Acute administration of conjugated equine oestrogen does not improve exercise-induced myocardial ischaemia in men with coronary artery disease.

BACKGROUND: The parenteral administration of oestradiol acutely protects against exercise-induced myocardial ischaemia in women, but whether this effect is sex-specific is not known. AIMS: The effects of acutely administered conjugated equine oestrogen on exercise-induced myocardial ischaemia in men with established coronary heart disease were investigated in a randomized, placebo-controlled, double-blind cross-over trial. METHODS: Twenty men, aged 62 +/- 11.6 years, with reproducible exercise-induced myocardial ischaemia were treated with either intravenous conjugated equine oestrogen (25 mg) or saline prior to undergoing an exercise stress test. Primary end-points were total exercise time and time to 1 mm ST-segment depression. RESULTS: All participants completed the protocol. Total exercise time exceeded the baseline value in 17 of the 20 men following saline, and in 17 of the 20 men following oestrogen pretreatment. Time to 1 mm ST-segment depression exceeded the baseline value in 14 of the 19 men following saline, and following oestrogen administration, exceeded baseline in 13 of the 19 men. There was no significant difference between the two treatments in either time to 1 mm ST-segment depression or total exercise time. A period effect was apparent for total exercise time (P = 0.05) but not for time to ST-segment depression. CONCLUSION: Acute parenteral oestrogen therapy did not increase total exercise time or time to the onset of electrocardiographic changes of ischaemia in men with chronic stable coronary artery disease. These findings contrast the favourable effects of oestrogen in women in comparable studies and indicate a sex specificity for the acute cardiovascular effects of oestrogen.

Percutaneous stent placement as treatment for an infant with superior vena cava syndrome.

The percutaneous use of stents for the treatment of superior vena cava (SVC) syndrome is well described in the adult population. We report the successful use of intravascular stents to treat an infant with severe SVC syndrome.

Cardiac pacing in infants and children.

Pacemakers have been implanted in pediatric patients since the late 1960s. Indications for cardiac pacing in infants and children have evolved to include controlling symptoms as well as providing a life-sustaining cardiac rhythm. Pacemakers have become smaller and able to perform more complex functions. Current pacemakers offer a variety of operation modes, which are chosen on the basis of the pacing indication or the potential hemodynamic benefit. Today's pacemakers have the ability to maintain AV synchrony, perform rate-responsive pacing, and sometimes prevent or treat tachyarrhythmias. Recent advances in pacing lead technology, such as steroid elution, have narrowed the gap between epicardial and endocardial leads in terms of chronic pacing thresholds and sensing characteristics. The choice of a permanent pacing system is determined by the patient's size, underlying arrhythmia, and the anatomic details of any structural heart disease. Selection of temporary pacing modalities depends on the urgency of initiating pacing and the anticipated duration of temporary pacing. The decision to implant a permanent pacemaker in a pediatric patient commits the patient to long-term follow-up of pacemaker function. Such follow-up is important to ensure adequate safety margins for pacing and sensing, anticipate the need for pacemaker replacement, screen for pacemaker malfunctions, and optimize programmable settings. Pediatric cardiac pacing has evolved into its own subspecialty over the past decade. As more infants with complex congenital heart disease are being successfully treated with surgical palliation and repair, the population of pediatric patients with permanent pacemakers is likely to increase.

Concurrent use of simvastatin and estrogen--progestin therapy compared with each therapy alone for hypercholesterolemia in postmenopausal women.

OBJECTIVE: Substantial improvements in lipoprotein-lipid profiles have previously been shown with both simvastatin and combined estrogen-progestin therapy in postmenopausal hypercholesterolemic women. Since little is known about the impact of the concomitant use of these therapies, the effects of concurrent hormone therapy and simvastatin in hypercholesterolemic postmenopausal women have been evaluated. METHODS: Twenty-three postmenopausal women with fasting serum total cholesterol levels greater than 250 mg/dl received, in a randomized cross-over design, simvastatin (10 mg daily) for 8 weeks or postmenopausal hormone therapy (up to 1.25 mg of conjugated equine estrogens plus 5 mg of medroxyprogesterone acetate daily) for 8 weeks, with an 8-week wash-out interval between the two treatment periods. In a third, non-randomized treatment period after a second wash-out interval, each woman received a combination of simvastatin and postmenopausal hormone therapy in the same dosage regimens as above. Fasting blood was sampled monthly from baseline to measure total cholesterol, high- and low-density lipoprotein (HDL and LDL) cholesterol, triglycerides and lipoprotein(a). RESULTS: For total cholesterol, the mean decreases with hormone therapy, simvastatin and combination therapy were 12% (95% confidence interval 6-17%), 26% (20-31%) and 28% (24-31%), respectively, and for LDL cholesterol 21% (14-27%), 37% (30-44%) and 46% (41-51%), respectively. Simvastatin was more effective than hormone therapy (p < 0.001), while the effect of the combined therapy was even greater (total cholesterol, p = 0.012; LDL cholesterol, p < 0.001). The level of HDL cholesterol increased similarly with each treatment: 4% (-3-11%), 6% (2-10%) and 7% (2-13%), respectively. Triglyceride levels increased with hormone therapy and decreased with simvastatin (p < 0.001), while there was little change with the combination (effect of combined therapy vs. simvastatin, p = 0.002; vs. hormone therapy, p < 0.001). Both hormone therapy and combined therapy reduced lipoprotein(a) similarly (-23% and -14%, respectively, p = 0.078). Simvastatin had no effect on lipoprotein(a) levels. CONCLUSION: For postmenopausal women with hypercholesterolemia, use of a statin in combination with continuous combined oral estrogen and progestin therapy can result in a more cardioprotective lipoprotein-lipid profile than that achieved with either therapy used alone.

Subatmospheric oxygen therapy complicating subcutaneous emphysema.

An infant with hypoplastic left heart syndrome, excessive pulmonary blood flow, and tachypnea was placed on subatmospheric oxygen (supplemental nitrogen) to increase pulmonary vascular resistance and decrease pulmonary blood flow. His cardiorespiratory status stabilized without mechanical ventilation, but 2 weeks later he developed spontaneous subcutaneous emphysema. The emphysema worsened over approximately 1 month. During this time his left-to-right shunt gradually decreased, and he was weaned to room air. Even without the use of supplemental oxygen the emphysema resolved without complication, and the patient underwent successful orthotopic heart transplantation at 65 days of age.

Estrogen and progestin compared with simvastatin for hypercholesterolemia in postmenopausal women.

BACKGROUND: Postmenopausal estrogen therapy has favorable effects on serum lipoproteins in women with normal serum lipid levels, but the effect of combined estrogen and progestin therapy on lipoproteins in women with hypercholesterolemia has not been determined, nor has it been directly compared with the effect of conventional lipid-lowering therapy. METHODS: In a randomized crossover trial, we studied 58 postmenopausal women with fasting serum total cholesterol levels greater than 250 mg per deciliter. Each woman received simvastatin (10 mg daily) for eight weeks and postmenopausal hormone therapy (up to 1.25 mg of conjugated equine estrogens daily, along with 5 mg of medroxyprogesterone acetate daily) for eight weeks, with an eight-week washout period between the two treatment phases. RESULTS: At base line, the mean (+/-SD) cholesterol values were as follows: total cholesterol, 305+/-39 mg per deciliter; high-density lipoprotein (HDL) cholesterol, 62+/-19 mg per deciliter; and low-density lipoprotein (LDL) cholesterol, 217+/-39 mg per deciliter. For total cholesterol, the mean decrease with hormone therapy was 14 percent (95 percent confidence interval, 11 to 16 percent) and the mean decrease with simvastatin was 26 percent (95 percent confidence interval, 23 to 29 percent). For LDL cholesterol, the mean decrease was 24 percent (95 percent confidence interval, 20 to 28 percent) with hormone therapy and 36 percent (95 percent confidence interval, 32 to 40 percent) with simvastatin. The effect of simvastatin was significantly greater than that of hormone therapy (P<0.001). HDL cholesterol increased similarly with hormone therapy (mean increase, 7 percent; 95 percent confidence interval, 2 to 12 percent) and simvastatin (mean increase, 7 percent; 95 percent confidence interval, 4 to 10 percent). Triglyceride levels increased with hormone therapy (mean increase, 29 percent; 95 percent confidence interval, 15 to 42 percent) but decreased with simvastatin (mean decrease, 14 percent; 95 percent confidence interval, 8 to 20 percent). Lp(a) lipoprotein decreased with hormone therapy (mean decrease, 27 percent; 95 percent confidence interval, 20 to 34 percent), but not with simvastatin. CONCLUSIONS: In postmenopausal women with hypercholesterolemia, therapy with estrogen plus progestin has beneficial effects on lipoprotein levels. Hormone therapy may be an effective alternative to treatment with simvastatin, especially in women with normal triglyceride levels.

Characteristics and management of chaotic atrial tachycardia of infancy.

Chaotic atrial tachycardia was observed in 7 infants without underlying structural heart disease. Clinical presentation and approach to management are discussed, with particular attention to the use of propafenone for this uncommon pediatric arrhythmia.

Clinical implications of the morphological features of central pulmonary artery thromboemboli shown by transoesophageal echocardiography.

OBJECTIVES: To illustrate the use of transoesophageal echocardiography in the detection of the morphological features of central pulmonary artery thromboemboli and their clinical implications. DESIGN: Review of five cases of central pulmonary artery thromboemboli detected by transoesophageal echocardiography. SETTING: University teaching hospital. PATIENTS: Five patients (three men and two women) admitted under general medical units. RESULTS: Central pulmonary artery thromboemboli were detected by the use of transoesophageal echocardiography in all the patients presented. Presentations were acute, subacute, or chronic. The morphological features of the thromboemboli on transoesophageal echocardiography were used to correlate with the time course of the illness, and to guide treatment. Two patients received thrombolytic treatment, one patient was treated with anticoagulation alone, and two patients had inferior vena caval filters implanted. CONCLUSIONS: Transoesophageal echocardiography is an alternative diagnostic tool in the detection of central pulmonary artery thromboemboli. Morphological features of central pulmonary thromboemboli on echocardiography can provide useful information that may help to guide treatment.

Pre-operative assessment of ventricular function in patients considered for Fontan procedure.

In 1978 Choussat and Fontan established ten criteria, which should be fulfilled to achieve a successful outcome in Fontan operation. Recent data suggest that while some of these ten criteria need not be necessarrily be fulfilled, new criteria should be added. These include 1. good diastolic function, 2. normal or only slightly increased ventricular mass, and 3. absence of systemic outflow obstruction. In addition the morphology of the single ventricle may be important as long-term results in patients with single ventricle of right ventricular morphology may be worse than results in patients with single ventricle of left ventricular morphology. Ventricular size and pump function can be assessed by cardiac catherization, echocardiography or magnetic resonance imaging. Estimation of ejection fraction under stress by nuclear angiography may be indicated. Diastolic function can be examined using Doppler echocardiography or nuclear angiography. Myocardial mass may be assessed by echocardiography or magnetic resonance imaging. Normal reference values for different parameters of systolic and diastolic function are listed in the enclosed tables. Patients scheduled for a Fontan operation should have an ejection fraction less than 50%. Patients with borderline ejection fraction should be examined by echocardiography to determine the end-systolic wall stress, a parameter of ventricular contraction, which is independent of pre- and afterload. As afterload may decrease after a Fontan operation some patients with reduced ejection fraction but normal end-systolic wall stress may still be suitable candidates for Fontan operation.(ABSTRACT TRUNCATED AT 250 WORDS)

Steroid-eluting epicardial pacing leads in pediatric patients: encouraging early results.

OBJECTIVES: This study evaluated the pacing and sensing characteristics of a new porous-tipped steroid-eluting epicardial lead in a group of pediatric patients. BACKGROUND: Pacing in children may be complicated by small patient size, patient growth and the prevalence of structural congenital heart disease in children requiring pacing. Epicardial pacing has been associated with a high incidence of problems with sensing and capture, prompting the use of transvenous endocardial pacing when possible. In some children, epicardial pacing may still be desirable because of small patient size, potential for caval obstruction, previous cardiac surgery limiting transvenous access to the heart, or the need to repair congenital heart disease at the time of pacemaker insertion. METHODS: Twelve patients aged 3 weeks to 18 years underwent placement of 23 epicardial pacing leads (8 atrial, 15 ventricular). Pulse width thresholds, sensing thresholds and lead impedance were measured weekly for 6 weeks, then at 3, 6, 12 and 18 months after pacemaker implantation. The median duration of follow-up was 12 months. RESULTS: Ventricular pulse width thresholds did not change over time, whereas atrial pulse width thresholds improved significantly. At 6 months, the mean pulse width threshold at 2.5 V for the atrial and ventricular leads was 0.10 +/- 0.03 and 0.19 +/- 0.09 ms, respectively. The thresholds were slightly lower at 12 and 18 months. At the most recent follow-up, all atrial leads sensed appropriately at 2.5 mV and all ventricular leads at 5 mV. CONCLUSIONS: These encouraging early results suggest that steroid-eluting epicardial pacing leads may be an attractive option for children needing epicardial pacing. Their excellent pacing and sensing characteristics may allow reliable dual-chamber pacing in infants who are too small for transvenous pacing.

Haemodynamic changes and physical performance at comparative levels of haemoglobin after long-term treatment with recombinant erythropoietin.

Physical performance and haemodynamic parameters at rest and with exercise were compared in a prospective, cross-over fashion in 12 anaemic haemodialysis patients (Hb 6.4 +/- 0.5, mean +/- SEM) at two levels of haemoglobin (Hb 9 and 12 g/dl) before and after long-term treatment with recombinant human erythropoietin (rHuEpo). Patients were divided into two groups and measurements made prior to treatment, upon reaching, and after 4 months at the first target Hb (9 g/dl group A, 12 g/dl group B), and after 4 months at the alternative target Hb. Tests included an exercise radionuclide ventriculogram, Doppler echocardiogram, and respiratory function exercise test. Compared to pretreatment, there was a significant reduction in resting pulse rate (P < 0.001), and in pulse rate (P < 0.001) and arterial lactate (P < 0.01) concentrations at specified levels of exercise. Work capacity improved 60% (P < 0.001), and left ventricular mass fell by 26% (P < 0.001). Although cardiac output (CO) during and after exercise was reduced (P < 0.05), resting CO, cardiac index, stroke volume and ejection fraction (rest and exercise) were not significantly altered. There appeared little benefit in having the higher target Hb: no significant difference could be found between target levels for almost any measure. In addition, despite marked improvement from pretreatment levels, performance parameters were still below those of non-uraemic age-matched controls. These results demonstrate the beneficial but incomplete effect of rHuEpo on resting and exercise-related factors, and suggest that most improvement is achieved with modest increments in haemoglobin.

Echocardiographic estimation of critical left ventricular size in infants with isolated aortic valve stenosis.

With the current trend to performing surgical valvotomy for infantile aortic stenosis without cardiac catheterization, there is a need to develop echocardiographic criteria for adequacy of left ventricular size. The echocardiograms and catheterization data of all 25 infants less than 3 months of age undergoing aortic valvotomy for isolated aortic valve stenosis from September 1980 through July 1990 were reviewed. Significant differences (p less than 0.05) between the survivors and nonsurvivors were noted for age at operation (30 +/- 28 vs. 3 +/- 1.5 days), mitral valve diameter (10.1 +/- 1.7 vs. 7.7 +/- 1.5 mm), left ventricular end-diastolic dimension (18.4 +/- 6.4 vs. 11.4 +/- 3 mm), left atrial dimensions (15.3 +/- 3.8 vs. 10 +/- 2.4 mm), left ventricular cross-sectional area on the parasternal long-axis echocardiogram (4 +/- 1.9 vs. 2 +/- 1.9 cm2) and angiographically determined left ventricular end-diastolic volume (43 +/- 23 vs. 11 +/- 5 ml/m2). There was no difference with respect to patient weight, body surface area, aortic root dimension or left ventricular ejection fraction. Left ventricular cross-sectional area less than 2 cm2 as measured on the parasternal long-axis echocardiogram was found in 5 of 7 nonsurvivors and 0 of 12 survivors, making this a risk factor for perioperative death (p less than 0.05). Left ventricular end-diastolic dimension less than 13 mm was found in 5 of 6 nonsurvivors and 2 of 17 survivors, making this another risk factor for early mortality (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Retinal vascular abnormalities in patients with coarctation of the aorta.

Pulsatile three-dimensional retinal arteriolar tortuosity has been previously reported in about 50% of patients with coarctation of the aorta. In a contemporary series of 20 patients with coarctation of the aorta, none exhibited this characteristic retinal vascular abnormality. Our findings suggest that the retinal vascular abnormalities in patients with coarctation of the aorta represent secondary hemodynamic changes. The prevalence of these abnormalities may be decreasing because of earlier surgical repair of coarctation.

Retinopathy of prematurity in infants with cyanotic congenital heart disease.

We undertook a study of premature infants with cyanotic congenital heart disease to determine whether these infants develop retinopathy of prematurity despite a persistent hypoxemic state. Using the computerized registry of the neonatal intensive care unit of Vanderbilt University Medical Center, Nashville, Tenn, we identified six premature infants (less than 37 weeks' gestational age, with birth weights of 1100 to 2050 g) with cyanotic congenital heart disease who survived the neonatal period and underwent ophthalmologic evaluation. Review of their charts revealed that three of six infants developed retinopathy of prematurity (two had grade 1 and one had grade 3 disease), but none required treatment. Our data support the findings of other investigators that elevated arterial oxygen tension is not the sole factor leading to the development of retinopathy of prematurity. Premature infants with cyanotic congenital heart disease can develop retinopathy of prematurity despite persistent hypoxemia. Cyanotic premature infants should be screened for retinopathy of prematurity with the same thoroughness as other premature infants.

The Senning operation for complete transposition: mid-term physiologic, electrophysiologic, and functional results.

SummaryWe report analysis of surgical results in 110 consecutive infants and children who underwent atrial repair of simple complete transposition using the Senning operation between February 1978 and May 1990. Mean age at operation was 5.4 months ± 6.1 (range 1 week to 4 years); 75 were less than 6 months old. There were 72 males and 38 females. Operative mortality rate was 5.5%, with one late death. Average follow-up is 48.1 months with 44 followed greater than 3 years, and 27 greater than 5 years. Postoperative cardiac catheterization was performed in 48 patients. Right ventricular ejection fraction averaged 0.52 ± 0.08 and was normal in 28 patients. Response of right ventricular ejection fraction to afrerload stress was abnormal in 12 of 14 patients tested. Right ventricular ejection fraction increased normally during exercise in 6 patients, but was abnormal in 15. Mild tricuspid regurgitation was noted in 12 patients. Mild obstruction of the superior caval vein was noted in 4 patients. Baffle leak requiring reoperation occurred in one patient. Fifty-seven of 90 patients are in sinus rhythm by latest electrocardiogram. Postoperative electrophysiologic studies were performed in 34 patients, and Holter monitoring in 25. Significant arrhythmia occurred in 26 patients: 6 patients required pacemakers for slow junctional rhythm or complete heart block; 20 additional patients have a junctional rhythm. Six patients have delayed sinus nodal recovery time. At last follow-up, 88 children (98%) are in New York Heart Association functional Class I, and 2 (2%) are in Class II. The Senning operation for compete transposition can be accomplished with a low operative and late mortality. Serious baffle complications requiring reoperation are rare. Surviving patients are clinically well, but arrhythmias and depressed right ventricular function may limit their long-term functional status.

Quantitation of acute myocardial infarct size by nuclear magnetic resonance imaging.

Nuclear magnetic resonance (NMR) imaging has shown potential in the detection and characterization of acute myocardial infarction in humans. This study was performed to evaluate the capability of NMR imaging in the measurement of infarct size in patients with recent myocardial infarction. Electrocardiographic (ECG)-gated spin-echo NMR imaging was performed in 26 patients a mean of 9 +/- 3 days (range 5 to 20) after infarction. The imaging technique used provided single-slice, spin-echo (time to echo [TE] = 60 ms) images of the left ventricle in its true short axis, allowing direct correlation of NMR infarct location and size with the region of severe hypokinesia on left ventriculography. In all 20 patients with complete NMR studies, infarct location was correctly identified by using specific, objective criteria. The correlation between the mean infarct volume (29 +/- 11 ml) and the quantitated left ventricular hypokinetic segment (7.5 +/- 4.0 cm) was good (r = 0.84, p = 0.0002), suggesting that NMR imaging of the heart may have a role in the noninvasive assessment of myocardial infarct size in patients.

Beneficial effects of low dose amiodarone in patients with congestive cardiac failure: a placebo-controlled trial.

The effects of amiodarone in a low dosage (200 mg every 8 h for 2 weeks, then 200 mg/day) was assessed in a double-blind placebo-controlled trial in 34 patients with a history of severe congestive heart failure but no sustained ventricular arrhythmia. Left ventricular ejection fraction, treadmill exercise tolerance and 48 h electrocardiographic monitoring were assessed before and repeatedly after beginning amiodarone or placebo therapy over 6 months, and side effects were monitored. In patients receiving amiodarone, the ejection fraction increased significantly from 19 +/- 7 to 29 +/- 15% at 6 months (p less than 0.01 from baseline), but not significantly in 14 placebo-treated patients (18 +/- 5 to 22 +/- 9%). Exercise tolerance increased significantly in amiodarone-treated patients (median 433 s to 907 s, p less than 0.05), but not significantly in placebo-treated patients (757 to 918 s). Nonsustained ventricular tachycardia was present in 88% of amiodarone-treated patients before, but in only 21% of patients after 6 months of treatment (p = 0.06); it was seen in 43% of placebo-treated patients at baseline and in 50% after 6 months. Fifty percent of amiodarone-treated patients had side effects (principally nausea) and the drug was withdrawn in 28% of cases; no life-threatening effects were seen. Low dose amiodarone appears to have a multifaceted potential to produce benefits in arrhythmia control, exercise tolerance and ventricular function in patients with a history of severe congestive heart failure, but better control of side effects (principally nausea) appears essential. Effects on mortality could not be determined from this study; such assessment requires a larger cohort of patients.

Absence of left ventricular volume loading in infants with coarctation of the aorta and a large ventricular septal defect.

Clinical characteristics and angiographic ventricular volume data were obtained in 25 infants aged 1 to 66 days who presented with coarctation of the aorta, ventricular septal defect and congestive heart failure to determine if left ventricular volume loading was present and if there were hemodynamic or volumetric variables that were predictive of operative mortality in this group. Pulmonary to systemic flow ratio averaged 2.8 +/- 0.8 and right ventricular/left ventricular peak pressure ratio was 0.96 +/- 0.12. Left ventricular end-diastolic volume averaged 116 +/- 49% of normal and was less than the investigators' lower limit of normal in 5 (20%) of 25 patients. In contrast, right ventricular end-diastolic volume, measured in eight patients, averaged 173 +/- 47% of normal and was greater than the investigators' upper limit of normal in seven (88%) of eight. Left ventricular ejection fraction averaged 0.47 +/- 0.17 and was below normal (less than 0.55) in 14 (58%) of 24 patients. Preoperative volume and ejection fraction data did not differ in infants with coarctation plus ventricular septal defect and a similar group of 19 infants with isolated coarctation. Abnormal left ventricular operative volume distensibility was inferred by normal or decreased left ventricular end-diastolic volume and increased left ventricular end-diastolic pressure (greater than 12 mm Hg) in 12 (55%) of 24 patients. Early plus late mortality was related to left ventricular size: 3 of 5 patients with a small left ventricular end-diastolic volume died, compared with only 4 of 20 with a normal or increased volume (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)