QT dispersion in patients with end-stage renal failure and during hemodialysis.

Interlead variability of the QT interval in surface electrocardiogram (ECG), i.e., QT dispersion, reflects regional differences in ventricular recovery time, and it has been linked to the occurrence of malignant arrhythmias in different cardiac diseases. The purpose of the study was to assess the effect of hemodialysis on QT and corrected QT (QTc) interval and dispersion in chronic hemodialyzed patients. Data of 34 nondiabetic patients (male/female = 21/13; mean age, 54 +/- 15 yr) on chronic hemodialysis were studied. Polysulfone capillaries and bicarbonate dialysate containing (in mEq/L) 135 Na+, 2.0 K+, 1.5 Ca2+, and 1.0 Mg2+ were used. Simultaneous 12-lead ECG were recorded before and after hemodialysis in a standard setting. The QT intervals for each lead were measured manually on enlarged (x3) ECG by one observer using calipers. Each QT interval was corrected for patient heart rate: QTc = QT/square root of RR (in milliseconds [ms]). The average cycle intervals were 853 +/- 152 ms predialysis and 830 +/- 173 ms postdialysis; the difference was not significant. The maximal QT interval changed significantly from 449 +/- 43 to 469 +/- 41 ms (P < 0.01). The corrected maximal QT interval increased significantly from 482 +/- 42 to 519 +/- 33 ms (P < 0.01). The QT dispersion changed from 56 +/- 15 to 85 +/- 12 ms (P < 0.001) and the corrected QT interval dispersion from 62 +/- 18 to 95 +/- 17 ms (P < 0.001). During hemodialysis, the serum potassium and phosphate levels decreased from 5.5 +/- 0.8 to 3.9 +/- 0.5 (mM) and from 2.3 +/- 0.5 to 1.6 +/- 0.4 (mM), respectively, whereas calcium increased from 2.2 +/- 0.23 to 2.5 +/- 0.22 (mM). It is concluded that hemodialysis increases the QT and QTc interval and QT and QTc dispersion in patients with end-stage renal failure. Thus, it may be stated that the nonhomogeneity of regional ventricular repolarization increases during hemodialysis. Measurement of QT and QTc dispersion is a simple bedside method that can be used for analyzing ventricular repolarization during hemodialysis.     

Carbon monoxide poisoning - a cause of increased QT dispersion

BACKGROUND: Carbon monoxide (CO) poisoning is associated with direct cardiovascular toxicity. QT dispersion (QTd) of the ECG is an indirect measure of heterogeneity of ventricular repolarization, which may contribute to ventricular arrhythmias. Our aim was to study QTd in patients with acute CO poisoning. METHODS: CO intoxication was confirmed by arterial blood gas analysis. A control group consisted of age- and sex-matched individuals admitted to the hospital for unrelated clinical conditions. 12-lead ECG's were recorded on admission and repeated 1 week after discharge from the hospital. QT dispersion was defined as the difference between the greatest and the least QT intervals in any of the 12 leads. RESULTS: Seventeen intoxicated patients, aged 5-46 years, had mean carboxyhemoglobin levels of 22.5 +/- 11.1%. On admission, corrected QT intervals of the intoxicated patients were significantly increased compared to the control group (431 +/- 18 ms vs. 404 +/- 28 ms, P = 0.008), but not the QT interval (358 +/- 25 ms vs. 345 +/- 20 ms, P = 0.17). Mean QTd and cQTd values (46 +/- 15 ms and 62 +/- 13 ms) of the intoxicated patients were significantly increased compared to the control group (17 +/- 4 ms and 33 +/- 15 ms, P < 0.0001 for both). Both QTd and cQTd decreased significantly after discharge from the hospital (P = 0.0001). CONCLUSION: Although QT dispersion increased in patients with CO poisoning, none of ECG's showed ventricular arrhythmia. Increased QTd in the absence of QT interval prolongation may have a lowered arrhythmogenic potential of CO poisoning.     

Relation of early changes of QT dispersion to changes in left ventricular systolic and diastolic function after a first acute myocardial infarction

OBJECTIVE: To describe the relation between changes of left ventricular systolic and diastolic function and changes of QT dispersion (difference in duration between longest and shortest QT interval) following acute myocardial infarction. DESIGN: QT dispersion was determined at admission, hospital discharge, and 1 and 3 months following myocardial infarction in 64 consecutive 1-year survivors. Patients were divided into Group A where QT dispersion was < 52 ms at all recordings or initially > 52 ms but decreased during follow-up, and Group B where QT dispersion remained increased > or = 52 ms at all measurements. Doppler-Echocardiography was carried out on day 1, day 5, and after 1, 3, and 12 months. RESULTS: In 26 patients QT dispersion remained increased > or = 52 ms during the first 3 months after infarction. Among these a significant increase of end-systolic volume was seen whereas low or rapid normalized QT dispersion was associated with a significant decrease of ventricular volumes. After 1 year end-systolic (70 +/- 32 ml vs 49 +/- 16 ml, p = 0.006) and end-diastolic volumes (138 +/- 41 ml vs 105 +/- 22 ml, p = 0.001) were higher in Group B. In a multivariate model Group B was significantly related to an increase of end-diastolic volume (p = 0.01). In Group A diastolic function improved in eight patients and in two it deteriorated, whereas improvement was seen in one patient and deterioration in nine patients from Group B (p < 0.01). CONCLUSION: Following myocardial infarction low QT dispersion is associated with preserved left ventricular function, whereas persistently increased dispersion is associated with left ventricular dilation and deterioration of diastolic function.     

Impact of papillary muscles approximation on the adequacy of mitral coaptation in functional mitral regurgitation due to dilated cardiomyopathy.

PURPOSE: We report early outcome of our modified papillary muscles approximation (PMA) as an adjunct to mitral annuloplasty (MAP) by analyzing the mitral coaptation zone echocardiographically and clinical outcome in three different procedures. METHODS: Mitral valve coaptation depth (MVCD) and tenting area were measured in patients with ischemic (n=8) or non-ischemic (n=22) dilated cardiomyopathy (ICM or non-ICM) undergoing either of following: Group I: isolated left ventricular volume reduction (LVVR) (n=11), Group II: PMA plus LVVR (n=14), Group III: isolated PMA (n=5). Clinical outcome including cardiac function were also investigated. RESULTS: Thirty-day mortality was 6.7%. Postoperative data in overall survivors showed significant improvement of ejection fraction (EF) (from 19+/-7 to 32+/-9%), left ventricular end-diastolic volume index (LVEDVI) (from 189+/-74 to 132+/-41 mL/m2), and left ventricular diastolic dimension (LVDd) (from 73+/-8 to 65+/-6 mm) (p<0.001). The overall preoperative MVCD (mm) and tenting area (cm2) was 10.4+/-2.8 and 2.4+/-0.6, respectively, which were both significantly reduced to 5.6+/-2.5 and 0.8+/-2.4 postoperatively (p<0.001). In comparison of the degree (%change) of improvement, Group II and III showed favorable effects on tethering force, compared with Group I. CONCLUSION: Our modified PMA is a relatively safe method to have the potential for improving tethering of the mitral valve and clinical outcome in evaluating mitral coaptation zone.     

QT dispersion in hemodialysis and CAPD patients

Prolongation of repolarization dispersion (QT interval dispersion) measured from the 12-lead surface ECG has been associated with sudden cardiac death and ventricular tachyarrhythmias in a variety of cardiac disorders. The aim of our study was to assess the effects of hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD) on QT dispersion in end-stage renal disease patients. 20 chronic HD patients (mean age 57.75 +/- 13.79 years) and 20 CAPD patients (mean age 50.79 +/- 14.94 years) who had no complaints and symptoms of cardiac arrhythmias as well as 20 healthy volunteers (mean age 48.74 +/- 10.88 years) underwent ECG testing. All HD patients were on bicarbonate three times weekly with cuprophane capillaries. 12-lead ECGs were recorded on the day after HD. The CAPD patients were on a standard CAPD program (four times daily with 2,000 cm(3) peritoneal fluid). ECGs were recorded when the patients were receiving their regular standard CAPD program. All ECGs were analyzed manually by one observer. There were no statistically significant differences in dialysis duration, blood urea nitrogen, creatinine, sodium, calcium, and parathormone values between the HD and CAPD patients. The serum potassium values were significantly higher in HD patients when compared to CAPD patients. There was no difference in the mean of maximal QT among all three groups. The rate of QT interval dispersions was significantly higher in HD and CAPD patients as compared with healthy controls (p < 0.05). There was no statistically significant difference in the QT dispersion rates between HD and CAPD patients. In conclusion, there is a tendency to cardiac arrhythmias in HD patients during the postdialysis period. Although CAPD patients are receiving dialysis daily, they also have higher rates of QT dispersions and accordingly a tendency to arrhythmias.     

Tissue Doppler echocardiographic identification of ischemic etiology in patients with dilated cardiomyopathy

OBJECTIVE: To compare the left ventricular function in patients with ischemic and nonischemic cardiomyopathy using tissue Doppler echocardiography (TDE). METHODS: We studied 30 patients after myocardial infarction (MI group), 30 patients with dilated cardiomyopathy (DCM group) and 60 healthy volunteers in corresponding control groups. TDE velocities, time intervals of cardiac cycle were measured and dispersion index of TDE parameters was calculated. RESULTS: Early diastolic velocities were lower in MI group than in DCM group, with similar systolic and late diastolic velocities. The dispersion index of systolic velocities was significantly higher in MI than in DCM group and in controls (respectively 33.1+/-6.0% vs 12.6+/-3.7% vs 15.9+/-5.6%; p < 0.001) and differentiated ischemic from idiopathic dilated cardiomyopathy. In MI group, preejection period was shorter and isovolumic relaxation and diastasis time were longer than in DCM group, with no differences in dispersion index of time intervals between the groups. CONCLUSIONS: TDE parameters: early diastolic velocity, preejection period, isovolumic relaxation time and the dispersion index of systolic velocities differentiate ischemic and nonischemic etiology of dilated cardiomyopathy.     

A surgical approach to severe congestive heart failure--overlapping ventriculoplasty

BACKGROUND: Previously we developed a new procedure of overlapping cardiac volume reduction (OLCVR) surgery for patients with dilated cardiomyopathy refractory to medical treatment. Papillary muscle plication (PMP) when combined with OLCVR may achieve a better clinical outcome. PURPOSE: To investigate the early and intermediate results of OLCVR with or without PMP. METHODS: Twenty-five patients (21 males, 4 females, aged 60 +/- 13 years) with either ischemic (n = 7) or nonischemic (n = 18) dilated cardiomyopathy underwent either isolated OLCVR (n = 11; Original Group) or PMP combined with OLCVR (n = 14; Integrated Group). RESULTS: Early deaths occurred in two (8%) from a noncardiac cause and late deaths in six, two from a cardiac and four from a noncardiac cause. Postoperative data in survivors were significantly improved in terms of NYHA functional class (from 3.6 +/- 1.9 to 1.6 +/- 1.1), ejection fraction (from 18 +/- 6% to 31 +/- 8%), left ventricular diastolic dimension (from 73 +/- 9 to 65 +/- 6 mm), and left ventricular end-diastolic volume index (from 194 +/- 81 to 128 +/- 43 mL/m2) (p < 0.05) in selected comparative cases. One-year crude and cause-specific survivals were 70.9% and 83.1%, respectively, at a mean follow-up of 12.8 months. One-year crude survival of the Integrated and Original Group was 85.7% and 55.6%, respectively (p = 0.24). CONCLUSIONS: Although limitations exist in evaluating operative results, we consider OLCVR to be a relatively safe and effective procedure for selected patients with dilated cardiomyopathy. The addition of PMP to OLCVR may enhance the elliptic formation of left ventricle shape and improve mitral valve tethering, but further study is mandatory.     

Myectomy versus myotomy as an adjunct to membranectomy in the surgical repair of discrete and tunnel subaortic stenosis

The results of membranectomy and deep myectomy in the left ventricular outflow tract were compared to those of membranectomy and myotomy in 42 patients who underwent surgical repair of discrete and tunnel subaortic stenosis. Fifteen consecutive patients (Group A) underwent membranectomy and myotomy, and 27 consecutive patients (Group B) underwent membranectomy and myectomy. Two patients of Group A and nine of Group B had tunnel subaortic stenosis. The preoperative mean (+/- standard deviation) peak systolic gradients across the left ventricular outflow tract in patients with discrete subaortic stenosis types I and II were 64 +/- 29 mm Hg in Group A and 52 +/- 3 mm Hg in Group B (p = not significant). In the patients with tunnel subaortic stenosis the preoperative mean gradients were 97 +/- 74 mm Hg in Group A and 73 +/- 26 mm Hg in Group B (p = not significant). In patients with discrete subaortic stenosis types I and II, postoperative catheterization at a mean follow-up of 21 months revealed residual mean gradients of 29 +/- 24 mm Hg in Group A and 10 +/- 13 mm Hg in Group B (p less than 0.01). In the patients with tunnel subaortic stenosis, the postoperative mean gradients were 25 +/- 7 and 30 +/- 30 mm Hg in Groups A and B, respectively (p = not significant). We conclude that in the surgical management of discrete subaortic stenosis types I and II, deep myectomy (in addition to membranectomy) produces better relief of the left ventricular outflow obstruction than do membranectomy and myotomy. In patients with tunnel subaortic stenosis myectomy is less effective than in the non-tunnel type but still produces acceptable results and may delay radical procedures to a later age.     

重症胰腺炎急性反应期控制性液体复苏策略

目的探讨重症胰腺炎急性反应期液体治疗策略。方法2001年3月至2006年1月将符合研究标准的83例重症急性胰腺炎（severe acute pancreatitis,SAP）患者纳人研究。根据人院后扩容达标时间分为早期扩容达标组（I组,21例）、中期扩容达标组（Ⅱ组,35例）和晚期扩容达标组（Ⅲ组,27例）。观察人院日至人院后72h内的液体治疗参数、血清乳酸水平、急性和慢性健康状况评分（APACHEⅡ评分）、机械通气率、腹腔间隔室综合征发生率及治愈率等指标。结果I组、Ⅱ组、Ⅲ组的扩容达标时间分别为（13±6）h,（38±5）h和（614-8）h,且3组间差异均有统计学意义（P〈0．05）;3组达标时的血清乳酸水平较人院水平差异有统计学意义（P〈0．05）,且恢复至正常水平。红细胞压积（HCT）：人院后第1天I组（334-6）％,显著低于Ⅱ组（404-6）％和Ⅲ组（424-11）％（P〈0．01）,Ⅱ组和Ⅲ组间差异无统计学意义。人院日,I组输注晶体（40144-2887）ml、胶体量（12204-705）ml,显著高于Ⅱ组（23664-1959）m1和（8214-600）ml以及Ⅲ组（26154-1574）m1和（7014-585）m1（P〈0．01）,Ⅱ组和Ⅲ组问差异无统计学意义（P〉0．05）。人院日,III组胶、晶体比值显著低于I组和Ⅱ组（P〈0．05）。4d的液体输注总量3组间差异无统计学意义（P〉0．05）。输液速率人院日I组显著高于Ⅱ组和Ⅲ组（P〈0．05）。4d液体潴留量Ⅱ组显著低于I组和Ⅲ组（P〈0．05）。人院后1～3dI组的APACHEⅡ评分显著高于Ⅱ组和Ⅲ组（P〈0．05）。I组的机械通气率（85．7％）显著高于Ⅱ组（37．1％）和Ⅲ组（63．0％）（P〈0．05）;Ⅱ组腹腔间隔室综合征发生率（37．1％）最低（P〈0．05）;I组存活率（38．1％）显著低于Ⅱ组（85．7％）和Ⅲ组（66．7％）（P〈0．05）。结论SAP发病72h内控制性血容量扩充和防止体液潴留可显著提高其治愈率。     

Nontransplant cardiac surgery for end-stage cardiomyopathy

OBJECTIVE: To treat end-stage cardiomyopathy, we evaluated endoventricular circular patch plasty, partial left ventriculectomy, and valvular reconstruction alone in our 2-year experience. METHODS: Among 86 patients with heart failure evaluated between December 1996 and February 1999, 33 patients with ischemic cardiomyopathy (25 men and 8 women; mean age 61 +/- 7.8 years; New York Heart Association class 3.5 +/- 0.5) were treated with endoventricular circular patch plasty combined with coronary bypass grafting (84%) and mitral reconstruction (36%). The other 53 patients with nonischemic cardiomyopathy (45 men and 8 women; mean age 48 +/- 14.3 years, New York Heart Association class 3.7 +/- 0.5), were treated by left ventricular reduction by partial left ventriculectomy (n = 37) or patch plasty (n = 3) and valve reconstruction alone (n = 13). The first 24 patients (group I) underwent ventriculectomy with or without valve reconstruction; the more recent 29 patients (group II) underwent left ventricular reduction (n = 16) or valve reconstruction alone (n = 13) on the basis of the intraoperative echocardiographic evaluation to observe changes of wall motion and thickness during cardiopulmonary bypass. RESULTS: Ischemic Group: Hospital mortality in elective (n = 26) and emergency (n = 7) operations was 4% and 43%, and 3 patients died in the late postoperative period. Mean New York Heart Association class and ejection fraction improved from 3.5 +/- 0.5 to 1.5 +/- 0.7 and from 23% +/- 7.7% to 36% +/- 8.6%, respectively. Left ventricular end-diastolic and end-systolic volume indexes decreased from 162 +/- 46 mL/m(2) to 110 +/- 39 mL/m(2) and from 130 +/- 47 mL/m(2) to 70 +/- 32 mL/m(2), respectively. Nonischemic Group: In 40 patients with left ventricular reduction, hospital mortality in elective (n = 33) and emergency (n = 7) operations was 6% and 86%, and 5 patients died in the late postoperative period. Mean New York Heart Association class and ejection fraction improved from 3.7 +/- 0.5 to 1.7 +/- 0.6 and from 18% +/- 6.4% to 31% +/- 5.9%. Left ventricular end-diastolic and end-systolic volume indexes decreased from 203 +/- 45 mL/m(2) to 110 +/- 37 mL/m(2) and from 164 +/- 40 mL/m(2) to 79 +/- 33 mL/m(2), respectively. In 13 patients undergoing valve reconstruction alone (12 mitral with or without tricuspid and 1 tricuspid plus left ventricular assist device), hospital mortality in elective (n = 9) and emergency (n = 4) operations was 0% and 50% with no late deaths. Mean New York Heart Association class and ejection fraction improved from 3.6 +/- 0.5 to 2.0 +/- 0.5 and from 22% +/- 6.0% to 30% +/- 14.5%, respectively. Mean left ventricular end-diastolic and end-systolic volume indexes decreased from 170 +/- 34 mL/m(2) to 150 +/- 50 mL/m(2) and from 140 +/- 38 mL/m(2) to 104 +/- 40 mL/m(2), respectively. Overall mortality decreased from 50% in group I to 10% in group II. The survival estimates at 2 years were 77% (confidence limits 57%-88%) in the ischemic group and 63% (confidence limits 47%-75%) in the nonischemic group (no significant difference). The analysis of our data showed that the factors influencing the surgical results for dilated cardiomyopathy were presence of severe mitral regurgitation, preoperative New York Heart Association functional class IV with emergency operation, and operative procedures with randomly performed partial left ventriculectomy without an intraoperative echo test. CONCLUSION: Endoventricular circular patch plasty, partial left ventriculectomy, and solo valve reconstruction can be performed with an acceptably low risk as elective operations. The selection of operative procedures in idiopathic dilated cardiomyopathy and avoidance of emergency surgery improved operative mortality and morbidity. Among patients who survived at least 1 year, there were no late deaths up to 30 months' follow-up.     

Electrocardiogram with prolonged QT interval in Gitelman disease

BACKGROUND: Potassium and magnesium deficiency prolong the QT interval on a standard electrocardiogram and predispose the patient to dangerous cardiac arrhythmias. No information is available on QT interval in patients diagnosed with Gitelman disease. METHODS: The QT interval was assessed on lead II in 27 patients with biochemically and genetically defined Gitelman disease, who had discontinued medical treatment for at least four weeks. They included 15 female and 12 male subjects, aged 6.7 to 40 years old, median 20 years old. The corrected QT interval was calculated from the measured QT interval and heart rate using the Bazett formula. RESULTS: The corrected QT interval was normal (between 391 and 433 msec) in 16 and prolonged in the remaining 11 patients (between 444 and 504 msec). Patients with prolonged and patients with normal QT interval did not significantly differ with respect to female to male ratio, plasma potassium, plasma total magnesium, and plasma ionized calcium. Plasma sodium and chloride values were slightly but significantly lower and bicarbonate levels higher in patients with a prolonged than in those with a normal QT interval. CONCLUSIONS: The corrected QT interval is often pathologically prolonged in patients with Gitelman disease, suggesting that there is an increased risk for development of dangerous arrhythmias. Further investigations are required in patients with a prolonged QT interval to assess the true hazard of dangerous arrhythmias.     

Effective cardiac resynchronization therapy for an adolescent patient with dilated cardiomyopathy seven years after mitral valve replacement and septal anterior ventricular exclusion

Cardiac resynchronization therapy (CRT) is a new treatment for refractory heart failure. However, most heart failure patients treated with CRT are middle-aged or old patients with idiopathic or ischemic dilated cardiomyopathy. We treated a 17 year 11 month old girl with dilated cardiomyopathy after mitral valve replacement (MVR) and septal anterior ventricular exclusion (SAVE). Seven years after the SAVE procedure, she presented complaining of palpitations and general fatigue with normal activity. Her echocardiogram showed reduced left ventricular function. Despite of optimal medical therapy, her left ventricular function continued to decline and she experienced regular arrhythmias such as premature ventricular contractions. We thus elected to perform cardiac resynchronization therapy with defibrillator (CRT-D). After CRT-D, her clinical symptoms improved dramatically and left ventricular ejection fraction (LVEF) improved from 31.2% to 51.3% as assessed by echocardiogram. Serum BNP levels decreased from 448.2 to 213.6 pg/ml. On ECG, arrhythmias were remarkably reduced and QRS duration was shortened from 174 to 152 msec. In conclusion, CRT-D is an effective therapeutic option for adolescent patients with refractory heart failure after left ventricular volume reduction surgery.     

Right ventricular cardiomyoplasty: 10-year follow-up

BACKGROUND: Chronically depressed right ventricular (RV) function presents an unsolved therapeutic challenge in cardiac surgery. Despite recent advances in medical and surgical therapies, prognosis remains poor and patient's quality of life and mortality are frequently unacceptable. The aim of this study is to present the first clinical report and long-term results of RV dynamic cardiomyoplasty applied in patients with RV failure caused by isolated RV cardiomyopathies. METHODS: Seven consecutive patients (5 males, 2 females; mean age, 40 +/- 9 years; range, 15 to 63 years) from a series of 113 cardiomyoplasty procedures performed at Broussais and Pompidou Hospitals were evaluated. The mean duration of follow-up was 10 +/- 3.5 years. All patients had predominant RV dysfunction, associated with tricuspid regurgitation in 6 patients. The cause of RV failure was arrhythmogenic cardiomyopathy (4 patients), ischemic (2 patients), and Uhl's disease (1 patient), and endomyocardial fibrosis (1 patient). Six patients were in preoperative New York Heart Association functional class III and 1 was in intermittent class III/IV. The mean preoperative ejection fraction (measured by isotopic technique) was 18% +/- 5.7% for the right ventricle and 40% +/- 13% for the left ventricle. Right ventricular dynamic cardiomyoplasty consists of wrapping the RV free walls with the left latissimus dorsi muscle flap. The distal part of the latissimus dorsi muscle is fixed to the diaphragm and then electrostimulated. Six patients required associated tricuspid valve surgery. RESULTS: There were no perioperative deaths. The mean duration of follow-up was 10 +/- 3.5 years. Six patients are alive with a remarkable quality of life, 4 are in New York Heart Association functional class I and 2 are in class II. One patient who was in New York Heart Association functional class II died in postoperative year 7 caused by stroke. At last follow-up, mean RV ejection fraction was 33% +/- 11.8% and left ventricular ejection fraction was 52% +/- 12.6%. CONCLUSIONS: The results of this long-term study demonstrate hemodynamic and functional improvements after RV cardiomyoplasty without perioperative mortality, no long-term malignant arrhythmias, and RV dysfunction related deaths. We believe that RV cardiomyoplasty, associated with tricuspid valve surgery when required, could be an effective treatment for severe RV failure.     

The influence of valve physiology on outcome following aortic valvotomy for congenital bicuspid valve in children: 30-year results from a single institution.

OBJECTIVE: Aortic valvotomy is widely used for the treatment of congenital aortic stenosis in children. We sought to evaluate whether the predominant post-valvotomy physiology, aortic insufficiency (AI) or aortic stenosis (AS) independently affected patient outcome. METHODS: From 1972-2002, 57 children with congenital aortic stenosis underwent valvotomy. We divided age-matched patients with residual lesions based on their predominant pathology into three groups: Group I (n=14), patients with moderate AI; Group II (n=14), patients with moderate AS, and Group III (n=14), patients with combined AI and AS. Fifteen patients with severe AI or mild residual lesions following valvotomy were excluded from analysis. RESULTS: mean freedom from aortic valve replacement (AVR) was 11.2+/-1.7 years in Group I and 21.5+/-3.9 years in Group II, P=0.05. AVR was required in 11 patients (79%) in Group I vs. only 5 (36%) in Group II, P=0.05. Group III was intermediate, with 9 (64%) requiring AVR. At the time of AVR, patients with aortic stenosis had significantly higher fractional shortening % than those with insufficiency or combined lesions, (Group 1: 38.2+/-7.9 vs. Group II: 46.3+/-5.5 vs. Group III: 39.2+/-3.7, P=0.007). Patients in Group II also had less severely dilated ventricles (mm) than those in the other groups, (Group 1: 50.2+/-12.5 vs. Group II: 39.5+/-8.3 vs. Group III: 49.0+/-8.1, P=0.030). CONCLUSIONS: patients with predominant AI following valvotomy are more likely to need AVR sooner than those with residual stenosis without AI. Therefore, cautious use of repeat valvotomy using maneuvers to avoid AI (small balloons), may prolong freedom from aortic valve replacement in those patients with significant residual AS.     

Effects of halothane and sevoflurane on QT dispersion in paediatric patients

BACKGROUND: The QT dispersion (QTd) of the ECG is an indirect measure of heterogeneity of ventricular repolarization which may contribute to complex ventricular arrhythmias. We compared the effects of halothane and sevoflurane on QTd, and heart-rate corrected QT dispersion (QTcd). METHODS: Fifty ASA physical status I patients, aged 5-15 years, undergoing general anaesthesia were studied. A control ECG recording was printed before induction of anaesthesia. In the halothane group, anaesthesia was induced with halothane 4% in 2 : 1 ratio of air : O2 mixture and in the sevoflurane group with sevoflurane 8% in 2 : 1 ratio of air : O2 mixture. The ECG was recorded 1 and 3 min after induction of anaesthesia, 1 and 3 min after the administration of vecuronium 0.08 m.kg(-1) intravenous and 1 and 3 min after the tracheal intubation. All ECGs were analysed by two cardiologists blinded to the anaesthetic. RESULTS: Although QTd increased in both groups following intubation, this difference was not statistically significant when compared with control values. Following intubation five patients in the halothane group had ventricular arrhythmias of short duration, whereas no arrhythmias were recorded in the sevoflurane group (P = 0.052). Following intubation, QTd (45 +/- 15 ms vs 40 +/- 14 ms) and QTcd (60 +/- 17 ms vs 55 +/- 16 ms) values in the halothane group were significantly greater than the sevoflurane group (P < 0.05). CONCLUSION: Neither sevoflurane nor halothane caused a significant increase in QTd compared with control values before induction. Only QTd following intubation was significantly greater in the halothane group than the sevoflurane group.     

Surgical treatment of ventricular tachycardias. Complete versus partial encircling endocardial ventriculotomy

Forty consecutive patients underwent electrophysiologically guided encircling endocardial ventriculotomy as treatment for recurrent sustained ventricular tachycardia resulting from coronary artery disease and previous myocardial infarction. Twelve patients (30%, Group I) had a complete encircling endocardial ventriculotomy and 28 (70%, Group II) had a partial encircling endocardial ventriculotomy (54.4% +/- 2.2% of the left ventricular endocardial circumference) at the earliest electrical activation during ventricular tachycardia. There were no significant differences between the two groups in age, sex ratio, New York Heart Association class, coronary disease, aneurysm location, concomitant bypass grafting, and left ventricular function. One patient of Group I and two patients of Group II did not survive the perioperative period (8% versus 7%, not significant). The survivors were restudied electrophysiologically about 3 weeks after the operation. Eight patients of Group I and 19 patients of Group II were free of ventricular tachycardia (no spontaneous or inducible ventricular tachycardia) without antiarrhythmic drugs (73% versus 73%, not significant). The mean follow-up period in Group I is 22.6 months and in Group II, 15.2 months. Five patients of Group I and of Group II developed severe left ventricular dysfunction (46% versus 8%; p = 0.025). Also, congestive heart failure was a significant cause of death in Group I patients (p = 0.036). In conclusion, electrophysiologically guided partial encircling endocardial ventriculotomy is highly efficient as a surgical treatment of recurrent sustained ventricular tachycardia. Complete encircling endocardial ventriculotomy offers no better ablation of arrhythmias and should be avoided because of its apparent hazards to left ventricular performance.     

Preparation of the left ventricle for anatomical correction in patients with simple transposition of the great arteries. Surgical guidelines

Pulmonary artery banding in combination with an aortopulmonary shunt was performed on 16 patients with simple transposition of the great arteries to prepare the left ventricle for anatomical correction. Three groups were identified after operation: Group I (four patients) had increased pulmonary blood flow and tight pulmonary artery banding; Group II (four patients) had increased pulmonary blood flow and moderate pulmonary artery banding; Group III (eight patients) had normal pulmonary blood flow and moderate pulmonary artery banding. Postoperative low cardiac output was present in all patients in Group I, whereas mild heart failure was present in two patients in Group II and in two in Group III. There was one hospital death (6%). The follow-up period was 125 patient-months. Left ventricular systolic pressure rose from 63 +/- 11 torr before the operation to 101 +/- 35 torr after the procedure in Group I (p less than 0.05), from 59 +/- 10 to 93 +/- 33 torr in Group II (p less than 0.05), and from 55 +/- 10 to 84 +/- 16 torr in Group III (p less than 0.005). The increase in left ventricular muscle mass was from 44 +/- 2 gm/m2 preoperatively to 108 +/- 12 gm/m2 after operation in Group I (p less than 0.01), from 43 +/- 3 to 93 +/- 8 gm/m2 in Group II (p less than 0.02), and from 46 +/- 3 to 55 +/- 14 gm/m2 in Group III (p = no statistically significant difference). The postoperative change in left ventricular end-diastolic volume was from 100% +/- 17% to 133% +/- 23% of normal in Groups I and II (p less than 0.05) and from 123% +/- 29% to 107% +/- 36% of normal in Group III (p = no statistically significant difference). In preparing the left ventricle for anatomical correction, avoidance of severe pulmonary artery banding decreases the incidence of postoperative myocardial dysfunction, a moderate degree of volume overload and pulmonary artery banding provides the most effective stimulus for ventricular growth, and a small to moderate atrial septal defect is advantageous because it ensures the volume preload necessary for the development of the left ventricle.     

Pulsatile mechanical cardiac assistance in pediatric patients with the Berlin heart ventricular assist device

Mechanical cardiac assistance for neonates, infants, children and adolescents may be accomplished with pulsatile ventricular assist devices (VAD) instead of extracorporeal membrane oxygenation or centrifugal pumps. The Berlin Heart VAD consists of extracorporeal, pneumatically driven blood pumps for pulsatile univentricular or biventricular assistance for patients of all age groups. The blood pumps are heparin-coated. The stationary driving unit (IKUS) has the required enhanced compressor performance for pediatric pump sizes. The Berlin Heart VAD was used in a total number of 424 patients from 1987 to November 2001 at our institution. In 45 pediatric patients aged 2 days-17 years the Berlin Heart VAD was applied for long-term support (1-111 days, mean 20 days). There were three patient groups: Group I: "Bridge to transplantation" with various forms of cardiomyopathy (N = 21) or chronic stages of congenital heart disease (N = 9); Group II: "Rescue" in intractable heart failure after corrective surgery for congenital disease (N = 7) or in early graft failure after heart transplantation (N = 1); and Group III: "Acute myocarditis" (N = 7) as either bridge to transplantation or bridge to recovery. Seventeen patients were transplanted after support periods of between 4 and 111 days with 12 long-term survivors, having now survived for up to 10 years. Five patients (Groups I and III) were weaned from the system with four long-term survivors. In Group II only one patient survived after successful transplantation. Prolonged circulatory support with the Berlin Heart VAD is an effective method for bridging until cardiac recovery or transplantation in the pediatric age group. Extubation, mobilization, and enteral nutrition are possible. For long-term use, the Berlin Heart VAD offers advantages over centrifugal pumps and ECMO in respect to patient mobility and safety.     

Optimal myocardial protection.

The low mortality and perioperative infarction rates for aortocoronary bypass (ACB) make them unsuitable for evaluating the adequacy of myocardial protection. Enzymatic and functional measurements were found to be sensitive and specific indicators of myocardial injury. A prospective concurrent study of 78 patients undergoing triple ACB was conducted to evaluate the effectiveness of three popular methods of myocardial protection. Group I (32 patients) had a single dose of cold (4 degrees C) potassium cardioplegic (CPC) solution infused inducing a mean myocardial temperature (MMT) of 31 +/- 4 degrees C/min. Group II (23 patients) had multiple doses of CPC solution 8nducing a MMT of 22 +/- 2 degrees C/min. Group III (23 patients) had intermittent anoxic arrest at a MMT of 28 +/- 1 degrees C. The groups were not randomized but had comparable clinical symptoms and catheterization findings. Serial measurements of cardiac specific creatine kinase (CK-MB) revealed a peak in enzymatic activity occurring 60 minutes following ACB. The highest CK-MB was significantly (P less than 0.01) lower in group II (25 +/- 8 IU/liter) than group I (50 +/- 8 IU/liter), or group III (68 +/- 14 IU/liter). Myocardial performance was evaluated after ACB by serially measuring left ventricular stroke work index (SW) and left atrial pressure (LAP) in response to volume loading. The rise in SW was significantly (P less than 0.01) greater in group II (3.0 +/- 0.7 gm.m/sq m/mm Hg) than in group I (1.4 +/- 0.7) or group III (1.8 +/- 0.9). The highest SW attained was higher (P less than .01) in group II (43 +/- 7 gm.m/sq m) than group I (19 +/- 6) or group III (34 +/- 8) at comparable LAP values (group I: 20 +/- 5 mm Hg; group II: 18 +/- 3; group III: 18 +/- 4). Post-operative clinical evaluation failed to differentiate among the three groups. The more sensitive indices, however, demonstrated the superiority of cold, multidose cardioplegia in providing optimal myocardial protection.     

Quantitative assessment of myocardial viability following coronary artery bypass grafting using exercise thallium-201 myocardial single photon emission computed tomography and left ventricular regional wall motion

Using exercise thallium-201 myocardial single photon emission computed tomography (SPECT) and % radial shortening (%RS), 58 patients were evaluated before and after coronary artery bypass grafting (CABG) to quantitatively assess myocardial viability and the effect of CABG. The patient was classified, according to redistribution pattern, as group I with only complete redistribution (20 cases) and group II with including incomplete redistribution (22 cases) and group III with no redistribution (16 cases). 1. Group I was expected complete improvement of ischemic myocardium after CABG but regional left ventricular wall motion was unchanged (sigma i%RS: 142.5 +/- 54.7----138.4 +/- 39.6, sigma a%RS: 201.2 +/- 51.1----238.2 +/- 68.2). 2. Group II was expected to diminish ischemic size after CABG and left ventricular regional wall motion was significantly improved (sigma i%RS: 68.8 +/- 25.9----154.9 +/- 42.6 p less than 0.01, sigma a%RS: 108.4 +/- 62.3----178.9 +/- 77.6, p less than 0.05). 3. Group III was no significant change of ischemic size and left ventricular wall motion after CABG (sigma i%RS: 67.8 +/- 24.1----83.9 +/- 19.2, sigma a%RS: 86.0 +/- 29.0----94.0 +/- 33.9). The present study suggests that quantitative assessment of myocardial viability using exercise thallium-201 myocardial SPECT and %radial shortening was useful method to determine the indication and to assess the effect of CABG.