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Objectives The aim of this study was to evaluate the efficacy of radiofrequency (RF) energy applications targeting the atrial side of a significant residual leak in patients with acute and chronic evidence of incomplete percutaneous left atrial appendage (LAA) occlusion. Background RF applications have been proved to prevent recanalization of intracranial aneurysms after coil embolization, thereby favoring complete sealing. From a mechanistic standpoint, in vitro and in vivo experiments have demonstrated that RF promotes collagen deposition and tissue retraction. Methods Forty-three patients (mean age 75 ± 7 years mean CHA2DS2-VASc score 4.6 ± 1.4, mean HAS-BLED score 4.0 ± 1.1) with residual leaks ≥4 mm after Watchman implantation were enrolled. Procedural success was defined as complete LAA occlusion or presence of a mild or minimal (1- to 2-mm) peridevice leak on follow-up transesophageal echocardiography (TEE), which was performed approximately 45 days after the procedure. Results RF-based leak closure was performed acutely after Watchman implantation in 19 patients (44.2%) or scheduled after evidence of significant leaks on follow-up TEE in 24 others (55.8%). The median leak size was 5 mm (range: 4-7 mm). On average, 18 ± 7 RF applications per patient (mean maximum contact force 16 ± 3 g, mean power 44 ± 2 W, mean RF time 5.1 ± 2.5 minutes) were performed targeting the atrial edge of the leak. Post-RF median leak size was 0 mm (range: 0-1 mm). A very low rate (2.3% [n = 1]) of major periprocedural complications was observed. Follow-up TEE revealed complete LAA sealing in 23 patients (53.5%) and negligible residual leaks in 15 (34.9%). Conclusions RF applications targeting the atrial edge of a significant peri-Watchman leak may promote LAA sealing via tissue remodeling, without increasing complications. (RF Applications for Residual LAA Leaks [REACT]; NCT04726943 )

In patients with atrial fibrillation, left atrial appendage (LAA) occlusion devices represent an alternative to anticoagulation but are associated with residual peridevice leaks (PDLs) and device-related thrombi (DRT). Similarly, cerebrovascular aneurysms can be treated with coil embolization, but pericoil leaks represent a significant limitation. In experimental models of cerebrovascular aneurysms, endothelial denudation achieved independently with (1) embolization with radioactive coils, (2) mechanical removal of the endothelium, or (3) radiofrequency ablation was dramatically effective in preventing or eliminating pericoil leaks. Anatomical, physiological, and blood flow similarities exist between the LAA and saccular aneurysms. Concepts developed in treating aneurysm leaks can be used to treat similar problems in the LAA. Learning from aneurysms, we conceived of a novel technique to denude local endothelium and thus eliminate residual leaks around LAA-occlusion devices. We recently successfully tested this hypothesis in patients with a PDL in a prospective manner in a multicenter study. In this article, we expand on the rationale of the technique developed to close PDLs and potentially also prevent DRTs., Graphical abstract

We investigated the feasibility to proactively stimulate subsequent closure of a patent foramen ovale (PFO) by injuring (mechanical trauma or radiofrequency [RF] energy) the opposing surfaces of the septum primum (SP) and septum secundum (SS). 1. Mechanical Injury: The interatrial septum of patients who underwent multiple left atrial (LA) ablations over 6 years, where a PFO was used for LA access, were examined. Patients whose PFO was absent during a later procedure were identified. Eleven patients with LA accessed via a PFO also underwent subsequent LA procedures. 2. Ablation: Ten patients undergoing ablation for drug-resistant atrial fibrillation (AF), who also had a PFO, were studied. RF delivery was extended along the upper SP. Transthoracic echocardiogram (TTE) bubble study was repeated after 3 months. 1. Mechanical Injury: Seven were male with a mean age of 58.3 ± 9.99. LA size was 42.73 ± 3.52 mm. The mean left ventricular ejection fraction (EF) was 62 ± 7.4%. During the repeat procedure, in 4 patients, the PFO could not be visualized and the fossa ovalis (FO) was punctured. The fourth patient had three procedures. During the second procedure the PFO was accessed, but with difficulty. During the third procedure, it was no longer present. All four patients had subsequent TTE showing no PFO. 2. Ablation: Seven were male with a mean age of 61.1 ± 9.8 years. The mean EF and LA diameters were 55 ± 5% and 4.4 ± 0.8 cm respectively. The mean RF time was 5.4 ± 2.2 min. At 3 months, 9 patients out of 10 showed no interatrial communication. Injury of tunnel surfaces of the SP and SS by mechanical trauma or ablation can fuse the foramen ovale.

Aims This study investigates the lateral displacement of the oesophagus at the level of the left atrium (LA) in 11 cadavers. Methods and results The study was conducted using human cadavers. An endotracheal stylet probe was inserted into the eosphagus. The pericardium overlying the posterior LA was fixed in place. The lateral movement of the oesophagus from side to side was recorded. The initial study method had the stylet probe extending to the gastroesophageal (GE) junction. A revised protocol had the distal end of the endotracheal stylet probe ∼4 cm cranial to the GE junction. In six cadavers using the initial study method, the oesophagus was displaced a mean of 1.8 ± 0.35 cm to the right and 2 ± 0.48 cm to the left. In five cadavers, using the revised method, the oesophagus was displaced by a mean of 2.26 ± 0.27 cm to the right and 2.3 ± 0.66 cm to the left. Conclusion Mediastinal anatomy, specifically the presence of a loose connective tissue that attaches the oesophagus to the parietal pericardium overlying the posterior LA wall will allow for a lateral displacement of the oesophagus. This should decrease or eliminate the likelihood of thermal injury of the oesophagus. Using an endotracheal stylet, we investigated the lateral displacement of the oesophagus in 11 human cadavers. In six with the stylet extending to the GE junction, the oesophagus was displaced a mean of 3.8 cm. In five, with stylet 4 cm cranial to the junction, the displacement was 4.56 cm.

Introduction Omega-3 polyunsaturated fatty acids (PUFA) have demonstrated to have antiarrhythmic properties. However, randomized studies have shown inconsistent results. Objective We aimed to analyze the effect of omega-3 PUFA on preventing potentially fatal ventricular arrhythmias and sudden cardiac death. Methods Randomized trials comparing omega-3 PUFA to placebo and reporting sudden cardiac death (SCD) or first implanted cardioverter-defibrillator (ICD) event for ventricular tachycardia or fibrillation were included in this study. A meta-analysis using a random effects model was performed and results were expressed in terms of Odds Ratio (OR) and 95% Confidence Interval (CI) after evaluating for interstudy heterogeneity using I2. The reported data were extracted on the basis of the intention-to-treat principle. Results A total of 32,919 patients were included in nine trials; 16,465 patients received omega-3 PUFA and 16,454 received placebo. When comparing omega-3 PUFA to placebo, there was nonsignificant risk reduction of SCD or ventricular arrhythmias (OR = 0.82 [95% CI: 0.60–1.21], p = 0.21 I2 = 49.7%). Conclusion Dietary supplementation with omega-3 PUFA does not affect the risk of SCD or ventricular arrhythmias.

To demonstrate coronary sinus-left atrium connections and evaluate coronary sinus function and anatomy in detail by using multidetector computed tomography (CT).In this institutional review board-approved retrospective study, the authors evaluated coronary CT angiograms obtained in 65 patients with normal sinus rhythm (normal group) and seven with atrial fibrillation at CT (atrial fibrillation group). Coronary sinus-right atrium muscle continuity was indirectly evaluated by measuring the length of the coronary sinus contraction during atrial systole. The length, number, and extent of coronary sinus-left atrium connections were recorded. The accuracy of CT was validated by comparing microscopic images of autopsied hearts with corresponding CT images. Comparisons were performed by using Student t tests for continuous variables. P ≤ .05 was considered indicative of a statistically significant difference.In the normal group, coronary sinus contraction was seen in 60 of the 65 patients (92%, mean length ± standard deviation, 25.7 mm ± 8.0). The coronary sinus narrowed 26% from middiastole to atrial systole (P.0001). Coronary sinus-left atrium muscle connections were seen in 58 of the 65 patients (89%). A single connection was seen in 43 of the 65 patients (66%), with a mean length of 21.0 mm ± 14.0 within 12.0 mm ± 11.0 of the coronary sinus ostium. In 10 of the 43 patients (26%) with single connections, the connection extended to the coronary sinus ostium. In 10 of the 65 patients (15%), the entire coronary sinus was attached to the left atrial wall. Fifteen patients (23%) had two connections; distal connections measured 9 mm ± 2.4 in length within 2.2 mm ± 3.8 of the coronary sinus ostium, and proximal connections measured 15.4 mm ± 10.0 in length within 24.0 mm ± 8.0 of the coronary sinus ostium. In seven patients (11%), no coronary sinus-left atrium connection was seen; however, all showed a coronary sinus constriction during atrial systole, indicating that coronary sinus-right atrium muscle continuity is likely the primary cause for coronary sinus contractions. In the atrial fibrillation group, no coronary sinus contraction was seen. All images in the atrial fibrillation group showed a coronary sinus-left atrium connection, which was single in five patients and double in two. The area of the coronary sinus during diastole was larger in the atrial fibrillation group than in the normal group (114 mm(2) ± 37 vs 77 mm(2) ± 40, respectively; P = .02).CT can provide excellent information about coronary sinus function and coronary sinus-left atrium muscle connections.

Objectives The purpose of this study was to develop a better understanding of the pathophysiology of the condition, we studied the patterns by which the septum primum (SP) and septum secundum (SS) fuse. Background A patent foramen ovale (PFO) is a communication across the interatrial septum between a nonadherent SP and SS and is considered to be a risk factor for serious clinical syndromes. Methods We examined the interatrial septum in 94 randomly selected autopsied hearts, with a focus on the SP and SS and the patterns by which the 2 structures fuse. Results Of the 94 specimens that were suitable for analysis, 26 (27.66%) had a PFO. Of the remaining 68 hearts, complete fusion of the SP and SS along the entire zone of overlap was seen in 27 (28.7%) hearts. In the remaining 41 hearts (60.29%), a PFO was absent, but incomplete fusion of the SP and SS was seen. Of 41 hearts, 37 (90%) had a septal pouch that opened into the left atrial (LA) cavity. Four hearts (10%) had a pouch accessible from the right atrium. Hearts with left-sided pouches tended to be younger (50 ± 18 years of age) than hearts where there was complete fusion (age 63 ± 23 years) (p = 0.06). Conclusions Our data suggest that when a foramen ovale closes spontaneously, the SP and SS fuse initially at the caudal limit of the zone of overlap of the 2 structures. This incomplete fusion results in a pouch that, in the majority of instances, communicates with the LA cavity.

Aims The coronary sinus (CS) is a commonly cannulated structure in patients undergoing electrophysiology studies, catheter ablation of arrhythmias, implantation of resynchronization therapy devices and, more recently, percutaneous mitral valve repair. The advent of these procedures has led to a renewed interest in the anatomy of the coronary venous system including its various components. To improve our understanding of this structure, we studied the anatomy of the human CS, including the valve that guards its ostium, the Thebesian valve. Methods and results In 75 randomly selected autopsied human hearts, we measured the transverse and craniocaudal dimensions of the CS ostium and characterized the shape, composition, per cent coverage, and attachment points of the Thebesian valve when present. Of the 75 hearts examined, 54 had organic heart disease including atherosclerotic coronary artery disease, left ventricular hypertrophy, dilated cardiomyopathy, rheumatic heart disease, infective endocarditis, and non-rheumatic valvular heart disease. A wide variety of Thebesian valve morphologies were seen, ranging from the absence of any valve to those where the valve was completely occluding the CS ostium. A Thebesian valve was present in the majority of the hearts examined (55/75 hearts—73%). The average transverse dimension of the CS ostium in hearts with Thebesian valves (7.3 ± 2.8 mm) was significantly shorter than those without Thebesian valves (9.4 ± 2.9 mm, P = 0.005). Similarly, the average craniocaudal dimension of the CS ostium in hearts with Thebesian valves (7.9 ± 2.7 mm) was also significantly shorter than those without Thebesian valves (9.3 ± 2.9 mm, P = 0.045). Conclusion Our study shows that some form of Thebesian valve is present in the majority of hearts (>70%). Of these, a significant minority (16%) had a valve morphology (covering >75% of the ostium, a fibrous, fibromuscular, or muscular composition, and devoid of fenestrations) that makes them a ‘potentially complicating’ structure interfering with the cannulation of the CS.

IN PATIENTS WITH CONGESTIVE HEART FAILURE DUE TO SYSTOLIC DYSFUNCTION WHERE ELECTRICAL AND MECHANICAL DYSSYNCHRONY IS PRESENT, cardiac resynchronization therapy has been shown to make patients “feel better” and “live longer” ([1][1]). In these procedures, left ventricular pacing is

To retrospectively investigate anatomy of Bachmann Bundle (BB) and its vascular supply at 64-section multidetector computed tomography (CT) in healthy patients and patients with abnormalities.The institutional review board approved this HIPAA-compliant study and waived informed consent. Clinical histories, electrocardiograms (ECGs), and coronary 64-section multidetector CT angiograms in 317 patients were reviewed (healthy group, 164; group with abnormalities, 153). Among patients with abnormalities, 68 had atrial fibrillation (AF) or interatrial conduction block (IAB) (P wave duration,or=120 msec), 46 had severe coronary artery disease (CAD) (or=70% stenosis of coronary artery giving rise to sinuatrial node [SAN] artery), and 39 had severe CAD and an abnormal ECG (AF or IAB). Length, anteroposterior and superoinferior diameters, attenuation, and vascular supply of BB were studied. Student t test for continuous variables and contingency tables for categorical variables were used.BB was visualized, to greater degree, in the healthy group (90.2% vs 73.9% for group with abnormalities, P.001). Visualization of BB was similar among subgroups with abnormalities: 71.7% in patients with severe CAD, 73.5% in patients with abnormal ECG, and 76.9% in patients with severe CAD and abnormal ECG. BB measurements were similar for both groups. Patients with nonvisualized BB displayed lower overall mean attenuation in the region, with -30.6 HU +/- 33.4 (standard deviation), but mean attenuation in healthy patients was 51.3 HU +/- 59.9 (P.001). This finding suggests fatty infiltration. BB and BB region were mainly supplied by the right SAN artery (55.5%), followed by the left SAN artery (39.6%) and both SAN arteries (4.9%). In the group with abnormalities, there was a significant difference for SAN artery nonvisualization between those with and without identifiable BB (P = .001).BB and its vascular supply can easily be demarcated on cardiac CT images. BB was visualized less in patients with severe CAD and abnormal ECG, a finding that suggests that disease of BB fibers may play a role in development of atrial arrhythmias.

To retrospectively evaluate the anatomic characteristics of the right atrial cavotricuspid isthmus (CTI) by using 64-section multi-detector row computed tomography (CT).Institutional review board approval and waiver of informed consent were obtained for this HIPAA-compliant study. The anatomic region of the CTI was evaluated in 201 patients (116 men and 85 women; mean age, 58 years +/- 11 [standard deviation]) who underwent coronary multi-detector row CT. CTI length was assessed along three parallel isthmic levels (paraseptal, central, and inferolateral). Central isthmus depth was classified as straight (3 mm), concave (3 to/=5 mm), or pouchlike (5 mm). Measurements were obtained during three cardiac phases: midsystole, middiastole, and atrial contraction. Subthebesian recess dimensions and eustachian ridge width were measured. Distances from the atrioventricular node artery to the coronary sinus, from the right coronary artery (RCA) to the inferior vena cava, and from the RCA to the tricuspid valve annulus were measured. Software was used for statistical analysis.At middiastole, the paraseptal isthmus (mean length, 20 mm +/- 3.5; range, 11-34 mm) was significantly shorter than the central isthmus (24 mm +/- 4.3; range, 12-43 mm) and the central isthmus was shorter than the inferolateral isthmus (27 mm +/- 4.8; range, 13-45 mm) (P.001). The longest CTI measurements were obtained during midsystole, and the shortest were obtained during atrial contraction (40% variation per cardiac cycle). Isthmus contraction occurred primarily in the posterior segment of the central isthmus (RCA to inferior vena cava distance). At middiastole, the central isthmus was straight in 8% of patients, concave in 47% of patients, and pouchlike (5 mm) in 45% of patients. The mean depth was greater during atrial contraction (6.3 mm +/- 2.1) than in midsystole (4.3 mm +/- 1.5) and middiastole (5.1 mm +/- 1.8) (32% variation during cardiac cycle). A subthebesian recess greater than 5 mm deep was identified in 45% of patients. In 24% of patients, a thick eustachian ridge greater than 4 mm was seen. The atrioventricular node artery passed close to the coronary sinus wall (mean distance, 2.1 mm +/- 0.7; range, 1-6 mm).Cardiac multi-detector row CT provides extensive information regarding the size and morphology of the CTI and its related structures.

The rapid development of clinical cardiac electrophysiology has triggered a renewed interest in the anatomy of the heart. A thorough knowledge of cardiac anatomy is a prerequisite for successful electrophysiologic procedures. Accurate description of the cardiac anatomy requires the use of a common language in describing this anatomy, as well as close interaction between radiologists, cardiologists, and surgeons. Given its capacity to provide relevant anatomic information in exquisite detail, multidetector computed tomography (CT) has the potential to allow faster and more accurate placement of intracardiac ablation catheters and pacemaker leads relative to the anatomy of interest. High-resolution reformatted images from 64-detector CT data provide accurate anatomic information for locating important landmarks relative to the cardiac conduction system or to current electrophysiologic interventions and cardiac resynchronization therapy.

The improved temporal and spatial resolution allowed by multidetector computed tomography (MDCT) has facilitated the noninvasive assessment of cardiac anatomy before transcatheter electrophysiologic procedures. Clarification of spatial relations of phrenic nerves and key cardiac structures is important to decrease potential complications. The purpose of this study was to reconstruct the course of the right and left phrenic pericardiophrenic bundles and their relations to cardiac structures using 64-slice MDCT. One hundred six consecutive subjects (age 61 +/- 13 years; 39% women) who underwent self-referred coronary computed tomographic angiography using 64-slice MDCT underwent retrospective assessment of the phrenic nerves contained within the pericardiophrenic bundles. The course of the nerves was outlined in relation to the left atrial appendage, coronary sinus, and cardiac veins. The ability to individually detect the left and right phrenic nerves, as well as the frequency of direct contact between the left phrenic nerve and cardiac veins, was recorded. The left phrenic nerve was identified in 78 of 106 patients (74%). It crossed the left atrial appendage (n = 72, 91%), great cardiac vein (n = 63, 80%), posterior vein of the left ventricle (n = 39, 49%), posterior interventricular vein (n = 8, 10%), and anterior interventricular vein (n = 7, 9%). Mean Hounsfield units (HUs) of the left phrenic nerve was 81 +/- 25. The right phrenic nerve was identified in 50 of 106 patients (47%). Mean HUs of the right phrenic nerve were 94 +/- 26. In conclusion, cardiac imaging using 64-slice MDCT enabled adequate detection of the left and right phrenic nerves in relation to cardiac anatomy. In the setting of electrophysiologic interventions, MDCT before a procedure may elucidate anatomic relationships and help minimize inadvertent complications.

ObjectivesIn order to more clearly understand the electrocardiographic manifestations of early transmural ischemia, we studied electrocardiograms (ECGs) in patients undergoing balloon angioplasty.BackgroundDecisions regarding reperfusion strategies in patients with acute myocardial infarction rely largely on the presence of ST-segment elevation (STE) in the ECG, consequently with significant limitations. Studies of the “ischemic cascade” show that ST-segment changes occur well after the onset of wall motion abnormalities.MethodsWe prospectively analyzed ECGs obtained at 20-s intervals in 74 patients undergoing elective balloon angioplasty. The ECGs were analyzed using 3 methodologies. In 74 patients, the ST-segment, the T-wave, and the QT-interval were analyzed using the MUSE (General Electric HC, Menomonee Falls, Wisconsin) automated system (MUSE). Fifty patients were also analyzed using the Interval Editor automated system (IE; General Electric HC). In 20 patients, measurements were made manually.ResultsTransmural ischemia prolonged the QTc interval (using the Bazett’s formula) in 100% of patients. In all 74 patients analyzed with MUSE, QTc interval prolonged from 423 ± 25 ms to 455 ± 34 ms (p < 0.001). In the 50 patients analyzed with IE, QTc interval prolonged in 50 of 50 (100%) patients (from 424 ± 27 ms to 458 ± 33 ms [p < 0.001]). Mean time to maximal QTc interval prolongation, changes in T-wave polarity, ≥1 mm STE, and ST-segment depression (STD) were 22, 24, 29, and 35 s, respectively. Although QTc interval prolonged in 100% of patients, T-wave changes, STE, and STD (≥1 mm) occurred in 7%, 15%, and 7%, respectively.ConclusionsThe QTc interval prolongs in 100% of patients with early transmural ischemia. When compared with clinically accepted indexes of transmural ischemia (i.e., STD and STE [≥1 mm]) it is the earliest ECG abnormality.

Congestive heart failure continues to be a very significant problem in cardiovascular medicine. Up to 8–10 million people in the western world are affected by clinical or subclinical forms of heart failure. Ischemic heart disease and consequent systolic dysfunction is the major cause of heart failure. However, in up to 40% of patients, the cause is not well understood [1]. Whether the original cause is a viral infection, prior myocardial infarctions, or hypertensive heart disease, the end result or phenotype is similar. The annual mortality, even with current therapy, remains between 5 to 20% depending upon the severity of the clinical state. Approximately 50% of deaths are sudden [2], presumed to be due to ventricular arrhythmias or asystole. The importance of sudden death as the mode of death in heart failure has been reemphasized in the last decade. This is the result of information collected from clinical trials, which have provided further insight into the natural history of the disease. The mode of death in heart failure is related in part to the severity of the disease. In patients with mild to moderate heart failure (NYHA class II and III) sudden death represents the major mode of death, accounting for approximately two thirds of the mortality. In more severe heart failure, progressive heart failure is the most frequent mode of death although sudden death still accounts for about a third of the deaths. The arrhythmia associated with sudden death is usually ventricular tachycardia or fibrillation although bradycardia or asystole is also seen in advanced heart failure [3,4]. Despite investigations, the underlying mechanisms responsible for sudden death in these patients remain poorly understood [4]. Heart failure is a heterogeneous problem where multiple mechanisms may contribute to the development of arrhythmias. These include fibrosis, conduction system disease, electrolyte abnormalities such as hypokalemia and hypomagnesemia, increased stretch of the heart chamber, hypertrophy and increased muscle mass, abnormal neurohormonal activation as well as the addition of antiarrhythmic drugs with potentially proarrhythmic effects. In addition to these, it is being increasingly recognized that these hearts may also have abnormalities in ion channels/currents as well as ion transport mechanisms which can lead to electrical dysfunction in both systole and diastole. In this article we will review the electrophysiological mechanisms that are thought to underlie the risk of sudden death in this condition, especially the available evidence on abnormalities of ion currents in patients with heart failure and their potential relevance to arrhythmogenesis.

Background: Catheter ablation (CA) of long-standing persistent (LSP) atrial fibrillation (AF) is associated with reduced success rates. This analysis examines the acute/long-term outcomes of a staged hybrid surgical and catheter-based ablation strategy for treatment of LSP AF. Methods: In this

cardioembolic strokes are responsible for more than 20% of all ischemic strokes. The examination of atrial sources of cardioembolic strokes has focused almost exclusively on the left atrial appendage (LAA) and the pathophysiology of thrombus formation at this site is well understood. However

Sodium Block-Induced ST Segment Elevation. Three patients in whom Class IC sodium channel blockers induced ST segment elevation in leads V1 through V3 are described. The underlying electrophysiologic mechanism, implications for drug-induced proarrhythmia, and the relationship of the finding to the Brugada syndrome type of idiopathic ventricular fibrillation are discussed.

We describe a case where a patient received multiple shocks from his implantable cardioverter defibrillator (ICD) for pause dependent polymorphic ventricular tachycardia. The stored far-field electrograms of the ICD were used to make the diagnosis of prolonged QT interval and Torsades de Pointes retrospectively.

This article summarizes the role of the cardiac consultant in the management of patients with a broad range of neurologic problems. It emphasizes the importance of anticoagulation in stroke prevention and of the recognition of electrocardiogram abnormalities which may reflect a predominantly neurologic process. A schema is presented that elucidates the mechanisms involved in the myocardial manifestations of central nervous system disease. Additionally, the myocardial involvement associated with neuromuscular diseases is presented, emphasizing the major roles of heart failure, arrhythmias, and sudden death in several of these diseases.

Objectives In this study, the feasibility, efficacy and safety of low energy internal atrial cardioversion were investigated in a sheep model. The relation between the level of energy used for atrial defibrillation and the probability of successful cardioversion was examined. Background Atrial fibrillation is a common clinical arrhythmia that frequently recurs after termination with high energy external cardioversion. In some patients with drug-refractory and poorly tolerated atrial fibrillation, an automatic implantable cardioverter may prove useful by providing rapid restoration of sinus rhythm. Methods In 16 pentobarbital-anesthetized sheep, a right atrial spring electrode was implanted percutaneously and a left thoracic cutaneous patch electrode was placed on the thorax. Sustained atrial fibrillation was induced by rapid atrial pacing and terminated by biphasic cathodal shocks synchronized to the R wave of the surface electrocardiogram (ECG). Results During 768 defibrillation attempts in 16 sheep, the percent of successful cardioversion attempts increased in a dose-response manner, reaching a plateau at the average energy level of 5 J. With greater than or equal to 1.5 and greater than or equal to 2.5 J energy levels, cardioversion was achieved, respectively, in greater than 50% and greater than 80% of attempts. Ventricular fibrillation occurred in 18 (2.4%) of 768 cardioversion attempts; in all 18 cases, the shock was poorly synchronized with the ECG R wave. Conclusions Low energy cardioversion of atrial fibrillation to sinus rhythm is feasible with use of a right atrial spring/cutaneous patch electrode configuration. The percent of successful cardioversion attempts depends on the level of energy output, and there is a risk of ventricular fibrillation if cardioversion is poorly synchronized with ventricular depolarization.

The purpose of this study was to develop a better understanding of the pathophysiology of the condition, we studied the patterns by which the septum primum (SP) and septum secundum (SS) fuse.A patent foramen ovale (PFO) is a communication across the interatrial septum between a nonadherent SP and SS and is considered to be a risk factor for serious clinical syndromes.We examined the interatrial septum in 94 randomly selected autopsied hearts, with a focus on the SP and SS and the patterns by which the 2 structures fuse.Of the 94 specimens that were suitable for analysis, 26 (27.66%) had a PFO. Of the remaining 68 hearts, complete fusion of the SP and SS along the entire zone of overlap was seen in 27 (28.7%) hearts. In the remaining 41 hearts (60.29%), a PFO was absent, but incomplete fusion of the SP and SS was seen. Of 41 hearts, 37 (90%) had a septal pouch that opened into the left atrial (LA) cavity. Four hearts (10%) had a pouch accessible from the right atrium. Hearts with left-sided pouches tended to be younger (50 +/- 18 years of age) than hearts where there was complete fusion (age 63 +/- 23 years) (p = 0.06).Our data suggest that when a foramen ovale closes spontaneously, the SP and SS fuse initially at the caudal limit of the zone of overlap of the 2 structures. This incomplete fusion results in a pouch that, in the majority of instances, communicates with the LA cavity.

A hiccup, or singultus, results from a sudden, simultaneous, vigorous contraction of the diaphragm and inspiratory muscles, accompanied by closure of the glottis. Hiccups can be associated with bradyarrhythmias. The mechanism of this phenomenon is likely hiccup-induced Valsalva maneuver and increased parasympathetic tone. We present a case of a patient with violent hiccups producing a bradyarrhythmia.

Sudden cardiac death from ventricular fibrillation (VF) typically occurs in patients with structural heart disease, but in 5 to 10 percent VF is “idiopathic,” occurring in normal hearts. Recently, there has been the description and growing recognition of patients with VF that has a focal origin, the common sites being in the right ventricular outflow tract (RVOT) and sites in the left ventricle. A focus within the right ventricle outside the RVOT is rare. We present a case of a woman with VF storm that was localized to the inferobasal right ventricle and was successfully treated with radiofrequency ablation.

Multidetector row computed tomography (MDCT) has a high diagnostic accuracy to evaluate coronary artery stenoses. Additionally, the 4-dimensional aspect of cardiac MDCT allows a comprehensive evaluation of cardiac structure and function. Left ventricular volumes and systolic function can be accurately assessed with MDCT, and imaging of myocardial infarction is a promising application of cardiac MDCT. In addition, MDCT may provide anatomical visualization of heart valves. Also, evaluation of anatomy of the pulmonary veins and cardiac venous system render MDCT a valuable tool for the cardiologist performing electrophysiological procedures. In this article, the role of MDCT in the noninvasive evaluation of cardiac structure and function is discussed. An overview of the wide range of noncoronary applications of cardiac MDCT is provided, focusing on the assessment of left ventricular function, valvular heart disease, and cardiac venous anatomy.

Background Changes in the amplitude of the R wave (RWA) on the electrocardiogram (ECG) have been described during acute myocardial ischemia and infarction. However, this has not been well studied in a controlled setting. We hypothesized that significant increase in RWA occurs during early transmural myocardial ischemia. Methods We prospectively evaluated changes in RWA in 50 patients during brief episodes of transmural ischemia induced by first balloon occlusion (mean, 38 seconds at 6-10 atmospheric pressures) during elective percutaneous coronary intervention. We recorded 12-lead ECGs at 20-second intervals before and during balloon inflation in 16 right coronary arteries, 14 left circumflex arteries, and 20 left anterior descending arteries. R wave amplitude was digitally measured in each of the 12 leads in every ECG using the ECG interval editor (General Electric HC, Menomonee Falls, WI). Intracoronary (IC) ECGs were also recorded in 4 patients. The mean of the RWA in each lead before balloon inflation was compared to the mean RWA during balloon inflation. Results R wave amplitude significantly increased during balloon inflation from baseline in limb leads I, II, aVL, and all the precordial leads with the exception of lead V 1 . The RWA increase did not reach statistical significance in leads III, aVF, and V 1 . Mean RWA increase was consistent in all leads except aVR during the brief episodes of ischemia during initial balloon inflation because of the inverse polarity of this lead. The increase in RWA was seen in most patients (mean, 75%) in whom transmural ischemia was induced by first balloon inflation. Besides, the RWA showed an increase from baseline in 3 patients who had IC-lead recordings. Conclusion R wave amplitude increases significantly in precordial leads (V 2 -V 6 ) and limb leads (I, II, aVL) of the surface ECG during brief episodes of transmural ischemia. The increase in RWA might be consistent with the expansion of the left ventricular cavity during ischemia and/or alterations in conduction that are intrinsic to the myocardium.

Restoring and maintaining optimal electrical activation of the cardiac chambers as well as atrioventricular synchrony are important aspects of heart failure management. The 12-lead electrocardiogram remains a simple and cost-effective diagnostic tool that can provide important clues in achieving this goal. We report a case where careful interpretation of the 12-lead electrocardiogram led to the diagnosis of pacemaker syndrome. This recognition led to a therapeutic intervention that resulted in the resolution of the patient's heart failure symptoms. The importance of electrocardiography and atrioventricular synchrony in the management of heart failure will also be discussed.

A 70-year-old black man with a history of hypertension and idiopathic cardiomyopathy was admitted to our hospital after presenting to the emergency department with cellulitis, sepsis, respiratory failure, and acute renal failure. The initial ECG revealed atrial fibrillation with a rapid ventricular response and a left bundle-branch block (LBBB). The ventricular response was accelerated by vasopressor agents administered for septic shock. He received intravenous esmolol …

The fluoroquinolone antibiotics sparfloxacin, grepafloxacin, gatifloxacin, and levofloxacin have been reported to cause torsades de pointes. Pre-existing risk factors increase vulnerability to this life-threatening arrhythmia. In a 65-year-old woman with a history of hypertension, coronary artery disease, systemic lupus erythematosus, and osteomyelitis, QTc interval prolongation (605 ms) and torsades de pointes developed after the initiation of levofloxacin, 250 mg intravenously once daily. The patient was hypokalemic and mildly hypomagnesemic before the initiation of levofloxacin and at the time of occurrence of torsades de pointes. The QTc interval decreased to 399 ms within hours of discontinuation of the levofloxacin, after which she had no further arrhythmias. In this and the majority of other published cases of fluoroquinolone-associated torsades de pointes, patients had at least 1 risk factor for the arrhythmia, and most had multiple risk factors. Fluoroquinolone antibiotics should be avoided whenever possible in patients with pre-existing risk factors for torsades de pointes.

In the transplanted heart with biatrial anastomosis, atrial flutter is common and is amenable to catheter ablation. Although this arrhythmia is isthmus dependent, the unique atrial architecture with a suture line through the inferior vena cava-tricuspid annulus isthmus makes the substrate atypical. A cardiac transplant recipient with atrial flutter underwent successful catheter ablation. Five weeks after the procedure, the patient died of a myocardial infarction. The autopsy and histological findings are described and correlated with the electroanatomic map obtained during the ablation. Due to the atrial suture lines, atrial flutter following cardiac transplantation is an isthmus dependent arrhythmia with a different arrhythmogenic substrate. The electrical isthmus (atrial tissue from the tricuspid annulus to the suture line) in these hearts is smaller than the anatomic isthmus.

"When the dust settles you will know if youhave been riding a horse or a donkey."ANCIENT SANSKRIT PROVERB The relatively recent recognition of apoptosis as a unique mechanism of cell death has sparked several interesting studies to examine its role in various disorders of the cardiovascular system. This article highlights the important aspects of the role of apoptotic cell death as it relates to the electrical function of the heart. Programmed cell death, consistent with its role in the development of other organ systems, is thought to play an important role in the normal development of the cardiac conduction system and involution of the postnatal right ventricle. Excessive apoptosis has been implicated as a pathogenetic mechanism responsible for several disorders of the cardiac conduction system and other regions of the heart. Several studies have detected programmed cell death in the setting of complete heart block, 17 atrial fibrillation, 2 and in disorders such as arrhythmogenic right ventricular dysplasia. 21 Apoptosis also could play an important role in progression of ventricular dysfunction. 24,25 Programmed cell death in such dysfunctional dilated hearts raises the possibility that apoptotic cell death could play a role in altering the myocardial substrate that is responsible for the arrhythmias encountered in this setting. These patients represent the major group in the clinical setting who eventually require antiarrhythmic or device therapy for the management of ventricular arrhythmias. Apoptosis seems to be an elegant explanation for some of the pathological findings seen in several disorders of the cardiac rhythm. A clear cause and effect relationship is hard to prove. The exact role of programmed cell death in these conditions is yet to be fully defined, however.

Sotalol-Induced Polymorphic VT. We present a patient with sotalol-induced polymorphic ventricular tachycardia that was seen only with programmed ventricular stimulation. Electrophysiologic studies performed prior to initiation of sotalol therapy revealed inducible monomorphic ventricular tachycardia. Possible underlying electrophysiologic mechanisms are discussed.

45-year-old woman was referred for evaluation of palpiations and supraventricular tachycardia. She had undergone n orthotopic heart transplant using a standard atrioatrial nastomosis 4 years earlier due to end-stage idiopathic diated cardiomyopathy. She had been experiencing several onths of intermittent palpitations associated with a regular achycardia of 150 bpm (Figure 1). Some episodes degenrated to atrial fibrillation prior to termination. Echocardigraphy showed normal left ventricular function. The most ecent right ventricular biopsy showed no evidence of graft ejection. At electrophysiologic study, the patient arrived in sinus hythm, with the same rate in both donor (transplant) and ecipient atria. A 20-pole catheter was looped in the right trium, with distal three bipoles in the donor coronary sinus. uadripolar catheters were placed in the His-bundle region nd right ventricular apex. Pacing in the donor right atrium howed 1:1 response in both donor and recipient atria to 260 s. Pacing in the recipient right atrium showed 1:1 response n the donor atria to 260 ms as well. Burst atrial pacing in he recipient right atrium induced the rhythm shown in igure 2. What is the mechanism of the tachycardia, and hat is the best approach to ablation?

The presence of ST-segment elevation in lead III exceeding that of lead II, particularly if combined with ST elevation in lead V1, proved to be a powerful marker for occlusion of the proximal or midportion of the right coronary artery. These findings helped to determine the extent of myocardium at risk in inferior wall myocardial infarction and may further guide the decision to administer thrombolytics.