Musical murmurs: an echo-phonocardiographic study

Five patients with muscial murmurs were studied noninvasively with simultaneous echocardiography and phonocardiograpy and phonocardiography. Three patients had aortic regurgitation, one mitral regurgitation and one tricuspid regurgitation. The frequency of the muscial murmurs ranged from 40 to 158 cycles/sec. The patient with tricuspid regurgitation manifested an inspiratory honk. Simultaneous echo-phonocardiography revealed regular valve leaflet flutter (aortic, mitral or tricuspid) at a frequency identical to that of the simultaneously recorded muscial murmur. This study demonstrates that echocardiography is a useful noninvasive tool in identifying the site of origin of musical murmurs.

Ultrastructure and mechanical activity expressed by striated muscle in culture

Newly devised assay procedures for quantitating the mechanical capabilities of striated muscle fibers grown in cell culture have permitted the correlation of cytological features with the ability to respond mechanically to electrical and chemical stimuli during development. By developmental timing and by physiological characteristics, three distinct mechanical activities can be distinguished: : TWITCH, contracture and wave propagation (escalation). Parallel electron microscopy studies suggest that contracture and escalation require significantly greater internal membrane development than twitch. The assay procedures have revealed that fibers developed in culture from genetically dystrophic chick muscle cells display a heightened electrical threshold for a twich response, but are otherwise similar to normal fibers. Cultured chick fibers, whether of leg or breast origin, exhibit similar ultrastructural and mechanical properties; yet these are different from those of in vivo adult muscle and may represent the avian striated muscle archetype expressed in the absence of innervation. Primary or cell line cultures of rat muscle produce far fewer mechanically active fibers than do avian cell cultures. The influence of culture conditions and cell source, whether avian or mammalian, on the extent of differentiation expressed in culture is so great that our understanding of studies on cultured muscle fibers would benefit from some characterization of both morphological and contractile properties of the fibers being used.

Management of sudden coronary death

Twenty-three survivors of out-of-hospital sudden coronary death (SCD) have been followed subsequent to initial hospitalization, cardiac catheterization and coronary angiography, and ultimate coronary revascularization (11 patients) or medical treatment (12 patients). All were treated at the Milwaukee County Medical Center. History of previous myocardial infarction (10 patients) and predominance of triple coronary artery disease (20 patients) with associated ventricular dysfunction (21 patients) demonstrated advanced coronary disease in both groups. Selection for revascularization (mean, 3 grafts per patient) was not randomized, but was based on precarious coronary anatomy and was reinforced by post-SCD ventricular dysrhythmias and angina. During an average follow-up of 13 months, there were 2 perioperative surgical deaths (1 recurrent SCD) and 3 medical deaths (2 recurrent SCDs), giving a mortality rate of 22%. This is an improvement over reported post-SCD natural history and may support a policy of offering revascularization to all SCD patients who have precarious coronary anatomy.

Problems with balloon-tipped stylet pacemaker catheters

Balloon-tipped stylet pacemaker catheters have two intraluminal stylet-related limitations that warrant extreme caution in their use. The first limitation involves manipulation of the stylet inside the catheter and appears to be a consequence of the angulation made by the catheter in the right atrium; the second limitation is a complication involving actual in vivo fracture of the stylet and is presumably related to tapering of the stylet at a point of stress in the right atrium. Although these pacemaker catheters have distinct advantages, the problem arising from their use cannot be ignored. Until modification can be made to resolve these problems, this catheter must be used with extreme caution.

Social-distance preferences among female and male medical students and cardiac patients toward various diseases and disabilities

Attitudinal differences of several non-disabled groups and one disabled group (cardiac) toward 33 disease/disability entities were investigated by using a modification of the Bogardus Social Distance Scale. 33 disease/disabilities were substituted for the original race names used by Bogardus. The scale was administered to several medical fraternities and a group of cardiac surgery patients. Significant differences were found between fraternity men and cardiacs on disease/disabilities which are usually not eligible for vocational services and between male and female medical students on the distance categories of “would marry” and “would not allow in home.” The results indicate definite attitudinal differences among non-disabled groups as well as between the disabled and non-disabled.