Subaortic obstruction after sildenafil in a patient with hypertrophic cardiomyopathy.
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Cardiomyopathy, Hypertrophic↗
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Mitral valve regurgitation.
The mitral apparatus is a complex structure composed of several components, each of which can be affected by a variety of diseases, resulting in mitral regurgitation. The physiologic consequences of mitral regurgitation include reduced forward stroke volume; increased left atrial volume and pressure; and reduced resistance to left ventricular ejection. The latter explains why indices of systolic left ventricular function (ejection fraction) are often increased early in the course of mitral regurgitation. With the insidious development of mitral regurgitation, the left atrium dilates to accommodate the increase in volume, thereby reducing the atrial pressure. However, with the acute development of mitral regurgitation into a nondilated left atrium, pressure rises rapidly, producing pulmonary edema. The predominant clinical symptoms in chronic mitral regurgitation of dyspnea and fatigue result from pulmonary venous hypertension and low cardiac output. The cardinal physical finding is a mitral systolic murmur. Since the murmur can assume various configurations, the most reliable way to establish its correct origin is by bedside physiologic maneuvers. Typically, in the beat following a premature contraction or after a long pause during atrial fibrillation, the murmur of mitral regurgitation is unchanged in intensity, but murmurs due to left ventricular outflow obstruction increase. Also, isometric handgrip exercise increases the intensity of the murmur and a Valsalva maneuver decreases it during the strain phase. Echocardiography is the most useful noninvasive technique for evaluating patients with mitral regurgitation. Visualization of the mitral apparatus may establish the etiology of regurgitation, and measurement of left atrial size and left ventricular size and performance is useful for assessing the functional significance of the lesion. Doppler echocardiography can establish the diagnosis of mitral regurgitation in difficult cases with multi valve disease and can estimate the severity of the regurgitation. Cardiac catheterization and angiography are usually reserved for the patient being considered for valvular surgery. The natural history of chronic mitral regurgitation is characterized by slowly progressive symptoms, and often the onset of disabling symptoms is the result of irreversible left ventricular dysfunction. Medical therapy consists of digitalis, diuretics, and vasodilators for symptomatic patients. When symptoms occur despite this therapy, valvular surgery should be considered before left ventricular function becomes abnormal.
Cardiac Catheterization↗
Sudden death in athletes.
HCM, as well as coronary and myocardial structural abnormalities, is the most common pathology leading to SCD in young athletes. Furthermore, SCD from fatal arrhythmia seems to be the most common mechanism of death. In this population, however, data are insufficient to support either invasive or noninvasive approaches to clarify risk stratification for SCD. Because of the large population, variants of normal found within the athletic population, and the rarity of the disease, screening for individuals at risk is neither practical nor cost-effective. Not all athletes with HCM are at the same risk for SCD; a thorough history and physical examination should alert the health professional to potential risk factors. Efforts are under way to stratify athletes at risk for SCD to determine who can participate in competitive sports and who should not. However, until research can accurately define variables of hemodynamic and electrical instability that permit reliable identification of athletes with HCM who are at risk for SCD, the recommendation is to disqualify athletes with confirmed HCM from moderate- to high-intensity competitive sports. This recommendation includes athletes with or without symptoms or left ventricular outflow obstruction. Due to the decreased risk of SCD in older athletes, individual judgment of eligibility may be used. Athletes thought to have had myocarditis should be withdrawn from all competitive sports for a convalescent period of approximately 6 months, with thorough cardiac assessment and testing performed before returning to training. Athletes with atrial or ventricular tachyarrhythmia must be screened for structural abnormality, heart response during exercise, and the frequency and duration of the arrhythmia.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Replacement of the aortic valve or root with a pulmonary autograft in children.
Between January 1967 and December 1988, 34 patients ranging in age from 3 to 18 years (mean, 14 +/- 3.6 years) underwent replacement of the aortic valve or root with their own pulmonary valve. The indication for operation was left ventricular outflow obstruction in 16 patients (47%), aortic regurgitation in 14 (41%), mixed aortic valve disease in 3 (9%), and failure of a previously implanted aortic homograft in 1 (3%). There were four early deaths, all before 1971, giving a hospital mortality of 11.8% (70% confidence interval, 6% to 20%). Surviving patients have been followed up a cumulative total of 214 patient-years, the longest period of observation being 16 years 8 months. Late mortality was 13.3% (70% confidence interval, 7% to 23%), and 4 other patients required removal of the pulmonary autograft for endocarditis. Actuarial rates at 16 years were 74% +/- 11% for freedom from reoperation on the left ventricular outflow tract, 80% +/- 10% for freedom from reoperation on the right ventricular outflow tract, and 77% +/- 10% for late survival. There was no instance of primary structural degeneration in the pulmonary autograft, and all surviving patients were in New York Heart Association functional class I without medication. This experience demonstrates that the pulmonary autograft can achieve good early and medium-term results in young patients. Should growth potential be realized, it might constitute the ideal biological valve for the left ventricular outflow in children.
Adolescent↗
The value of exercise test, Holter monitoring, and programmed electrical stimulation in detection of ventricular arrhythmias in patients with hypertrophic cardiomyopathy.
To determine the best way to detect serious ventricular arrhythmia in patients with hypertrophic cardiomyopathy (HCM), 15 patients with HCM performed an exercise test, had Holter monitoring during 24 hours, and programmed electrical stimulation (PES) in a randomized order, and the presence and type of ventricular arrhythmia was noted. During exercise testing, only one patient demonstrated ventricular tachycardia (VT) just prior to the test. By Holter monitoring, four patients had short episodes of asymptomatic VT. PES, using up to three extrastimuli induced VT or ventricular fibrillation (VF) in ten patients including those with VT during exercise testing and Holter monitoring. There were no differences between patients with and without ventricular arrhythmia during PES regarding age, left ventricular outflow obstruction, thickness of interventricular septum, interventricular septum/posterior wall thickness ratio, corrected QT interval, or the amplitude of the R wave in lead aVR in electrocardiography. Our results indicate that inducible VT/VF during PES is a common finding in patients with HCM. Twenty-four hour Holter monitoring was superior to exercise testing in revealing serious ventricular arrhythmia in those patients.
Cardiac Pacing, Artificial↗
Clinical practice. Hypertrophic obstructive cardiomyopathy.
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Adrenergic beta-Antagonists↗
Aortic arch interruption in infancy: radio- and angiographic features.
The radio- and angiocardiographic characteristics of 19 infants with an interrupted aortic arch were reviewed. There were three with type A (distal to the left subclavian artery), 15 with type B (between the left carotid and subclavian arteries), and one with type C (between the innominate and left carotid arteries). Associated cardiovascular anomalies were numerous, a ventricular septal defect (19/19) and a patent ductus arterisous (18/19) being the most common. Plain film signs of aortic interruption were nonspecific. Left ventriculography using angled oblique views was diagnostic of the interruption and most other abnormalities. The constant presence of a ventricular septal defect and frequent occurrence of left ventricular outflow obstruction in these infants lends support to the theory that decreased flow in the fetal ascending aorta predisposes to interruption of the aortic arch.
Angiocardiography↗
Airway obstruction in children with congenital heart disease: assessment by flexible bronchoscopy.
We assessed the spectrum of airway disorders in children with congenital cardiac anomalies, and reviewed our experience in using flexible bronchoscopy for assessment of airway problems in this patient group. The clinical records, flexible bronchoscopic findings, and cardiac imaging results of pediatric cardiac patients who presented with either clinical or radiological signs of airway obstruction between 1992-1999 were reviewed. Flexible bronchoscopic assessment was performed with the patients under sedation and topical anesthesia, using one of two bronchoscopes, i.e., an Olympus BFN20 or Olympus BF3C20. Of a total of 52 patients, 33 had acyanotic cardiovascular lesions, the commonest being left-to-right shunts (61%), while 19 had cyanotic heart lesions, with right ventricular outflow obstruction being the commonest (63%). Twenty-seven patients had undergone either surgical or transcatheter interventions. The median age at bronchoscopic assessment was 6 months (range, 4 days to 6 years). None of the patients developed significant procedural complications. A definitive diagnosis was made in 48 (92%) patients, 8 of whom had abnormalities involving only the upper airways, 35 only the lower airways, and 5 both. Abnormalities of the upper airway included laryngomalacia (n = 6), subglottic stenosis (n = 3), pharyngeal collapse (n = 2), and 1 each of choanal stenosis and supraglottitis. Extrinsic compression was the commonest lower airway abnormality that was found in 27/40 patients (67%), with a predilection for the left main bronchus (18/27, 67%). The structures that caused extrinsic compression included dilated pulmonary arteries with or without left atrial dilation (n = 20), an anomalous aortic or pulmonary arterial course (n = 3), a dilated aorta (n = 1), and a shunt (n = 1), but were not obvious in 2 patients. Intrinsic lower airway abnormalities included bronchomalacia (n = 4), tracheal stenosis (n = 4), and one each of variant bronchial bifurcation and a pouch arising from the tracheal wall. Intraluminal mucus plugging of the lower airways occurred in the remaining 3 patients. Children with congenital heart disease are at risk of airway obstruction both before and after surgery. Flexible bronchoscopy, being safe and effective in diagnosing airway disorders in this patient group, should be considered as the first line of investigation.
Airway Obstruction↗
Gated SPECT in patients with hypertrophic obstructive cardiomyopathy undergoing transcoronary ethanol septal ablation.
BACKGROUND: Transcoronary ethanol septal ablation (TESA) is a novel treatment for obstructive hypertrophic cardiomyopathy (HOCM). Our objective was to evaluate the use of gated single photon emission computed tomography (SPECT) in patients with HOCM and the effects of TESA on myocardial perfusion. METHODS AND RESULTS: We performed gated SPECT and Doppler echocardiography before and 6 weeks after TESA in 30 patients with severe HOCM. The lung-to-heart and septal-to-lateral wall count-activity ratios were calculated. Before ablation, SPECT showed perfusion abnormalities in only 6 patients. Asymmetric septal hypertrophy was noted in 21 patients (70%). In patients with a lung-to-heart ratio greater than 0.50 before ablation, the ratio decreased from 0.56 +/- 0.04 to 0.45 +/- 0.08 after ablation (P <.01). The septal-to-lateral wall ratio also decreased significantly after ablation. Mean Doppler pressure gradient across the left ventricular outflow tract decreased from 52 +/- 39 mm Hg to 13 +/- 13 mm Hg (P <.01) immediately after ablation and to 10 +/- 21 mm Hg 6 weeks later (P <.01). There were no significant changes in left ventricular ejection fraction by gated SPECT after the procedure. SPECT studies done after ablation showed fixed septal defects in 29 of 30 patients (96.7%). The defects involved the basal and mid septum in 100% and 38% of patients, respectively, and ranged in size from 2% to 30% of the left ventricle (mean, 8.8% +/- 7.0%). CONCLUSIONS: TESA is an effective technique for relieving left ventricular outflow obstruction in patients with HOCM. Myocardial gated SPECT can identify the presence and location of infarction after TESA.
Adolescent↗
Two-dimensional echocardiography in the older child.
The role of two-dimensional echocardiography in the management of any congenital cardiovascular anomaly depends on the lesion's natural history and surgical alternatives. Diagnostic assessment of subaortic stenosis and postoperative follow-up of Fontan and Mustard/Senning procedures and tetralogy of Fallot reconstruction illustrate the application of two-dimensional echocardiography to the management of these problems in the older child. Two-dimensional echocardiography displays the static anatomic as well as dynamic functional sequels of left ventricular outflow obstruction. Detailed anatomic display of Fontan reconstruction is compromised by its somewhat unpredictable spatial organization. Combining two-dimensional imaging with gated pulsed Doppler techniques, however, supplements limited anatomic definition with flow profile data specific to the varied surgical interpretations of the Fontan principle. In a similar manner, combined imaging after Senning/Mustard procedures permits detailed anatomic and hemodynamic interrogation of pulmonary and systemic venous return to the neo-left and neo-right atria. The limitations of cardiac ultrasound imaging of the older child after tetralogy of Fallot reconstruction offer some insight into the future directions that are necessary in the application of this imaging technique. Imaging of these patients is compromised by the prosthetic material, which compromises the assessment of right ventricular outflow pulmonary artery reconstruction and ventricular septal closure. Although gated pulsed Doppler echocardiography overcomes some of these limitations, better tissue characterization in the presence of bioprosthetic material is necessary.
Aortic Valve Stenosis↗
Mitral regurgitation due to ruptured chordae tendineae in patients with hypertrophic obstructive cardiomyopathy.
Mitral valve regurgitation in association with hypertrophic obstructive cardiomyopathy is usually caused by the systolic anterior motion of the anterior mitral leaflet. Recently, five patients were encountered with hypertrophic obstructive cardiomyopathy who had mitral regurgitation due to ruptured chordae tendineae. The diagnosis was confirmed in all patients during operation for left ventricular septal myectomy-myotomy (Morrow procedure). Preoperative identification of ruptured chordae tendineae as the cause of mitral regurgitation was established by transesophageal echocardiography in the three most recent cases. All patients had successful septal myectomy-myotomy for relief of left ventricular outflow obstruction, and mitral valve competence was restored by valve repair rather than by prosthetic valve replacement. The clinical course of these patients illustrates important management considerations as well as the utility of transesophageal echocardiography for diagnosis. Chordal rupture should be considered in the differential diagnosis of mitral regurgitation in patients with hypertrophic obstructive cardiomyopathy, especially in those with acute hemodynamic deterioration.
Adult↗
Interruption of aortic arch associated with pulmonary valve stenosis.
A newborn male is described who presented with interruption of aortic arch associated with ventricular septal defect and pulmonary valve stenosis. He underwent total corrective surgery and was discharged with good clinical results. The combination of significant right ventricular outflow obstruction and interruption of aortic arch is incompatible with fetal survival unless there are large collateral arteries which arise early in pregnancy. This is the first report of this combination of lesions.
Aorta, Thoracic↗
Evolution of the electrocardiogram in young dogs with congenital heart disease leading to right ventricular hypertrophy.
In 18 pups obtained from a breeding colony established for investigation of hereditary heart disease, ECG's were recorded shortly after birth. The ECG's, as well as clinical examinations, were repeated weekly in pups surviving the first week of life. The QRS modal axis was constructed in the frontal, transverse and sagittal planes. Cardiac catheterization was performed on all pups reaching the age of 8 to 12 weeks. VCG's were taken on selected pups. All dogs were necropsied terminally. In pups with severe pulmonic stenosis a pathological right ventricular hypertrophy was recognized immediately after birth. No evolution to a left ventricular dominance occurred in the serial tracings. Pups with milder grades of right ventricular outflow obstruction showed a normal evolution pattern or some minor deviations from the normal QRS complex evolution. In pups with patent ductus arteriosus (PDA) and left-to-right shunt, there was no difference from the normal ECG evolution within the first 12 weeks of life, except for some increase in amplitude. Two cases of PDA and right-to-left shunt were not different from the "physiologic right ventricular hypertrophy" at birth, but developed a severe right ventricular hypertrophy pattern within the first 12 weeks of life without any clinical signs of a left-to-right shunting within the period.
Animals↗
Causal relation between the pressure gradient and left ventricular ejection time in hypertrophic cardiomyopathy.
This study was designed to evaluate the relation between severity of obstruction to left ventricular outflow and left ventricular ejection time in hypertrophic obstructive cardiomyopathy. With dual catheters across the left ventricular outflow tract, the pressure gradient and corresponding left ventricular ejection time were measured in 10 patients as the pressure gradient was pharmacologically provoked or abolished, or both. The patients were studied during constant atrial pacing to avoid the potential errors introduced with heart rate correction equations. The pressure gradient was pharmacologically provoked or reduced over a range of greater than or equal to 62 mm Hg per patient. In each patient the left ventricular ejection time varied directly with the pressure gradient (mean r = 0.97, range 0.92 to 1.00). The change in magnitude of the pressure gradient varied directly with the corresponding change in the measured ejection time (mean r = 0.98, range 0.97 to 1.00). When the data from all 10 patients were pooled with use of Weissler's heart rate correction equation, the relation between the corrected left ventricular ejection time and the pressure gradient was still significant and linear (r = 0.86), but less so than in individual patients. This difference was the result of marked interpatient variability in the slope of this linear relation reflecting interpatient differences in other important factors, such as underlying myocardial contractility and stroke volume, that influence left ventricular ejection time. This study demonstrates a clear, direct and highly significant relation between the magnitude of the pressure gradient and the left ventricular ejection time in hypertrophic obstructive cardiomyopathy.(ABSTRACT TRUNCATED AT 250 WORDS)
Cardiac Catheterization↗
Comparison of ethanol septal reduction therapy with surgical myectomy for the treatment of hypertrophic obstructive cardiomyopathy.
OBJECTIVES: This study was designed to compare the hemodynamic efficacy of nonsurgical septal reduction therapy (NSRT) by intracoronary ethanol with standard therapy (surgical myectomy) for the treatment of hypertrophic obstructive cardiomyopathy (HOCM). BACKGROUND: Nonsurgical septal reduction therapy has gained interest as a new treatment modality for patients with drug-refractory symptoms of HOCM; however, its benefits in comparison to surgery are unknown. METHODS: Forty-one consecutive NSRT patients at Baylor College of Medicine with one-year follow-up were compared with age- and gradient-matched septal myectomy patients at the Mayo Clinic. All patients had left ventricular outflow obstruction with a resting gradient > or =40 mm Hg and none had concomitant procedures. RESULTS: There were no baseline differences in New York Heart Association class, severity of mitral regurgitation, use of cardiac medications or exercise capacity. One death occurred during NSRT because of dissection of the left anterior descending artery. At one year, all improvements in both groups were similar. After surgical myectomy, more patients were on medications (p < 0.05) and there was a higher incidence of mild aortic regurgitation (p < 0.05). After NSRT, the incidence of pacemaker implantation for complete heart block was higher (22% vs. 2% in surgery; p = 0.02). However, seven of the nine pacemakers in the NSRT group were implanted before a modified ethanol injection technique and the use of contrast echocardiography. CONCLUSIONS: Nonsurgical septal reduction therapy resulted in a significantly higher incidence of complete heart block, but the risk was reduced with contrast echocardiography and slow ethanol injection. Surgical myectomy resulted in a significantly higher incidence of mild aortic regurgitation. Nonsurgical septal reduction therapy, guided by contrast echocardiography, is an effective procedure for treating patients with HOCM. The hemodynamic and functional improvements at one year are similar to those of surgical myectomy.
Analysis of Variance↗
Baffle fenestration with subsequent transcatheter closure. Modification of the Fontan operation for patients at increased risk.
Ventricular dysfunction, elevated pulmonary vascular resistance, and residual distal pulmonary artery distortion contribute to early mortality after a Fontan operation; they may be transient or reversible. A baffle fenestration, allowing right-to-left shunting, maintains cardiac output and limits right atrial pressure. A baffle fenestration was surgically created at the time of a modified Fontan repair in 20 consecutive patients. Risk factors included pulmonary artery pressure of 18 mm Hg or more, end-diastolic pressure of 12 mm Hg or more, valvar regurgitation, pulmonary artery distortion, pulmonary vascular resistance of 2 Woods' units or more, ventricular outflow obstruction, and complex anatomy. Nineteen of 20 patients survived. After the operation, mean arterial oxygen saturation was 86%, mean right atrial pressure was 15 mm Hg, and mean duration of pleural effusions was 6 days. Twelve of 19 survivors tolerated early test occlusion and had permanent transcatheter umbrella closure. Four patients failed early test occlusion, with a significant decrease in venous O2 saturation and a rise in central venous pressure, due to ventricular dysfunction, pulmonary artery distortion, or aortopulmonary collaterals. Three of four had successful late closure of the fenestration after correction of these abnormalities.
Cardiac Catheterization↗
Ross/Konno procedure for critical aortic stenosis in infancy.
Although the Ross procedure has been applied successfully to the pediatric age group, it may have its ideal application in the selected infant with critical aortic stenosis and complex left ventricular outflow tract obstruction with adequate ventricular function and size. Two neonates presented with critical aortic stenosis and complex left ventricular outflow tract obstruction, and a combined Ross/Konno procedure was performed successfully. These cases are presented along with a discussion of this topic.
Aortic Valve Stenosis↗
Clinical utility and safety of exercise testing in patients with hypertrophic cardiomyopathy.
BACKGROUND: Exercise testing has long been employed in patients with hypertrophic cardiomyopathy (HCM), although concerns have constantly been expressed regarding its safety. This study reviews a large number of exercise tests performed in a community-based population with HCM, in terms of safety and clinical utility. METHODS: We analyzed a total of 243 maximal symptom-limited cycloergometer exercise tests performed at our institution in 138 patients with HCM (age 42 +/- 14 years, M/F 99/39), who were followed systematically for 9.4 +/- 6.5 years. RESULTS: In none of the 243 exercise tests did cardiac arrest, hemodynamic collapse or malignant arrhythmia occur, although 53 of the study patients (38%) had > or = 1 risk factors including previous cardiac arrest, recurrent syncope, malignant family history and resting left ventricular outflow obstruction. Early termination of the test was necessary in only 8 patients due to symptomatic hypotension with dizziness, but none had syncope. Mean predicted functional capacity achieved by the study group was 77 +/- 22%. Poor performance (< 60% of predicted functional capacity) was observed in 32 patients (23%), and it was associated with a NYHA functional class > 1 and an abnormal blood pressure response to exercise. Non-malignant arrhythmias occurred in 41 patients (30%), including multiple premature ventricular beats (PVB), paroxysmal atrial fibrillation, non-sustained ventricular (NSVT) and supraventricular tachycardia. The combined presence of multiple exercise-induced PVB and NSVT on Holter ECG had a 14% positive but a 97% negative predictive value for sudden death or cardiac arrest. CONCLUSIONS: 1) Exercise testing is safe in a community-based population of patients with HCM, and provides useful information regarding functional capacity, efficacy of treatment, blood pressure response to exercise and inducible ischemia. Thus, ergometry should routinely be included in the standard evaluation and follow-up protocols of HCM patients. 2) Conversely, the utility of ergometry in the evaluation of the arrhythmic risk in HCM patients appears to be limited to the identification of low-risk patients.
Adult↗