Cardiac arrhythmias,electrolyte abnormalities and serum cardiac glycoside concentrations in yellow oleander (Cascabela thevetia) poisoning – a prospective study

Background: Consumption of yellow oleander (Cascabela thevetia) is a popular method of intentional self-harm in South India.

Objectives: The objectives of this study were to identify the cardiac arrhythmias and electrolyte abnormalities in yellow oleander poisoning and to identify the association between electrolyte abnormalities, cardiac glycoside concentrations at admission and the severity of cardiotoxicity. This study was also designed to identify clinical and biochemical parameters at presentation which predict serious arrhythmias and determinants of mortality.

Materials and methods: This was a prospective study among 192 patients who attended our Emergency department after consuming yellow oleander seeds. Patients were monitored with serial ECGs. Serious cardiac arrhythmias included sinus bradycardia <40/min, sinus arrest/exit block, second or third degree AV block, atrial tachyarrhythmias and ventricular tachyarrhythmias. Serum sodium, potassium, magnesium, total calcium and cardiac glycoside concentrations were measured at presentation for all 192 patients. Serial estimation of cardiac glycoside concentration was done in 43 patients who presented within 24?hours of consuming at least five seeds.

Results: At presentation, 46 patients had serious arrhythmias and on follow-up, 11 developed new-onset serious arrhythmia. Sinus bradycardia (27%) was the most common arrhythmia followed by second-degree AV block (17%); multiple arrhythmias were observed in 18%. Digoxin effect in ECG correlated significantly with hyperkalemia. Mortality rate was 5%. Serum sodium, total calcium and magnesium levels did not correlate with cardiotoxicity. Cardiac glycoside concentration was of relatively modest clinical utility to discriminate patients with serious dysrhythmias (AUC: 0.719, 95% CI: 0.63–0.81). Prolonged PR interval and digoxin effect in ECG were significantly associated with an increased likelihood of serious dysrhythmias. Increase in 0.4 number of seed intake increased the odds of mortality by 1.5 times when all other independent variables were kept constant.

Conclusion: Cardiac glycoside concentration at the time of presentation predicted the development of new-onset serious arrhythmias. Although serum potassium correlated significantly with cardiac glycoside concentration at admission and overall serious dysrhythmias, it did not predict the development of new-onset serious arrhythmia. On the whole, serious dysrhythmias were significantly associated with higher number of seeds ingested, hypotension at admission, PR interval prolongation, presence of digoxin effect in ECG, hyperkalemia and higher cardiac glycoside concentration. The independent determinants of mortality were larger number of seeds ingested and hypotension at admission. Cardiac glycoside concentration and hyperkalemia failed to be independent markers of serious dysrhythmias as well as mortality.     

Structural and functional cardiac abnormalities identified prior to 16 weeks' gestation in fetuses with increased nuchal translucency.

OBJECTIVE: To determine the accuracy and practicality of fetal echocardiography in the identification of structural and functional cardiac abnormalities prior to 16 weeks' gestation in fetuses with increased nuchal translucency thickness (NT). METHODS: Between January 1996 and June 2002 early fetal echocardiography using the transvaginal route was performed at 12-16 weeks' gestation on 275 fetuses with increased NT. The abnormal cardiac findings were classified as either structural (congenital heart defects) or functional, defined as transient phenomena which might later disappear, such as isolated tricuspid regurgitation and an enlarged ascending aorta. The abnormal findings were related to pregnancy outcome, including autopsy results, karyotyping results, and late fetal and neonatal echocardiography. RESULTS: Cardiac abnormalities were present in 61 fetuses overall (22.2%); including structural cardiac defects in 37 fetuses (13.5%) and functional abnormalities in 24 fetuses (8.7%). Structural cardiac abnormalities were associated with abnormal karyotype in 24 fetuses and normal karyotype in 13 fetuses. Of the 24 fetuses with functional cardiac abnormalities, 2 (8.3%) had isolated tricuspid regurgitation and 22 (91.7%) had enlarged ascending aorta. Abnormal karyotype was present in this group in 4 cases (16.7%). CONCLUSION: Increased NT can be used to define a high-risk group that should receive specialized early fetal echocardiography. This is a reliable technique with great potential for the diagnosis of both structural and functional cardiac abnormalities.     

Cardiac loop ECG recording: a new noninvasive diagnostic test in recurrent syncope

The most crucial step in diagnosing syncope is determining whether or not an arrhythmia is the cause. A new recording device, the continuous cardiac loop ECG recorder, affords prolonged ambulatory monitoring and can capture the rhythm at the time of syncope. To determine the impact of cardiac loop ECG recorders in diagnosing syncope, we reviewed the records of the first 48 patients referred for cardiac loop recording because of unexplained syncope or presyncope. Previous cardiac studies were nondiagnostic in all patients. In 36% of these patients, loop recording definitively determined whether an arrhythmia was the cause of symptoms. Median duration of monitoring was 28 days, with an average charge of $180 per month. Cardiac loop ECG recording is a convenient, safe, inexpensive, and potentially highly effective means of diagnosing unexplained syncope.     

Diagnostic assessment of recurrent syncope

The definitive diagnosis of a cardiac arrhythmia as the basis for syncope is made by electrocardiographic monitoring during a syncopal episode. In the absence of this evidence, abnormalities demonstrated by an electrophysiologic study may suggest the etiology of syncope. Cardiac electrophysiologic testing in patients with recurrent syncope should probably be limited to patients with underlying cardiac disease. These patients are at a higher risk for sudden death and have a high incidence of electrophysiologic abnormalities. In particular, ventricular tachycardia may be evoked and specific therapy for this abnormality is associated with remission of syncope. In contrast, electrophysiologic studies in patients with no underlying cardiac disease have a very low yield of abnormal findings in the order of 10–20%, and should be performed only when there are reasons to suspect the presence of arrhythmias. Furthermore, in patients with no underlying cardiovascular disease there is a high spontaneous remission rate of syncope and the late incidence of sudden death is low, and related to the presence of other systemic illnesses. At present, the significance of nonsustained ventricular tachycardia or ventricular fibrillation induced during cardiac electrophysiologic studies in patients with no documented arrhythmias is unknown, and further prospective studies are necessary to define appropriate therapy for these patients. Further investigation is also required to clarify the spontaneous remission rate of syncope, as this information is of vital importance in assessing the success of any therapeutic modality.     

产前超声心动图对胎儿心脏横纹肌瘤和并发症的诊断及评价

摘要 目的 探讨产前超声心动图对胎儿心脏横纹肌瘤和并发症的诊断价值,并提高对胎儿横纹肌瘤的认识。方法 总结在我院进行产前超声心动图常规筛查和会诊的11例本病患儿,分析其瘤体和并发症声像图特点。结果 11例患儿中有3例合并其他心内并发症,分别是心律失常、流入或流出道狭窄、心功能异常、心包积液。结论 产前超声心动图可以发现胎儿期心内横纹肌瘤,并分析有无合并症,对患儿妊娠结局做出提示性诊断。     

Inflammation as a link between brain injury and heart damage: the model of subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) serves as a good model for the study of heart-brain interactions because it is associated with both a high incidence of arrhythmia and a low prevalence of coronary heart disease. The pathophysiology of cardiac abnormalities in SAH is unsettled. Initial theories focused on sustained stimulation of cardiomyocytes at sympathetic nerve endings, but recent data suggest that dysfunction of the parasympathetic nervous system may contribute as well. We believe that the coupling of catecholamine release with parasympathetic dysfunction may allow unchecked inflammation that leads to myocardial dysfunction and cell death. We have developed a novel murine model of SAH to explore these potential inflammatory underpinnings of cardiac damage in SAH.     

The pharmacology of cardiac memory

Cardiac memory is an altered T wave during sinus rhythm that is induced by a period of ventricular pacing or arrhythmia. The T wave is characterized by a vector that tracks that of the previously paced or arrhythmic QRS complex. Although initially considered a clinical oddity, cardiac memory is of interest both as an example of the general biological property of memory - as studied most extensively in neural tissues - and because of its implications regarding the control of cardiac rhythm. Signal transduction of cardiac memory appears to involve an angiotensin II-regulated pathway initiated by altered stress/strain patterns in the myocardium. The end result is altered density and kinetics of the transient outward current and perhaps other ion currents as well, and an altered transmural gradient for repolarization. The altered repolarization pattern is accompanied by altered responses to specific antiarrhythmic drugs that may be anti- or proarrhythmic.     

Neonatal and Infant Tachyarrhythmias: Differentiation and Treatment

Cardiac arrhythmia recognition is essential in the neonatal population, because premature newborns are at risk for arrhythmias due to immature heart muscle, function, and congenital heart abnormalities. An increased heart rate is the appropriate reaction to stress, and some tachycardias can lead to congestive heart failure or death if not treated appropriately. Although bradycardia is the most frequently seen arrhythmia in the newborn period, four additional arrhythmias may occur in the neonatal and infant populations: sinus tachycardia, supraventricular tachycardia, ventricular tachycardia, and complete heart block. As the tachyarrhythmias appear similar on the monitor, the treatment of each is very different. The nurse must be able to differentiate them. The nurse must take the initiative to discern the differences between the arrhythmias, have complimentary assessment skills to determine the severity of the associated signs, and be able to communicate this to the care provider to ensure appropriate treatment. An educated nurse is the most important link in this process.     

Cardiac Magnetic Resonance Findings in Isolated Congenital Left Ventricular Diverticuli

Congenital ventricular diverticulum is a rare cardiac abnormality, frequently associated with other cardiac or non-cardiac congenital malformations. Clinically, congenital ventricular diverticulum may be asymptomatic or cause systemic embolization, heart failure, ventricular rupture, ventricular arrhythmia and sudden death. Cardiac magnetic resonance (CMR) can be a useful non-invasive and non-ionizing method to confirm the presence, size and extent of left ventricular (LV) diverticulum and its tissue characterization. In these reports we documented the presence of six diverticuli in patients underwent to CMR for other clinical indications. In all the cases, magnetic resonance showed an accurate assessment of diverticuli.     

Pharmacotherapy of Cardiac Arrhythmias—Basic Science for Clinicians

Cardiac arrhythmias occur in approximately 5.3% of the population and contribute substantially to morbidity and mortality. Pharmacological therapy still remains the major approach in management of patients with nearly every form of cardiac arrhythmia. Effective and safe management of cardiac arrhythmias with antiarrhythmic drugs requires understanding of basic mechanisms for various cardiac arrhythmias, clinical diagnosis of an arrhythmia and identification of underlying cardiac diseases, pharmacokinetics, and antiarrhythmic properties of each individual antiarrhythmic drug. Most cardiac arrhythmias occur via one of the two mechanisms: abnormal impulse formation and reentry or both. Antiarrhythmic drugs primarily work via influencing cardiac automaticity or triggered activity or by their effects on effective refractoriness of cardiac cells. Proarrhythmic effects of antiarrhythmic drugs are also briefly discussed in this review article.     

Disproportionality analysis of buprenorphine transdermal system and cardiac arrhythmia using FDA and WHO postmarketing reporting system data

Objective: Positive-controlled clinical studies have shown a dose dependent effect of buprenorphine transdermal system on QTc interval prolongation. This study provides assessment of the buprenorphine transdermal system and cardiac arrhythmia using US FDA and WHO postmarketing reporting databases.

Methods: Disproportionality analysis of spontaneously reported adverse events to assess whether the reporting rate of cardiac arrhythmia events was disproportionately elevated relative to expected rates of reporting in both FDA and WHO databases. Cardiac arrhythmia events were identified using the standardized Medical Dictionary for Regulatory Activities query for torsade de pointes and/or QT prolongation (TdP/QTP). The threshold for a signal of disproportionate adverse event reporting was defined as the lower 90% confidence limit ≥ 2 of the Empiric Bayes geometric mean in FDA database and as the lower 95% confidence limit of the Informational Component >0 in WHO database.

Results: There were 124 (<1%) and 77 (2%) cardiac arrhythmia event cases associated with buprenorphine transdermal as compared to 3206 (12%) and 2913 (14%) involving methadone in the FDA and WHO databases, respectively. In the FDA database methadone was associated with a signal of disproportionate reporting for TdP/QTP (EB05 3.26); however, buprenorphine transdermal was not (EB05 0.33). In the WHO database methadone was associated with a signal of disproportionate reporting for TdP/QTP (IC025 2.66); however, buprenorphine transdermal was not (IC025 ?0.88). Similar trends were observed in sensitivity analyses by age, gender, and specific terms related to ventricular arrhythmia.

Conclusions: The signal identified in the transdermal buprenorphine thorough QTc study, which led to a dose limitation in its US label, does not translate into a signal of increased risk for cardiac arrhythmia in real world use, as assessed by this method of analyzing post-market surveillance data.     

高龄食管癌、贲门癌术后心律失常的临床分析

目的探讨高龄食管癌、贲门癌术后心律失常的危险因素及防治措施。方法对198例高龄食管癌、贲门癌术后患者进行连续心电监护,其中52例发生心律失常。对多项临床因素进行分类统计。结果术后72 h内是高峰期,以窦性心动过速多见。术前心电图异常、第1秒用力呼气容积/用力肺活量(FEV1/FVC)<70%、弓上吻合、胃扩张、术前血钾<4 mmol/L,有并发症者,术后易发心律失常。结论年龄、术前心电图、FEV1/FVC、术式、术前血钾水平以及胃扩张、胃排空障碍等临床因素,与术后发生心律失常有密切关系。寻找并及时纠正诱因,合理应用抗心律失常药物,是治疗心律失常的非常重要的方法。     

Cerebrogenic cardiac arrhythmia in patients with organic brain diseases of nonvascular genesis

Cardiological examination covered 115 patients (79 males and 36 females aged 16-44 years) with organic brain pathology of nonvascular genesis: epilepsy (n = 51), sequelae of closed craniocerebral trauma (n = 37) or cerebral inflammation (n = 27). The control group consisted of 15 healthy subjects. It was found that patients with brain diseases have a variety of cardiac rhythm and conduction disturbances which occur much more often than in the control group (p < 0.01). Cardiac arrhythmia was encountered most often in epileptics and patients with complications of closed craniocerebral trauma (96.1% and 70.3%, respectively). Rates of cardiac arrhythmia and conduction disorders in patients with brain diseases correlated with frequency of epileptic fits and severity of organic alterations in the brain. The pattern of rhythmic and conduction disorders was formed according to dysfunction of suprasegmentary vegetative centers with prevalent activation of the sympathetic or parasympathetic autonomic nervous system. Cardiac arrhythmia and related negative feelings deteriorate "quality of life" in patients with brain pathology that's why it is necessary to detect and treat them early.     

Secondary cardiomyopathy accompanied by neuromuscular disorders

There are many neuromuscular diseases associated with cardiomyopathy. Cardiac involvement with progressive muscular dystrophy (Duchenne and Becker type) and some type of limb-girdle muscular dystrophy were characterized by impaired left ventricular systolic function, such as dilated cardiomyopathy like status. In Friedreich ataxia various types of left ventricular hypertrophy were reported. While in myotonic dystrophy and Emery-Dreifuss muscular dystrophy, conduction disturbance and tachyarrhythmia are common types of cardiac manifestation. The severity of cardiac involvement in these diseases is not necessarily concordant with that of skeletal muscle. Recently the genes of these diseases were identified by linkage analysis. We review cardiac abnormalities of these diseases, especially relationship between severity of cardiac disorder and gene abnormalities.     

Cardiac lipoma: A rare cause of right-to-left interatrial shunt with normal pulmonary artery pressure

Cardiac lipomas are rare tumors. They usually remain asymptomatic for a long time and cause angina, arrhythmia, dysfunction of the ventricles or valves, and peripheral embolization during the later stages of development. There is little or no information about right-to-left interatrial shunt with normal pulmonary artery pressure, produced as a consequence of the infiltration of the atrial septum, the right atrial wall, and the myocardium because of the presence of fat in patients with platypnea-orthodeoxia syndrome. We present a patient with this syndrome who was identified through transesophageal echocardiography. The study showed a massive right-to-left shunt without pulmonary hypertension, produced by an important cardiac infiltration of adipose tissue that created a narrow passage in the right atrium, and a redirection of the flow to a patent foramen ovale, explaining the pathophysiology of the syndrome.     

The clinical implications of myocardial perfusion abnormalities in patients with esophageal or lung cancer after chemoradiation therapy

Purpose This study aims to identify the clinical implications of myocardial perfusion defects after chemoradiation therapy (CRT) in patients with esophageal and lung cancer. Methods We retrospectively compared myocardial perfusion imaging (MPI) results before and after CRT in 16 patients with esophageal cancer and 24 patients with lung cancer. New MPI defects in the radiation therapy (RT) fields were considered related to RT. Follow-up to evaluate for cardiac complications and their relation with the results of MPI was performed. Statistical analysis identified predictors of cardiac morbidities. Results Eleven females and twenty nine males at a mean age of 66.7 years were included. Five patients (31%) with esophageal cancer and seven patients (29%) with lung cancer developed myocardial ischemia in the RT field at mean intervals of 7.0 and 8.4 months after RT. The patients were followed-up for mean intervals of 15 and 23 months in the esophageal and lung cancer groups, respectively. Seven patients in each of the esophageal (44%) and lung (29%) cancer patients (P = 0.5) developed cardiac complications of which one patient with esophageal cancer died of complete heart block. Six out of the fourteen patients (43%) with cardiac complication had new ischemia on MPI after CRT of which only one developed angina. The remaining eight patients with cardiac complications had normal MPI results. MPI result was not a statistically significant predictor of future cardiac complications after CRT. A history of congestive heart failure (CHF) (P = 0.003) or arrhythmia (P = 0.003) is a significant predictor of cardiac morbidity after CRT in univariate analysis but marginal predictors when multivariate analysis was performed (P = 0.06 and 0.06 for CHF and arrhythmia, respectively). Conclusions Cardiac complications after CRT are more common in esophageal than lung cancer patients but the difference is not statistically significant. MPI abnormalities are frequently seen after CRT but are not predictive of future cardiac complications. A history of arrhythmia or CHF is significantly associated with cardiac complications after CRT.     

Does cirrhotic cardiomyopathy exist? 50 years of uncertainty

Subtle abnormalities of cardiac structure or function are often identified in patients with liver cirrhosis and have been termed cirrhotic cardiomyopathy. However, in the absence of a precise definition, its diagnosis remains a challenge. Cardiac dysfunction in patients with cirrhosis can often be attributed to concomitant diseases such as hypertension, ischaemic heart disease or excess alcohol consumption in many patients. Further research is required to identify the existence, origin and importance of abnormal cardiac function due specifically to liver disease. Cardiac dysfunction may be masked by treatments given to cirrhotic patients, such as mineral-corticoid receptor antagonists, or by co-existing conditions, such as anaemia. New imaging tests or plasma biomarkers might be able to detect abnormal cardiac function at an early stage of its development.     

The genetics of cardiac arrhythmias

Cardiac rhythm problems result in high levels of morbidity and mortality, with sudden arrhythmic death claiming approximately 300,000 lives in the United States each year. Investigations into the genetic contributions to rhythm and conduction disorders have found genes or loci associated with primary rhythm/conduction disorders such as familial atrial fibrillation and atrio-ventricular block, underscoring the importance of collecting a thorough family history. Combinations of single or multiple genes and environmental risk factors may place only certain family members at risk. Some cardiac muscle problems, such as cardiomyopathy, predispose to arrhythmia and have documented genetic components. Primary health care providers need current knowledge of genetic contributions to rhythm/conduction problems so that family members at risk can be identified early and cared for appropriately. This article provides an overview of the genetic contributions to cardiac rhythm and conduction problems.     

Factors associated with the occurrence of cardiac arrest during hospitalization for acute myocardial infarction in the second national registry of myocardial infarction in the US.

Cardiac arrest can occur as a complication of acute myocardial infarction (AMI). To date, few studies have described factors associated with cardiac arrest occurrence and survival during hospitalization for treatment of AMI. We used data from a large national registry of hospitalized AMI patients to identify these factors. Data were collected from 1073 participating institutions, representing 14.4% of US hospitals. Hospital site coordinators conducted periodic chart reviews for AMI patients and data were submitted to an independent center for periodic review. Univariate analysis and multivariate logistic regression were used to identify factors associated with cardiac arrest. We found that cardiac arrest occurred in 4.8% (14,725/305,812) of hospitalized AMI patients. The survival rate to hospital discharge for these individuals was 29.4%. Sustained ventricular tachycardia or fibrillation (VT/VF) was present in 34.7% and was associated with a higher rate of survival to hospital discharge compared to cardiac arrest patients without a ventricular tachyarrhythmia (47.5 vs. 19.8%, P < 0.00001). Hypotension (initial systolic BP < 90 mmHg), q-wave AMI, old age, heart failure and initial heart rate abnormalities (bradycardia or tachycardia) were associated with a higher prevalence of cardiac arrest. A higher percentage of women compared to men experienced cardiac arrest (6.0 vs. 4.41%, P < 0.0001). Cardiac arrest prevalence was lower in patients with inferior wall infarction than in other types of ST-elevation infarction. Use of reperfusion therapy (PTCA or tPA) was associated with improved survival compared to hospitalized AMI patients who did not receive such therapy.