ABSTRACTS

LEFT VENTRICULAR FUNCTION IN PATIENTS WITH

NONTRANSMURAL MYOCARDIAL INFARCTION

Pierre Rigo, M.D., H. William Strauss, M.D., Dean R. Taylor, M.D.,

David T. Kelly, M.D., Myron L. Weisfeldt, M.D., Bertram Pitt, M.D.

Johns Hopkins University and Hospital, Baltimore, Md. 21205

Patients with nontransmural myocardiol infarction (NTMI) as diog-

nosed by ST-T wave changes on the electrocardiogram and elevation

of serum enzymes are thought to have less left ventriculardysfunction

and a better prognosis than those with transmurol myocardial inforc-

tion (TMI) with Q waves. Myocordial performance wos assessed in

11 patients with NTMI, 7 of whom were uncomplicated (Class I) and

4 of whom had evidence of mild to moderate congestive heart failure.

(Class II); and in 25 with TMI, 14 in Class I, and 13 in Class II.

The left ventricular filling pressure (LVFP) and cordioc index (Cl)

were measured with a Swon-Gonz thermodilution catheter. Left ven-

tricular ejection fraction (LVEF), end diastolic volume (EDV), and

percent of left ventricular wall akinesis were measured by gated car

disc blood pool scanning (GBPS) with I.V. technetium99n albumin.

NTMI TMI

LVEF % 39+8 37+6

EDV ml 116T28 127738

% Akinesis 24+13 30Tll

LVFP mm Hg 1475 16?8

Cl liters/min/M2 2.871 2.7T.6

There were no significant diRerences between thevalues in those

with NTMI and TMI. LVEFand EDV in both groups were significant-

ly different (P<O.Ol) from that obtained in 10 normol patients using

GBPS 56+3% and 81+4 ml respectively. In conclusion this study

suggests patients with NTMI hove the same degree of myocordial

dysfunction as TMI and does not support functional seporotion of

potients on these electrocardiographic criteria.

MYOCARDIAL IMAGING WITH 99mTc MACROAGGREGATES. CLINICAL, HRMODYNAMIC, ECG, SURGICAL AND AUTOPSY CORRELATIONS James Ritchie, MD, Glen Hamilton, MD, John Murray, MD, Eugene Lapin, MD, VA Hospital, Seattle, Washington.

Scintillation camera‘myocardial perfusion images were performed in 51 patients (pts) with proven or suspected ischemic disease. 1.5 mCi 99mTc macroaggregated albumin was injected directly into one or both coronary arteries.

Myocardial images were classified as normal (26) or abnormal (25) and the location of abnormality noted. 25 pts with abnormal images had myocardial infarction based on history (16/25), Q wave (19/25), or local contractile abnormality (22/25) singly or in combination. No pt with a normal image had a Q wave and only one of 25 had a local contractile abnormality. There was no correlation between an image defect and the presence of exercise in- duced ST depression. Ejection fraction was reduced (p c.001) in pts with abnormal images (43+14% vs. 61+11%). Pts with image defects (11) had trans&ral scar (TO) or inferior hypokinesis (1) observed at surgery or autopsy; pts with normal images all had normal ventricles at sur- gery (414). A single pt with preinfarction angina with- out evidence of infarction had an image defect. Pts with less than 50% stenosis all had normal myocardial images (19 of 19). Pts with complete occlusions had correspond- ing image defects. Two pts with complete occlusions without infarctions had normal images. Six patients with stenoses of 75-99X had image defects; 5 had normal images

We conclude that this technique identifies myocardial scarring secondary to infarction rather than areas of is- chemia. Its sensitivity in the diagnosis of myocardial scar was better than the ECG or clinical history and com- parable to the presence or absence of local contractile abnormalities on ventriculography. It appears useful in identifying scar and as a baseline for stress studies which may induce ischemia.

INCREASED CARDIAC OUTPUT DURING INDUCED IRRlIGULARRHYTHMS

Keith Ritchie, MD; Robert Lux; G. Michael Vincent, MD; Ray Millar, MD, University of Utah, Salt Lake City, Utah.

Irregular rhythm (IR) can increase cardiac output (CO), probably by potentiating contractility. Additional evi- dence for increased inotropic state during IR was obtain- ed in 10 dogs. Aortic flow and left ventricular pressure were measured during regular rhythm (RR) and IR induced by simultaneous atria1 and ventricular pacing from com- puter generated stimuli. IR patterns included 1) random sequences of cycle lengths with a flat distribution (RF), 2) ordered sequences alternating short and long cycles from the same flat distribution (ASL), and 3) sequences alternating maximum and minimum cycle lengths present in those patterns (AWM). Stimulus patterns had the same mean cycle length and the RF and ASL patterns contained equal numbers of any given cycle length. CO was higher with IR than with RR in all experiments. Compared to RR, increases in CO were 5% during RF rhythm, 15% during ASL rhythm and 25% during AMM. Since the cycle lengths in RF and ASL rhythms were identical, it is likely that differ- ences in CO were due to differences in inotropic state. However, the Frank-Starling mechanism could not be total- ly excluded. Evidence that differences were due to vary- ing inotropic state was obtained in 3 experiments in which pressures were recorded in a balloon in an isovol- umic left ventricle preparation. Average peak pressures, maximum dP/dt and dP/dt at selected pressures were higher with IR than with RR and in most observations higher with ASL than with RF. Findings confirm that IB results in changed inotropic state, and show the maximizing of this effect by optimal sequencing of cycle lengths. A new method for study of rhythm effects on the cardiac state by controlling the sequence of a set of identical cycle lengths is reported.

LONG TERM SURVIVAL FOLLOWING AORTIC VALVE REPLACEMENT Douglas L. Roberts, MD; James A. DeWeese, ND; Earl B. Ma- honey, MD; Paul N. Yu, MD, FACC, University of Rochester, Rochester, New York.

Study is made of 77 long term survivors of aortic valve replacement. During follow up (24-98 mos, avg 50.2) an- gina was the leading cause of morbidity (21%) followed by symptoms of congestive heart failure (CHF) (19%). Compli- cations consisted of peripheral emboli (8 pts), hepatitis (5 pts.), and endocarditis (3 pts.). Over one quarter of the patients had a persistent diastolic aortic murmur and 16% clinical evidence of hemolysis. Of the 7 deaths oc- curring in these patients over the follow up period, post mortem information was available in 6. These long term survivors (77) were compared to the group dying within 1 month of valve replacement (24) and those short term sur- vivors (18) living less than 2 years. CHF was the most frequent preoperative disability and occurred with equal incidence in all 3 groups. Angina and syncope, however, were found with a statistically higher incidence in the short term survivors and hospital mortality groups, re- spectively. No statistical difference was found among the 3 groups in respect to patient age, functional class, hemodynamic lesion, duration of preoperative symptoms, left ventricular end diastolic pressure (LVEDP) or right ventricular systolic pressure (RVSP). There was, how- ever, a significantly lower cardiac index (c.i.) of the hospital mortality group as compared with the 2 surviving groups. No significant correlation was noted between the duration of survival and the c.i., LVEDP, or RVSP. 59% of the patients were alive at the end of the follow up. Life table analysis showed marked drops at the end of 12 and 36 mos. It would appear that cardiac index is the best predictor of hospital mortality and that once a pa- tient has survived 3 years, his chances for long term survival are excellent.

January 1974 The American Journal of CARDIOLOGY Volume 33 165