Ventricular late potentials are low-amplitude signals originating from damaged myocardium and detected on the body surface by ECG filtering and averaging. Digital filters present in commercial equipment may interfere with the ability of arrhythmia stratification. We compared 40-Hz BiSpec (BI) and classical 40- to 250-Hz band-pass Butterworth bidirectional (BD) filters ...

Peripheral nerve blocks are associated with minimal haemodynamic disturbance. It is perhaps ideal for high-risk surgical patients who cannot tolerate the adverse consequences of even the slightest attenuation of haemodynamic response. However, peripheral nerve blockade is often perceived to be time consuming and undependable as the sole anaesthetic. In this ...

Baseline and perianaesthetic 24-hour Holter recordings were carried out in six healthy beagles. After dexmedetomidine premedication anaesthesia was induced with propofol and maintained with propofol infusion or isoflurane for one hour. Dexmedetomidine alone was used as control. The recordings were analysed for ventricular premature complexes (VPC), atrioventricular (AV) blocks and ...

INTRODUCTION: A proposed mechanism of the maintenance of ventricular fibrillation (VF) determined by studying small hearts or segments of large hearts is that a single stable rotor exists at the site of maximal activation rate, which gives rise to activation fronts that propagate into slower activating regions where they frequently ...

OBJECTIVE: To compare the effects of the stimulation of adenosine receptors and acetylcholine receptors in the cardiac conduction system in patients with ischemic heart disease. DESIGN: Prospective. SETTING: University hospital. PARTICIPANTS: Patients scheduled for coronary artery bypass graft surgery (n = 37). INTERVENTIONS: The patients were divided into 3 groups: ...

A 20-year-old man was discharged from the U.S. Army because of increasing gait abnormalities. One year later, he developed episodes of syncope secondary to high-degree atrial/ventricular block with periods of complete heart block and ventricular asystole. A permanent dual-chamber, rate-responsive cardiac pacemaker was implanted. At age 29 years, an abnormal ...

Bradycardia due to sinus node dysfunction and atrioventricular block is more commonly observed in the elderly. Aging is associated with progressive fibrosis in both the sinus node and atrioventricular conduction system (AV node, His bundle, right and left bundles). In the absence of reversible causes implantation of a permanent pacemaker ...

OBJECTIVE: To assess the complications of percutaneous tansluminal septal myocardial ablation (PTSMA) for the treatment of hypertrophic obstructive cardiomyopathy (HOCM). METHODS: Seventy-two patients with symptomatic left ventricular outflow tract obstruction were diagnosed by echocardiography or catheterization procedures. Absolute ethanol was injected into the target coronary artery branch (branches) for septal ...

BACKGROUND: Complete right bundle branch block carries a deleterious effect on the long-term outcome of patients who undergo surgical treatment of the perimembranous ventricular septal defect. We describe a novel suturing method to reduce the prevalence of complete right bundle branch block. METHODS: From March 1996 through December 2000, 48 ...

The developing cardiovascular system is known to operate normally in a hypoxic environment. However, the functional and ultrastructural recovery of embryonic/fetal hearts subjected to anoxia lasting as long as hypoxia/ischemia performed in adult animal models remains to be investigated. Isolated spontaneously beating hearts from Hamburger-Hamilton developmental stages 14 (14HH), 20HH, ...

Cardiac complications of iron overload are the most common cause of death in patients with thalassemia major. These complications include recurrent pericarditis, refractory congestive heart failure and rhythm disorders. The usual rhythm disturbances are supraventricular or ventricular premature contractions and first-or second-degree heart block. Complete heart block is a very ...

Walter Holbrook Gaskell was a nineteenth-century British physiologist whose investigations from 1874 until 1889 became central to our current understanding of cardiac physiology. His many cardiac contributions include the following: 1) the recognition of certain inherent properties of cardiac muscle; 2) the experimental proof that led to the acceptance of ...

BACKGROUND: K(ATP) channels, activated by ischemia, participate in the arrhythmogenic response to acute coronary occlusion. The function of these channels in border zones of healing infarcts, where arrhythmias also arise, has not been investigated. Do these channels remain maximally activated during infarct healing, or do they downregulate after a period ...

Wegener's granulomatosis is a systemic inflammatory disorder of unknown cause that usually affects the upper and lower respiratory tracts as well as the kidney. Cardiac involvement is rare, although electrocardiographic abnormalities, coronary artery vasculitis, cardiac arrhythmias, and myocardial infarction have been reported in the literature. A 27-year-old female patient with ...

A patient with an acute anteroseptal myocardial infarction and intermittent right bundle-branch block is presented. Abnormal Q waves in right precordial leads were only observed during right bundle-branch block. In the absence of right bundle-branch block, depolarization of the right ventricular free wall concealed the abnormal Q waves typical of ...

This chapter has summarized briefly the current state of our knowledge on the incidence, etiology, presentation, investigation, and management of patients with AV block. The scope of the material covered has been widened intentionally to include a plethora of AV-conduction abnormalities because of the increases in the understanding of their ...

The relationship between anatomy and function has long been recognised. Understanding the gross structure, and the myoarchitecture, of the atriums is fundamental to investigations into the substrates and therapy of atrial fibrillation. Based primarily on our experience with normal human hearts, this review provides, firstly, a basis of comparison of ...

The newer implantable loop recorders recently introduced (Reveal Plus. Medtronic Inc, Minneapolis, MN, U.S.A.). equipped with auto activation capabilities, are expected to expand our diagnostic abilities in the investigation of syncopal episodes. The case presented here is that of a man with pre-syncopal and syncopal episodes, without organic heart disease, ...

INTRODUCTION: The length of the His bundle and the precise location of injury responsible for split His potentials have not been fully established in patients with intra-Hisian block. We conducted an autopsy study comparing histologic findings in intra-Hisian block versus control hearts. METHODS AND RESULTS: We studied hearts from 4 ...

Solution properties of amphiphilic methoxy poly(ethylene oxide)-block-amyloses (MPEO-amyloses) in chloroform were investigated by SLS and DLS. The results indicated that MPEO-amyloses dissolved in chloroform containing 2 wt % DMSO by their self-associations. The complexation of MPEO-amylose with methyl orange (MO) was significantly enhanced in the amylose domain of the associate ...

Bidirectional isthmus block is associated with successful atrial flutter ablation, whereas creation of increased isthmus conduction delay without block can be proarrhythmic. Often, halo catheter electrodes fail to provide adequate sub-Eustachian isthmus recordings. The aim of this study was to determine if progressive isthmus conduction delay results in the false ...

This revised classification system is designed to etch the indicators of a block into your memory. You only have to remember that the degree is the number of atrial beats getting through to the ventricles (all, some or none) and the type is where the block occurs (AV node or ...

BACKGROUND: Percutaneous transluminal septal ablation was recently introduced as an alternative to surgical treatment of hypertrophic obstructive cardiomyopathy. In this procedure, alcohol is injected into a proximal septal artery to create a localized myocardial infarction. OBJECTIVES: To characterize the immediate and medium-term results following PTSMA. METHODS: Of 13 patients referred ...

First-degree heart block is a common electrocardiographic manifestation of acute rheumatic fever and is included in Jones' diagnostic criteria. Other electrocardiographic changes such as sinus tachycardia, bundle branch blocks. nonspecific ST-T wave changes, atrial and ventricular premature complexes have been reported with variable frequency. However, complete heart block is an ...

A 41-year-old man with no relevant cardiac history presented for evaluation of episodic syncope. Electrocardiography showed sinus rhythm with right bundle-branch block and Q waves in leads II, III, and aVF. Subsequent exercise treadmill testing and technetium 99m sestamibi study revealed a reversible posterior defect. Coronary angiography later showed a ...

BACKGROUND: Early reperfusion therapy has reduced the infarct size and mortality rate in patients with acute myocardial infarction (AMI). The occurrence of bundle-branch block in AMI is related to the amount of myocardial damage and the insult to the conduction system. HYPOTHESIS: To evaluate the clinical and angiographic factors related ...

Between 1989 and 2000, 21 fetuses were diagnosed with complete atrioventricular block. Seven women with fetal ventricular rates of less than 60 were given oral terbutaline, and 6 of these had an initial increase in the fetal ventricular rate. Four fetuses (57%) maintained an increased average rate of 60 beats ...

Tall lead V1 (tall RV1), defined as an R/S ratio equal to or greater than 1, is not an infrequent occurrence in emergency department patients. This electrocardiographic finding exists as a normal variant in only 1% of patients. Physicians should therefore be familiar with the differential diagnosis for this important ...

The study of the dissemination of the electric impulse throughout the ventricular myocardium, which gave rise to the current theories, was performed without taking into consideration the complex architecture of the cardiac muscle elucidated by more recent researchers. We propose a novel hypothesis based on the special macroscopic structure of ...

Familial atrioventricular heart block affected by the autonomic nervous system has rarely been documented. We describe a 35-year-old man who had first-degree atrioventricular heart block with a PR interval of 0.46 s. He had a family history of 2 members with complete heart block and 1 with documented atrial standstill. ...

Symptomatic second- or third-degree atrioventricular (AV) block at any anatomical level is a class I indication for permanent pacemaker implantation. We describe a 44-year-old male with acute viral myocarditis who suffered from syncope followed by a seizure attack associated with AV conduction disturbance. His initial electrocardiogram in our emergency room ...

INTRODUCTION: There is scant information about the effects of thrombolysis in the evolution of right bundle-branch block (RBBB) in the setting of acute anterior myocardial infarction. The aim of this study has been to analyse these effects and its impact on prognosis. METHODS: We studied 54 patients who presented a ...

A variety of atrial and ventricular arrhythmias are encountered in patients with acute coronary syndromes. These include both brady and tachyarrhythmias of supraventricular and ventricular origin. Sinus bradycardia and atrial fibrillation are the most common of supraventricular origin. Ventricular arrhythmias that merit consideration include premature ventricular complexes, accelerated idioventricular rhythm, ...

The effects of biventricular pacing on myocardial wall function are well known, but, at the moment, its real effects on myocardial metabolism are unclear. In patients affected by left bundle branch block, at positron emission tomography a septal defect of the uptake of 18F-fluorodeoxyglucose (FDG) was referred. There were no ...

BACKGROUND: Deterioration of left ventricular function during follow-up was reported in some patients with syndrome X and concomitant left bundle branch block. The patients with syndrome X and left bundle branch block has been frequently presented with elevated Endothelin-1 (ET-1) level while brain natriuretic peptide (BNP) (a sensitive marker of ...

2:1 AV block can occur in either the AV node or the His-Purkinje system and cannot be classified into type I or type II second-degree AV block because there is only one PR interval to examine before the blocked P wave. It is inappropriate to use terms such as 2:1 ...

BACKGROUND: The presence of bundle-branch block (BBB) is associated with high mortality rates and is considered an important predictor of poor outcome in patients with acute myocardial infarction (AMI). HYPOTHESIS: The objective of this study was to assess the prognostic significance of BBB in patients with AMI depending on its ...

Complete right and left bundle branch block and advanced atrioventricular block present on admission electrocardiograms of patients with acute myocardial infarction, are associated with poor short and long-term outcome. Little is known about the impact of intermediate QRS prolongation (0.09-0.11 s) on the prognosis of acute myocardial infarction. In this ...

Dysrhythmic causes of syncope may elude diagnosis in postinfarction patients despite elaborate testing, including electrophysiologic study. For a correct diagnosis, capture of cardiac rhythm during patient's typical symptoms is crucial. This report describes a patient with coronary artery disease and decreased left ventricular ejection fraction who experienced recurrent syncopal episodes ...

BACKGROUND: Structural complexities of the intact ventricular wall cause a very complex spread of activation. The effects of regional tissue damage and of antiarrhythmic drugs on directional differences in activation should help to further elucidate intramural conduction patterns. METHODS AND RESULTS: In 10 healthy dogs and in 5 dogs with ...

BACKGROUND: The diagnosis of acute myocardial infarction in the presence of left bundle branch block is difficult. Recently a diagnostic ECG scoring system was suggested, showing good diagnostic abilities. This scoring system has never been tested in a prospective manner; we have done so and investigated if it might bear ...

OBJECTIVES: Within the adult heart, it is convention to distinguish the conduction system and working (atrial and ventricular) myocardium. The adult conduction system (CS) comprises the sinoatrial (SAN), and atrioventricular (AVN) nodes, the atrioventricular bundle (AVB), the bundle branches and the peripheral Purkinje fibers, each of which display distinct functional ...

It has been reported that cardiac function can be improved by implanting a DDD pacemaker (PM) and setting a short atrioventricular (AV) delay in patients with impaired cardiac function. A previous report found that the critical AV delay that induces diastolic mitral regurgitation (MR) may represent the upper limit of ...

We report a case of fetal congenital heart block treated with maternal administration of beta-sympathomimetics. The case was diagnosed as fetal complete heart block associated with maternal anti-Ro/SS-A antibody at 22 weeks of gestation. By fetal sonography, the ventricular rate was revealed to be 60 beats/min and mild cardiomegaly was ...

In this review, we discuss the various forms and causes of second-degree atrioventricular (AV) block and the reasons they remain poorly understood. Both type I and type II block characterize block of a single sinus P wave. Type I block describes visible, differing, and generally decremental AV conduction. Type II ...

Under physiological conditions, slow conduction is essential for the function of the atrioventricular (AV) node, whereas, under pathophysiological conditions, slow conduction contributes importantly to the generation of life-threatening reentrant arrhythmias. This article addresses characteristics of slow conduction at the cellular network level during (a) a reduction of excitability, (b) a ...

BACKGROUND: RS morphology of the unipolar electrogram is associated with propagation of the wave front through the exploring electrode, whereas positive uniphasic (R) unipolar electrograms are characteristic of the end of activation. METHODS AND RESULTS: Unipolar electrograms were recorded in 45 consecutive patients with atrial flutter who were undergoing radiofrequency ...

OBJECTIVE: To compare rocuronium and succinylcholine for rapid-sequence intubation (RSI) in the emergency department (ED). METHODS: A one-year prospective cohort comparison study was performed using a data collection form completed at the time of intubation. Data collected included the reason for the neuromuscular-blocking agent (NMBA) chosen, the time to onset ...

OBJECTIVE: To study early diagnosis, treatment and outcome in patients with bundle branch block and clinically suspected acute myocardial infarction. DESIGN: A prospective multicenter study including 14 Swedish coronary care units. The study included 257 consecutive patients with bundle branch block and clinical suspicion of acute myocardial infarction. RESULTS: Left ...

Systemic metastatic calcification is a common complication of chronic renal failure. Cardiac involvement is particularly ominous, especially when the cardiac conduction system is affected. Conduction defects, arrhythmias, and sudden death have all been reported with conduction system calcification; however, these are relatively under-reported or unrecognized causes of cardiac morbidity and ...