bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cocaine: The Newest Risk Factor for Cardiovascular Disease
Authors: Cregler Louis L. 
Published: February 2009

AbstractSummary: Cocaine‐related cardiovascular events escalated during the 1980s as cocaine became purer, cheaper, and easier to obtain. Cocaine abuse is a risk factor for myocardial ischemia and/or infarction, cardiac arrhythmias, pulmonary edema, ruptured aortic aneurysm, cerebral infarction, infective endocarditis, vascular thrombosis, myocarditis, and dilated cardiomyopathy. As medical and social complications of cocaine have become evident, and with the growing negative image of cocaine, the number of first‐time users has begun to decline. Cocaine abuse is seen on all levels of our society and has emerged as an issue of significant medical and public health importance. All routes and forms of cocaine abuse are potentially cardiotoxic and can be lethal. Fatal cardiac complications can occur in a first‐time user. All physicians should be alert for cocaine abuse when confronted with unexplained cardiac symptoms. Cocaine is the newest and sometimes unrecognized risk factor for cardiovascular disease in young individuals otherwise free of cardiovascular risk factors.
The Prognostic and Economic Implications of a Strategy to Detect and Treat Asymptomatic Ischemia: The Atenolol Silent Ischemia Trial (ASIST) Protocol
Authors: Pepine Carl J. , Cohn Peter F. , Deedwania Prakash C. , Gibson Robert S. , Gottlieb Sidney O. , Handberg Eileen , Hill James A. 
Published: February 2009

AbstractSummary: Although silent ischemia may be linked to increases in cardiovascular morbidity and mortality, the long‐term effects of a strategy aimed at the detection and treatment of this asymptomatic condition have not been fully explored. We therefore have developed the Atenolol Silent Ischemia Trial (ASIST), the first multicenter, randomized, prospective study of the prognostic implications of silent ischemia in asymptomatic and minimally symptomatic patients with coronary artery disease. Inclusion criteria for study patients were documented coronary artery disease, evidenced angiographically or by previous myocardial infarction, and transient ischemia, evidenced by abnormalities of regional wall motion, stress thallium‐201, or exercise electrocardiogram. The main objective of ASIST is to assess the influence of frequency and duration of symptomatic and asymptomatic ischemic episodes on the occurrence of fatal and nonfatal cardiac events. Atenolol, a beta1‐selective adrenergic blocker, was chosen as the therapeutic intervention because of its potential benefits in treating both symptomatic and asymptomatic ischemia. Ambulatory electrocardiographic monitoring will be used to measure the frequency and duration of ischemic episodes during daily life. The predictive ability of short‐term (4‐week) effects on long‐term (52‐week) response to atenolol treatment is also being assessed, along with the economic impact of this diagnostic and therapeutic strategy. Given the current emphasis on reducing morbidity and mortality associated with coronary artery disease, ASIST results should shed light onto the long‐term management and prognostic implications of this otherwise asymptomatic condition.
Acute effects of the ACE inhibitorlisinopril on cardiac electrophysiological parameters of isolated guinea pig hearts
Authors: Stark G. , Stark U. , Nagl S. , Klein W. , Pilger E. , Tritthart H.A 
Published: February 2009

AbstractAngiotensin‐converting enzyme (ACE) in‐hibitors are of benefit in life‐threatening ventricular ar‐rhythmias in patients with congestive heart failure and ven‐tricular tachycardia caused by the onset of myocardialischemia as well as by reperfusion of an ischemic area. The aim of the present study was to investigate whether di‐rect electrophysiological effects are responsible for these observations. Therefore, we investigated the electrophysi‐ological effects of lisinopril on the whole cardiac conduc‐tion and pacemaker system in isolated guinea pig hearts perfused by the method of Langendorff at concentrations of 0.01, 0.1, 1, and 10 μM. Lisinopril did not affect heart rate, atrioventricular, His bundle, or intraventricular conductionat any of the concentrations tested. Likewise the frequency‐dependent QT duration was unchanged. At a concentra‐tion of 10 pM, lisinopril prolonged effective refractory pe‐riod evaluated by premature beats (46 ± 15%, n = 8, p < 0.01) as well as the rate‐dependent effective refractoryperiod (31 ± 12, n = 8, p < 0.0l) of the atrioventricular con‐duction. These effects can be explained by lisinopril's ac‐tion as a minor calcium antagonist at a toxic concentrationof 10 μM. The present results show that electrophysiolog‐ical parameters are not substantially altered by lisinopril.Therefore, several other mechanisms such as the unloadingof the left ventricle and/or the suppression of noradrenalinrelease and the electrolyte (potassium and magnesium) re‐pletion and/or regression of left ventricular hypertrophy aslong‐term effects may play a major role in the antiarrhyth‐mic efficacy of ACE inhibitors.
Effects of atrioventricular block on ventricular fibrillation threshold in dog
Authors: Kumagai Koichiro , Tashiro Eiichiro , Moroe Kazuo , Hiroki Tadayuki , Arakawa Kikuo 
Published: February 2009

AbstractThe effects of complete atrioventricular block (CAVB) on ventricular vulnerability were studied 1 week after a transcatheter electrical ablation of the AV junction in 18 closed‐chest dogs. All dogs exhibited CAVB and a stable ventricular escape rhythm with a mean cycle length of 1795±600 ms. Although QT interval during CAVB was significantly prolonged compared with that during the sinus rhythm, QTc interval was significantly shortened. The ventricular fibrillation threshold was significantly elevated after creation of the block (from 9.35±2.28 to 12.3±3.69 mA, p < 0.01). Thus, CAVB which is not associated with QTc prolongation would be even less likely to play an important role in producing ventricular fibrillation presumably including torsades de pointes or polymorphous ventricular tachycardia.
Management of coronary heart disease in the elderly
Authors: Rogers, Ward B. , Von Dohlen, Thomas W. , Frank, Martin J. 
Published: February 2009

AbstractThe prevalence of coronary heart disease (CHD) increases rapidly with advancing age and remains the major cause of death among elderly Americans. The number of elderly has doubled in the last 30 years and is projected to continue growing at more than twice the rate of the general population. The resources required in managing CHD in this population will reach astronomical levels during the next few decades and will severely tax our ability to provide adequate medical care to all citizens, unless cost effective diagnostic and therapeutic strategies are developed which do not severely compromise health care. Risk factors for CHD should be identified and modified as early in life as possible. Modification of risk factors begun at advanced age appears to confer benefit, however. Anti‐ischemic drug therapy is the treatment of choice for patients with mild or moderate stable angina. Select elderly may be willing to accept the increased risks of coronary revascularization to achieve relief from debilitating angina or prolongation of life. Physicians must use care in planning diagnostic and therapeutic strategies. Quality of life and independence are often more important considerations than longevity in this age group.
Changes in left atrial size in patients with lone atrial fibrillation
Authors: Suarez, Guillermo Sosa , Lampert, Steven , Ravid, Shmuel , Lown, Bernard 
Published: February 2009

AbstractA retrospective analysis was performed on 23 subjects with lone atrial fibrillation who were followed for an average of 6.2 years (1.1–12.8 years). In all patients, underlying organic heart disease was excluded based on history, physical exam, electrocardiogram, echocardiogram, and Doppler ultrasound interrogation. All patients had at least two echocardiographic studies during the period of observation. Atrial fibrillation was chronic in 11 subjects and paroxysmal in 12. All echocardiographic measurements were obtained by averaging the measurements of two blinded investigators. Left atrial size increased an average of 5.6 mm which translates into a 14.7% increase over the baseline measurement. This increase in size was not associated with a change in left ventricular mass or fractional shortening as determined by echocardiography. Subjects with chronic atrial fibrillation had a larger percent increase than subjects with paroxysmal atrial fibrillation (18.9 vs. 10.8%), although this relative change in size failed to reach statistical significance. The only variable which significantly contributed to the change in left atrial size was the duration of follow‐up. We conclude that atrial fibrillation occurring in patients with lone atrial fibrillation may cause a slow and progressive increase in left atrial size independent of changes in left ventricular size or function.
Heart rate variability: An important new risk factor in patients following myocardial infarction
Authors: John Camm, A. , Ewing, D. J. 
Published: February 2009

AbstractAfter acute myocardial infarction, cardiac autonomic, and particularly parasympathetic, activity decreases, followed by a gradual return toward normal over the next few weeks and months. The easiest measureable index of autonomic activity is heart rate variability, which can be assessed in a number of different ways. Where heart rate variability is low after myocardial infarction, long‐term survival is considerably reduced, independent of other known risk factors. This may be caused by patchy autonomic denervation, rendering the heart more susceptible to potentially fatal arrhythmias. Prophylactic drug therapy might reduce mortality in patients with low heart rate variability.
Catheter balloon valvuloplasty of stenotic porcine bioprosthetic valves: Part I: anatomic considerations
Authors: Waller, Bruce F. , Mckay, Charles , Tassel, James Van 
Published: February 2009

AbstractDuring the last several years, dilating balloons have been applied in the treatment of stenotic cardiac valves. This interest has recently been extended to stenotic porcine bioprosthetic valves. Part I of this review discusses the pathologic processes responsible for degeneration of porcine prostheses: intrinsic calcification (mineralization), cuspal tears and perforations, and cuspal thrombosis (non‐infective). These changes form the basis of applied balloon valvuloplasty techniques.
The stunned and hibernating myocardium: A brief review
Authors: Richard Conti C. 
Published: February 2009

AbstractDefinitions: Stunned myocardium is viable myocardium salvaged by coronary reperfusion that exhibits prolonged postischemic dysfunction after reperfusion. Hibernating myocardium is ischemic myocardium supplied by a narrowed coronary artery in which ischemic cells remain viable but contraction is chronically depressed.Clinical evidence: Stunned myocardium has been identified in the following patient groups: (1) thrombolysis or percutaneous transluminal coronary angiography (PTCA) in patients with acute evolving infarction; (2) unstable angina; (3) exercise‐induced angina; (4) coronary artery spasm; (5) platelet aggregation or transient thrombosis of a coronary artery; (6) PTCA for chronic myocardial ischemia; and (7) immediately following coronary artery bypass graft (CABG). Evidence of hibernating myocardium (LV dysfunction) is found in the patient with severe coronary artery stenosis, even in asymptomatic patients at rest. Stunned myocardium returns to normal after a prolonged period of time (hours to weeks). Hibernating myocardium returns to normal function rather quickly if the cause is removed.Differentiation: Stunned myocardium can be differentiated from hibernating myocardium by three clinical parameters, namely, LV wall motion, myocardial perfusion, and myocardial metabolism. Stunned myocardium has abnormal wall motion that tends to normalize in response to inotropes and postextrasystolic potentiation. Perfusion is adequate and metabolism is also adequate. Hibernating myocardium also has abnormal wall motion, which normalizes after nitrates, inotropes, post extrasystolic potentiation (PESP), PTCA, or CABG. Myocardial perfusion is reduced but can be reversed with PTCA or CABG and metabolism is adequate.
24‐hour blood pressure profiles in hypertensive patients administered ramipril or placebo once daily: Magnitude and duration of antihypertensive effects
Authors: Mccarron David ,   The Ramipril Multicenter Study Group
Published: February 2009

AbstractRamipril is a new, potent nonsulfhydryl inhibitor of angiotensin converting enzyme. The magnitude and duration of its antihypertensive effect were evaluated in a multicenter, placebo‐controlled, randomized clinical trial conducted in 100 patients with mild to moderate essential hypertension. Ramipril significantly reduced both supine and standing blood pressures measured 24 h after dosing. Automated blood pressure monitoring showed that ramipril significantly reduced systolic and diastolic pressures for 24 h after dosing. The peak effect occurred between 3 and 6 h after dosing, with approximately 50% of this effect retained after 24 h. Ramipril was well tolerated; there was no significant difference between active drug and placebo in the overall incidence of side effects. Ramipril is an effective and well‐tolerated antihypertensive agent, which reduces both supine and standing blood pressure over the entire 24‐h period after dosing.
Repetitive reentrant and non‐reentrant ventriculoatrial synchrony in dual chamber pacing
Authors: Serge Barold S. 
Published: February 2009

AbstractRepetitive retrograde ventriculoatrial (VA) conduction in patients with dual chamber pacemakers may cause two forms of VA synchrony. (1) Endless loop tachycardia (pacemaker‐mediated tachycardia) or repetitive reentrant VA synchrony occurs when the pacemaker senses retrograde P waves. Appropriate programming can prevent pacemaker reentrant tachycardia in almost all cases. However, the measures used to control tachycardia may themselves create new problems. (2) AV desynchronization arrhythmia or repetitive non‐reentrant AV synchrony occurs when the pacemaker does not sense retrograde P waves. In this form of VA synchrony, the atrial stimulus is ineffectual because it falls in the atrial myocardial refractory period generated by the preceding unsensed retrograde P wave. A long atrioventricular interval and a relatively fast lower rate (or sensor‐driven rate with DDDR pacing) favor the development of AV desynchronization arrhythmia and its unfavorable hemodynamic consequences.
Critical noise level reduction for correct identification of late potentials: An illustrative case report
Authors: Kulakowski Piotr , Murgatroyd Francis D. , John Camm A. 
Published: February 2009

AbstractThe precision of detection of late potentials (LPs) on signal‐averaged electrocardiography (SAECG) depends on the degree of noise reduction. The recommended low‐noise endpoint is 0.3 μV. We describe a patient with sustained ventricular tachycardia after myocardial infarction with very low amplitude LPs in whom a noise level lower than 0.3 μV was necessary in order to obtain an abnormal result of the SAECG. The presence of LPs was confirmed by spectral temporal mapping of the SAECG.
The influence of the presence of collaterals on restenoses after PTCA
Authors: Probst Peter , Baumgartner Christoph , Gottsauner‐Wolf Michael 
Published: February 2009

AbstractTo assess the influence of collaterals on the long‐term follow‐up after successful percutaneous transluminal coronary arteriography (PTCA), 120 consecutive patients were studied. Of these, 104 (87%) had an adequate reangiogram and were included. At the time of PTCA the collaterals were estimated by a scoring system. In addtion, the coronary wedge pressure was measured in 49 patients six months after PTCA, a follow‐up angiogram was performed, and the patients were split up into a group with restenoses (stenosis >50%), 34 patients (32.7%); and a group without restenoses (stenosis <50%), 70 patients (67.3%). A total of 35 patients (30.7%) had collaterals. A comparison between both groups showed no significant differences in clinical parameters (age, angina duration, vessel involvement, lipids, blood sugar, and blood pressure), and stenoses‐related parameters (degree of stenoses, eccentricity, balloon size, inflation pressure, dissection, gradient after dilatation, and residual stenoses). Patients with collaterals had a significantly higher incidence of restenoses than those without collaterals (45.7% vs. 26.1%, p<0.05). Patients with wedge pressure of <45 mmHg (n = 30) had a significantly lower restenosis rate (23.3%) than patients with a coronary wedge pressure of >45 mmHg (n= 19) (restenosis rate 52.6%). It is concluded that the presence of collaterals indicates a high restenosis rate after PTCA within 6 months.
Operations for Atrial Fibrillation
Authors: John Camm A. , Cox James L. , Boineau John P. , Schuessler Richard B. , Bruce Ferguson T. , Cain Michael E. , Lindsay Bruce D. , Corr Peter B. , Kater Kathy M. , Lappas Demetrios G. 
Published: February 2009

AbstractAtrial fibrillation is the most common of all sustained cardiac arrhythmias, yet it has no effective medical or surgical therapy. During the past decade, multipoint computerized electrophysiological mapping systems were used to map both experimental and human atrial fibrillation. On the basis of these studies, a new surgical procedure was developed for atrial fibrillation. Between September 25, 1987, and May 1, 1991, this procedure was applied in 22 patients with either paroxysmal atrial flutter (n = 2). paroxysmal atrial fibrillation (n= 11), or chronic atrial fibrillation (n = 9) of 2 to 21 years' duration. All patients were refractory to all antiarrhythmic medications and each patient failed an average of 5.2 drugs preoperatively. There were no operative deaths and all perioperative morbidity resolved. All 22 patients have been cured of atrial fibrillation with surgery alone. One late isolated episode of atrial flutter occurred in a patient who is now receiving encainide. Preservation of atrial transport function has been documented in all of the patients postoperatively and all have experienced marked clinical improvement.
Perforated ventricular aneurysm in a male suffering from pneumonia
Authors: Eber Bernd , Neumann HansjÖRg , Dusleag Johann , Klein Werner , Rigler Bruno 
Published: February 2009

AbstractIn a 49‐year‐old male with fever, dyspnea, and chest pain, thoracic x‐ray revealed pneumonia with enlarged heart silhouette. Antibiotics were successful, pneumonia healed and complaints disappeared. Yet, during the following 3 months, echocardiography showed mild persistent pericardial effusion while in ECG both sinus tachycardia and ST‐T changes were found suggesting chronic pericarditis. Magnetic resonance imaging, however, revealed an extensive posterobasal aneurysm with pericardial effusion substantiated by ventriculography. Coronary angiography showed diffuse three‐vessel disease. Surgery revealed aneurysm with distinct perforation of the left ventricle and pericardial thrombi, thus aneurysmectomy as well as bypass grafts were performed. One year postoperatively, magnetic resonance imaging confirmed the absence of aneurysm with only a small irreversible posterobasal perfusion defect remaining as shown by thallium scintigraphy.
Improvement of exercise capacity after nifedipine in patients with eisenmenger syndrome complicating ventricular septal defect
Authors: Wong Cheuk‐Kit , Yeung David W. C. , Lau Chu‐Pak , Cheng Chun‐Ho , Leung Wing‐Hung 
Published: February 2009

AbstractWe investigated the potential benefit of a preferential pulmonary vasodilatory effect of nifedipine in 4 patients with Eisenmenger syndrome complicating ventricular septal defect. First‐pass radionuclide scan was performed at rest to measure intracardiac shunting before and after nifedipine. Two hours after 20 mg sublingual nifedipine, right‐to‐left shunt increased from 16.3 ± 1.4 to 20.4 ± 1.5% (p<0.05), but systemic arterial oxygen saturation (SAO2) remained steady. With 4 weeks of maintenance nifedipine therapy, resting intracardiac shunting and SAO2 were unchanged from baseline. Symptom‐limited cycle ergometry was performed before and after maintenance nifedipine with placebo control. Exercise duration was prolonged (8.7±0.6 vs. 6.8±0.9 min; p<0.02) and SAO2 at each stage of exercise was consistently increased in all patients after nifedipine. Cardiac output and the SAO2 at peak exercise were similar. Thus, chronic nifedipine therapy increases SAO2 on exercise and improves maximal exercise capacity in patients with Eisenmenger syndrome, which is not predicted by study of resting intracardiac shunting after acute therapy.
Prospective community evaluation of the signal‐averaged electrocardiogram in predicting malignant ventricular arrhythmias: Beneficial outcome with electrophysiology guided therapy
Authors: Nalos Peter C. , Pappas Jina M. , Nyitray William , Ishimori Tetsuo , DonMichael T. Anthony 
Published: February 2009

AbstractThe role of the signal‐averaged ECG was prospectively assessed in 517 patients in whom there was a suspicion for malignant ventricular arrhythmias. Patients were divided into Group I with a normal surface QRS width < 120 ms (426 patients) and Group II with a prolonged QRS duration > 120 ms (91 patients). Late potentials were present in 42 (10%) Group I patients and in 24 (26%) Group II patients. Programmed ventricular stimulation was performed for standard indications in 55 patients without late potentials and in 42 patients with late potentials, combining both groups. The sudden death or recurrent sustained ventricular tachycardia rate in follow‐up was evaluated based on the presence or absence of late potentials and whether programmed ventricular stimulation was performed. In the patients without late potentials, these rates were 4 patients (1.0%) in the no EP group and 3 patients (5.5%) in the EP group (p<.05), respectively (overall 1.6%). In the patients with late potentials, these rates were 7 patients (29%) in the no EP group and 7 patients (17%) in the EP group (p = .19), respectively (overall 21%). In addition, appropriate automatic defibrillator shocks were present in 1 patient without late potentials and in 8 patients with late potentials which were not included in the recurrent sudden death or sustained ventricular tachycardia statistics. The signal‐averaged ECG accurately defines patients at a higher risk for malignant ventricular arrhythmias regardless of unfiltered QRS duration. There is a trend toward improved survival with electrophysiology guided therapy in the late potential positive group with added incremental benefit from patients undergoing automatic defibrillator implantation.