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Biomedical subjects

A N DeMaria

Publications and source records attributed to A N DeMaria.

At least 235 records · Page 13Linked to original sources
PubMed1976

Reduction of S-T segment elevation with infusion of nitroprusside in patients with acute myocardial infarction.

The effect of infusion of sodium nitroprusside on S-T segment elevation was evaluated in 12 patients with acute anterior myocardial infarction. Precordial 35 lead S-T segment maps were obtained in each patient immediately before and 10 minutes after infusion of 53 mug/min (range 20 to 100 mug/min) of nitroprusside. The following measurements were made from each S-T map: sigmaST (total S-T elevation in all leads), NST (number of leads with S-T elevation greater than 1 mm) and ST (average (S-T elevation in leads with more than 1 mm elevation). After administration of mitroprusside, evidence of myocardial ischemic injury as assessed by S-T mapping decreased in association with reduction of the myocardial oxygen consumption index of pressure-time per minute. Group mean values diminished significantly for sigmaST (41.7 to 28.6 mm, P less than 0.001), NST (20.3 to 14.6, P less than 0.001) and ST (1.6 to 1.2 mm, P less than 0.005). Pressure-time per minute decreased from 2,690 to 2,372 mm Hg-sec/min (P less than 0.001). Because there was no significant relation (P less than 0.05) between reductions in S-T elevation and lower indexes of myocardial oxygen consumption, it is suggested that nitroprusside may possess a separate action of augmenting regional blood flow to ischemic myocardium. Evaluation with the precordial S-T mapping technique suggested that intravenous administration of nitroprusside was associated with evidence of reduced ventricular ischemic injury in patients with acute myocardial infarction. This effect appears to be related to reduction of myocardial oxygen demand by the peripheral cardiac unloading mechanisms of nitroprusside as well as to a possible direct action of the drug in improving regional blood flow to ischemic heart muscle.

Acute Disease↗
PubMed1976

Comparative effects of morphine, meperidine and pentazocine on cardiocirculatory dynamics in patients with acute myocardial infarction.

The cardiocirculatory effects of the commonly used parenteral analgesics, morphine sulfate 15 mg, meperidine hydrochloride 100 mg and pentazocine 60 mg, each administered intravenously, were compared in 12 patients with acute myocardial infarction during cardiac catheterization and by echocardiogram. No untoward hemodynamic effects occurred following the administration of morphine or meperidine. In contrast, pentazocine produced significant (p less than 0.01 to less than 0.05) increases in systemic and pulmonary arterial pressures, left ventricular filling pressure, systemic vascular resistance, and systolic and diastolic dimensions; and decreases in left ventricular ejection fraction and mean velocity of circumferential fiber shortening. These deleterious actions of pentazocine appeared due to peripheral vasoconstriction and negative inotropic properties. Further, pentazocine-induced increases in left ventricular preload and afterload increased myocardial oxygen demands. Since this study demonstrates that pentazocine is hazardous in myocardial infarction, morphine and meperidine are the preferred analgesics in this condition.

Adult↗
PubMed1976

Alterations in ventricular contraction pattern in the Wolff-Parkinson-White syndrome. Detection by echocardiography.

The effects of abnormal ventricular activation upon the contractile pattern of the ventricles in patients with the Wolff-Parkinson-White syndrome (WPW) remain uncertain. Therefore we compared the motion of the anterior right ventricular wall (RV), the interventricular septum (IVS), and left ventricular posterior wall (LVPW) on echogram in nine patients with WPW and one patient with a coronary sinus pacemaker (CSP) to 20 normal subjects. Normal subjects manifested posterior RV motion which began and reached maximal excursion at 175 and 366 msec (group mean), respectively, after the onset of the QRS complex; posterior movement of the IVS which started and peaked at 90 and 30 msec, respectively; and anterior contraction of the LVPW which began and peaked at 159 and 406 msec, respectively. Five of seven patients with Type A WPW demonstrated a localized area of premature contraction of the LVPW occuring during the initial 100 msec interval following the onset of the QRS complex which was accompanied by paradoxic anterior motion of the IVS. Thereby in Type A patients initial and maximal posterior motion of the IVS occurred later, 230 (P less than 0.001) and 400 (P less than 0.05) msec, and anterior motion of the LVPW occurred earlier, 75 (P less than 0.001) and 367 (P less than 0.05) msec as compared to normal. The amplitude and duration of early contraction could be related to the prominence of the delta wave during atrial pacing. Similar premature contraction was also observed in the patient with CSP during paced beats. One Type B WPW patient exhibited abnormal IVS motion while the additional patient manifested premature LVPW contraction similat to that seen in Type A patients. The contractile pattern of the right ventricular anterior wall was recorded in five of seven Type A Wolff-Parkinson-White patients and manifested prolongation of the interval from the onset of the QRS complex to the initial posterior movement (group mean 234 msec, P less than 0.05) as compared to normal. Thus echocardiography can be used to confirm the diagnosis and to improve understanding of the pathophysiology of the Wolff-Parkinson-White syndrome.

Adolescent↗
PubMed1976

Reduction of ischemic injury by sublingual nitroglycerin in patients with acute myocardial infarction.

The effect of sublingual nitroglycerin (NTG) on myocardial ischemic injury was evaluated in eleven patients with acute anterior myocardial infarction. Precordial 35-lead ST-segment maps were obtained in each patient immediately before and 3-10 minutes after 0.4 mg sublingual NTG. The following measurements were made from each ST map: N-ST (number of leads showing ST elevation greater than 1mm), sigmaST (total ST elevation in all leads), ST (average ST-segment elevation in those leads with less than 1mm elevation). Following 0.4 mg sublingual NTG evidence of myocardial ischemic injury as assessed by ST-segment mapping decreased in association with reduction of heart rate X systolic blood pressure product (10.80 X 10(3) to 9.49 X 10(3), P less than 0.001). Group mean values diminished significantly for N-ST (18.1 to 14.4, P less than 0.001), sigma ST (37.9 to 30.1 P less than 0.005) and ST (1.7 to 1.4, P less than 0.001). Evaluation performed by the technique of precordial ST-segment mapping suggests that sublingual nitroglycerin in a commonly employed clinical dose is associated with evidence of reduced ischemic cardiac injury in patients with acute myocardial infarction. This effect appears to be related to reduction of myocardial oxygen demand by the nitrate.

Acute Disease↗
PubMed1976

Intraventricular free wall dissection causing acute interventricular communication with intact septum in myocardial infarction.

This report delineates a previously unrecognized complication of acute myocardial infarction, an intraventricular wall dissection producing interventricular communication without septal perforation. The clinical, hemodynamic, and pathologic features of this unique condition are documented, as well as the factors important in the mechanism of its production.

Aged↗
PubMed1976

Arrhythmias in the mitral valve prolapse syndrome. Prevalence, nature, and frequency.

Ambulatory monitoring and maximal treadmill exercise were compared in 40 normal subjects and 31 patients with mitral prolapse. A variable arrhythmia spectrum was observed in prolapse during monitoring: premature ventricular contractions in 18 (58%), supraventricular arrhythmias in 11 (35%), and bradyarrhythmias in 9 (29%). Significantly less arrhythmias occurred in normal subjects during monitoring: 10 (25%, P greater than 0.001), 3 (8%, P less than 0.001), 4 (10%, P less than 0.05), and 2 (5%, P less than 0.02), respectively. In patients with prolapse, arrhythmias occurred on resting electrocardiogram (ECG), 35% premature ventricular contractons, 6% supraventricular arrhythmias, and 10% bradyarrhythmias, and on treadmill exercise, 45%, 10%, and 3%; therefore, ambulatory monitoring was the most sensitive method of arrhythmia detection. No correlation existed between clinical features of prolapse and arrhythmias. Thus, arrhythmias occur in most patients with mitral prolapse, are not predictable by clinical characteristics, comprise a spectrum of ventricular and supraventricular tachyarrhythmias and bradyarrhythmias, and are best detected by ambulatory ECG monitoring.

Adult↗
PubMed1976

Rapid overdrive pacing of refractory tachyarrhythmias in patients after open-heart surgery.

The efficacy of rapid ventricular pacemaker overdrive in the treatment of supraventricular and ventricular tachyarrhythmias is presented as a new approach to the management of these rhythm disorders inpatients after cardiac surgery. This mode of therapy is exemplified in the control of heart rate and return of normal sinus rhythm in patients with both types of tachyarrhythmias refractory to conventional antiarrhythmic agents. In addition, the pathogenesis and mechanisms of pacemaker overdrive in termination these rhythm disturbances are delineated.

Bundle-Branch Block↗
PubMed1975

Improvement of reduced left ventricular diastolic compliance in ischemic heart disease after successful coronary artery bypass surgery.

To determine the effects of myocardial revascularization on decreased left ventricular diastolic compliance consequent to chronic stable coronary artery disease, 15 patients with patent coronary artery bypass grafts (Group I) were compared with 8 patients with occluded grafts (Group II) studied before and after operation. In addition, eight normal patients served as controls. Left ventricular diastolic compliance was assessed by: (1) total observed diastolic compliance: stroke volume (V) related to left ventricular diastolic pressure (P) change (deltaV/deltaP) normalized for end-systolic volume; (2) left ventricular stiffness index of passive elastic modulus (a equals slope of deltaP/deltaV related to mean left ventricular diastolic pressure); and (3) fractional pattern of left ventricular filling. All patients had normal sinus rhythm and none had preoperative or postoperative mitral regurgitation. The two groups with coronary disease were well matched preoperatively for ventricular function, volumes, mass, segmental contraction and compliance. Ejection fraction increased in Group I (0.56 preoperatively to 0.65 postoperatively, P less than 0.05) but was unchanged in Group II (0.63 To 0.61, P greater 0.05). Postoperative indexes of left ventricular compliance improved in Group I: (1) 0.110 to 0.150 (P less 0.05); (2) 0.030 TO 0.019 (P less 0.05); and (3) 37 to 30 percent filling during last one third of diastole (P less 0.05). These indexes were unchanged postoperatively in Group II: (1) 0.109 to 0.102 (P greater 0.05); (2) 0.033 to 0.039 (P greater than 0.05); and (3) 36 to 41 percent (P greater 0.05). Compliance indexes were not altered (P greater 0.05) in a subset of seven patients in Group I with preoperative or intercurrent myocardial infarction. Thus, this investigation demonstrates the relatively reversible nature of abnormal left ventricular compliance after successful coronary artery bypass surgery in certain patients with ischemic heart disease.

Angiocardiography↗
PubMed1975

Unusual echographic manifestations of right and left heart myxomas.

Although echocardiography has provided a useful noninvasive means for detecting cardiac myxomas, the ultrasound manifestations of these tumors may be variable. We describe our experiences with unusual echographic features encountered in left and right heart myxomas. Thus the left atrial tumor may be manifested predominantly by multiple, discrete, linear echoes behind the mitral valve, the anterior leaflet of which may exhibit an abrupt mid-systolic posterior movement. In right heat myxomatous tumor arising from the septal tricupsid leaflet and adjacent interventricular septum, the echographic characteristics include a cloud of echoes throughout the cardiac cycle in the right ventricular outflow tract which are present in the right ventricle body only during relaxation and are anterior to the tricuspid valve in early diastole. Therefore, discrete linear echoes may be the principal echographic presentation of left atrial myxoma, and special attention should be focused on all areas of the tricuspid valve and right ventricle by ultrasound in patients in whom diagnosis of myxoma is suspected.

Adolescent↗
PubMed1975

Evaluation of arrhythmias in the late hospital phase of acute myocardial infarction compared to coronary care unit ectopy.

To evaluate the prevalence and nature of arrhythmias during the entire three-week period in hospital after myocardial infarction, the results of coronary care unit monitoring (initial 3 to 5 days) were compared with continuous 8-hour portable monitoring during the ambulatory phase (second and third weeks) in 83 consecutive survivors. Arrhythmias were detected in 84.3 per cent (70/83) of patients while in the coronary care unit and in 85.5 per cent (71/83) during hospital stay after the coronary care unit. Ventricular ectopic depolarizations were classified as complicated (multifocal, paired, R on T, or five or more a minute) or uncomplicated. Importantly, the high frequency of complicated ventricular extrasystoles and tachycardia persisted during the entire period in hospital (early 34.9% and late 42.5% of all patients). However, only 16.9 per cent (14/83)had these ventricular arrhythmias during both coronary care unit and ward monitoring. Thus, the absence of complicated ventricular ectopic depolarization and ventricular tachycardia in the coronary care unit did not exclude their subsequent occurrence in the majority of the large number of patients with late hospital complicated ventricular ectopy.

Adult↗
PubMed1975

Echographic assessment of atrial transport, mitral movement, and ventricular performance following electroversion of supraventricular arrhythmias.

Controversy attends the extent and temporal sequence of improvements in hemodynamic function resulting from the return of atrial contraction following cardioversion of supraventricular arrhythmias. Thus, mitral, left atrial (LA) and left ventricular (LV) echograms were obtained before and one hour after conversion of supraventricular arrhythmias to normal sinus rhythm by direct current countershock in patients with chronic coronary disease or cardiomyopathies without valvular dysfunction. The duration of the rhythm disturbance varied from one day to five years in 22 patients and was indeterminate in 13. Atrial systole immediately produced prominent mitral "A" waves with anterior valve excursion of 7.5 mm (range 3 to 12) in 33 of the 35 patients (94%). The two patients with atrial electromechanical dissociation reverted to atrial fibrillation within one week. Cardioversion caused a decline in LA diameter (3.5 to 3.2 cm, P less than .001) and a rise in LV end-diastolic dimension (5.2 to 5.5 cm, P less than .001) while LV end-systolic dimension was unchanged (4.2 cm). Thereby stroke volume rose. Heart rate fell an average of 16 beats/min. Depressed cardiac output was improved + 0.84 L/min/m-2. Thus, in the majority of patients with acute or chronic supraventricular arrhythmias without mitral valve disease, cardioversion promptly restores effective atrial contraction, decreases LA size, and results in substantial hemodynamic benefit.

Adult↗
PubMed1975

Echography and phonography of acute aortic regurgitation in bacterial endocarditis.

Since management of acute aortic regurgitation in bacterial endocarditis is enhanced by early recognition, echocardiography and phonocardiography were evaluated in three such cases documented by catheterization and surgery without positive blood cultures and compared to echophonograms of 34 patients with aortic regurgitation of other origins. Endocarditis manifested distinctive, thickened, irregular aortic leaflet echoes with normal systolic excursion and mitral echopreclosure with anterior leaflet fluttering. Mitral preclosure resulted in mid- or end-diastolic crescendo murmur accompanied by soft first heart sound. Aortic echograms in nonendocarditis showed either widened root, diminished leaflet excursion, absence of irregular valvular thickening, or normal leaflets, all without mitral preclosure. This study shows specific echophonographic findings of aortic regurgitation due to endocarditis that enable diagnosis of this condition in the absence of positive blood cultures.

Acute Disease↗