Superior Axis Research Articles

Electrocardiographic characteristics in right ventricular vs biventricular pacing in patients with paced right bundle-branch block QRS pattern

A paced right bundle-branch block (RBBB) QRS morphology is present in most patients with biventricular pacing (BiVP) but is also present in some patients with right ventricular pacing (RVP). The aim of this study was to determine if there are electrocardiographic characteristics that distinguish BiVP from RVP in patients with a paced RBBB QRS pattern. Twelve-lead-paced electrocardiograms (ECGs) were analyzed from 356 consecutive patients (302 RVP and 54 BiVP). Further analyses were performed on those ECGs with a paced RBBB morphology, which included QRS pattern, axis, amplitude, and precordial transition. Chest radiography and coronary sinus venography were used to determine the location of the pacing leads. Fifty (16.6%) of 302 RVP ECGs and 50 (92.6%) of 54 BiVP ECGs had RBBB-paced morphology, respectively. Electrocardiographic characteristics identified in this study with a paced RBBB QRS morphology that are associated with RVP but not with BiVP (P < .05) include positive concordance in the precordial leads, qR configuration in lead V(1), and a late QRS transition beyond lead V(3). Biventricular pacing had shorter mean-paced QRS duration than did RVP and was associated with right superior quadrant mean frontal QRS axis (P < .05). Right ventricular pacing was associated with a mean frontal QRS axis in the left superior quadrant (P < .05). Regarding left ventricular (LV) pacing site, a late precordial transition (especially beyond lead V(2)) was significantly associated with a more posterior LV lead location (P < .05). Even among patients with a paced RBBB QRS pattern, the 12-lead ECG can help distinguish RVP from BiVP and determine LV lead location during BiVP. This information may be useful in evaluating nonresponse to BiVP resulting either from LV noncapture (with consequent RVP) or from suboptimal LV lead location during BiVP.

Causes of Decentration After Laser-Assisted Subepithelial Keratectomy

To determine important factors causing decentration after laser-assisted subepithelial keratectomy (LASEK). A total of 223 cases (446 eyes) were evaluated after LASEK using corneal topography to determine the amount of decentration. Decentration and pupillary offset values and their components on the nasal, temporal, superior, and inferior axes were analyzed with the t test and the two-way repeated measures analysis of variance test in patients with myopia or hypermetropia. Correlation analysis between the amount of decentration and the possible determinative variables (age, gender, spherical refractive error, magnitude of astigmatism, spherical equivalent, average keratometry, mesopic pupil diameter, decentration, and pupillary offset) were performed. Although decentration up to 0.99 mm was observed, mean decentration was 0.26 ± 0.16 mm. Alternatively, pupillary offset values were higher and the mean pupillary offset was 0.28 ± 0.16 mm. In myopia, mean total decentration was significantly less than hyperopia (P = .001). The inferior component of decentration was higher than the other locations in both myopia and hypermetropia. The nasal component of pupillary offset was highest among others. When all cases were included in the analysis, Pearson correlation analysis showed a statistically significant correlation between decentration and presence of hyperopia (r = 0.162 and P =.001) and amount of pupillary offset (r = 0.296 and P = .001). Mean decentration was higher in hyperopia than in myopia. Most of the decentration may be attributed to inferior decentration. Pupillary offset values were the factor most significantly correlated to the amount of decentration in all cases.

Focal ventricular arrhythmias originating from the left ventricle adjacent to the membranous septum

We report the features of focal ventricular arrhythmias (VAs) arising from the left ventricle (LV) adjacent to the membranous septum. We studied eight patients (five men, 65 ± 10 years) with (n = 2) or without structural heart disease (n = 6) who had ventricular tachycardia (n = 4) or premature ventricular contractions (n = 4) originating from the LV septum underneath the aorta. Ventricular arrhythmias exhibited a focal activation pattern, left (n = 4) or right bundle branch block (n = 4), respectively, left superior (n = 4) or inferior axis QRS morphology (n = 4), negative QRS polarity in lead III and early or no precordial transition in all. During all of these VAs, far-field electrograms in the His bundle (HB) region preceded the QRS onset. In all patients, ventricular pre-potentials were recorded during VAs while late potentials were recorded in sinus rhythm at the border of a localized low-voltage area underneath the aorta. Radiofrequency catheter ablation at the presumed sites of origin successfully eliminated VAs in five patients and was abandoned in the remaining three because the HB electrogram was recorded at that site. Focal VAs may arise from the LV adjacent to the membranous septum as a part of the LV ostium, and broadens the spectrum of LV ostium VAs.

Acute retroperitoneal bleeding due to inferior mesenteric artery aneurysm: Case report

BackgroundVisceral artery aneurysms (VAA), although uncommon, are increasingly being detected. We describe a case of spontaneous retroperitoneal hemorrhage from a ruptured IMA aneurysm associated with stenosis of the superior mesenteric artery (SMA) and celiac trunk, successfully treated with surgery.MethodsA 65-year-old man presented with abdominal pain and hypovolemic shock. Abdominal CT scan showed an aneurysm of the inferior mesenteric artery with retroperitoneal hematoma. In addition, an obstructive disease of the superior mesenteric artery and celiac axis was observed.ResultsUpon emergency laparotomy a ruptured inferior mesenteric artery aneurysm was detected. The aneurysm was excised and the artery reconstructed by end-to-end anastomosis.ConclusionsThis report discusses the etiology, presentation, diagnosis and case management of inferior mesenteric artery aneurysms.

Are wide complex tachycardia algorithms applicable in children and patients with congenital heart disease?

Introduction Several algorithms have been developed to help determine the etiology of wide complex tachycardias (WCTs) in adults. Sensitivity and specificity for differentiating supraventricular tachycardia (SVT) with aberration from ventricular tachycardia (VT) in adults have been demonstrated to be as high as 98% and 97%. These algorithms have not been tested in the pediatric population. We hypothesize that these algorithms have lower diagnostic accuracy in children and patients with congenital heart disease. Methods A retrospective review of the pediatric electrophysiology database at Stanford from 2001 to 2008 was performed. All children with WCT, a 12-lead electrocardiogram (ECG) available for review, and an electrophysiology study confirming the etiology of the rhythm were included. Patients with a paced rhythm were excluded. The ECGs were analyzed by 2 electrophysiologists blinded to the diagnosis according to the algorithms described in Brugada et al, 2 and Vereckei et al. 5 Additional ECG findings were recorded by each electrophysiologist. Results A total of 65 WCT ECGs in 58 patients were identified. Supraventricular tachycardia was noted in 62% (40/65) and VT in 38% (25/65) of the ECGs. The mean age was 13.5 years (SD ± 5.1), the mean weight was 51.8 kg (SD ± 22.4), and 48% (31/65) were male. The mean tachycardia cycle length was 340 milliseconds (SD ± 95). Congenital heart disease (CHD) was present in 37% (24/65) of patients (7 tetralogy of Fallot, 6 Ebstein's, 4 double-outlet right ventricle, 3 complex CHD, 2 d-transposition of great arteries, 1 status-post orthotopic heart transplantation, 1 ventricular septal defect). The Brugada algorithm correctly predicted the diagnosis 69% (45/65) of the time, the Vereckei algorithm correctly predicted the diagnosis 66% (43/65) of the time, and the blinded reviewer correctly predicted the diagnosis 78% (51/65) of the time. There was no difference in the efficacy of the algorithms in patients with CHD vs those with structurally normal hearts. The findings of left superior axis deviation ( P < .01) and a notch in the QRS downstroke of V 1 or V 2 ( P < .01) were more common in VT than SVT, whereas a positive QRS deflection in V 1 ( P = .03) was more commonly present in SVT than VT. Conclusion The Brugada and Vereckei algorithms have lower diagnostic accuracy in the pediatric population and in patients with congenital heart disease than in the adult population. Left superior axis deviation and a notch in the QRS downstroke were more commonly associated with VT, whereas a positive QRS deflection in V 1 was more commonly associated with SVT in this population.

Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy Diagnostic Task Force Criteria

Background— Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy (ARVD/C) Diagnostic Task Force Criteria (TFC) proposed in 1994 are highly specific but lack sensitivity. A new international task force modified criteria to improve diagnostic yield. A comparison of diagnosis by 1994 TFC versus newly proposed criteria in 3 patient groups was conducted. Methods and Results— In new TFC, scoring by major and minor criteria is maintained. Structural abnormalities are quantified and TFC highly specific for ARVD/C upgraded to major. Furthermore, new criteria are added: terminal activation duration of QRS ≥55 ms, ventricular tachycardia with left bundle-branch block morphology and superior axis, and genetic criteria. Three groups were studied: (1) 105 patients with proven ARVD/C according to 1994 TFC, (2) 89 of their family members, and (3) 39 patients with probable ARVD/C (ie, 3 points by 1994 TFC). All were screened for pathogenic mutations in desmosomal genes. Three ARVD/C patients did not meet the new sharpened criteria on structural abnormalities and thereby did not fulfill new TFC. In 62 of 105 patients with proven ARVD/C, mutations were found: 58 in the gene encoding Plakophilin2 ( PKP2 ), 3 in Desmoglein2, 3 in Desmocollin2, and 1 in Desmoplakin. Three patients had bigenic involvement. Ten additional relatives (11%) fulfilled new TFC: 9 (90%) were female, and all carried PKP2 mutations. No relatives lost diagnosis by application of new TFC. Of patients with probable ARVD/C, 25 (64%) fulfilled new TFC: 8 (40%) women and 14 (56%) carrying pathogenic mutations. Conclusions— In this first study applying new TFC to patients suspected of ARVD/C, 64% of probable ARVD/C patients and 11% of family members were additionally diagnosed. ECG criteria and pathogenic mutations especially contributed to new diagnosis. Newly proposed TFC have a major impact in increasing diagnostic yield of ARVD/C.

Celiac Axis and Common Hepatic Artery Variations in 5002 Patients: Systematic Analysis with Spiral CT and DSA

To identify and evaluate the spectrum and prevalence of celiac axis (CA) and common hepatic artery (CHA) variations by using spiral computed tomography (CT) and digital subtraction angiography (DSA). Institutional review board approval was obtained, and the requirement for informed patient consent was waived. The findings in 5002 patients who underwent spiral CT and DSA were retrospectively evaluated. CHA was defined as an arterial trunk containing at least one segmental hepatic artery and the gastroduodenal artery. The pattern of the aortic origin of the branches of the CA and superior mesenteric arteries was analyzed. The CHA anatomy was then investigated. Of 15 possible types of CA variation, 13 types were identified. A normal CA was noted in 4457 (89.1%) of the 5002 patients. Twelve types of CA variation were identified in 482 (9.64%) patients. In the remaining 63 (1.26%) patients, the CA anatomy was classified as ambiguous because the CHA was absent owing to separate origins of the hepatic arteries and the gastroduodenal artery (n = 55) or because the origin of the CHA could not be determined owing to persistent anastomotic channels (n = 8). Seven CHAs originating from the normal CA had a retroportal (n = 6) or transpancreatic (n = 1) course. All eight CHAs originating from the left gastric artery passed the fissure of the ligamentum venosum. The 148 CHAs originating from the superior mesenteric artery showed diverse relationships with the pancreas--being supra-, trans-, or infrapancreatic--and the superior mesenteric-portal venous axis--being pre- or retroportal. The 20 CHAs originating from the aorta had a normal suprapancreatic preportal course. Known or newly found CA and CHA variations could be systematically described in detail. The authors propose a hypothetical anatomic model for summarizing the observed CHA variations.

Intestinal derotation in emergency surgery.

Intestinal derotation (ID) is a rarely used surgical technique which allows elegant and effective surgical access to the superior mesenteric axis and third and fourth portion of the duodenum. ID proves an extremely useful technique especially in the emergency setting when access to the "surgical soul" is needed. To master this technique the surgeon has to become familiar with the anatomical landmarks of that area along with the embryological background.

Ventricular arrhythmias originating from papillary muscles in the right ventricle

Premature ventricular complexes (PVCs) and ventricular tachycardia (VT) with origin in the left ventricular papillary muscle have recently been described. There are no prior studies describing the characteristics of the ventricular arrhythmias (VAs) arising from the right ventricular papillary muscles (RV PAPs). Among 169 consecutive patients who underwent a catheter ablation of a VA, eight patients with RV PAPs were identified (seven men, mean PVC burden 17.0% +/- 20%). A control group consisted of 10 consecutive patients with arrhythmias originating from the right ventricle (10 women, mean PVC burden 13.9% +/- 12.8%). All patients underwent cardiac magnetic resonance imaging (MRI). Intracardiac echocardiography was used to identify the site of origin of the RV PAP arrhythmias. The site of origin of a total of 15 distinct PAP arrhythmias was mapped to the following papillary muscles: posterior (n = 3), anterior (n = 4), or septal (n = 8). Postablation echocardiograms did not reveal new tricuspid regurgitation. During a mean follow-up of 8 +/- 9 months, there were no adverse outcomes. The PVC burden was reduced from 17% +/- 20% preablation to 0.6% +/- 0.8% postablation in the RV PAP group and from 13.9% +/- 12.8% to 0.3% +/- 0.4% in the control group. The QRS complex was broader in the RV PAP group compared with in the control group (163 +/- 21 ms vs. 141 +/- 22 ms; P = .02). RV PAP arrhythmias originating from the posterior or anterior RV PAPs more often had a superior axis with late R-wave transition (>V4) compared with septal RV RAP arrhythmias, which more often had an inferior axis with an earlier R-wave transition in the precordial leads (<or=V4; P <.05). PVCs and VT may originate in the RV PAPs. Radiofrequency ablation is effective in eliminating these arrhythmias.

Pleomorphic ventricular tachycardia originating from Purkinje fiber network of left anterior fascicle

A 55-year-old woman with recurrent syncope and palpitation experienced polymorphic ventricular tachycardia (VT) and more than 3 monomorphic VTs with a right bundle branch block configuration as inferior, middle, and superior axis. During the pleomorphic VT, the diastolic potential (dp) was recorded at the anterolateral left ventricle. Changes in the QRS morphology were associated with the time between dp and onset of QRS complex (dp-V interval), and prolongation of dp-V interval terminated the VT. In addition, the delayed potentials were seen during sinus rhythm around this area. Delivery of radiofrequency current targeting the delayed potentials abolished all the VTs. Different exits from relatively large area of slow conduction in the left anterior fascicle might have produced the pleomorphic VTs.

Automated Quantification and Topographical Distribution of the Whole Population of S- and L-Cones in Adult Albino and Pigmented Rats

To quantify the whole population of S- and L-cones in the albino (Sprague-Dawley, SD) and pigmented (Piebald Virol Glaxo, PVG) rats and to study their topographical distribution within the retina. Retinal radial sections and whole-mounted retinas were double immunodetected with antibodies against UV-sensitive and L-opsins to detect the S- and L-cones, respectively. Two automated routines were developed to quantify the whole population of S- and L-cones. Detailed isodensity maps of each cone type were generated. In both strains, the presence of dual cones was detected, these were semiautomatically quantified and their distribution determined. The matching distribution of retinal ganglion cells (RGCs) and L-cones was attained by double immunodetection of Brn3a and L-opsin, respectively. The mean number +/- SEM of L- or S-cones in SD and PVG retinas was 231,736 +/- 14,517 and 239,939 +/- 6,494 or 41,028 +/- 5,074, and 27,316 +/- 2,235, respectively. There was an increasing gradient of S-cone density along the inferonasal quadrant, although the highest densities were found in the retinal rims. The distribution of L-cones seemed to be complementary to the S-cones. The highest densities were observed in the superior nasotemporal axis, paralleling the distribution of Brn3a-positive RGCs. These data establish, for the first time, the total number and the topographical distribution of S- and L-cones in two rat strains and demonstrate the correlation of L-cones and RGC spatial distribution.

Unusual cause of syncope in young girl: arrhythmogenic right ventricular cardiomyopathy

A 15-year-old girl was admitted because of syncope during handball match. On examination the patient was oriented in every condition; blood pressure was 80/50 mmHg and her pulse around 190 beats/min. Electrocardiogram (Fig. 1a) revealed ventricular tachycardia (VT) with left bundlebranch QRS pattern and superior axis. ECG recorded under stable clinical conditions displayed significant repolarization abnormalities and negative T-waves in almost all precordial leads (Fig. 1b). After i.v. administration of Amiodarone VT converted to sinus rhythm. Bedside transthoracic echocardiography showed a severely hypokinetic dilated right ventricle (RV) and dilation of the right ventricular outflow tract (Fig. 1c–e). Left ventricular systolic function was normal. Cardiac MR (CMR) showed dilation of the RV with extreme thinning of the RV myocardium (Fig. 1f) and signs of myocardial late enhancement (not shown). Initial evaluation of our patient focused on structural (e.g. hypertrophic cardiomyopathy) or primary electrical (long QT syndrome, Brugada syndrome, etc.) causes of syncope [1]. However, symptoms, ECG and imaging procedures suggested diagnosis of arrhythmogenic right ventricular cardiomyopathy (ARVC). An implantable defibrillator (ICD) was implanted due to prognostic reasons after sustained VT. In follow-up visits our patient has not shown any signs of heart failure. ICD delivered one episode of successful antitachycardia pacing (ATP) and one ICD shock due to VT. Screening (echocardiography, ECG, exercise testing) of parents and siblings has not shown any cardiac abnormalities.

Diagnosis and Ablation of Fascicular Tachycardia

Verapamil-sensitive fascicular ventricular tachycardia (VT) is the most common form of idiopathic left VT. According to the QRS morphology and the successful ablation site, left fascicular VT can be classified into three subgroups: left posterior fascicular VT, whose QRS morphology shows right bundle branch block (RBBB) configuration and superior axis (common form); left anterior fascicular VT, whose QRS morphology shows RBBB configuration and right-axis deviation (uncommon form), and upper septal fascicular VT, whose QRS morphology shows narrow QRS configuration and normal or right-axis deviation (rare form). Posterior and anterior fascicular VT can be successfully ablated at the posterior or anterior mid-septum with a diastolic Purkinje potential during VT or at the VT exit site with a fused pre-systolic Purkinje potential. Upper septal fascicular VT can also be ablated at the site with diastolic Purkinje potential at the upper septum. Recognition of the heterogeneity of this VT and its unique characteristics should facilitate appropriate diagnosis and therapy.

225 Long-term prognosis of ventricular tachycardia without apparent heart disease

Cardiac MRI can now identify heart diseases which were not apparent with conventional techniques. The prognosis of a ventricular tachycardia (VT) depends on the presence or not of heart disease. Only VT in patients (pts) without heart disease (HD) seems benign. The purpose of the study was to evaluate the long-term prognosis of pts with spontaneous VT and without apparent HD at conventional methods. During the last 30 years, 820 pts were admitted for a sustained VT. ECG, signal averaged ECG, Holter monitoring, exercise testing, echocardiography, right angiography in VT with left bundle branch block (LBBB) pattern, coronary angiography after 40 years and electrophysiological study were indicated. 81 pts (10%), aged from 11 to 75 years (46±18), 46 men, 35 women had normal echocardiogram and hemodynamic study. VT had a LBBB pattern (51), right bundle branch block (RBBB) pattern (26) or both patterns (4). VT developed at exercise testing in 15 pts and was inducible or occurred with isoproterenol in 61 pts (75%). Pts were followed from 1 to 20 years (mean 8±6); 3 were lost of view. Beta blockers and/or antiarrhythmic drugs were initially prescribed. Defibrillator was implanted in 4 pts, 2 of them for arrhythmogenic right ventricular dysplasia (ARVD) diagnosed at least 4 years later. VT catheter ablation was performed in 5 pts, only for a job in 1 pt. Three pts aged more 75 years died from non arrhythmic cause; one of them had a defibrillator. Other pts are alive without VT and without drugs in half of them. One pt developed dilated cardiomyopathy; 3 pts with initially LBBB pattern and left axis VT have signs of ARVD at MRI; 2 pts had permanent atrial fibrillation. All events occurred after 70 years or in pts with LBBB pattern and left axis VT. Secondary diagnosis of ARVD in pts with VT and apparent normal heart was not associated with a higher risk of events. The prognosis was only dependent on the age and the pattern of ECG in VT. It was favourable in pts younger than 70 years and those with typical ECG in VT, LBBB and inferior axis, RBBB and inferior or superior axis. A non medical treatment was rarely required.

Ventrikuläre Tachykardien mit Ursprung im spezifischen Reizleitungssystem

Ventricular tachycardias (VT) associated with the His-Purkinje system may occur in patients with and without organic heart disease. The former may encounter bundle branch reentrant VT, a macroreentrant VT utilizing the specific conduction system. It frequently occurs in patients with preexisting conduction disturbance such as complete left bundle branch block and may be eliminated by catheter ablation of the right bundle branch. After successful ablation, patient's prognosis depends on the presence or absence of structural heart disease.In patients without structural heart disease, VT with right bundle branch block pattern and superior axis, referred to as idiopathic left ventricular tachycardia, is observed. It is a reentrant VT utilizing the posterior left fascicle and the Purkinje network. The two treatment options include antiarrhythmic drug therapy with verapamil or curative catheter ablation.Another form of ventricular arrhythmia originating in the Purkinje network is idiopathic ventricular fibrillation (IVF). Focal triggers from the right and left ventricular Purkinje network induce premature ventricular contractions inducing IVF. This is amenable to catheter ablation leading to a significant reduction in ICD (implantable cardioverter defibrillator) interventions in sudden cardiac death survivors.

Tympanic-membrane and malleus–incus-complex co-adaptations for high-frequency hearing in mammals

The development of the unique capacity for high-frequency hearing in many mammals was due in part to changes in the middle ear, such as the evolution of three distinct middle-ear bones and distinct radial and circumferential collagen fiber layers in the eardrum. Ossicular moment(s) of inertia (MOI) and principal rotational axes, as well as eardrum surface areas, were calculated from micro-CT-based 3-D reconstructions of human, cat, chinchilla, and guinea pig temporal bones. For guinea pig and chinchilla, the fused malleus–incus complex rotates about an anterior–posterior axis, due to the relatively lightweight ossicles and bilateral symmetry of the eardrum. For human and cat, however, the MOI calculated for the unfused malleus are 5–6 times smaller for rotations about an inferior–superior axis than for rotations about the other two orthogonal axes. It is argued that these preferred motions, along with the presence of a mobile malleus–incus joint and asymmetric eardrum, enable efficient high-frequency sound transmission in spite of the relatively large ossicular masses of these species. This work argues that the upper-frequency hearing limit of a given mammalian species can in part be understood in terms of morphological co-adaptations of the eardrum and ossicular chain.

Electrophysiologic Characteristics of Wide QRS Complexes during Pharmacologic Termination of Sustained Supraventricular Tachycardias with Verapamil and Adenosine: Observations from Electrophysiologic Study

In this study we evaluate wide QRS complexes observed during pharmacologic termination of supraventricular tachycardias. Patients with supraventricular tachycardia, undergoing electrophysiologic study were enrolled. 12 mg of adenosine or 10 mg of verapamil were administered during tachycardia, under continuous monitoring of intaracardiac and surface electrocardiograms. Electrocardiographic features of ventricular ectopy were noted. Seventy-four patients were enrolled. 48 patients were randomized to adenosine and 26 to verapamil. Five different appearance patterns of ventricular ectopy were observed during termination of tachycardias. All wide QRS complexes were of ventricular origin and all of them were observed during the termination of tachycardia. Adenosine more frequently resulted in appearance of ventricular beats (15.4% vs 41.7%, P = 0.003), and this was more frequently observed in patients with atrioventricular nodal reentrant tachycardia. Patients with ventricular beats were younger than those without, in both, verapamil (47.5 +/- 15.6 vs 65.0 +/- 8.8 years, P = 0.04) and adenosine (40.9 +/- 13.8 vs 49.7 +/- 16.8, P = 0.03) groups. Left bundle branch block (LBBB)/superior axis morphology was most frequent morphology in adenosine group (55%). Two of 4 patients in verapamil group displayed LBBB/inferior axis QRS morphology and another 2 patients displayed LBBB/superior axis morphology. Noncatheter induced, five different appearance patterns and four distinct morphologies of ventricular origin were observed. Most of them do not directly terminate tachycardia, but are associated with its termination and are not observed in ongoing tachycardia.

A HUMERAL COORDINATE SYSTEM FOR IN VIVO 3-D KINEMATICS OF THE GLENOHUMERAL JOINT

The aim of this study was to define axes from clearly identifiable landmarks on the proximal aspect of the humerus and to compare these for reasonable best alternatives to the use of the humeral canal and elbow epicondylar axes to define a humeral coordinate frame (HCF). The elbow epicondylar axis (EC) and six different humeral canal axes (HC) based on varying lengths of humerus were quantified from 21 computed tomography (CT) scans of humeri. Six additional axes were defined using the proximal humerus only. These included a line from the center of a sphere fit on the humeral head to the 3D surface area centroid of the greater tubercle region, (GT). The inclinations of these axes relative to EC were calculated. GT was found to be the most closely aligned to EC (13.4° ± 6.8°). The inclinations of the other axes ranged from 36.3° to 86.8°. The HC axis orientation was found to be insensitive to humeral shaft lengths (variability, within average: 0.6°). This was chosen as one of two axes for the HCF. It was also the most inter-subject related axis to EC with inclination standard deviation of ±1.8°. EC was therefore predicted from this such that if the superior axis [1 0 0] of an image scan is maintained and the humerus rotated to make its quantified HC align superiorly in the direction [0.98 0.01 0.01], then its EC axis lies laterally in the direction [0 0 1]. This study demonstrates that it is possible with confidence to apply an orthogonal coordinate frame to the humerus based on proximal imaging data only.

New ECG Criteria in Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy

Desmosomal changes, electric uncoupling, and surviving myocardial bundles in fibrofatty tissue characterize arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). Resultant activation delay is pivotal for reentry and thereby ventricular tachycardia (VT). Current task force criteria (TFC) for diagnosis have limited sensitivity. The aim of this study was to assess the diagnostic value of additional criteria on activation delay and VT to improve identification of affected individuals. ECG criteria were studied, while off drugs, in 50 index patients with proven ARVD/C according to TFC (TFC > or = 4 points) and 33 patients with probable ARVD/C (TFC 3 points, or TFC3), being 21 index patients and 12 family members of proven ARVD/C patients. Newly proposed additional criteria are (1) prolonged terminal activation duration in V(1)-V(3), an indicator of activation delay, (2) VT with left bundle-branch block morphology and superior axis, and (3) multiple VT morphologies. All index patients were screened for mutations in ARVD/C-related genes encoding desmosomal proteins. Altogether, 23 of 33 (70%) TFC3 patients fulfilled ARVD/C diagnosis when newly proposed criteria were applied additionally to current TFC. VT with left bundle-branch block morphology and superior axis or multiple VT morphologies were recorded in 12 and 9 of 33 TFC3 patients, respectively, all being index patients. When applying prolonged terminal activation duration additionally to TFC on depolarization/conduction abnormalities, 14 (42%) TFC3 patients fulfilled ARVD/C diagnosis. Results were not significantly different between mutation carriers and noncarriers. Adding the newly proposed criteria to current TFC for ARVD/C will improve identification of affected individuals importantly, independent of outcome of DNA analyses.

Epicardial Macro‐Reentrant Ventricular Tachycardia Exhibiting an Endocardial Centrifugal Activation Pattern in a Case with Arrhythmogenic Right Ventricular Cardiomyopathy

Macro-Reentrant ARVC epi-VT with a Focal Endo-Activation. A 55-year-old man with arrhythmogenic right ventricular cardiomyopathy underwent catheter ablation of ventricular tachycardia (VT) with left bundle branch block and left superior axis QRS morphology with an early precordial transition. Endocardial mapping during the VT revealed a focal activation pattern from a small region of low voltage in the left ventricular (LV) septum. Despite earliest endocardial activation in the LV septum, epicardial mapping demonstrated a macro-reentrant circuit with successful catheter ablation at an inferior peritricuspid annular site. Activation from the reentrant circuit propagated through the scar area in the epicardial right ventricle to the remote endocardial LV breakout site.