In 151 patients experiencing acute myocardial infarction, emergency coronary angioplasty was performed as primary therapy. Overall, angioplasty was successful in 132 patients (87%); it was successful in 91 (85%) of 107 patients with a totally occluded infarct-related artery and in 41 (93%) of 44 patients with a subtotally occluded infarct-related artery. After successful angioplasty, mean residual stenosis was 29% (range 0 to 70). Eighteen patients were in cardiogenic shock (12%) including four patients receiving cardiopulmonary resuscitation during the angioplasty procedure. Hospital mortality was 9%, with 7 of 13 deaths occurring in patients presenting with cardiogenic shock or intractable ventricular arrhythmia. Hospital mortality was 5% in patients with successful angioplasty versus 37% in those with unsuccessful angioplasty (p less than 0.001). In the immediate period after angioplasty, left ventricular ejection fraction was significantly lower for patients with lesions of the left anterior descending artery (34 +/- 10%) than for patients with lesions of the left circumflex or right coronary artery (43 +/- 11%). In patients with successful angioplasty, significant improvement in left ventricular ejection fraction averaged 13 +/- 12% (p less than 0.001) for those with lesions of the left anterior descending artery and 10 +/- 12% (p less than 0.001) for those with lesions of the left circumflex or right coronary artery. Repeat coronary angiography was performed in 85 (70%) of 121 patients who had successful angioplasty and survived hospitalization without requiring bypass surgery; restenosis was found in 26 (31%), and angioplasty was repeated in 22 patients, successfully in each.(ABSTRACT TRUNCATED AT 250 WORDS)

A B S T R A C T Pulsus alternans was induced in 11anesthetized, open-chest dogs by rapid atrial pacing, and the left ventricular filling characteristics and lengthtension-velocity relationship of alternating beats were compared. The end-diastolic circumferences (circ) of the strong beats were slightly, but significantly, increased over the weak beats (7.3 > 6.9 cm, P < 0.01), confirming that diastolic filling does alternate in pulsus alternans. This alternation in initial fiber length seemed to result from an alternation in the prior end-systolic length, rather than from an alternation in diastolic filling time or compliance. There was also no difference in enddiastolic tension as measured by an isometric strain gauge suggesting no difference in contractile element relaxation before weak and strong beats.The contractile state of the strong beats was consistently greater than that of the weak beats when contractility was defined in terms of: (a) Vmax (3.13 > 2.53 circ/sec, P <0.01); and (b) the velocity of circumferential fiber shortening (0.84 > 0.39 circ/sec, P < 0.001) and developed tension (82.5 > 74 g/cm, P < 0.01) at isolength. The length-tension-velocity relationship of the left ventricle also varied between strong and weak beats when: (a) the maximum velocity of contractile element shortening at least common tension (1.68> 1.28 circ/sec, P <0.05); and (b) the velocity of circumferential fiber shortening (0.81 > 0.39 circ/ sec, P < 0.001) at maximum developed tension were examined. Analysis of the length-tension-velocity characteristics of sequential beats at the onset of alternans in three dogs suggests that an alternation in contractility initiates alternans, with secondary alternations in ventricular filling. Cross-clamping of the aorta in three

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A formula was derived for calculating mitral valve stroke volume (MVSV) using the rate of mitral valve (MV) opening (DE slope on the MV echogram), the vertical disease between the mitral leaflet echoes early in diastole (EE), the electrocardiographic PR interval and heart rate. The formula was tested prospectively on 80 consecutive patients from whom 95 simultaneous MV echograms and either thermodilution (45) or Fick (50) cardiac outputs were obtained. Sixteen patients were normal; 54 had coronary artery disease; three had cardiomyopathy; and seven had nonrheumatic mitral regurgitation (MR). Linear regression for stroke volume was r = 0.90, SEE +/- 6, and for cardiac output r = 0.83, SEE +/- 0.5 liter for the 73 patients without MR. The presence or absence of ventricular dyssynergy did not alter statistical findings. MVSV consistently overestimated forward stroke volume for the seven patients with MR. This study shows that the MV echogram provides an accurate, widely applicable method for calculating MVSV.

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