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Biomedical subjects

H C Dittrich

Publications and source records attributed to H C Dittrich.

At least 37 records · Page 2Linked to original sources
PubMed1992

Pericardial adaptation in severe chronic pulmonary hypertension. An intraoperative transesophageal echocardiographic study.

BACKGROUND: The pericardium both limits cardiac distension and accentuates ventricular interdependence. Although this effect appears minimal under normal circumstances, the pericardium markedly restricts acute cardiac enlargement. Animal studies have demonstrated gradual pericardial adaptation and expansion in chronic volume overload and cardiomegaly, but the pericardial response in humans with cardiac hypertrophy and enlargement has not been examined fully. To investigate this further, 14 patients with right ventricular hypertrophy and cardiomegaly secondary to chronic pulmonary thromboembolic disease and severe pulmonary hypertension were studied during pulmonary thromboendarterectomy. METHODS AND RESULTS: Simultaneous intraoperative transesophageal Doppler echocardiography and direct biventricular hemodynamic measurements were performed at steady state immediately before and after pericardiotomy. All hemodynamic variables showed no significant change before and after pericardiotomy, including heart rate (76 +/- 16 versus 75 +/- 15 beats per minute), mean pulmonary arterial pressure (46.3 +/- 11.1 versus 45.5 +/- 11.7 mm Hg), cardiac index (1.8 +/- 0.5 versus 2.0 +/- 0.6 l/min/m2), left ventricular end-diastolic pressure (5.9 +/- 5.7 versus 7.1 +/- 5.0 mm Hg), and right ventricular end-diastolic pressure (7.9 +/- 6.6 versus 8.0 +/- 6.7 mm Hg). Similarly, there were no significant changes in all Doppler echocardiographic parameters, including right ventricular end-diastolic area (23.2 +/- 5.7 versus 22.6 +/- 5.4 cm2), left ventricular end-diastolic area (15.3 +/- 5.9 versus 15.5 +/- 4.4 cm2), the position of the interventricular septum, and the Doppler-derived mitral inflow measures of diastolic function. CONCLUSIONS: The pericardium appears to have little influence on the marked cardiac and septal deformations seen in patients with chronic, severe right ventricular pressure overload and cardiomegaly. This study confirms that the human pericardium is capable of adapting over time to changes in cardiac size and geometry.

Adaptation, Physiological↗
PubMed1992

Nonbacterial thrombotic endocarditis. Assessment by transesophageal echocardiography.

Nonbacterial thrombotic endocarditis (NBTE) is difficult to detect antemortem and is often not suspected until embolic events occur. Transthoracic echocardiography is useful in diagnosing NBTE, but it may be limited by suboptimal imaging and resolution. Herein we describe the first reported case of NBTE diagnosed by transesophageal echocardiography. As early detection and treatment may avert significant embolic complications, transesophageal echocardiography should be strongly considered if other techniques are nondiagnostic and clinical suspicion of NBTE remains high.

Echocardiography↗
PubMed1991

Reversibility of cardiac abnormalities in human immunodeficiency virus (HIV)-infected individuals: a serial echocardiographic study.

Seventy adults who tested positive for human immunodeficiency virus (HIV) were prospectively studied with serial echocardiography to better define the prevalence and progression of cardiac disease in such patients. Fifty outpatients (Group A), including 44 with acquired immunodeficiency syndrome (AIDS) and 6 with AIDS-related complex, and 20 additional patients (Group B) with asymptomatic HIV infection had baseline echocardiographic studies at a time when no patient had symptomatic heart disease. Follow-up studies were performed at 9 +/- 3 months in 52 patients (74%) and again at 15 +/- 3 months after baseline studies in 29 patients (41%). During the study, 22 patients (44%) in Group A and 1 patient (5%) in Group B died. Cardiac abnormalities were noted in 26 patients (52%) in Group A and 8 patients (40%) in Group B (p = NS) on initial or follow-up study. An abnormal left ventricular ejection fraction (less than 45%) or fractional shortening (less than 28%) was seen in seven patients in Group A; of these, three had normal left ventricular function on a later echocardiogram. One patient in Group B had persistent left ventricular dysfunction. All patients in Group A with left ventricular dysfunction on two serial studies died within 1 year after the initial echocardiogram. Ejection fraction did not change between baseline and two follow-up studies in either group (A: 52 +/- 9 vs. 56 +/- 9 vs. 55 +/- 5%, p = NS; B: 58 +/- 6 vs. 58 +/- 5 vs. 59 +/- 6%, p = NS). Right-sided cardiac enlargement resolved in 18 patients (44%), including 5 of 10 in Group A and 3 of 8 in Group B.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Detection of massive pulmonary embolus-in-transit by transesophageal echocardiography.

Pulmonary embolus-in-transit represents an important cause of morbidity and mortality in the critically ill patient. Unexplained shock and acute pulmonary hypertension were evaluated with echocardiography. Standard transthoracic echocardiography failed to identify a large embolism-in-transit that was easily visualized by transesophageal imaging. A review of the literature involving emboli-in-transit suggests that early intervention in these patients may be beneficial.

Adult↗
PubMed1989

Echocardiographic and clinical predictors for outcome of elective cardioversion of atrial fibrillation.

Previous studies have suggested that success of elective direct-current cardioversion for atrial fibrillation (AF) can be predicted from clinical features and M-mode echocardiographic left atrial diameter. We evaluated clinical variables as well as M-mode and 2-dimensional echocardiographic measurements of atrial size in 85 patients undergoing electrical cardioversion for AF. Of 65 patients who were initially converted to sinus rhythm, 45 (69%) and 38 (58%) remained in sinus rhythm at 1 and 6 months, respectively. No historical feature predicted initial success, although patients with cardiomyopathy or pulmonary disease underlying their AF had significantly lower success rates compared with those having other etiologies. Furthermore, no M-mode or 2-dimensional echocardiographic measurements of atrial size predicted initial success of cardioversion. Maintenance of sinus rhythm at 1 month was related to short duration of AF before cardioversion (less than 3 months vs greater than 12 months, p less than 0.05). Left atrial area and long axis dimension by 2-dimensional echocardiography were significantly larger in patients remaining in sinus rhythm than in those who had reverted to AF at 1 month (28 +/- 7 vs 24 +/- 5 cm2 and 65 +/- 9 vs 59 +/- 8 mm, respectively, both p less than 0.05), but overlap was great. No significant difference in atrial dimensions was noted at 6-month follow-up. It appears that, although no clinical or echocardiographic variable predicts initial success for cardioversion of AF, duration of AF does predict maintenance of sinus rhythm 1 month after initial success.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

Successful pregnancy after cardiac transplantation.

A case report of a successful pregnancy after cardiac allotransplantation is presented. The patient underwent transplantation for an inoperable cardiac tumor 5 years before conception. Cardiac function before and during all stages of pregnancy was normal. Maintenance immunosuppressive therapy consisting of prednisone and azathioprine was continued through gestation. The pregnancy was complicated by a primary herpes virus infection requiring parenteral acyclovir treatment and a single episode of preterm labor that was successfully treated. The infant was born at term, weighed 3278 gm, and has developed normally during the first 3 years of life. The patient died 5 months after delivery as a result of an acute immunologic rejection 5 months post partum caused by self-initiated discontinuation of immunosuppressive therapy. Preconceptional counseling and pregnancy care guidelines are discussed.

Adult↗
PubMed1989

Effect of thyroid replacement therapy on the frequency of benign atrial and ventricular arrhythmias.

Whether thyroid replacement therapy can trigger cardiac arrhythmias in patients with hypothyroidism is not known. In this prospective study, 24 h ambulatory electrocardiographic (ECG) monitoring was used to assess the frequency of atrial and ventricular premature beats in 25 patients with hypothyroidism (5 men and 20 women, aged 56 +/- 3 years) before and 3.5 +/- 0.5 months (mean +/- SEM) after thyroid replacement therapy. Plasma thyroid-stimulating hormone was 73.6 +/- 12.3 and 3.1 +/- 0.6 microU/ml and free thyroxine index was 2.4 +/- 0.4 and 9.8 +/- 0.9 micrograms/100 ml at baseline and after thyroid replacement therapy, respectively. The frequency of ventricular premature beats was not affected by thyroid replacement therapy (from 273 +/- 221 at baseline to 352 +/- 235 beats/24 h after therapy), even in patients with frequent baseline arrhythmias. In contrast, the frequency of atrial premature beats was slightly increased after thyroid replacement therapy (from 47 +/- 17 to 279 +/- 197 beats/24 h), largely as a result of changes seen in three patients. No patient developed new onset of sustained ventricular or supraventricular arrhythmias. Average, basal and maximal heart rates during ECG monitoring increased significantly after thyroid replacement therapy (average 72 +/- 2 to 80 +/- 2; basal 64 +/- 2 to 70 +/- 2; maximal 114 +/- 3 to 130 +/- 3 beats/min, respectively, p less than 0.001). In conclusion, thyroid replacement therapy is safe in patients with common benign cardiac arrhythmias, and does not trigger an increase in arrhythmia frequency except in rare patients with baseline atrial premature beats. It is, however, associated with an increase in basal, average and maximal heart rates.

Adult↗
PubMed1989

Early improvement in left ventricular diastolic function after relief of chronic right ventricular pressure overload.

Chronic right ventricular pressure overload is associated with left ventricular diastolic dysfunction. Whether or not an abrupt reduction in pulmonary artery pressure in patients with chronic pulmonary hypertension results in early improvement of left ventricular diastolic function is unknown. To assess this, the Doppler indexes of left ventricular diastolic function and echocardiographic measures of left ventricular volume were analyzed in 22 patients (age, 41 +/- 14 years, mean +/- SD) before and within 1 week after pulmonary thromboendarterectomy for chronic thromboembolic pulmonary hypertension. Mean duration of cardiopulmonary symptoms was 37 months (range, 4 months to 9 years). After operation, mean pulmonary artery pressure and pulmonary vascular resistance decreased (50 +/- 13 to 29 +/- 9 mm Hg and 904 +/- 654 to 283 +/- 243 dynes.sec/cm5, respectively, both p less than 0.001), pulmonary artery wedge pressure was unchanged (11 +/- 5 to 12 +/- 5 mm Hg), and cardiac index increased (2.0 +/- 0.5 to 2.8 +/- 0.7 l/min/m2 p less than 0.001). Left ventricular end-diastolic volume and stroke volume increased significantly (58.5 +/- 18.0 to 76.6 +/- 25.0 ml and 30.3 +/- 12.3 to 41.8 +/- 12.5 ml, respectively, both p less than 0.001) after surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Acute anticoagulation following cardioembolic stroke.

Whether acute anticoagulation after cardioembolic stroke affords substantial protection against early recurrent emboli or an unacceptable risk of hemorrhage remains controversial. To assess this further, we evaluated 121 consecutive patients with acute cardioembolic stroke. Forty-nine were therapeutically anticoagulated within 96 hours of stroke onset, and 41 received no anticoagulants within the first 2 weeks after stroke. These two groups did not differ significantly with regard to age, sex, severity of acute neurologic deficit, or spectrum of underlying cardiac disease. The incidences of clinically significant brain hemorrhage (2%) and early recurrent embolization (2%) were equally low in both groups. Our data suggest that acute acute anticoagulation may be employed safely in most patients with cardioembolic stroke but that such treatment does not clearly benefit this population as a whole.

Adult↗
PubMed1988

Endomyocardial biopsy in patients with unexplained congestive heart failure.

STUDY OBJECTIVE: To determine the incidence of myocarditis proved by biopsy findings in patients presenting with unexplained congestive heart failure. DESIGN: Retrospective review. SETTING: General medical services of a Veterans Administration and university hospital. PATIENTS: Ninety consecutive patients presenting with unexplained congestive heart failure who had endomyocardial biopsy as a part of their diagnostic evaluation. MEASUREMENTS AND MAIN RESULTS: Classification of biopsy findings according to a recently proposed scheme for histologic diagnosis of myocarditis (Dallas criteria) showed myocarditis in only 4 of 90 (4.4%) patients (95% CI, 0.2 to 8.6), although two thirds of the patients had symptoms of congestive heart failure for less than 3 months. CONCLUSIONS: The incidence of myocarditis proved by endomyocardial biopsy findings is low in patients presenting with unexplained congestive heart failure and raises questions concerning the need for this procedure in this patient group.

Adolescent↗
PubMed1988

Doppler assessment of changes in right-sided cardiac hemodynamics after pulmonary thromboendarterectomy.

It is not known whether Doppler echocardiography can accurately follow changes in right-sided cardiac hemodynamics after a therapeutic intervention in patients with pulmonary artery (PA) hypertension. Therefore, Doppler measurements of the maximal velocity of the tricuspid regurgitant jet and the acceleration time of the PA velocity profile were obtained in 28 patients before and after pulmonary thromboendarterectomy for chronic thromboembolic PA hypertension. Doppler values were compared with hemodynamic variables obtained at cardiac catheterization. Postoperatively, decreases in mean PA pressure (50 +/- 14 to 28 +/- 8 mm Hg), transtricuspid systolic pressure difference (69 +/- 21 to 36 +/- 14 mm Hg) and Doppler measurement of the maximal velocity of the tricuspid regurgitant jet (4.1 +/- 0.7 to 2.7 +/- 0.5 m/s) were noted, while acceleration time increased (57 +/- 16 to 94 +/- 18 ms, all p less than 0.001) compared with preoperative values. For the population as a whole, the calculated systolic transtricuspid pressure difference determined from the maximal velocity of tricuspid regurgitation correlated well with the catheterization systolic transtricuspid pressure difference (r = 0.93, p less than 0.001) and the acceleration time correlated with mean PA pressure (r = -0.81, p less than 0.001). More importantly, the change in the maximal velocity of tricuspid regurgitation for postoperative patients was found to correlate with the change in catheterization systolic transtricuspid pressure difference (r = 0.82, p less than 0.001), while the change in acceleration time correlated weakly with the change in mean PA pressure (r = -0.41, p = 0.053).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Early changes of right heart geometry after pulmonary thromboendarterectomy.

To determine the changes in right heart hemodynamics and geometry early after surgery for chronic pulmonary hypertension due to large vessel thromboembolic occlusion, 30 patients were evaluated 8 +/- 8 days (mean +/- SD) before and 6 +/- 4 days after pulmonary thromboendarterectomy by two-dimensional echocardiography and right heart catheterization. Surgery resulted in an early significant improvement in hemodynamic variables including mean pulmonary artery pressure (48 +/- 12 to 28 +/- 8 mm Hg, p less than 0.001), right ventricular systolic pressure (76 +/- 20 to 47 +/- 15 mm Hg, p less than 0.001), pulmonary vascular resistance (935 +/- 620 to 278 +/- 252 dynes.s.cm-5, p less than 0.001) and cardiac index (2.0 +/- 0.5 to 2.9 +/- 0.6 liters/min per m2, p less than 0.001). Similarly, echocardiographic variables of right heart structures, which were well outside the normal range preoperatively, improved significantly early after thromboendarterectomy. These included diameters of the pulmonary artery (2.8 +/- 0.3 to 2.4 +/- 0.4 cm, p less than 0.001), inferior vena cava (2.9 +/- 0.6 to 2.2 +/- 0.4 cm, p less than 0.001) and right atrium (6.8 +/- 1.5 to 5.9 +/- 1.5 cm, p less than 0.001) as well as right ventricular short axis (4.5 +/- 0.8 to 3.7 +/- 0.8 cm, p less than 0.001) and long axis (8.7 +/- 0.9 to 8.1 +/- 0.9 cm, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Accurate localization of ruptured sinus of Valsalva aneurysm by real-time two-dimensional Doppler flow imaging.

The surgical approach to the repair of a ruptured sinus of Valsalva aneurysm can depend on the cardiac chamber into which rupture occurs. This report details the color flow Doppler images in two patients who developed a right sinus of Valsalva aneurysm to right atrial fistula owing to bacterial endocarditis. In both cases, the color flow Doppler image was superior to contrast aortography in identifying the chamber into which rupture had occurred. The early experience with real-time two-dimensional Doppler flow imaging suggests that this noninvasive technique is valuable in the management of ruptured sinus of Valsalva aneurysms.

Adult↗