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We assessed simultaneously left ventricular filling pressure and stroke index with left ventricular ejection fraction in 22 patients who had had their first transmural myocardial infarction about 11 days before the examination. Eleven were classified as anterior myocardial infarctions and 11 as inferior. Left ventricular ejection fraction was determined by equilibrium radionuclide angiocardiography. Significant correlations between left ventricular ejection fraction and left ventricular filling pressure or stroke index were obtained both at rest and during exercise. Left ventricular dysfunction was more severe in patients with anterior myocardial infarction whose left ventricular ejection fraction at rest was 34.9±3.4% as compared to 52.6±2.1% in inferior myocardial infarction. We conclude that the radionuclide method is as sensitive as catheterization for detecting left ventricular dysfunction at rest and during exercise in patients with myocardial infarction.

Cardiogenic shock caused by papillary muscle rupture in acute myocardial infarction is potentially reversible by surgical treatment. A case of inferior myocardial infarction in a 56-year-old previously healthy man is reported, in which the first event was papillary muscle rupture. The patient was in shock and had a mitral insufficiency murmur. The diagnosis was made by echocardiography and ventriculography. A St. Jude valve was implanted, and the patient was discharged in good health. It is suggested that routine echocardiography be carried out on patients with sudden cardiogenic shock, when a mitral murmur is present.

In a 43 year old man with a well documented inferior myocardial infarction, coronary angiography performed 16 months later revealed a widely patent right coronary artery supplying the infarcted area. Although the fate of the original lesion is unknown, lysis of a previous thrombus seems likely.

Atrioventricular conduction occurred intermittently in a patient paced for complete heart block produced by inferior myocardial infarction. Atrial stimuli were conducted to the ventricles only when they occurred 320 to 360 msec after the spike of the right ventricular endocardial pacemaker. This phenomenon is attributed to the production of supernormal atrioventricular conduction by the pacemaker induced beats.

A patient with a variant form of angina pectoris occurring after an acute nontransmural inferior myocardial infarction is described. A rare simultaneous manifestation of the myocardial ischemic episodes was the recurrence of transient complete A-V block, which on one occasion resulted in an Adams-Stokes attack. Concomitant with the administration of a longacting, oral, coronary vasodilator drug, isosorbide dinitrate, the episodes of chest pain, S-T segment elevation and heart block ceased.

Summary The criteria of the Minnesota code for Q-QS patterns were used in the analysis of a single electrocardiogram during the acute stage of an “inferior” infarction and also after a follow-up period of at least 3 months in 103 patients. During the acute stage 14.5 per cent of the cases showed borderline and 14.5 per cent no codable Q-QS abnormalities. At the time of the follow-up period these figures were 16 and 34 per cent, respectively. At the time of the follow-up, codable ST-T junction and segment, and or T wave abnormalities were no longer present in 23 patients. Seventeen patients had a completely normal electrocardiogram. It was concluded that the Minnesota code applied in the analysis of a single ECG has definite limitations in the recognition of an acute, and certainly of an old, inferior infarction during epidemiological studies.

Two patients with inferior wall myocardial infarction are described in whom “color vectorcardiograms” in the horizontal plane were recorded with an apparatus we have devised. The dashes of the vector loop were colored to indicate variations in height of the deflections in the Y axis. In both cases, the early half of the QRS loop was mostly reddish in color, indicating that this segment of the loop, including its initial deflection, projected abnormally upward. Thus, the diagnosis of inferior wall myocardial infarction was made by the use of a colored vectorcardiogram in a single plane.

1.1. Vectorcardiograms and electrocardiograms were studied in thirteen selected cases with acute cor pulmonale and fifty selected cases with inferior (posterior) myocardial infarction. 2.2. The following diagnostic features were noted in the vectorcardiograms of patients with acute cor pulmonale: increase in duration and magnitude of the initial vectors beyond that found in the normal, but not equalling or exceeding that occurring in inferior myocardial infarction; clockwise rotation of the QRSsE loop as indicated by transient counterclockwise inscription in the sagittal plane and clockwise inscription in the frontal plane; a large terminal appendage directed to the right, posteriorly, and, in some cases, superiorly; a tendency to increased horizontal electrical position; displacement of the S-T junction to the right; and abnormalities of the QRS-T angle. 3.3. The following features were noted in the electrocardiograms of the patients with acute cor pulmonale: clockwise rotation as judged by terminal s waves in Leads I and aV L , late R waves in aV R , q waves in II, III, and aV F , and a shift in the transitional zone to the left; and s waves in II, III, and aV F . 4.4. The sudden appearance following pulmonary embolism of s waves in Leads II, III, and aV F or sudden increase in their magnitude is of diagnostic significance. 5.5. The vectorcardiograms of inferior myocardial infarction can be distinguished from those found in pulmonary embolism principally by the greater duration and magnitude of the initial superiorly directed vectors, and absence of superiorly oriented terminal vectors. Consequently, the corresponding distinguishing features in electrocardiograms of inferior myocardial infarction are broad large Q waves in aV F , initial r waves in aV R , absence or smallness of terminal r waves in aV R , and the absence of terminal s waves in aV F .

To assess whether the site of myocardial infarction is an independent prognostic indicator, the outcome of patients with anterior myocardial infarction was compared with that of patients with inferior infarction. A consecutive series of patients who had suffered their first myocardial infarction was analyzed (398 with anterior and 391 with inferior infarction). Patients with anterior myocardial infarction had a higher 1 year mortality than those with inferior infarction (18.3% vs 10.5%, p = .002). When patients were matched for infarct size determined by peak creatine kinase (CK) level expressed as a multiple of the upper limit of normal, those with anterior myocardial infarction tended to have a higher 1 year mortality than those with inferior infarction for all subgroups of peak CK. Early mortality (day 1 to 28 after myocardial infarction) was greater in the anterior than in the inferior myocardial infarction group (10% vs 6.4%, p = .03); this was most significant when peak CK was greater than four times normal (12.4% vs 7.0%, p = .04). Late mortality was also higher in the anterior (8.4% vs 4.1%, p = .04) than the inferior infarction group and this was most significant when peak CK was less than two times normal (15.2% vs 0%, p = .02) or greater than eight times normal (10.6% vs 4.1%, p = .04). Multivariate analysis with proportional-hazards regression confirmed the prognostic significance of location of infarction independent of peak CK level. Thus, infarct location was found to be a predictor of prognosis that is independent of infarct size based on peak CK levels.

A woman had severe cardiogenic shock complicating rupture of both the interventricular septum and the inferior free wall of the left ventricle. She survived with emergency surgery.

Amiodarone has proved to be a valuable drug in atrial fibrillation associated with the Wolff-Parkinson-White syndrome. When it was administered to a patient with this syndrome in atrial fibrillation, who had previously suffered an inferior myocardial infarction, the ventricular rate accelerated from 170 to 230 beats/minute. This unusual case emphasises the need for full electrophysiological assessment of patients with the Wolff-Parkinson-White syndrome for whom amiodarone treatment is being considered.

The electrocardiogram (EKG) is one of the most widely used diagnostic tests in clinical medicine and is generally considered to be an excellent means of detecting many important cardiac abnormalities. However, when the EKG is interpreted in the traditional manner, its diagnostic performance is not as good as clinicians might wish. For example, a recent study showed that three sets of commonly used traditional EKG criteria for inferior myocardial infarction (MI) had such low sensitivities that they missed between 66% and 96% of the MIs that they were supposed to detect. 1 In contrast, three different sets of vectorcardiographic (VCG) criteria for inferior MI exhibited much better diagnostic performances. The investigators found that the superior performance of the VCG was due to its ability to display information about the contour of the pathway followed by the electrical forces of ventricular depolarization. Despite the reported advantages of the VCG, it is

Initial hemodynamics were studied in 50 patients with acute myocardial infarction classified according to anterior or inferior location. Twenty-two had anterior transmural infarction (indicated by Q wave changes), 12 had anterior necrosis (S-T and T wave changes plus increases in serum enzymes), 11 had inferior transmural infarction and 5 inferior necrosis. When initial left ventricular filling pressure, stroke index, heart rate and stroke work index were considered together in all patients, there was a significant difference (P