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Biomedical subjects

I Kronzon

Publications and source records attributed to I Kronzon.

At least 145 records · Page 8Linked to original sources
PubMed1992

The alternation between atrial flutter and atrial fibrillation.

Atrial fibrillation and atrial flutter share a common reentrant mechanism. However, the relationship between these arrhythmias has not been systemically studied to date. To evaluate the degree to which these arrhythmias may alternate, consecutive Holter monitor recordings which showed fibrillation or flutter in 96 patients were reviewed. One half of the patients were studied after open-heart surgery and the other half for varying indications. One quarter of the patients had atrial flutter in addition to fibrillation, and this alternation with flutter was significantly associated with the use of a type 1A antiarrhythmic drug (p = 0.007), but not with the use of digoxin or beta blockers (p = NS for both). Furthermore, this alternation with flutter was more common in the postoperative group (p = 0.01). A history of embolization was less common in patients who were in the postoperative group (p = 0.003) and patients who had flutter in addition to fibrillation (p = 0.05).

Adolescent↗
PubMed1992

Silent maladie de Roger.

A patient with no cardiac murmur was found to have a ventricular septal defect by Doppler echocardiography yet no evidence of pulmonary or right ventricular hypertension. This array of findings is distinctly unusual and appears to be at odds with the clinical teachings concerning small ventricular septal defects.

Adult↗
PubMed1992

Experience with twenty-eight cases of systolic anterior motion after mitral valve reconstruction by the Carpentier technique.

Systolic anterior motion of the mitral valve with left ventricular outflow tract obstruction after Carpentier-type mitral reconstruction with ring annuloplasty has led some surgeons to abandon an otherwise successful repair or to avoid use of a rigid ring. To assess the long-term significance of such motion, we studied 439 patients undergoing Carpenter mitral reconstruction at our institution between March 1981 and June 1990. The hospital mortality rate was 4.8% (21/439) overall and 3.7% (9/243) for isolated mitral reconstruction. Systolic anterior motion was found in 6.4% (28/438) after the operation, and 2.3% (10/438) had a coexisting left ventricular outflow tract gradient (mean 53 mm Hg). Of the 28 patients with systolic anterior motion, 27 (96.4%) had leaflet prolapse, 17 (60.7%) had undergone more than a 3 cm resection of the posterior leaflet, and two (7.1%) had preexisting idiopathic hypertrophic subaortic stenosis. All patients were treated medically, 14 with negative inotropic agents. Follow-up echocardiograms at a mean of 32 months demonstrated the disappearance of systolic anterior motion in 13 of 28 patients (46.4%) and resolution of the outflow tract gradient in 10 of 10 (100%). At follow-up only one patient was in New York Heart Association class III or IV and required reoperation for rheumatic mitral insufficiency. These data demonstrate that systolic anterior motion after Carpentier mitral reconstruction with ring annuloplasty is not prevalent and should be managed medically in most cases. Associated left ventricular outflow tract obstruction resolves with medical treatment.

Cardiac Surgical Procedures↗
PubMed1991

Protruding atheromas in the thoracic aorta and systemic embolization.

OBJECTIVE: To determine whether protruding atheromas in the thoracic aorta are a risk factor for systemic embolization. DESIGN: Case-control study. SETTING: A referral hospital. PATIENTS: A total of 122 patients with a history of stroke, transient ischemic attack, or peripheral emboli and an equal number of age- and sex-matched control patients. MEASUREMENTS: Evaluation using transesophageal echocardiography was done in case patients to detect protruding atheromas in the thoracic aorta and in control patients for cardiac indications other than emboli. MAIN RESULTS: Matched logistic regression showed that the presence of protruding atheromas was strongly related to the occurrence of embolic symptoms (odds ratio, 3.2; 95% Cl, 1.6 to 6.5; P less than 0.001). Furthermore, atheromas with mobile components were present only in case patients. When known risk factors for stroke (hypertension and diabetes) were added to the model, the presence of protruding atheromas remained an independent risk factor for embolic symptoms (odds ratio, 3.8). Hypertension was also independently associated with embolic symptoms (odds ratio, 2.7), but diabetes was not (odds ratio, 1.0). CONCLUSION: Protruding atheromas in the thoracic aorta can be detected by transesophageal echocardiography and should be considered as a cause of strokes, transient ischemic attacks, and peripheral emboli.

Aorta, Thoracic↗
PubMed1991

Congestive heart failure, coronary events and atherothrombotic brain infarction in elderly blacks and whites with systemic hypertension and with and without echocardiographic and electrocardiographic evidence of left ventricular hypertrophy.

Hypertension was present in 50% of 196 blacks and in 36% of 382 whites (p less than 0.001). A prospective study of 84 elderly blacks (70% women) and 326 elderly whites (73% women) with hypertension correlated echocardiographic and electrocardiographic left ventricular (LV) hypertrophy with incidences of congestive heart failure (CHF), coronary events and atherothrombotic brain infarction (ABI). Echocardiographic LV hypertrophy (p less than 0.02) and concentric LV hypertrophy (p less than 0.001) were more prevalent in hypertensive blacks than in hypertensive whites. Hypertensive blacks were younger (78 +/- 9 years) than hypertensive whites (82 +/- 7 years) (p less than 0.001). Other coronary risk factors were similar, except for higher serum triglycerides in whites than in blacks (p less than 0.02). Follow-up was 37 +/- 18 months in blacks and 43 +/- 18 months in whites (p less than 0.01). Incidences of CHF and coronary events were not significantly different in blacks and whites. ABI incidence was 38% in blacks and 21% in whites (p less than 0.005). Multiple logistic regression analysis showed that prior CHF (p = 0.000), concentric LV hypertrophy (p = 0.018) and echocardiographic LV hypertrophy (p = 0.022) were independent risk factors for CHF. Echocardiographic LV hypertrophy (p = 0.001), serum total cholesterol (p = 0.002), concentric LV hypertrophy (p = 0.005) and prior coronary artery disease (p = 0.042) were independent risk factors for coronary events. Prior ABI (p = 0.001), echocardiographic LV hypertrophy (p = 0.001) and electrocardiographic LV hypertrophy (p = 0.034) were independent risk factors for ABI.

Aged↗
PubMed1991

Transesophageal echocardiography is superior to transthoracic echocardiography in the diagnosis of sinus venosus atrial septal defect.

The purpose of this study was to compare transthoracic and transesophageal echocardiography in the diagnosis of various types of atrial septal defects. Forty-one adult patients with the clinical diagnosis of atrial septal defect were studied by transthoracic and transesophageal echocardiography (30 women, 11 men; 18 to 81 years of age). Transthoracic echocardiography demonstrated the atrial septal defect in 33 patients (secundum type in 28, primum type in 3 and sinus venosus type in 2). Transesophageal echocardiography demonstrated the defect in all 41 patients. Thus, in 8 (20%) of 41 patients the atrial septal defect was demonstrated by transesophageal and not by transthoracic echocardiography. Six of the eight had a sinus venosus type atrial septal defect; the other two patients had a secundum atrial septal defect (one of these two had a technically poor transthoracic echocardiogram and the other had a small atrial septal defect). Transthoracic echocardiography, therefore, failed to demonstrate the sinus venosus defect in six (75%) of eight patients. An anomalous venous connection associated with the sinus venosus defect was visualized by transesophageal echocardiography in seven of the eight patients but was not seen on transthoracic echocardiography in any patient. Sinus venosus type atrial septal defects are frequently not visualized in adults by conventional transthoracic echocardiography. Transesophageal echocardiography is recommended when an atrial septal defect is clinically suspected but cannot be visualized by transthoracic echocardiography.

Adult↗
PubMed1991

Prevalence of coronary risk factors in elderly blacks and whites.

Coronary risk factors were determined in a prospective study of 1,414 elderly persons (999 women and 415 men), mean age 82 +/- 8 years. Of 1,414 persons, 215 (15%) were black and 1,140 (81%) were white. The prevalences of cigarette smoking, hypercholesterolemia, low serum high-density lipoprotein cholesterol, and increased serum total cholesterol/high-density lipoprotein cholesterol ratio were not significantly different in elderly blacks and whites. Elderly blacks had a higher prevalence of hypertension (50% versus 36%, P less than 0.001), diabetes mellitus (27% versus 19%, P less than 0.01), and obesity (11% versus 5%, P less than 0.005) and a lower prevalence of hypertriglyceridemia (9% versus 15%, P less than 0.05) than elderly whites. In elderly persons with hypertension, electrocardiographic left ventricular hypertrophy occurred in 19% of blacks and 14% of whites (P not significant), echocardiographic left ventricular hypertrophy occurred in 72% of blacks and 56% of whites (P less than 0.01), and concentric left ventricular hypertrophy occurred in 60% of blacks and 39% of whites (P less than 0.001).

Aged↗
PubMed1990

Effect of quinidine or procainamide versus no antiarrhythmic drug on sudden cardiac death, total cardiac death, and total death in elderly patients with heart disease and complex ventricular arrhythmias.

A prospective study correlated the effect of quinidine or procainamide versus no antiarrhythmic drug on sudden cardiac death, total cardiac death and total death in 406 elderly patients with heart disease and asymptomatic complex ventricular arrhythmias detected by 24-hour ambulatory electrocardiograms. Of 397 patients treated with quinidine, 184 (46%) developed adverse effects during the first 2 weeks of therapy and were given no further antiarrhythmic therapy. Of 9 patients treated with procainamide, 2 (22%) developed adverse effects during the first 2 weeks of therapy and were given no further antiarrhythmic therapy. Adverse effects developed during long-term therapy in 6 patients (2%) receiving quinidine and in 3 patients (33%) receiving procainamide. Mean follow-up was 24 +/- 15 months in both groups. Sudden cardiac death, total cardiac death and total death occurred in 21, 43 and 65% of patients receiving quinidine or procainamide, respectively, and in 23, 44 and 63% of patients receiving no antiarrhythmic drug, respectively (difference not significant). Survival by Kaplan-Meier analysis showed no significant difference between the 2 groups for sudden cardiac death, total cardiac death or total death through 4 years. Patients with abnormal left ventricular ejection fraction had a 3.4 times higher incidence of sudden cardiac death, a 2.4 times higher incidence of total cardiac death and a 1.4 times higher incidence of total death than patients with normal left ventricular ejection fraction. These data showed no significant difference in sudden cardiac death, total cardiac death or total death between patients treated with quinidine or procainamide or with no antiarrhythmic therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Doppler echocardiographic flow velocity measurements in the superior vena cava during the Valsalva maneuver in normal subjects.

The hemodynamic manifestations of the Valsalva maneuver are in part the result of changes in the venous return accompanying changes in intrathoracic pressure. Doppler echocardiography was performed during Valsalva maneuver in 13 normal subjects. Superior vena cava flow velocities and flow velocity integrals were measured in all 13 subjects. In the 5 subjects in whom the superior vena cava was clearly visualized throughout the maneuver, vena cava diameter was also analyzed. The superior vena cava flow velocity integral at rest was 17 +/- 2 cm. It diminished significantly, disappeared or reversed (-13 +/- 6 cm, p less than 0.001) with phase I of the maneuver. During the maintenance phase (phase II), the flow velocity integral increased significantly (31 +/- 2 cm, p = 0.05 vs baseline and phase I) and was associated with a decrease in superior vena cava lumen diameter at the time of Valsalva and continuing throughout the strain. With release of the maneuver (phase III), there was a sudden significant increase in flow velocity integral (61 +/- 2 cm, p = 0.005 vs phase II) and superior vena cava lumen diameter. Subsequently, superior vena cava flow velocity integral returned to baseline values. This study suggests that one of the ways in which the Valsalva maneuver leads to decreased venous return may be by direct external compression of the superior vena cava.

Adult↗
PubMed1990

Effect of aortic valve replacement for aortic stenosis on severity of mitral regurgitation.

The severity of mitral regurgitation (MR) was determined by color Doppler echocardiography in 44 adult patients with severe symptomatic aortic stenosis before and after isolated aortic valve replacement. Preoperative MR was absent in 17, mild in 14, moderate in 11 and severe in 2 patients. Three to 388 (mean 58) days after surgery, 14 patients continued to have no MR. In the other 30 patients, MR decreased in 18 (60%), remained unchanged in 8 (27%) and increased in only 4 (13%). Furthermore, in 13 patients with significant (moderate or severe) MR, the severity decreased in 12 (92%). Thus, the severity of MR often decreases after aortic valve replacement for aortic stenosis.

Adult↗
PubMed1990

Diagnosis of unexpected atrial septal defect by inspired hydrogen appearance time in adult patients referred for cardiac catheterization.

Atrial septal defects may have clinical consequences regardless of their size. We evaluated the incidence of clinically unsuspected atrial septal defects in 4,411 consecutive adult patients referred for cardiac catheterization by the previously validated method of inspired hydrogen appearance time. Oximetry was performed only when an abnormally short inspired hydrogen appearance time was measured. Seventy-five patients (1.7%) were discovered to have a left-to-right shunt by this method. The shunting was at the atrial level in 65 patients. Thirty-five of these patients (0.8% of all catheterizations) were not suspected of having any form of congenital heart disease by history, physical examination, chest X-ray, EKG, or echocardiogram. In 19 cases there was no significant oxygen step-up and the diagnosis would have been missed by oximetry. The atrial septum was explored during open heart surgery in 7 patients. Atrial septal defects were detected and closed in all. Four patients had the finding confirmed by echocardiography after the catheterization. Small atrial septal defects are frequently not detected by clinical evaluation, noninvasive testing, or oximetry and are easily detected by the rapid, safe, and accurate method of inspired hydrogen appearance time.

Cardiac Catheterization↗