Familial hypertrophic cardiomyopathy and atrial fibrillation caused by Arg663His beta-cardiac myosin heavy chain mutation.

More than 40 different beta-cardiac myosin heavy chain (beta-MHC) missense mutations have been identified that cause familial hypertrophic cardiomyopathy (FHC). Some of these are recognized to have important clinical manifestations, such as an increased incidence of sudden death. We report that the beta-MHC missense mutation Arg663His causes predominant cardiac morphology and atrial fibrillation. Longitudinal clinical evaluations were performed in a kindred with FHC. The nucleotide sequence of the beta-MHC gene was analyzed to define the causal mutation. A missense mutation in the beta-MHC gene, Arg663His, was identified in 24 individuals. Clinical studies demonstrated modest left ventricular hypertrophy in affected individuals, predominantly localized in the proximal segment of the interventricular septum, which increased (average = 40 +/- 8%) during 7 years of follow-up. Results showed that 47% of Arg663His adults (age > 16 years) with ventricular hypertrophy developed atrial fibrillation, significantly more (p <0.001) than observed in ungenotyped FHC populations. Survival of affected individuals remained near normal. The beta-MHC missense mutation Arg663His causes a characteristic pattern of ventricular hypertrophy. Arg663His individuals have a markedly higher prevalence of atrial fibrillation, compared with a population with ungenotyped hypertrophic cardiomyopathy. The demonstration of phenotype as a direct consequence of genotype further extends the utility of molecular data in clinical medicine. Early identification of Arg663His individuals has the potential to minimize the serious sequelae of this arrhythmia in this FHC group.

Aortic valve replacement after repair of pulmonary atresia and ventricular septal defect or tetralogy of Fallot.

OBJECTIVE: Little attention has been paid to the occurrence of aortic regurgitation after complete repair in patients with pulmonary atresia and ventricular septal defect or tetralogy of Fallot. To highlight the development of aortic regurgitation or aortic root dilation severe enough to necessitate aortic valve replacement with or without aortic aneurysmorrhaphy or aortic root replacement, we retrospectively reviewed the records of patients who underwent aortic valve operation at our institution subsequent to repair of pulmonary atresia and ventricular septal defect or tetralogy of Fallot. METHODS: We searched the Mayo Clinic database for patients with pulmonary atresia and ventricular septal defect or tetralogy of Fallot who subsequently had aortic valve or aortic root operations. The degree of aortic regurgitation before operation was noted. Aortic sinus and root dimensions were measured. RESULTS: Sixteen patients underwent complete repair at a median age of 17 years, followed by an aortic operation a median of 13.5 years later. All 16 patients had dilated aortic sinuses at the time of the aortic valve operation. These 16 patients had aortic valve replacement: 11 with mechanical prostheses and 5 with bioprostheses. Five of the 16 also had reduction of aortic dilation by lateral aneurysmorrhaphy, and 1 had graft replacement of the ascending aorta. Five patients had associated conditions (evidence of valvular damage, recurrent ventricular septal defect, or history of endocarditis) discovered at the aortic valve operation that have been reported to be related to the development of aortic regurgitation. The remaining 11 patients had progressive aortic regurgitation despite complete, uncomplicated repair. CONCLUSIONS: Progressive aortic regurgitation and aortic root dilation can occur despite complete repair of pulmonary atresia and ventricular septal defect or tetralogy of Fallot.

Systolic aortic valve compression from partial dehiscence of an aortic valve homograft.

Implantation of valve prostheses provide improvement of symptoms and prolongation of life in selected patients with valvular heart disease. Meticulous follow-up of patients after valve surgery is essential as complications of valve failure, valve dehiscence, valve thrombosis, and infection may occur. The major mode of failure of aortic valve homografts is valve regurgitation, which is readily detected by physical examination. We report a case of left ventricular outflow obstruction after implantation of an aortic valve homograft.

Evaluation of the effect of transthoracic cardioversion from ventricular tachycardia to sinus rhythm on left atrial mechanical function.

We measured left atrial function during sinus rhythm before and after ventricular tachycardia was induced in an electrophysiology laboratory, using peak transmitral A-wave velocity from pulsed-Doppler transthoracic echocardiography as a marker of left atrial mechanical function. The results of this prospective study do not support the hypothesis that a transthoracic shock of mild to moderate energy diminishes atrial mechanical function.

Negative predictive value of the Duke criteria for infective endocarditis.

With use of new Duke criteria, 405 episodes of suspected endocarditis were previously classified as "definite," "possible," or "rejected" endocarditis. To determine the negative predictive value of the Duke clinical criteria for the classification of suspected endocarditis, chart review and follow-up were performed for the 52 episodes in which the diagnosis of endocarditis was rejected. Three of 52 episodes were reclassified to possible endocarditis; 49 episodes in 48 patients met the criteria for rejected endocarditis. Of these 49 episodes, 31 (63%) had a firm alternate diagnosis other than endocarditis, 17 (35%) had resolution of the clinical syndrome leading to the suspicion of endocarditis with < or = 4 days of antibiotics, and 1 patient had no evidence of endocarditis at surgery. Echocardiograms recorded in 3 patients with rejected endocarditis had evidence of oscillating valvular masses, and blood cultures were positive in 13 episodes; none of these patients had evidence of endocarditis at follow-up. Follow-up or outcome information was available in all 49 episodes. Excluding the 5 in-hospital deaths, mean duration (+/- SD) of follow-up was 39.9 +/- 28.8 months (range 0.5 to 108.0); in living patients, mean time to final follow-up was 56.2 +/- 25.2 months (range 25.0 to 108.0). One patient had possible infective endocarditis at autopsy. No patient in our series whose diagnosis of endocarditis had been rejected had proven endocarditis. Therefore, the negative predictive value of the Duke clinical criteria for endocarditis is at least 92%.

Criteria for the diagnosis of endocarditis and the role of echocardiography.

When infective endocarditis is a diagnostic possibility, echocardiography permits noninvasive imaging of cardiac structures. As involvement of the endocardium is a sine qua non of endocarditis, echocardiography may assist in its diagnosis by demonstrating such involvement. The ability of echocardiography to detect the intracardiac manifestations of infective endocarditis has continued to improve, especially with the introduction of transesophageal imaging. This article will discuss some of the echocardiographic findings in endocarditis and elucidate the incorporation of these findings in the new Duke criteria for the diagnosis of endocarditis.

Relief of superior vena cava syndrome due to fibrosing mediastinitis using the Palmaz stent.

Relief of superior vena cava (SVC) syndrome due to non-neoplastic mediastinal disease presents a formidable challenge. Long-term patency of surgically created bypass grafts has been poor, and the morbidity associated with these procedures is substantial. We report a case of SVC syndrome, caused by fibrosing mediastinitis, treated with Palmaz balloon expandable intravascular stents. Intravascular stents are a promising alternative for relief of non-neoplastic SVC obstruction.

Incidence of anatomic variants in Guyon's canal.

This study was undertaken to determine the frequency of variations involving the anatomy of Guyon's canal. A series of 58 wrist dissections revealed a 22.4% incidence of anomalous muscles and a 1.7% incidence of anomalous nerve paths. The relationship of the deep branch of the ulnar artery to the superficial and deep branches of the ulnar nerve was found to vary. Accessory muscles passing through Guyon's canal are common, and are often found bilaterally. Aberrant branching of the ulnar nerve in this area is rare.