Superior Axis Morphology Research Articles

ACUTE MYOCARDIAL INJURY IN A PATIENT WITH TYPE–1 NEUROFIBROMATOSIS: A CASE OF SUSPECTED PHEOCROMOCYTOMA–ASSOCIATED MYOCARDITIS

Abstract A 54–year–old patient with an history of type–1 neurofibromatosis presented to the emergency department (ED) due to recurrent abdominal pain with diarrhea. Clinical examination didn’t show anything remarkable. She was mildly hypertensive, apyretic. During her staying in the ED, she complained about chest pain and an electrocardiogram (ECG) was performed. ECG showed sinus rhythm, normal heart rate, left ventricular (LV) hypertrophy with marked horizontal ST segment depression in the precordial leads and bimorphic ventricular ectopic beats with prevalent right bundle branch block superior axis morphology, likely from the medio–basal inferior LV. Troponin T (peak 958 ng/L, normal <15 ng/L) and NTproBNP (peak 2357 ng/L, normal <180 ng/L) were elevated, hemoglobin, creatinine and liver function were normal, C–reactive protein peaked at 120 mg/dL. Echocardiogram showed mildly reduced left ventricular ejection fraction (LVEF) with inferior and inferolateral hypokinesia and moderate mitral regurgitation (MR). She was admitted to cardiac intensive care unit with the suspected diagnosis of an acute coronary syndrome and was started on acetylsalicylic acid, metoprolol, furosemide and potassium canrenoate. Amiodarone was added due to frequent ventricular tachycardias. Due to the symptoms and the history of neurofibromatosis a whole body computed tomography (CT) was done. CT showed a 53 mm mass on the left adrenal gland with intense enhancement, suspected for a neoplastic origin (Figure 2). Plasmatic and urinary cathecolamines and metanephrines were increased. Positron–emission tomography (PET)/CT with 68Ga showed left adrenal uptake, compatible with a neuroendocrine tumor. Coronary arteriography showed normal coronary arteries. The patient underwent a cardiac magnetic resonance (CMR) study in the suspect of acute myocarditis. CMR showed normal biventricular function, an inferior basal hypokinesia with focal intramyocardial late gadolinium enhancement (LGE) suspected for a post–inflammatory origin and mild pericardial effusion. After pharmacological preparation a laparoscopic left adrenalectomy was performed, and histology confirmed the diagnosis of a composite pheocromocytoma. Three months after, the patient was asymptomatic, biochemistry showed normalization of both troponin T and endocrinological biomarkers, the echocardiogram showed preserved LVEF without areas of hypokinesia and mild MR. A follow–up CMR at six months from the acute injury has been scheduled.

P11 RISK STRATIFICATION IN ATHLETES: AN "IRREDUCIBLE" MASTER ATHLETE

Abstract We describe the clinical case of a 48–year–old master athlete, runner (marathon runner), always asymptomatic at rest and during effort, with a family history of ischemic heart disease and no other known cardiovascular risk factors. On the occasion of the pre–partecipation screening visit, he presented an altered baseline electrocardiogram with low peripheral voltages and T wave inversion in V1–V5 leads and inferior leads. The echocardiogram documented morphofunctional alterations in the right ventricle and raises the suspicion of arrhythmogenic cardiomyopathy, later confirmed by cardiac magnetic resonance with Gadolinium. During effort, even repetitive premature ventricular beats LBBB with superior axis morphology appeared. Also, torsade de pointes episode with presyncopal sensation. He was hospitalized with a diagnosis of threatening arrhythmias in right ventricular arrhythmogenic heart disease. Coronary angiography was negative. We recommend beta–blocker therapy, genetic analysis, screening of family members. A subcutaneus defibrillator has been placed. The patient, against the advice of the Physicians, continued to train even at high intensity until he has a syncopal episode with correct intervention of the device on ventricular fibrillation. Since the patient has requested specific indications to continue training independently, an exercise test in beta–blocker therapy is repeated and the training thresholds are calculated. The case of this master athlete highlights the issue of the difficulty of screening the master athlete with frequent omission of symptoms (the patient already had syncopal/presyncopal episodes at home which he had omitted), poor adherence to therapeutic indications, possible negative effects of high intensity physical training on the evolution of arrhythmogenic cardiomyopathy.

A rapid wide complex tachycardia

A rapid wide complex tachycardia

317 IMPLANTABLE CARDIOVERTER-DEFIBRILLATOR IN ARRHYTMIC MITRAL VALVE PROLAPSE: YOU'LL BE CONSIDER IT FOR PRIMARY PREVENTION OF SUDDEN CARDIAC DEATH?

Abstract A 50-year-old female with a history of bileaflet mitral valve prolapse (MVP) was admitted to our Department for persistent palpitation. Physical examination revealed a mid-systolic click, followed by a mid-to-late apical systolic murmur. The electrocardiogram showed sinus rhythm with negative T-waves in inferior leads and repetitive polymorphic premature ventricular contractions (PVCs) with a right bundle branch block pattern and superior axis morphology suggestive of a possible origin from the posterior papillary muscle. The echocardiography confirmed normal ventricular ejection fraction, bileaflet MVP with moderate regurgitation, systolic curling and mitral annulus disjunction. Exercise stress testing demonstrated an increase of polymorphic PVCs during maximum effort. The cardiac magnetic resonance showed an underlying late gadolinium enhancement at the level of the papillary muscles and in the inferobasal region. After a multidisciplinary evaluation, a transvenous implatable cardioverter defibrillator (ICD) was implanted for primary prevention without clear indications deriving from current guidelines. After eleven years, the patients experienced two appropriate shocks due to polymorfic ventricular tachycardia while she was sleeping. Furthermore, the patient underwent successful mechanical transvenous lead extraction and ICD re-implantation for lead failure. During this hospitalization a subsequent echocardiography detected severe ventricular dilatation with moderate systolic disfunction. Conclusion Our report demonstrated that MVP represents potentially cause of life-threatening ventricular arrhythmias and tachycardia induced cardiomyopathy. Beta-blockers are often inadequate in order to reduce PVCs burden. We need more arrhytmic predictors to assestment of sudden cardiac death risk and evaluate ICD for primary prevention. Obtain left ventricular function recovery is difficult and it requires a multidisciplinary approach. It will be important in the future to better define the role will play cathether ablation and mitral valve repair or replacement to prevent malignant arrhytmias.

Long or short postpacing interval response to ventricular tachycardia entrainment: What is the mechanism?

A 58-year-old man with nonischemic cardiomyopathy and an ejection fraction of 25% presented with ventricular tachycardia (VT) storm. Epicardial mapping revealed an inferolateral scar, and during tolerated VT with right bundle branch superior axis morphology with V3 transition (tachycardia cycle length [TCL] 325 ms), overdrive pacing was performed. What is the response to entrainment and why (Figure 1A)?

Fascicular Tachycardia: The Great Masquerader

SESSION TITLE: Cardiovascular Disease SESSION TYPE: Affiliate Case Report Poster PRESENTED ON: Tuesday, October 31, 2017 at 01:30 PM - 02:30 PM INTRODUCTION: Hemodynamically stable tachycardia in a young seemingly healthy individual is generally assumed to be supraventricular in origin. However there is a type of ventricular tachycardia (VT) that has a relatively narrow complex that presents in young healthy individuals and is frequently misdiagnosed as supraventricular ventricular tachycardia (SVT). We present such a case and demonstrate the consequence of delayed diagnosis. CASE PRESENTATION: Our case is a 39 year old male with no past medical history who presented to our emergency department with one day of palpitations and diaphoresis. He first noted these symptoms in adolescence, which were of shorter duration and therefore medical attention was never sought. On arrival to our institution the patient was hemodynamically stable on presentation with an unremarkable physical exam other than a pulse rate of 200 bpm with an EKG showing wide complex tachycardia (figure 1). In addition his blood chemistries were all within normal limits. Despite receiving multiple rounds of adenosine (6mg, 12mg, 12mg) followed by electrical cardioversion, patient remained in wide complex tachycardia. Patient was then given Diltiazem 20mg IVP, which resulted in conversion to normal sinus rhythm (figure 2). Closer investigation of the presenting ECG revealed a leftward (northwest) axis and an incomplete RBBB pattern with RSR’ complexes, a finding highly specific for ventricular tachycardia (VT). An Echocardiogram at our institution revealed no structural heart disease with normal ventricular systolic function. Patient was taken for further electrophysiological testing which confirmed Left Fascicular VT. Patient underwent radiofrequency catheter ablation without any complications. DISCUSSION: Fascicular tachycardia typically originates in the region of the left posterior fascicle and has a RBBB, left superior axis morphology and AV disassociation. In most, a resting EKG is normal and there is no evidence of structural heart disease evidenced by echocardiography and coronary angiography. The narrow QRS complex (typically 0.12 to 0.14 sec) morphology distinguishes fascicular VT from most VTs, but it also resembles SVT frequently leading to misdiagnosis. CONCLUSIONS: Our goal is to help clinicians, especially those who first encounter patients’ with this presentation, be cognizant about the subtle important features of fascicular tachycardia. When it comes to wide complex tachyarrhythmias’ clinicians often have a sense of uneasiness, further clouding their clinical judgment. It is therefore imperative to recognize cases of Idiopathic VT, precisely fascicular tachycardia so they can be differentiated from svt and treated appropriately. Reference #1: Brooks R, Burgess JH. Idiopathic ventricular tachycardia. A review. Medicine (Baltimore) 1988; 67:271. Reference #2: Belhassen B, Viskin S. Idiopathic ventricular tachycardia and fibrillation. J Cardiovasc Electrophysiol 1993; 4:356. DISCLOSURE: The following authors have nothing to disclose: Shahab Khan, Ravi Mann, Fawzi Ameer, David Slotwiner No Product/Research Disclosure Information

Arrhythmogenic effect of flecainide toxicity

Flecainide is a class 1C antiarrhythmic drug especially used for the management of supraventricular arrhythmia. In overdose cases, flecainide can induce life treating ventricular arrhythmias and cardiogenic shock. We report the case of a 72-year-old woman admitted to our intensive care unit for a regular monomorphic wide complex tachycardia (QRS duration 240 ms, right bundle branch block and superior axis morphology) without apparent P waves. Clinical examination showed slight left congestive heart failure signs without cardiogenic shock. An intravenous bolus of 10 mg adenosine 5'-triphosphate (ATP) was ineffective to stop the tachycardia. The diagnosis of ventricular tachycardia induced by flecainide overdose was considered. 500 mL of intravenous 84‰ sodium bicarbonate was administrated. The patient's QRS narrowed immediately and 12-lead ECG showed sinus rhythm. Blood samples confirmed the flecainide overdose and the clinical status progressively improved.

Reversal of left bundle and His bundle potentials during wide complex tachycardia: What is the mechanism?

Case presentation A 14-year-old male patient presented to our institution with a wide complex tachycardia. An echocardiogram showed an ejection fraction of 60%, moderate mitral and tricuspid regurgitation, mild aortic regurgitation, and moderate pulmonary hypertension. He had a history of 2 prior ablations at another institution. During his first procedure, he was found to have ventricular tachycardia with a right bundle branch block, left superior axis morphology at a cycle length of 375 ms. Cryoablation was performed along the mid-left ventricular septum, after which the patient developed a left posterior fascicular block pattern during sinus rhythm. The next day, the patient developed ventricular tachycardia with a right bundle branch block, right inferior axis morphology. Ablation was targeted in the region of the left anterior fascicle and rendered the tachycardia noninducible. After the procedure, the electrocardiogram demonstrated a left bundle branch block configuration. Several months later, the patient presented to our institution in a wide complex tachycardia with a left bundle branch block, left superior axis morphology. Electrocardiograms during sinus rhythm and tachycardia are shown (Figures 1A and 1B). During electrophysiological study, baseline AH and HV intervals were 87 ms and 55 ms, respectively. The HV remained constant during incremental atrial pacing. Tachycardia was reproducibly induced with rapid atrial and ventricular pacing, and had a cycle length of 370 ms and an HV interval of 55 ms. Atrial activity was dissociated from the tachycardia. Adenosine 24 mg had no effect on tachycardia cycle length. Intracardiac tracings during sinus rhythm (Figure 2) and tachycardia (Figure 3) are shown. What is the mechanism of the wide complex tachycardia?

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.

Idiopathic left ventricular tachycardia: clinical features, mechanisms and management.

Sustained monomorphic ventricular tachycardia (VT) most often occurs in patients with structural heart diseases including healed myocardial infarction, dilated and hypertrophic cardiomyopathies, and arrhythmogenic right ventricular cardiomyopathy. It also occurs in patients without any apparent structural abnormality, and VT in these cases is referred as idiopathic. Idiopathic VT accounts for approximately 20% of all sustained monomorphic VT in Japan, whereas it does for approximately 10% in the United States [1]. More than a half of idiopathic VT originates from the right ventricle especially from the right ventricular outflow tract and the reminder from the left ventricle (LV). The mechanism, pharmacological responses and treatment of idiopathic VT entirely differ by the origin. Idiopathic VT originating from the LV has been classified into verapamil-sensitive type, adenosine-sensitive type and automatic propranolol-sensitive type [1]. Verapamilsensitive type of VT is the most common form and shows right bundle branch block (RBBB) and superior axis morphology in most cases. It is due to reentry utilizing the left posterior fascicle and responds to verapamil and not to adenosine. Adenosine-sensitive type shows RBBB and inferior axis morphology in most cases and is due to cyclic AMP-mediated triggered activity. It frequently is induced by exercise and appears as both sustained and repetitive forms. It responds not only to adenosine, but also to verapamil and propranolol. Automatic propranolol-sensitive type shows RBBB and inferior axis morphology in most cases and is due to enhanced automaticity. Although clinical characteristics and electrophysiologic properties of these types of VT have been extensively, their pathogeneses at the cellular level still remain unclear. In this article, we focused on the clinical features, mechanism and management of verapamil-sensitive type of idiopathic VT.

Catheter Ablation of the Mitral Isthmus for Ventricular Tachycardia Associated With Inferior Infarction

Intraoperative mapping studies suggest that an isthmus of myocardium between the mitral valve annulus and the border of inferior myocardial infarction may play a role in the genesis of ventricular tachycardia. We examined the frequency with which a slow conduction zone within the mitral isthmus was critical to the maintenance of ventricular tachycardia associated with remote inferior infarction in patients undergoing catheter ablation. In 4 of 12 patients, a critical zone of slow conduction was identified within the mitral isthmus. In each of these patients, two characteristic and morphologically distinct tachycardias were induced: a left bundle (rS in V1, R in V6), left superior axis morphology and a right bundle (R in V1, QS in V6), right superior axis morphology (cycle length, 610 to 320 ms). In each patient, a zone of slow conduction, shared by both morphologies, was characterized by diastolic potentials with electrogram-QRS intervals of 85 to 161 ms (21% to 47% of tachycardia cycle length) and entrainment with concealed fusion during pacing associated with stimulus-QRS intervals of 81 to 400 ms (20% to 91% of tachycardia cycle length). In each patient, a single radiofrequency energy application at the shared site of slow conduction eliminated inducibility of both morphologies. During follow-up of 1 to 11 months, no patient had recurrent tachycardia. The mitral isthmus contains a critical region of slow conduction in some patients with ventricular tachycardia after inferior myocardial infarction, providing a vulnerable and anatomically localized target for catheter ablation. Characteristic tachycardia morphologies may provide clinical markers for this underlying mechanism.

705-2 Catheter Ablation of the Mitral Isthmus for Ventricular Tachycardia Associated with Inferior Infarction

Catheter ablation (CA) of ischemic sustained monomorphic ventricular tachycardia (SMVT) remains problematic due to the presence of multiple potential functional circuits. We identified 3 pts with SMVT and a posterior akinetic/dyskinetic segment in whom anatomic constraints on the reentrant circuit facilitated CA. Each pt had 2-40 episodes of spontaneous SMVT in the previous month despite amiodarone. SMVT had either a LBBB (rS in V1, R in V6) right superior axis morphology (M), or a RBBB (R in V1, QS in V6) left superior axis M. Both M were reproducibly induced in each pt (cycle length [CL] 600-320 ms). In each pt, both M appeared to share a similar slow conduction zone in the inferobasal left ventricle adjacent to the mitral valve annulus. During SMVT of either M, these sites were characterized by diastolic potentials with electrogram-ORS intervals of 115-251 ms (24-58% of SMVT CL) and concealed entrainment during pacing associated with stimulus-ORS intervals of 105-411 ms (23-92% of SMVT CL). Application of radiofrequency energy (50 W for 90-120 s) at one of these sites in each pt (figure) resulted intermination of SMVT within 2-12 complexes. Following CA, neither M couldbe induced in any pt. In 1 pt, SMVT with a third nonclinical ORS M (CL 250 ms) remained inducible. All pts had implantable defibrillators with RR interval and/or electrogram storage. During 1-5 mo follow-up, no pt has had spontaneous SMVT or shocks. An isthmus of surviving myocardium adjacent to the mitral valve annulus may constitute a critical region of slow conduction in some pts with inferior MI and recurrent SMVT, providing a vulnerable and anatomically localized target for CA. Characteristic SMVT morphologies may identify candidates for this approach.