bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relation of ventricular repolarization to cardiac cycle length in normal subjects, hypertrophic cardiomyopathy, and patients with myocardial infarction
Authors: Savelieva Irina , Yap Yee Guan , Yi Gang , Guo Xiao Hua , Hnatkova Katerina , John Camm A. , Malik Marek 
Published: February 2009

AbstractBackground: Prolonged QT interval and QT dispersion have been reported to reflect an increased inhomogeneity of ventricular repolarization, which is believed to be responsible for the development of arrhythmic events in patients with long QT syndrome, coronary heart disease, and myocardial infarction, congestive heart failure, and hypertrophic cardiomyopathy (HC).Hypothesis: This study was undertaken to determine whether an abnormal QT/RR dynamicity may reflect autonomic imbalance and may contribute to arrhythmogenesis in patients with heart disease.Methods: The relation between QT, QTpeak (QTp), Tpeak‐Tend (TpTc) intervals and cardiac cycle length was assessed in 70 normal subjects, 37 patients with HC, and 48 survivors of myocardial infarction (MI). A set of 10 consecutive electrocardiograms was evaluated automatically in each subject using QT Guard software (Marquette Medical Systems, Milwaukee, Wisc.).Results: In patients with HC, all intervals were significantly prolonged compared with normals (p <0.001 for QT and QTp; p <0.04 for TpTc); in survivors of MI, this was true for the maximum QT and QTp intervals (p <0.05). A strong linear correlation between QT, QTp, and RR intervals was observed in normals and in patients with MI and HC (r = 0.65–0.59, 0.82–0.77, 0.79–0.74, respectively, p <0.0001). TpTc interval only showed a weak correlation with heart rate in normals (r = 0.24, p <0.05) and was rate‐independent in both patient groups (p = NS). Compared with normals, the slopes of QT/RR and QTp/RR regression lines were significantly steeper in patients with MI and HC (0.0990–0.0883, 0.1597–0.1551, 0.1653–0.1486, respectively). Regression lines were neither parallel nor identical between normals and patients (T> 1.96, Z> 3.07). There was no difference in steepness for TpTeR/RR lines between groups (0.0110, 0.0076, 0.0163, respectively). TpTe/QTp ratio was similar in normals and in patients with MI and HC (0.30 ± 0.03, 0.31 ± 0.07, 0.30 ± 0.04, respectively), in the absence of any correlation between QTp and TpTe intervals, suggesting disproportional prolongation of both components of QT interval.Conclusion: Compared with normals, a progressive increase in QT and QTp intervals at slower heart rates in patients with MI and HC may indicate an enhanced variability of the early ventricular repolarization and may be one of the mechanisms of arrhythmogenesis.
Evaluation of endothelial function in hypertensive elderly patients by high‐resolution ultrasonography
Authors: Wang Xin‐Fang , Deng You‐Bin , Zhang Qing‐Ping , Li Chun‐Lei , Zhang You‐Gen , Le Gui‐Rong 
Published: February 2009

AbstractBackground:Multiple investigations, both in experimental models and in middle‐aged patients with essential hypertension, demonstrate impaired endothelium‐dependent vasodilatation.Hypothesis:We attempted to determine whether hypertension still exerts additional negative effect on endothelial function of large arteries in hypertensive elderly patients who may already be affected by endothelial dysfunction due to aging.Methods:We compared 13 elderly patients with hypertension [69 ± 9 years, (mean ± standard deviation)] with 13 matched healthy elderly subjects (72 ± 6 years) as controls. Using high‐resolution vascular ultrasound, we measured brachial artery responses to reactive hyperemia (with increased flow causing endothelium‐dependent dilatation) and sublingual nitroglycerin (causing endothelium‐independent dilatation).Results:Flow‐mediated dilatation correlated inversely with age (r = –0.60, p = 0.03) in the controls. Flow‐mediated dilatation was significantly impaired in hypertensive elderly patients (6.7 ± 3.3 vs. 13.3 ± 1.8% in controls, p<0.0001). No significant difference could be found in nitroglycerin‐induced dilatation between controls (12.1 ± 4.9%) and hypertensive elderly patients (10.2 ± 6.8%, p=0.5). On multivariate analysis, flow‐mediated dilatation in hypertensive elderly patients was inversely related to aging (r = –0.37, p = 0.04) and mean blood pressure (r = –0.57, p = 0.03).Conclusions:Our study showed decreased flow‐mediated dilatation with aging even in the healthy controls, and further decline in flow‐mediated dilatation in hypertensive elderly patients compared with controls. This impairment of flow‐mediated dilatation in hypertensive elderly patients was related to age and mean blood pressure, indicating that aging and hypertension may independently impair endothelial function in the brachial artery of these patients.
The use of atropine for facilitation of direct current cardioversion from atrial fibrillation—results of a pilot study
Authors: Sutton A. G. C. , Khurana C. , Hall J. A. , De Belder M.A. , Davies A. 
Published: February 2009

AbstractBackground:The importance of the role of the autonomic nervous system (ANS) in the initiation and propagation of atrial fibrillation has been demonstrated in the condition of paroxysmal atrial fibrillation. However, the role of the ANS in patients with chronic atrial fibrillation is less clear. Some patients with chronic atrial fibrillation are resistant to the standard techniques of direct current (DC) cardioversion.Hypothesis:We sought to investigate whether excessive vagal tone might prevent the restoration of sinus rhythm and to establish that the abolition of vagal tone using intravenous atropine will facilitate DC cardioversion in patients with atrial fibrillation who are resistant to the standard cardioversion techniques.Methods:Beginning in August 1994, a change in the protocol for elective DC cardioversion of atrial fibrillation was made to include the use of intravenous atropine for patients resistant to the standard techniques of DC cardioversion.Results:Over a 2‐year period, 140 elective cardioversions were performed for atrial fibrillation. Sinus rhythm could not be restored on 31 occasions. Intravenous atropine prior to a further 360 J shock with paddles in the anteroposterior position allowed sinus rhythm to be restored on nine occasions. Patients with successful cardioversion after atropine had significantly better left ventricular function than those who remained in atrial fibrillation (p = 0.001) as well as a tendency toward a smaller left atrium.Conclusion:This study suggests that high vagal tone, which is dominant in patients with structurally normal hearts, may prevent the termination of atrial fibrillation by standard techniques of DC cardioversion, and that the abolition of high vagal tone by atropine facilitates the restoration of sinus rhythm.
Acute myocardial infarction following sildenafil citrate (viagra®) intake in a nitrate‐free patient
Authors: Porter Avital , Mager Aviv , Birnbaum Yochai , Strasberg Boris , Sclarovsky Samuel , Rechavia Eldad 
Published: February 2009

AbstractSince its introduction to the market in March 1997, sildenafil acetate (Viagra®) has been prescribed to 1.7 million people. Sixteen men who were taking the drug have died, 7 of them during or soon after sexual activity. Most of these data have been derived from the media and not from the scientific literature. There is a general impression that cardiovascular complications of sildenafil occur mainly when the drug is taken concomitantly with nitrates. We describe a 65‐year‐old man with known coronary artery disease who had an acute myocardial infarction shortly after taking sildenafil and engaging in sexual activity. The patient had not been using nitrates. We suggest that the emotional arousal induced by Viagra, followed by the heavy physical exertion during sexual activity, triggers plaque rupture that leads to acute myocardial infarction.
Methods used to interpret the 12‐lead electrocardiogram: Pattern memorization versus the use of vector concepts
Authors: Hurst J. Willis 
Published: February 2009

AbstractThis article extols the value of using Grant's approach to the interpretation of electrocardiograms (ECGs). The essay includes a discussion on how people learn and emphasizes the difference in memorizing information, thinking, and learning. Simply stated, the brains of most people are not designed to memorize countless numbers of ECG patterns. Accordingly, the essay supports the view that a method of interpretation must be used, and the reader is encouraged to use basic principles of electrocardiography, including vector concepts, to interpret each ECG.
Selective estrogen receptor modulators—A new age of estrogens in cardiovascular disease?
Authors: Guzzo Joseph A. 
Published: February 2009

AbstractA large body of evidence suggests hormone replacement therapy (HRT) reduces cardiovascular risk in postmenopausal women. It is, however, associated with serious side effects, such as increased risk of breast and endometrial cancer. This has likely caused uneasiness among both women and health care providers. A new class of compounds, called selective estrogen receptor modulators (SERMs), have emerged. Through their interactions at the estrogen receptor level they have become a class of compounds distinct from estrogen. While they share similar effects with estrogen on such factors as lipid profile and bone density, they affect other tissues differently. Specifically, they do not induce endometrial hyperplasia and are therefore not associated with endometrial cancer. In vitro studies have also shown that they inhibit lipoprotein oxidation and vascular smooth muscle cell proliferation. The cumulative effects of these compounds may prove quite beneficial in reducing cardiovascular risk in postmenopausal women while avoiding serious side effects. This may, in turn, ease much of the anxiety surrounding the issue of HRT. Clinical trials are presently being conducted to evaluate the effectiveness of raloxifene, a SERM, on cardiovascular risk reduction in postmenopausal women.
Dipyridamole‐Induced reversible Thallium‐201 defect in patients with vasospastic angina and nearly normal coronary arteries
Authors: Fujita Hideki , Yamabe Hiroshi , Yokoyama Mitsuhiro 
Published: February 2009

AbstractBackground: Dipyridamole is a vasodilator of resistance vessels and has no vasoconstrictive effect on large coronary arteries.Hypothesis: The present study used dipyridamole thallium‐201 (201Tl) scintigraphy to clarify the role of microvasculature in coronary flow limitation in patients with vasospastic angina and normal coronary arteries.Methods: Sixteen patients underwent dipyridamole and exercise 201Tl scintigraphy and provocative coronary angiography with acetylcholine. All patients showed coronary spasm (>90% vasoconstriction concomitant with ST change) in at least one vessel.Results: Dipyridamole or exercise caused only ST depression despite the ST elevation observed at spontaneous attack. Dipyridamole 201Tl scintigraphy demonstrated the reversible defects (11 cases), as did exercise 201Tl scintigraphy (13 cases). The region of 201Tl defect was not always consistent with the territories of angiographically depicted vasospastic arteries. Basal coronary tone, assessed by percentage of diameter change of epicardial arteries from baseline to isosorbide dinitrate administration, did not differ between the positive and the negative defect regions.Conclusion: These results support the hypothesis that, in addition to epicardial coronary spasm, the dysfunction of microvasculature is responsible for abnormal coronary perfusion in the subgroup of patients with vasospastic angina and normal coronary arteries.
Incidence and significance of profound hypotension during dobutamine stress echocardiography
Authors: Dhond Milind R. , Whitley Teresa B. , Singh Satnam , Nguyen Thanh T. , Bommer William J. 
Published: February 2009

AbstractBackground: Mild hypotension (drops of systolic blood pressure of ≥20 mmHg) occurs in 14‐‐38% of dobutamine stress echo (DSE) and carries a good prognosis for subsequent cardiac events. The incidence and significance of more profound hypotension (PH) (≥ 50mmHg) is unknown.Hypothesis: The aim of the study was to determine the incidence of PH during DSE and its prognosis for subsequent cardiac events.Methods: We reviewed 617 DSE performed at our institution between 1992 and 1996 and identified two DSE subgroups. The first group (PH group) consisted of all patients with PH during DSE. A second group was selected with baseline characteristics similar to the PH group but without PH during DSE (non‐PH group). Follow‐up was by a physician chart review and direct telephone contact. Cardiac event rates were determined for hard [myocardial infarction (MI), or cardiac death] and soft (angina, congestive heart failure, coronary angioplasty, or coronary bypass surgery) events occurring after the DSE.Results: Of the 617 DSE performed, 16 (3%) patients developed PH (PH group) during DSE, with 13 showing no inducible ischemia. The hard and soft cardiac event rate in this 13 PH group was 46% (mean follow‐up of 28.7 ± 18 months). Of the non‐PH group, 32 patients had a negative DSE with a coronary event rate of 12.5%. Profound hypotension correlated with a significantly higher cardiac event rate (p < 0.02).Conclusions: The incidence of PH during DSE is low (3%) and appears to predict a worse prognosis for subsequent cardiac events.
Tachycardia‐dependent right bundle‐branch block with supernormal conduction
Authors: Katoh Takakazu , Kinoshita Shinji , Oyama Yohtaro , Tsujimura Yoshinori , Sasaki Yoshihiko 
Published: February 2009

AbstractThis paper reports the case of a 76‐year‐old man in whom atrial flutter with varying atrioventricular block and intermittent right bundle‐branch block was found. This is the first report on tachycardia‐dependent right bundle‐branch block associated with supernormal conduction in a case of atrial flutter. When an impulse is conducted to the ventricles beyond 0.72 s after a QRS complex of right bundle‐branch block configuration, the impulse falls after the abnormally long effective refractory period of the right bundle branch and passes through the right bundle branch. When the conducted impulse occurs within 0.72 s after a QRS complex of right bundle‐branch block configuration, the impulse usually falls in the refractory period and is blocked in the right bundle branch; however, only when the impulse occurs 0.48 or 0.49 s after that does it fall in the supernormal period and passes through the right bundle branch. The findings in the present report strengthen our previous suggestion that the presence of supernormal conduction plays an important role in the initiation of reentrant ventricular tachycardia.
Five‐year mortality in patients with acute chest pain in relation to smoking habits
Authors: Herlitz Johan , Karlson Björn W. , Sjölin Margareta , Lindqvist Jonny , Karlsson Thomas , Caidahl Kenneth 
Published: February 2009

AbstractBackground: Smoking is one of the major risk indicators for development of coronary artery disease, and smokers develop acute myocardial infarction (AMI) approximately a decade earlier than nonsmokers. In smokers with established coronary artery disease, quitting smoking has been associated with a more favorable prognosis. However, most of these studies comprised younger patients, the majority of whom were males.Hypothesis: The purpose of the study was to determine mortality, mode of death, and risk indicators of death in relation to smoking habits among consecutive patients admitted to the emergency department with acute chest pain.Methods: In all, 4,553 patients admitted with acute chest pain to the emergency department at Sahlgrenska University Hospital during a period of 21 months were included in the analyses and were prospectively followed for 5 years.Results: Of these patients, 36% admitted current smoking. They were younger and had a lower prevalence of previous cardiovascular diseases than did nonsmokers. The 5‐year mortality was 19.4% among smokers and 24.9% among non‐smokers (p<0.0001). However, when adjusting for difference in age, smoking was associated with an increased risk [relative risk (RR) 1.51; 95% confidence interval (CI) 1.32–1.74; p< 0.0001]. Among patients presenting originally with chest pain, the increased mortality for smokers was more pronounced in patients with non‐acute than acute myocardial infarction (AMI). Among patients who died, death in smokers was less frequently associated with new‐onset myocardial infarction (MI) and congestive heart failure. Among those who smoked at onset of symptoms and were alive 1 year later, 25% had stopped smoking. Patients with a confirmed AMI who continued smoking 1 year after onset of symptoms had a higher mortality (28.4%) during the subsequent 4 years than patients who stopped smoking (15.2%; p = 0.049).Conclusion: In consecutive patients admitted to the emergency department with acute chest pain, current smoking was significantly associated with an increased risk of death during 5 years of follow‐up. Among patients who died, death in smokers was less frequently associated with new‐onset MI and congestive heart failure than was death in nonsmokers.
Effects of early captopril therapy after myocardial infarction on the incidence of late potentials
Authors: Chiladakis John A. , Karapanos George , Agelopoulos George , Alexopoulos Dimitris , Manolis Antonis S. 
Published: February 2009

AbstractBackground: Late potentials (LP) on signal‐averaged electrocardiography (SAECG), recorded 6 to 30 days after an acute myocardial infarction (AMI), identify patients at risk for late arrhythmic events. Angiotensin‐converting enzyme (ACE) inhibitors have been shown to reduce ventricular remodeling and cardiovascular mortality after AMI.Hypothesis: The aim of this study was to investigate the effect of early (< 24 h) administration of captopril on the presence of LP on Days 6–30 after AMI.Methods: The study included 117 patients with a first AMI; 63 patients (53 men and 10 women, aged 59±12 years), 35 with an anterior and 28 with an inferior AMI (44 thrombolyzed), received early captopril therapy. The control group consisted of 54 age‐matched patients (39 men and 15 women, aged 60 ± 12 years), 19 with an anterior and 35 with an inferior AMI (31 thrombolyzed, p = NS), who did not receive early therapy with an ACE inhibitor. The mean left ventricular ejection fraction was similar in both groups (48 vs. 46%). Time domain analysis of SAECG was performed using a band‐pass filter of 40–250 Hz. Late potentials were considered present if any two of three criteria were met: (1) Filtered QRS duration (QRSD) > 114 ms, (2) root‐mean‐square voltage of the last 40 ms of the QRS complex (RMS) > 20 m̈V, and (3) duration of low amplitude (< 40 m̈V) signal of the terminal portion of the QRS (LAS) > 38 ms.Results: In the two groups of patients there were no differences in mean values of SAECG parameters. No patient was receiving any antiarrhythmic drugs. In the captopril group LPs were present in 9 of 63 patients (14%) and in the control group in 17 of 54 patients (31 %) (p =0.046). There was no difference in the number of patients with a patent infarct‐related artery in the two groups (76 vs. 59%).Conclusion: Captopril treatment early after an AMI reduces the incidence of LPs recorded on Days 6–30 and may thus favorably affect the arrhythmogenic substrate.
Refractory vasospasm with a malignant course
Authors: Kumar Ananth , Chandna Harish , Santhanam Vimala , Denes Pablo 
Published: February 2009

AbstractWe present a patient with two rare disorders, recurrent vasospastic angina leading to cardiac transplant and acute aortic occlusion. The patient had recurrent episodes of coronary vasospasm presenting with unstable angina, acute myocardial infarction, and sudden cardiac death in spite of adequate therapy with nitrates and calcium‐channel blockers. He went on to have a cardiac transplant. The patient later presented with acute aortic occlusion with concomitant renal and mesenteric artery spasm. The circumstances of the presentation raise the possibility of a generalized vasospastic predisposition that is responsible for both events. Smoking, the only known major risk factor other than atherosclerosis, was noted to be temporally related to both events in our patient.
Echocardiography of the coronary sinus in adults
Authors: D'Cruz Ivan A. , Shala M. Bashar , Johns Cameila 
Published: February 2009

AbstractThe coronary sinus (CS) is a small tubular structure just above the posterior left atrioventricular junction. The CS can be imaged in several different echocardiographic views. Using zoom M‐mode recordings of the CS in apical two‐chamber view, CS caliber can be sharply imaged and easily measured during different phases of the cardiac cycle. We have recently shown that the CS narrows during atrial contraction in persons with sinus rhythm, but does not narrow at all if atrial fibrillation is present. Attenuation of CS narrowing occurs in patients with congestive heart failure and inferior vena cava plethora. Maximal CS caliber occurs during ventricular systole. Patients with poor left ventricular systolic function show mild CS dilatation. Greater CS dilatation is present in patients with persistent left superior vena cava, and huge dilatation when this anomaly is accompanied by absence of a right superior vena cava. Injection of sonicated saline into a left and then a right arm vein is diagnostically useful in confirming these two venous anomalies. Pulsed‐wave Doppler of the CS can be recorded in the parasternal right heart inflow view. From this and from the CS cross‐section area it may be possible to estimate coronary blood flow.
Atrial fibrillation independently prolongs hospital stay after coronary artery bypass surgery
Authors: Tamis Jacqueline E. , Steinberg Jonathan S. 
Published: February 2009

AbstractBackground: Atrial fibrillation (AF) is the most common arrhythmia occurring in patients after coronary artery bypass surgery (CABG).Hypothesis: The purpose of this study was to determine whether AF independently prolonged postoperative length of stay (LOS).Methods: Consecutive patients undergoing elective CABG were identified. Baseline clinical variables, postoperative course including the development of AF, and postoperative LOS were recorded.Results: In all, 216 patients (aged 61 ± 13 years) were examined. Postoperative LOS was 11.3 ± 6.4 days (median LOS = 9 days). Fifty‐five patients (25%) developed AF. Among 16 variables examined, the univariate predictors of LOS included age (p < 0.001), preoperative left ventricular ejection fraction (p < 0.001), absence of a prior smoking history (p < 0.05), bypass limited to venous conduits (p < 0.001), postoperative AF (p < 0.001), and the occurrence of a postoperative event (p < 0.001). Length of stay for patients who developed AF was significantly longer than that for patients who did not (15.1 ± 9.0 vs. 10.0 ± 4.6 days, p < 0.001). After adjusting for other significant variables, the occurrence of AF after CABG independently prolonged LOS: patients who developed AF stayed 3.2 ± 1.7 days longer than patients who did not (p < 0.001).Conclusions: Atrial fibrillation lengthens hospital stay after CABG, and its effect is independent of other important variables. Identification of patients who are at risk for AF and successful treatment to prevent AF will likely contribute to major reductions in consumption of health care resources in patients with CABG.