validity of electrocardiographic criteria for left ventricular hypertrophy in children with pressure- or volume-loaded ventricles: Comparison with echocardiographic left ventricular muscle mass

To determine the correlation between electrocardiographic (ECG) findings and anatomy utilizing echocardiography in children with pressure- or volume-loaded left ventricles, we analyzed the preoperative ECG tracings of 19 patients who underwent surgery for significant aortic stenosis and 12 patients who underwent cardiac catheterization or surgery for clinically significant ventricular septal defects. We then compared them with a group of 21 normal controls. The left ventricular muscle mass in these patients was calculated from echocardiograms using the simplified cubed formula. Posterior and septal wall thickness and cavity size were significantly greater in the aortic stenosis group than in the normal group. Only cavity size was significantly greater in the ventricular septal defect group than in the normal group. Eighteen aortic stenosis patients (95%) and ten ventricular septal defect patients (83%) had a left ventricular muscle mass greater than 2 standard deviations above the mean for the normal group. Significant differences were found in the voltages of SV1+RV6 and in the voltage of RV6 alone between normals, aortic stenosis patients, and ventricular septal defect patientsregardless of age. Using conventional ECG criteria for left ventricular hypertrophy, the highest sensitivity in aortic stenosis patients (67%) and ventricular septal defect patients (60%) was modest. The likelihood ratio for a positive test in either group was the best for SV1+RV6 >98^th centile for age; RV6>98^th centile for age was the best single measurement. No correlation was found between voltage and any measurable hemodynamic or anatomic data. Conventional pediatric ECG criteria for left ventricular hypertrophy have only modest sensitivity regardless of whether the heart is under pressure or volume load. Because left ventricular muscle mass can be precisely determined by echocardiography, these ECG criteria should be applied cautiously.     

Improvement of left ventricular dysfunction after control of persistent tachycardia

Five children are described who had persistent, chronic tachycardia and left ventricular dysfunction manifested by decreased left ventricular percent fractional shortening on echocardiogram (five patients) cardiomegaly on chest roentgenogram (three), ventricular or atrial hypertrophy on ECG (three), and symptoms of congestive heart failure (three). After antidysrhythmia therapy and control of the tachycardia, signs and symptoms of congestive heart failure resolved in two infants. Moreover, in each patient signs of cardiomegaly resolved on chest roentgenogram, hypertrophy resolved on ECG, and the fractional shortening improved to normal (mean 20.2% +/- 2.4% SEM before vs 36.2% +/- 2.4%, P = 0.02, after treatment). Evaluation in the child who has dilated cardiomyopathy should include assessment of heart rate and rhythm. Moreover, when persistent tachycardia is found in an asymptomatic child, evaluation of left ventricular function is indicated.