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The return of atrial mechanical function and its relationship to embolic events following cardioversion of atrial arrhythmias is controversial. Fourteen patients with atrial arrhythmias were evaluated with pulsed Doppler echocardiography before and after direct current (DC) cardioversion. The atrial filling fraction increased significantly: 1.14 +/- 4.3% at baseline versus 14.9 +/- 13.3%, 13.4 +/- 11.4%, and 21.9 +/- 13.5% at 5 minutes, 30 minutes, and 24 hours, respectively, following cardioversion. Absent atrial mechanical activity was noted in four patients immediately after cardioversion. Mechanical activity resumed by 30 minutes in one patient and at 24 hours in two others. Those with delayed atrial function had lower stroke volumes and atrial filling fractions following cardioversion. An embolic event occurred in one patient who had immediate return of atrial mechanical activity. This patient also had the largest atrial filling fraction of any patient at 24 hours (41%). These data suggest that the degree of atrial mechanical activity following cardioversion is variable and that embolic episodes are not necessarily related to delayed return of atrial mechanical activity following cardioversion.

Analysis of 99 M-mode echocardiograms recorded during and up to 144 months after healing of active bacterial endocarditis limited to the mitral valve in 27 patients disclosed the following: (1) Little to no change occurred in the echocardiographic size of the vegetations during the first 6 weeks after diagnosis and institution of appropriate antibiotic therapy unless a major systemic embolus occurred. (2) The echocardiographic size of the vegetations did not determine the amount of cardiac damage or dysfunction produced by the valvular infection. (3) The larger the vegetations by echocardiogram, the greater was the likelihood of a clinical event compatible with a systemic embolus. (4) The gravest prognostic sign yielded by the echocardiogram was evidence of rupture of chordae tendineae. (5) Although a useful adjunct to diagnosis before appropriate antibiotic therapy was instituted, once bacteriologic cure was achieved, the echocardiogram was of limited value in delineating an active from a heated vegetation. (6) The echocardiographic appearance of the vegetations was not determined by the type of infecting bacterium.

Analysis of 37 M-mode echocardiograms recorded during the period of active bacterial endocarditis (ABE) involving the aortic valve (AV) in 17 patients disclosed one or more echocardiographic abnormalities involving the aortic valve cusps or their immediate vicinity in 15 (88%), including "shaggy" echoes indicative of vegetations in 12 (71%). Of the 12 patients with echocardiographic evidence of AV vegetation, 11 developed overt congestive heart failure (CHF) and either died or had AV replacement, and seven had clinical events compatible with systemic emboli; of the five patients without echo-demonstrated vegetations, only one had CHF, none had AV replacement, two died, and one had a systemic embolus. In comparison to our previously reported echocardiographic observations in patients with ABE involving either the mitral (29 patients) or tricuspid valve (23 patients), infection involving the AV was far more liable to produce overt CHF and systemic emboli, to necessitate valve replacement, and to cause death during the period of active infection.

Sixty-nine patients receiving atrioventricular sequential (DVI) pacemakers are compared to 67 patients receiving ventricular demand (VVI) pacemakers for control of the symptoms of sinus node dysfunction. The populations were similar with comparable preparing incidences of each assayed symptom and number of symptoms per patient (symptom density). Syncope was well controlled by both DVI and VVI pacing. DVI pacing was better than VVI pacing for control of all other symptoms. Symptom density response: DVI pre, 3.3 +/- 0.95; post, 0.43 +/- 0.63; VVI pre, 3.2 +/- 0.97; post 1.75 +/- 1.44 (p less than 0.000). Atrial electrode problems were encountered in five (7.3%) of the DVI patients and one (0.74%) ventricular electrode required repositioning.

A review of 494 myocardial lesions at least 3 cm. in one dimension reveal 418 (85 per cent) related to atherosclerotic coronary lesions, 55 (11 per cent) related to coronary emboli of various types, 18(3.5 per cent) without specific coronary lesions but related to clinical events associated with coronary hypoperfusion, and 3 (0.5 per cent) associated with miscellaneous coronary lesions. In 399 of 418 (96 per cent) atherosclerotic coronary lesions of all ages complete occlusion (remote of fresh) or histological evidence of lumenal recanalization was present. These coronary lesions were situated within extramural coronary artery segments one to several centimeters proximal to the myocardial lesions which were confined to the distribution of the respective partially or totally occluded coronary segments. In the atherosclerotic cornary lesions less than 2 weeks of age partially or totally occlusive thrombus was found in 67 of 69 (97 per cent) cases and a underlying plaque ulceration, erosion, or rupture was present in 64 of 69 (93 per cent) instances. These endothelial and intimal injuries were generally focal in nature, often extending over a length of only 100 to 200 mu. In no instance could it be stated with certainty that the oldest portion of the atherosclerotic ulceration-thrombus complex was younger in age than its associated myocardial lesion. On the contrary, in 10 of 69 (14 per cent) of the cases portion of the coronary thrombus, usually at the site of plaque ulceration, were histologically older than the myocardial lesion. In addition, the presence of thrombus and plaque debris admixtures further suggested the antecedent nature of the coronary lesion in relation to the myocardial lesion. Atherosclerotic coronary lesions associated with myocardial lesions of 2 to 8 weeks of age had identifiable thromboses in all instances and underlying plaque ulceration, erosions, or ruptures in 17 of 21 (80 per cent). Endothelial injuries were more difficult to assess due to the obscuring features of organizing lumenal thrombus. Interface i.e., plaque ulceration, erosions, or ruptures, were reliably detectable up to approximately on month of age. Coronary arter thromboemboli accounted for a significant percentage of myocardial lesions, were usually associated with normal or minimal coronary artery disease, and frequently involved smaller intramural coronary vessels of the heart. Organization and recanalization of thromboemboemboli tended to be rapid and complete so that in the late stages the residual intimal plaque was sometimes difficult to identify. Myocardial lesions related to clinical events associated with coronary artery hypoperfusion centric, and not confined to the distribution of a single coronary artery. They were unassociated with acute coronary lesions and histologically displayed contraction band necrosis more frequently than the embolic and atherosclerotic related lesions. An explanation was found for the overwhelming majority of myocardial lesions...

It is generally appreciated in the cardiovascular literature that calcium emboli to a central retinal artery or its branches may be the presenting feature of otherwise uncomplicated calcific aortic stenosis. The ophthalmologic literature provides good evidence for this point. Over a 7-month period, four such cases have come to our attention. Other potential sources of emboli were excluded by standard noninvasive and invasive diagnostic techniques, and two patients underwent successful aortic valve replacement. Previous studies of calcific aortic stenosis have demonstrated postmortem histologic evidence of calcium emboli to various organs, for example, heart, kidney, or brain. Since these emboli are small, their occurrence is clinically silent. The retinal circulation is unique in that its occlusion by a calcium microembolus results in loss of vision, and this symptom may be a clue to the presence of calcific aortic stenosis.

The use of electrical energy for the immediate treatment of atrial and ventricular arrhythmias is practical and easily applied. The method, though simple, is the most effective method for terminating cardiac arrhythmias and is associated with only a low risk if properly employed. In symptomatic patients, the utilization of cardioversion reduces patient discomfort and complications which may occur while awaiting pharmacologic reversion of arrhythmia. At present, transthoracic defibrillation is the only practical method for terminating VF. Despite the safety of electrical reversion, proper precautions are necessary to prevent complications. In particular, the discharge of excessive energies, especially in the presence of digitalis toxicity, promises grave and life-threatening consequences. The use of antiarrhythmic medications is not supplanted by cardioversion and defibrillation. Rather, ongoing drug therapy is frequently necessary to prevent recurrence of arrhythmia.