Right ventricular infarction. Clinical and hemodynamic features

Six patients with acute myocardial infarction presented with hemodynamic evidence of predominant right ventricular failure, characterized by a mean right atrial pressure averaging 20.2 mm Hg and left ventricular filling pressure averaging 16.3 mm Hg. Autopsy in two cases revealed extensive involvement of the right as well as the left ventricle. Clinically the patients usually had evidence of diaphragmatic wall infarction, distended neck veins, hypotension and heart block. Pressure contours and mean pressure often showed no significant change as the catheter was advanced from the right atrium to the pulmonary artery. Shock in three patients was effectively treated with plasma volume expansion, to increase further right-sided pressure, or the administration of sodium nitroprusside, to reduce left-sided filling pressure. It is suggested that when right ventricular infarction accompanies left ventricular infarction, a unique clinical and hemodynamic syndrome occurs because the ability of the right ventricle to maintain adequate left ventricular filling is impaired. Recognition of this syndrome is vital if appropriate therapy is to be instituted.     

Criteria for electrocardiographic differentiation of right ventricular hypertrophy from true posterior myocardial infarction

Electrocardiograms recorded from patients with true posterior myocardial infarction show an abnormal anterior shift in the QRS forces. Differentiation of these records from those of right ventricular hypertrophy has been recognized as a difficult problem for a long time. An attempt was made to establish criteria for separating electrocardiograms of posterior myocardial infarction from those of right ventricular hypertrophy exhibiting a similar pattern. Frank lead electrocardiograms obtained from 81 patients with posterior myocardial infarction were compared with electrocardiograms recorded from 71 patients with right ventricular hypertrophy.With two measurements that can be easily obtained, 70 percent of the posterior myocardial infarction records were classified correctly with 15 percent of the right ventricular hypertrophy records being misclassified. A set of three measurements for right ventricular hypertrophy correctly identified 55 percent of cases of right ventricular hypertrophy; however, 13 percent of the posterior myocardial infarction records were misclassified as right ventricular hypertrophy.With seven measurements obtained on the basis of multivariate analysis, 78 percent of the posterior myocardial infarction and 79 percent of right ventricular hypertrophy cases were correctly classified. These measurements were found to be useful in classifying records that could not be categorized by hand measurements. Classification procedures were also tested in 23 autopsy cases with results equal to or slightly better than those obtained in clinical samples.Several measurements on the QRS vector loop previously considered useful in the differentiation of right ventricular hypertrophy from posterior myocardial infarction gave disappointing results when tested in our samples.     

Clinical application of a second generation electrocardiographic computer program

An electrocardiographic computer program based on multivariate analysis of orthogonal leads (Frank) was applied to records transmitted daily by telephone from the Veterans Administration Hospital, West Roxbury, Mass., to the Veterans Administration Hospital, Washington, D.C. A Bayesian classification procedure was used to compute probabilities for all diagnostic categories that might be encountered in a given record. Computer results were compared with interpretations of conventional 12 lead tracings. Of 1,663 records transmitted, 1,192 were selected for the study because the clinical diagnosis in these cases could be firmly established on the basis of independent, nonelectrocardiographic information. Twenty-one percent of the records were obtained from patients without evidence of cardiac disease and 79 percent from patients with various cardiovascular illnesses. Diagnostic electrocardiographic classifications were considered correct when in agreement with documented clinical diagnoses. Of the total sample of 1,192 recordings, 86 percent were classified correctly by computer as compared with 68 percent by conventional 12 lead electrocardiographic analysis. Improvement in diagnostic recognition by computer was most striking in patients with hypertensive cardiovascular disease or chronic obstructive lung disease. The multivariate classification scheme functioned most efficiently when a problem-oriented approach to diagnosis was simulated. This was accomplished by a simple method of adjusting prior probabilities according to the diagnostic problem under consideration.     

Inotropic properties of an isoquinoline derivative (NC 7197) in man

An isoquinoline derivative (NC 7197) was administered intravenously in a dose of 0.2 to 1.0 mg. per kilogram of body weight in four normal subjects and in 18 patients with shock or heart failure. An increase in cardiac output averaging 45 per cent in the normal subjects and 47 per cent in the patients was sustained for at least two hours. Heart rate was only slightly increased and stroke volume consistently rose. Arterial pressure was unchanged in normals but rose in the patients, although peripheral vascular resistance usually fell. Forearm blood flow rose only with the higher doses but renal and hepatic flow rose in the two patients studied. Norepinephrine-induced forearm vasoconstriction was not blocked during intra-arterial administration of NC 7197. Infusion into the left circumflex coronary artery of dogs led to a localized increase in myocardial contractility which was blocked by propranolol or pretreatment with reserpine. These data indicate that NC 7197 is a potent inotropic drug of prolonged duration of action which acts through an adrenergic mechanism and may be useful in the treatment of low output states.     

Blood pressure and cardiac performance

The factors which control the performance of the left ventricle include the determinants of myocardial function (preload, afterload, contractility and heart rate) and peripheral vascular function (capacitance and impedance). Arterial pressure represents an interaction of myocardial and vascular factors. When left ventricular function becomes impaired, impedance to left ventricular ejection becomes increasingly important in determining cardiac performance. Increases in impedance may result from the influence on arteries of neural, humoral or structural changes which can occur in response to a fall in cardiac output or an impairment of cardiac reserve. This increased impedance may further reduce cardiac output while myocardial oxygen consumption is increased. Alterations in the peripheral vascular bed therefore probably play an important role in the hemodynamic and metabolic events which usually are attributed to progressive impairment of the heart. Pharmacologie reduction of impedance with vasodilator drugs could become an important adjunct in the management of heart failure of diverse etiologies.     

Minoxidil in severe hypertension with renal failure. Effect of its addition to conventional antihypertensive drugs

Minoxidil, a new vasodilator antihypertensive compound, was given to 9 uremic patients with severe hypertension uncontrollable with currently available drugs. Addition of minoxidil in doses of 5 to 10 mg twice daily to their prior therapy, resulted in satisfactory control of blood pressure in all patients. Supine blood pressure fell from a control value of 200 ± 6/124 ± 3 to 164 ± 5/91 ± 2 mm Hg (mean and standard error) after administration of minoxidil, and no patient experienced orthostatic hypotension. Tachyphylaxis has not been seen during a follow-up period averaging 26 weeks. Side effects resulting from minoxidil have been limited to mild hypertrichosis in 2 patients, nausea in another 2 and fluid retention, which was readily controlled by either hemodialysis or furosemide. Minoxidil appears, therefore, to provide a means for controlling blood pressure in patients with severe hypertension resistant to all other antihypertensive drugs.     

Increased right ventricular wall thickness in left ventricular pressure overload: echocardiographic determination of hypertrophic response of the "nonstressed" ventricle

Left ventricular hypertrophy in left ventricular pressure overload occurs in response to excessive work load imposed on the left ventricle by increased impedance to ejection. Right ventricular hypertrophy may occur in patients with these findings, but has been considered to be secondary to pulmonary hypertension. To determine the frequency of right ventricular hypertrophy and its relation to increased left ventricular wall thickness in patients with left ventricular pressure overload, right ventricular wall thickness was measured using M-mode echocardiography with two-dimensional echocardiographic guidance in 65 patients with left ventricular pressure overload; 49 patients had essential hypertension and 16 had aortic valve stenosis. These measurements were compared with data from 13 patients with "thin-walled" dilated cardiomyopathy and 20 normal subjects. Average right ventricular wall thickness in hypertensive patients (7 +/- 2 mm) and patients with aortic stenosis (6 +/- 2 mm) was significantly greater than that in normal subjects (4 +/- 1 mm) and patients with dilated cardiomyopathy (4 +/- 1 mm) who had normal left ventricular wall thickness, even though left ventricular mass was increased in all patient groups. Increased right ventricular wall thickness was present in 40 (80%) of 49 patients with hypertension and 10 (63%) of 16 patients with aortic stenosis. The magnitude of increase in right ventricular wall thickness was linearly correlated (r = 0.76, p less than 0.005) with left ventricular wall thickness, but was not associated with pulmonary hypertension. It is concluded that increased right ventricular wall thickness is common in patients with left ventricular pressure overload, is directly related to increases in left ventricular wall thickness, and is independent of right ventricular hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)     

Lorcainide for high-frequency ventricular arrhythmia: preliminary results of a short-term double-blind and placebo-controlled crossover study and long-term follow-up

Lorcainide, 100 mg twice daily was compared with placebo in 39 patients with frequent ventricular arrhythmias in a randomized double-blind crossover trial. A mean frequency of ventricular premature beats (VPBs) of at least 30 VPBs/hour was required during a drug-free period of 48 hours. Holter monitoring and a maximal symptom-limited exercise test were performed at the end of each of the 2-week double-blind treatment phase. The group averaged 350 +/- 361 (standard deviation) VPBs/hour. Lorcainide decreased the mean VPB frequency of the group by 46% (p less than 0.01), with VPB reduction beyond the expected variation in 22 of 39 patients. In 13 patients VPBs were unchanged and in 4 they increased. Eight additional patients responded during drug titration, for an overall response rate of 77% (30 of 39). Lorcainide did not significantly reduce the exercise-related VPB frequency. At 6 months 61% of patients had significant VPB suppression. Thus, lorcainide was effective in reducing the frequency and grade of spontaneous ventricular arrhythmias during short- and long-term evaluation.     

Effects of disopyramide on left ventricular function: Assessment by radionuclide cineangiography

To determine the effects of disopyramide on resting systolic left ventricular (LV) function and LV functional reserve, gated equilibrium radionuclide cineangiography was performed at rest and during maximal symptom-limited supine bicycle exercise in 12 patients after a single 300 mg oral loading dose of disopyramide, and in 22 patients (including the 12 patients just mentioned) after they received disopyramide 150 mg 4 times daily for 5 to 10 days (average 7). The oral loading dose (average serum level 3.6 ± 1.3 μg/ml [standard deviation]) produced decreases in ejection fraction in 9 of 12 patients with a decrease in average resting ejection fraction from 40 ± 15% to 33 ± 11% (p <0.005). However, the lower, sustained dosage of disopyramide was associated with a lower average serum level of 2.5 ± 0.8 μg/ml and with smaller but significant decreases in ejection fraction in 3 of 22 patients during exercise only. At this dosage there was no significant decrease in average ejection fraction for the group at rest or during exercise. Adverse effects of disopyramide on ejection fraction occurred even in patients with previously normal LV function at rest. Hence, disopyramide may be associated with significant decreases in LV systolic function, particularly when given in high, oral “loading” doses. However, sustained therapy with lower dosages as well as lower drug levels is also associated with less depression of LV function.     

Day-to-day variation of the Frank electrocardiogram and vectorcardiogram in heart disease

Day-to-day variation of the Frank electrocardiogram and vectorcardiogram was studied in 20 patients with clinically stable hypertensive and/or coronary heart disease. Ten recordings were made on each patient during two consecutive five-day periods separated by a two-day weekend. Fifty-four selected measurements including durations, amplitudes, amplitude ratios, spatial magnitudes, and angles were computed on each of the records. Mean and maximal day-to-day variations of these measurements were compared with variations observed in 20 normal subjects reported in a previous study.Although considerable repeat variability was observed for several parameters, the magnitude of variability was not significantly different from that in normal subjects. However, abrupt and marked change in the electrocardiographic pattern seen in two patients suggests that sudden alterations in conduction may be common in patients with heart disease.The data presented can be helpful in assessing the significance of variations observed in serial electrocardiography in clinical practice.     

Early changes in plasma and urinary potassium in diuretic-treated patients with systemic hypertension

Two groups of patients with uncomplicated systemic hypertension were studied. Group 1 included 11 patients who had overt hypokalemia with diuretic drug treatment, and group 2 included 11 patients who remained normokalemic. After baseline studies without treatment were performed, both groups received hydrochlorothiazide, 50 mg twice daily. Plasma potassium (PK) was significantly reduced within the first day of treatment and stabilized by day 7 in both groups. The average decrease in PK was 1.0 +/- 0.1 mEq/liter (p less than 0.01) in the first group and 0.6 +/- 0.2 mEq/liter (p less than 0.01) in the second group. Cumulative losses of K were approximately 200 mEq in the hypokalemic group and were minimal in the normokalemic group as assessed by 24-hour urinary collections. Patients in the hypokalemic group also had a greater reduction in body weight and blood pressure. Supplementation with KCl, 96 mEq/day, or triamterene, 200 mg/day, in 9 hypokalemic patients resulted in an increase of PK to approximately 3.5 mEq/liter leveling off by day 7, and a cumulative K retention of approximately 200 mEq. Thus, overt thiazide-induced hypokalemia was associated with small and biologically unimportant losses of K from body stores. With replacement therapy the estimated amount of retained K was also small.     

Bepridil for chronic stable angina pectoris: Results of a prospective multicenter,placebo-controlled,dose-ranging study in 77 patients

Bepridil, a new calcium-channel blocking agent with an extended plasma elimination half-life of > 50 hours, was compared to placebo in 77 patients with confirmed coronary artery disease and chronic stable angina pectoris. The effects of bepridil were compared with those of placebo on angina frequency, nitroglycerin tablet use, the resting ECG and hemodynamics at rest and maximal exercise using a study design comprising 5 sequential 2-week single-blind treatment phases. After 2 weeks of placebo (phase 1), bepridil was given for 3 phases (2, 3 and 4) at total daily dosages of 200, 300 and 400 mg, respectively; the study was completed after a final reintroduction of placebo (phase 5). Within each phase once- and twice-daily regimens of bepridil were randomly compared.Bepridil (300 mg/day) reduced anginal frequency 68 %, from 8.5 ± 1.1 (standard error of the mean) to 2.7 ± 0.7 attacks/week and nitroglycerin tablet use 76% (p < 0.001). Bepridil improved exercise duration 26 %, from 6.9 ± 0.4 to 8.7 ± 0.5 minutes (p < 0.001) and exercise work 52%, from 2.7 ± 0.3 to 4.1 ± 0.4 kpm × 10^?3 (p < 0.001) on a standardized treadmill protocol. Resting and peak exercise heart rate and blood pressure were unaffected by bepridil. The antianginal effects were similar with either once- or twice-daily treatment schedules. Minor side effects of nausea, epigastric discomfort and tremor were infrequent and there were no major side effects. The results of this large but preliminary, single-blind and short-term study suggest that bepridil is an effective and well tolerated antianginal agent when administered once daily.     

Arterial pulse waves and velocity and systolic time intervals in diabetic children

Arterial pulse wave velocities, pulse wave contours, and systolic time intervals were recorded in thirty-nine diabetic children and were compared with recordings taken in twenty-seven normal children. Systolic time intervals were similar in the two groups of subjects. However, brachial and aortic pulse wave velocities were significantly greater in the diabetic than in the normal children (p < 0.025 and < 0.005, respectively). Also, in the diabetic children the time interval from the incisura to the midpoint of the dicrotic wave (I-D) was significantly shortened in both the brachial (p < 0.005) and carotid (p < 0.05) pulse waves as compared to the normal children. These changes in pulse wave velocity and contour are associated with increased wall stiffness that occurs with aging and suggest that the large arteries of diabetic children may exhibit acceleration of the aging process. The severity of these changes bore no direct correlation with the degree of carbohydrate intolerance as judged by insulin requirement.     

Noninvasive diagnosis of left ventricular pseudoaneurysm: role of two dimensional echocardiography and radionuclide gated pool imaging.

This report describes a case of left ventricular pseudoaneurysm diagnosed with two dimensional real time echocardiography. The two dimensional echocardiogram identified not only the pseudoaneurysmal sac but also the site of left ventricular rupture. When supplemented with radioisotope gated cardiac blood pool scanning, the noninvasive studies demonstrated combined true and false left ventricular aneurysms. Left ventricular pseudoaneurysm can be diagnosed using two dimensional echocardiography and nuclear imaging, permitting early operative intervention before fatal rupture.     

Effect of moricizine hydrochloride in reducing chronic high-frequency ventricular arrhythmia: results of a prospective, controlled trial

The antiarrhythmic efficacy of moracizin HCl (Ethmozine), a new oral phenothiazine derivative, was evaluated in 20 patients with chronic high-frequency ventricular arrhythmia confirmed by multiple ambulatory electrocardiographic recordings. Comparison with 72 +/- 24 hours (+/- standard deviation) of ambulatory recordings on moracizin treatment (average dose 295 +/- 58 mg 3 times daily or 9.8 +/- 1.0 mg/kg/day) was made. Maximal treadmill exercise provocation of arrhythmia and echocardiographic studies to detect effects on left ventricular function were also compared. The group had an average of 378 +/- 97 ventricular premature beats (VPBs) per hour while receiving placebo, with a mean VPB grade of 3.4 +/- 1.1 (modified Lown). When the patients received moracizin HCl, VPB frequency was reduced 53% (p less than 0.01), to a mean VPB grade of 2.2 +/- 1.4 (p less than 0.05). Seventy percent of the patients (14 of 20) showed a reduction in VPB frequency that exceeded the maximal expected variation; in 3 the frequency did not change and in 3 it increased with moracizin HCl. Resting electrocardiographic changes consisted of modest prolongations of PR interval (0.03 second) and QRS duration (0.02 second); however, QT prolongation was not observed. Heart rate and blood pressure at rest and peak exercise, exercise-related arrhythmia, exercise durations and echocardiographic measures of left ventricular function were unchanged by moracizin HCl compared with placebo. Side effects of moracizin++ HCl at these dosages were minimal (diarrhea in 1 patient, dizziness in 1 and diaphoresis in 1), although 2 patients tested at higher dosages had sustained ventricular tachycardia that may have been related to moracizin HCl.(ABSTRACT TRUNCATED AT 250 WORDS)     

Left ventricular relaxation,mitral valve prolapse,and intracardiac conduction in myotonia atrophica: Assessment by digitized echocardiography and noninvasive His bundle recording

Myotonia atrophica, a neuromuscular disease marked by autosomal dominant transmission and delayed relaxation of skeletal muscle, has been associated with cardiac failure, conduction abnormality, and mitral prolapse (MVP). In order to determine the relaxation rate of cardiac muscle, left ventricular (LV) size and function, and the presence of MVP, 30 patients with myotonia atrophica were studied using digitized M-mode echocardiography (MME). Intracardiac conduction intervals were determined by noninvasive His bundle recording (HBR) from surface electrodes using a high-resolution, R-wave triggered, signal averaging computer. Neurologically unaffected first-degree relatives of the patients with myotonia atropica were also studied to determine if cardiac abnormalities may be present in the absence of neurologic manifestations of the disease. Peak normalized diastolic endocardial velocity in patients with myotonia atrophica (3.7 ± 0.8 sec^?1) did not differ from unaffected first-degree relatives (3.8 ± 0.8 sec^?1) or normal subjects (3.6 ± 0.8 sec^?1). Systolic LV function and LV dimensions on MME were normal in both groups. However, MVP was present in 7 or 24 (29%) of patients who could be evaluated, but not in unaffected first-degree relatives. Despite normal LV systolic and diastolic function, infranodal intracardiac conduction was prolonged in patients with myotonia atrophica (average HV interval 50 ± 5 SD msec) but not in neurologically unaffected relatives (average HV interval 40 ± 5 msec). Delay in proximal intracardiac conduction was also found in patients with myotonia atrophica (average PH interval 140 ± 20 msec) but not in neurologically unaffected relatives (average PH interval 115 ± 6 msec). Hence cardiac findings in myotonia atrophica include proximal and distal conduction delay by external HBR even in the absence of abnormality of the standard 12-lead ECG. There may also be an increased frequency of MVP; however, early diastolic relaxation of the LV is unimpaired, and cardiac manifestations of myotonia are not transmitted independently of neurologic abnormality.     

Computer analysis of the orthogonal electrocardiogram and vectorcardiogram in 939 cases with hypertensive cardiovascular disease

Orthogonal ECG's (Frank system) were recorded from 939 male patients with hypertensive cardiovascular disease (HCVD) and were compared with records from 229 normal subjects, matched for age, race, and sex. The hypertensive subjects were divided into three clinical groups: (1) patients without cardiac enlargement by chest x-ray and no history of congestive heart failure (CHF), (2) patients with cardiac enlargement but without past or present CHF, and (3) patients with cardiac enlargement and one or more episodes of CHF. A sustained blood pressure level of $\text{150}\text{90}\text{mm. Hg}$ or more was present in all cases.First an attempt was made to identify optimal scalar and vectorial ECG measurements for discriminating between HCVD and normal, testing a total of 333 variables. With four scalar measurements at a specificity level of 95 per cent, 24 per cent of Group 1, 37 per cent of Group 2, and 44 per cent of Group 3 could be correctly classified. Vector measurements were found mostly redundant.Using linear discriminant function analysis and a likelihood ratio test with 13 different ECG variables at a level of specificity of 95 per cent, it was possible to identify correctly 53 per cent, 75 per cent, and 87 per cent of Groups 1, 2, and 3, respectively.Comparison of results with other reports on ECG changes caused by left ventricular overload (LVO) suggested that the degree of LVO in HCVD, even in the most advanced Group 3, was considerably less than that reported in patients with valvular heart disease with the only exception of terminal cases with HCVD who had come to autopsy. Antihypertensive therapy was considered as one factor which might have contributed to this finding.Multivariate ECG analysis was found an efficient means for diagnostic classification, leading to results which equalled those reported for multiple dipole analysis. As compared to scalar or vector measurements, either used individually or in combination, the multivariate technique exceeded all of these methods for LVO diagnosis by a wide margin when specificity was kept at a constant level.     

Marrow granulocyte reserves in black Americans. Hydrocortisone-induced granulocytosis in the "benign" neutropenia of the black.

The bone marrow granulocyte reserves of nine black patients with "benign" neutropenia were estimated by measuring the maximum neutrophil increment after the administration of hydrocortisone. Thirty control subjects, including 16 black and 14 white adults, were also studied. The mean neutrophil increment in the black patients with neutropenia was significantly less than that in the control subjects. The mean increment in the black control was also significantly less than that in the white control subjects. Four of the 16 black control subjects had neutrophil counts below 2,000/microliter; if these four are excluded from the analysis, the difference between the black and white control subjects is no longer significant. These data suggest that there is a subpopulation of healthy black adults with neutrophil counts below 2,000/microliter with reduced marrow granulocyte reserves as tested by corticosteroids. Bone marrow aspirates in four of the neutropenic patients showed normal cellularity and myeloid maturation suggesting that the lower increments are due to a difference in granulocyte release rather than to a difference in granulocyte production.     

Evaluation of frontal plane QRS loop rotation in vectorcardiographic diagnosis

The diagnostic usefulness of frontal plane QRS loop rotation in the Frank vectorcardiogram (VCG) was evaluated in a series of 598 normal subjects, 301 patients with postero-diaphragmatic myocardial infarction (PDMI), 84 with lateral myocardial infarction (LMI), 844 with left ventricular hypertrophy (LVH), and 190 with right ventricular hypertrophy (RVH). In normals 62% showed clockwise (CW) rotation of the QRS loops; 28%, figure-of-eight; and 10%, counterclockwise (CCW). The respective distributions were 68%, 23%, and 9% in PDMI; and 23%, 40%, and 37% in LMI. In normals the superior and inferior limits (96% range) of the maximal QRS vector angles were +15° and +79° in VCGs with CW rotation, +12° and +62° in VCGs with figure-of-eight, and −4° and +58° in VCGs with CCW rotation. Based on these limits, approximately half of PDMI cases (with 2% false positives) and a little over two-thirds of LMI cases (with 4% false positives) could be separated from normal. In LVH and RVH groups without clinical evidence of ischemic heart disease, the superior and inferior limits (96% range) of the maximal QRS vector angles differed from those of normal. In LVH such limits were +1° and +86° in VCGs with CW rotation, +12° and +62° in VCGs with figure-of-eight, and −86° and +48° in VCGs with CCW rotation. The respective limits in RVH were +13° and −160°, −3° and +76°, and −30° and +65°. Thus, when LVH or RVH is present, the foregoing limits separating PDMI or LMI from normal need to be modified accordingly.Results of the study demonstrate the diagnostic significance of QRS rotation analysis in the frontal plane VCG. These findings should prove useful as the standard of reference for clinical interpretation of the Frank VCG.