Usefulness of a new automatic boundary detection system (acoustic quantification) for assessing stiffness of the descending thoracic aorta by transesophageal echocardiography.
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Aging↗
Biomedical subjects
P R Lichtlen
Publications and source records attributed to P R Lichtlen.
[Results and experiences of transvenous endocardial defibrillator therapy].
We studied the follow-up of 72 patients who underwent implantation of a transvenous defibrillation lead system (ELS) (Endotak, CPI). All patients had ventricular tachycardia (VT) or fibrillation (VF) refractory to antiarrhythmic drug therapy. There were 51 patients with coronary disease and 21 patients had non-ischemic VT/VF. ELS was combined with a subcutaneous patch in 52 patients and implanted alone ("single lead only") in 20 patients. 40 patients received the ELS combined with antitachycardia pacing devices (Ventak PRx, CPI; Cadence, Ventritex) and 32 patients with the Ventak P 1600 or P2, CPI. Implantation of the ELS was attempted in 80 patients and performed in 72 patients (90%): Intraoperatively, the mean defibrillation threshold (DTF) was > 25 Joule (J) in five patients and no reliable ELS position was possible to achieve in three patients. These eight patients underwent thoracotomy with epicardial patch implantation. The mean DFT was < or = 20 J in all 72 patients with a mean DFT of 14 +/- 8 J in VT patients and 17 +/- 10 J in VF patients. Two of 80 patients (3%) died: one patient died intraoperatively and one during the mean follow-up of 6 +/- 2 (< 1 to 18) months. Complications occurred in three patients (4%): Dislocation of the Endotak electrode was observed in two patients (3%) and one patient developed pneumothorax postoperatively. Our data show that the ELS is most suitable in the majority of patients with VT/VF and is the approach of first choice for cardioverter defibrillator implantation at the present time. However, despite a relatively low intra- and perioperative complication rate, this approach should not be performed in institutions without cardiac surgery.
Adolescent↗
Increased myocardial cAMP in patients with transplant coronary vasculopathy.
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Adult↗
Usefulness of nifedipine in acute myocardial infarction.
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Death, Sudden↗
Role of mapping-guided surgery in patients with recurrent ventricular tachycardia.
To assess the value of ventricular tachycardia (VT) surgery 108 patients with recurrent episodes of VT were studied. There were 97 patients with coronary artery disease (group I) and 11 patients without coronary artery disease (group II). All patients in group I underwent subendocardial resection; 12 patients also underwent cryoablation. Cryoablation alone was performed in all patients in group II. During a mean follow-up period of 40 +/- 27 months, 29 patients (30%) in group I and two patients (18%) in group II died (p = 0.33). There were nine patients (9%) in group I and six patients (55%) in group II who had nonfatal recurrences of VT after surgery (p less than 0.01). In group I, there was a higher mortality rate among patients who had VT of posterolateral origin (14 of 31 patients; 45%) compared with 3 of 11 patients (28%) who had VT of anterolateral origin, 1 of 8 patients (12%) who had VT of inferoseptal, and 11 of 39 (29%) patients who had VT of anteroseptal origin. None of the eight patients with two distinct origins of VT died.
Adult↗
Surgical therapy for drug-refractory ventricular tachycardia: role of additional aneurysmectomy or bypass grafting.
To assess whether additional aneurysmectomy and/or bypass grafting influence prognosis we studied 97 patients with recurrent sustained monomorphic ventricular tachycardia after an old myocardial infarction. All patients underwent subendocardial resection due to drug-refractory ventricular tachycardia. There were 41 patients who had resection alone, 27 patients had resection and aneurysmectomy, 13 patients had resection and bypass grafting and the remaining 16 patients had resection with both, aneurysmectomy and bypass grafting. During the mean follow-up of 40 +/- 27 months 29 patients died (30%) (total mortality), 7 patients suddenly (7%) and 20 patients from cardiac causes (20%). There were no significant differences in total mortality between patients with resection alone (32%), patients with resection and aneurysmectomy (22%), patients with resection and bypass grafting (31%) and patients who had resection, aneurysmectomy and bypass grafting (38%). In addition, no significant differences were observed in the incidence of sudden death and nonfatal recurrences between patients with resection alone: sudden death 12%, recurrences 7%; patients with resection and aneurysmectomy: sudden death 0%, recurrences 19%; patients with resection and bypass grafting: sudden death 0%, recurrences 8%; and patients with resection, aneurysmectomy and bypass grafting: sudden death 13%, recurrences 0%. Postoperatively, left ventricular function improved in 56% of patients who had resection and aneurysmectomy compared to 17% of patients with resection alone, 31% of patients with resection and bypass grafting and 19% of patients who had resection, aneurysmectomy and bypass grafting. There is a low risk of sudden death and nonfatal recurrences after subendocardial resection. An influence of additional surgical approaches (aneurysmectomy or bypass grafting) on prognosis is not visible.
Adult↗
Catheter ablation of ventricular tachycardia: role of the underlying etiology and the site of energy delivery.
The role of DC catheter ablation (CA) to treat patients with sustained monomorphic ventricular tachycardia (VT) is still debated. To assess the efficacy of VT CA, we studied the follow-up of 49 patients with VT who underwent CA. There were 33 patients with an old myocardial infarction (MI) (group G I) and 16 patients had noncoronary VT (group G II): CA was performed at the earliest endocardial activation (EEA) (20 patients in G I, 14 patients in G II) or at the area of slow conduction (ASC) (13 patients in G I, 2 patients in G II). During the mean follow-up of 35 +/- 25 (1-79) months, there were 17 patients in G I (52%) and 12 patients in G II (75%) with VT recurrences (P less than 0.05). Recurrences of VT was observed in 4 of 15 patients (27%) when CA was performed at the ASC, compared to 25 of 34 patients (74%) with CA at the EEA (P less than 0.01). These data show that DC CA is more successful in patients with coronary artery disease, particularly when CA is performed at the ASC.
Adult↗
Anatomical progression of coronary artery disease in humans as seen by prospective, repeated, quantitated coronary angiography. Relation to clinical events and risk factors. The INTACT Study Group.
BACKGROUND: At present, there is extensive knowledge on the clinical course of coronary artery disease (CAD), whereas data on the underlying anatomical changes and their relation to clinical events are still limited. METHODS AND RESULTS: We investigated progression and regression of CAD prospectively over 3 years in 230 patients (average age, 53.2 years) with mild to moderate disease by applying quantitated, repeated coronary angiography. Minimal stenotic diameters, segment diameters, and percent stenosis were analyzed by the computer-assisted Coronary Angiography Analysis System (CAAS). Progression was defined either as an increase in percent stenosis of preexisting stenoses by greater than or equal to 20% including occlusions or as formation of new stenoses greater than or equal to 20% and new occlusions in previously angiographically "normal" segments. At first angiography, we found 838 stenoses greater than or equal to 20% (average degree, 39.3%) and 135 occlusions in the four major coronary branches (4.23 lesions per patient). At second angiography, 82 (9.8%) of the preexisting stenoses had progressed, 15 of them up to occlusion (1.8%; preocclusion degree averaging 46.6%; 29.7-65.6%). In addition, there were 144 newly formed stenoses (average degree, 39.2%) and 10 new occlusions. Hence, 25 (2.6%) of all stenoses had become occluded. Altogether, 129 patients (56.1%) showed progression: 68 (29.6%) with new lesions only, 27 (11.7%) with preexisting lesions, and 34 (14.8%) with both types. Regression (decrease in degree of stenoses greater than or equal to 20%) was present in 29 stenoses (3.6%) and 28 patients (12%). The incidence of new myocardial infarctions was low, with three originating from occluding preexisting stenoses and one from new stenoses; hence, only four (16%) of the 25 new occlusions led to myocardial infarctions. Risk factor analysis showed that cigarette smoking correlated significantly with the formation of new lesions (p = 0.001), whereas total cholesterol correlated with the further progression of preexisting stenoses (p = 0.017) but not with the incidence of new lesions. CONCLUSIONS: In patients with mild to moderate CAD, the angiographic progression is slow (in this study 18.7% of patients and 7% of stenoses per year) but exceeds regression (4.1% of patients and 1.2% of stenoses per year). Progression is predominantly seen in the formation of new coronary stenoses and less in growth of preexisting ones. Most of the stenoses were of a low degree (less than 50%), clinically not manifest including those going into occlusion and leading to myocardial infarction. Progression was influenced by risk factors, especially cigarette smoking (formation of new lesions) and high cholesterol levels (progression of preexisting stenoses).
Constriction, Pathologic↗
[Recent progress regarding nitrates and their use in stable and unstable angina pectoris, pre-infarction syndrome and myocardial infarct].
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Angina Pectoris↗
[Acoustic quantification--a new online procedure for automatic recording of left ventricular areas and area changes in the echocardiogram].
Initial experiences were obtained with a new technique for automatic quantification of left ventricular areas and area changes in two-dimensional (2D) echocardiograms (acoustic quantification, AQ). AQ is based on integrated back-scatter-analysis in real-time. Practicality and reliability of AQ were studied in 50 non-selected patients. AQ measurements of left-ventricular (LV) cavities were compared with off-line measurements which were obtained by analysis of videotaped images. Thirty-two (64%) and 39 (78%) patients could be studied by AQ from parasternal and apical views, respectively. LV areas measured from parasternal views or apical views showed a good correlation with corresponding values obtained by off-line analysis (r = 0.78 to 0.91). In addition, LV fractional area changes measured by AQ showed an excellent correlation with off-line measurements (parasternal: r = 0.86; apical: r = 0.84). During infusion of dobutamine (n = 3; 5, 10, 20 micrograms/kg/min, 10 min each dose), reduction of LV cavity areas could be continuously monitored and quantified by AQ for each cardiac cycle. In five of six patients who underwent transesophageal echocardiography, AQ could easily detect LV contours in the transgastric short axis view. Although AQ is not practicable in all patients, this new technique appears to be a promising and reliable approach for real-time, automatic boundary detection in 2D echocardiograms.
Adolescent↗
[Modulation of vascular tone of normal and arteriosclerotic arteries by leukocytes].
Leukocytes, in particular mononuclear cells, play a central role in the pathogenesis of arteriosclerosis. The arteriosclerotic vessel wall is chemotactic for circulating leukocytes. Activated leukocytes are known to release a variety of vasoactive substances. Thus, activation of leukocytes in diseased arteries is not only an epiphenomenon of an inflammatory process, but instead may contribute to arteriosclerosis-associated complications such as vasoconstriction/vasospasm and thrombotic vessel occlusion. Influence of leukocytes on vascular tone appears to be complex and may be modulated by the presence of intact endothelium and additional blood constituents such as platelets. In vitro, mononuclear and polymorphonuclear leukocytes both relax and contract isolated arteries according to experimental conditions and leukocyte isolation protocols. In vivo, activation of leukocytes by chemotactic peptides f-met-leu-phe or complement C5a produces pronounced vasoconstriction. Mediators of these leukocyte-induced vascular responses are partially characterized and consist of nitric oxide (or EDRF-like factor), superoxide anions, thromboxane A2, peptidoleukotrienes, and an unknown contractile factor. In addition, leukocytes may indirectly modulate vascular tone by cleavage of angiotensin II from angiotensinogen or angiotensin I, and by inhibiting or stimulating platelet aggregation. Thus, leukocytes and their products may have several pathways to modulate vascular tone. Abnormal interactions between endothelium-platelet-leukocytes with vascular tone may play an important role in the pathogenesis of vascular complications in patients with coronary artery disease.
Animals↗
[Etiology of acute cardiovascular arrest].
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Arrhythmias, Cardiac↗
[Long-term follow-up of patients after interruption of the atrioventricular conduction by electrode catheter and DC shock: experiences with 100 patients].
Long-term follow-up (44 +/- 21 months) was studied in 100 patients (pts) (mean age 56 +/- 12 years) who underwent direct current ablation because of drug-resistant supraventricular arrhythmias. In 85 pts (85%) complete atrioventricular (AV) block was initially achieved. During the follow-up period, AV conduction resumed in 15 pts (15%). Thirteen pts underwent another ablation session and complete AV block was achieved in 11/13 pts (85%). After catheter ablation complete AV-block was achieved in 96 pts and the remaining four pts had second-degree AV-block. Complications like pericardial effusion, arterial hypotension or ventricular arrhythmias occurred in 18 pts. Total mortality was 13% (13 pts): one patient died suddenly, and seven pts died from cardiac causes (heart failure in six pts, reinfarction in one patient). Transcatheter direct-current ablation is an effective method to interrupt AV conduction and to treat patients with drug-resistant supraventricular arrhythmias. Although there is a small risk of severe complications, this procedure should be reserved for pts with supraventricular arrhythmias who do not respond to conventional drug treatment.
Adult↗
[Drug therapy prevention of coronary sclerosis].
Primary preventive drug treatment of coronary artery disease (CAD) has gained importance in recent years as more efficient lipid lowering drugs and substances with new mechanisms become available, e.g. calcium entry blockers and antioxidants. For lipid lowering drugs, the exact mechanism of action is still not clear; the results of quantitated coronary angiography (QCA) revealing a small but significant increase in luminal size in stenotic areas can be explained both by stabilization of endothelial function (increased EDRF production)--as demonstrated in animal studies--leading to a decrease in basal tone, and by a decrease in plaque volume (so far not evidenced by QCA in man). Calcium entry blockers and antioxidants inhibit the formation of new atherosclerotic lesions, mainly by improving cholesterol excretion from vascular smooth muscle cells and macrophages into the extracellular space, and by suppression of proliferation and differentiation of vascular smooth muscle cells. The ensuing reduction of cardiac events is not yet proven for calcium entry blockers and also needs further confirmation for lipid lowering drugs; the difficulty of studies looking for clinical endpoints (myocardial infarction on sudden coronary death, unstable angina) lies in the very slow anatomical progression of CAD as demonstrated by QCA, demanding large numbers of patients and long intervals to demonstrate statistical significance.
Calcium Channel Blockers↗
[Can drugs, especially calcium antagonists, bring about regression of atherosclerosis, especially coronary sclerosis?].
The feasibility of true regression of human atherosclerotic plaques (reduction in volume) through drug therapy is still debated; the increase in coronary artery diameter, especially eccentric stenoses during massive reduction of serum cholesterol, can also be due to stabilization of endothelial function and improvement of the abnormally raised basal coronary tone. Today, there are two groups of substances with anti-atherosclerotic properties: lipid-lowering drugs, and calcium-entry blockers. As evidenced both from animal experiments and prospective studies in man by quantitated coronary angiography (QCA), the latter act mainly by retarding the evolution of new plaques, and possibly even of fatty streaks. In man, four studies with calcium-entry blockers so far exist, all demonstrating a significant reduction (average -46%) of new lesions (stenoses and occlusions) in previously angiographically normal segments. To what extent these favourable anatomical results will lead to an improvement of cardiac events caused by plaque rupture (unstable angina, myocardial infarction) later on is still an open question. The slow anatomical progression of coronary artery disease, as evidenced by prospective repeated QCA, calls for studies with long-term follow-ups (10 and more years) and large numbers of patients.
Calcium Channel Blockers↗
Percutaneous transluminal angioplasty of aortocoronary venous bypass grafts and effect of the caliber of the grafted coronary artery on graft stenosis.
The influence of morphologic parameters on the recurrence of stenosis after percutaneous transluminal coronary angioplasty of 49 stenoses in aortocoronary venous bypass grafts of 41 patients was investigated. Vessel dimensions were measured quantitatively. Angioplasty was successful in 46 stenoses (94%) of 38 patients (93%). In 35 patients (92% of successfully treated patients) with 42 stenoses, control angiography was performed after a mean interval of 189 +/- 186 days. In 9 patients (26%), 9 stenoses (21%) had recurred. The diameter of the grafted coronary artery distal to the anastomosis was significantly smaller in grafted arteries with than without recurrent stenoses (1.92 +/- 0.52 vs 2.45 +/- 0.50 mm; p less than 0.01). Recurrence also correlated with the ratio between graft diameter and coronary artery diameter greater than 1.35 (p less than 0.02) and with the stenosis length greater than 10 mm before angioplasty (p less than 0.01). Graft age, graft diameter and stenosis location in the graft had no significant influence on recurrence. Thus, the diameter of the grafted coronary artery and the length of the critical stenosis are parameters for recurrence after angioplasty of graft stenoses and should be considered in the selection of patients for this intervention.
Aged↗
Improvement in the diagnosis of abscesses associated with endocarditis by transesophageal echocardiography.
BACKGROUND: Echocardiography is recognized as the method of choice for the noninvasive detection of valvular vegetations in patients with infective endocarditis, with transesophageal echocardiography being more accurate than transthoracic echocardiography. The diagnosis of associated abscesses by transthoracic echocardiography is difficult or even impossible in many cases, however, and it is not known whether transesophageal echocardiography is any better. METHODS: To determine the value of transesophageal echocardiography in the detection of abscesses associated with endocarditis, we studied prospectively by two-dimensional transthoracic and transesophageal echocardiography 118 consecutive patients with infective endocarditis of 137 native or prosthetic valves that was documented during surgery or at autopsy. RESULTS: During surgery or at autopsy, 44 patients (37.3 percent) had a total of 46 definite regions of abscess. Abscesses were more frequent in aortic-valve endocarditis than in infections of other valves, and the infecting organism was more often staphylococcus (52.3 percent of cases) in patients with abscesses than in those without abscesses (16.2 percent). The hospital mortality rate was 22.7 percent in patients with abscesses, as compared with 13.5 percent in patients without abscesses. Whereas transthoracic echocardiography identified only 13 of the 46 areas of abscess, the transesophageal approach allowed the detection of 40 regions (P less than 0.001). Sensitivity and specificity for the detection of abscesses associated with endocarditis were 28.3 and 98.6 percent, respectively, for transthoracic echocardiography and 87.0 and 94.6 percent for transesophageal echocardiography; positive and negative predictive values were 92.9 and 68.9 percent, respectively, for the transthoracic approach and 90.9 and 92.1 percent for the transesophageal approach. Variation between observers was 3.4 percent for transthoracic and 4.2 percent for transesophageal echocardiography. CONCLUSIONS: The data indicate that transesophageal echocardiography leads to a significant improvement in the diagnosis of abscesses associated with endocarditis. The technique facilitates the identification of patients with endocarditis who have an increased risk of death and permits earlier treatment.
Abscess↗
Anginal symptoms without ischemic electrocardiographic changes during ambulatory monitoring in men with coronary artery disease.
Episodes of angina pectoris without electrocardiographic (ECG) signs of myocardial ischemia during 24-hour ambulatory monitoring were studied in 128 patients with a history of stable angina, angiographically proven coronary artery disease and positive exercise test results. In all, 341 episodes of ischemic ECG changes (ST-segment depression greater than 1 mm for greater than 1 minute) and 190 episodes of angina pectoris were observed: 86 episodes consisted of both ECG changes and angina pectoris, 255 episodes consisted only of ECG changes, and 104 episodes only of angina pectoris. Duration and magnitude of ST-segment deviation and heart rate at the onset of ischemia were similar in the 86 symptomatic and the 255 asymptomatic episodes with ECG changes. The 104 episodes of angina pectoris without ECG changes were detected in 44 patients (34%) (group A); 29 of them had only episodes with angina pectoris and 15 patients had both--episodes of angina pectoris with and without ECG changes. In 84 patients (66%) (group B) angina pectoris without ECG changes was not observed; all episodes were accompanied by ischemic ECG changes in these patients. No differences in the angiographic extent of coronary artery disease and in exercise test data were seen in both groups A and B; however, maximal ST-segment depression during exercise testing was significantly greater in group B than in group A patients (2.4 +/- 0.8 mm vs 1.9 +/- 0.9 mm; p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗