April 9th Question.

Abstract

HomeCirculation: Arrhythmia and ElectrophysiologyVol. 11, No. 4April 9th Question Free AccessArticle CommentaryPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessArticle CommentaryPDF/EPUBApril 9th Question Amit Noheria, MBBS, SM Amit NoheriaAmit Noheria Search for more papers by this author Originally published9 Apr 2018https://doi.org/10.1161/CIRCEP.118.006444Circulation: Arrhythmia and Electrophysiology. 2018;11:e006444See Answer to April 2nd Following QuestionA 60-year-old man with hypertension, frequent symptomatic premature atrial complexes, and paroxysmal atrial fibrillation underwent radiofrequency catheter ablation with wide area circumferential ablations for pulmonary vein isolation. After pulmonary vein isolation, provocation with isoproterenol resulted in frequent premature atrial complexes with a constant activation sequence as shown in Figure 1 along with the catheter locations on fluoroscopy in Figure 2. Based on the intracardiac electrogram recordings, what is the most likely site of origin for the premature atrial complex?Download figureDownload PowerPointFigure 1. Surface ECG and intracardiac electrograms showing the premature atrial complex. ABL indicates ablation catheter; CS, coronary sinus; HIS, hexapolar His-bundle recording catheter; LAA, left atrial appendage circular mapping catheter; and RA, right atrium.Download figureDownload PowerPointFigure 2. Fluoroscopic projections to show catheter locations. Right anterior oblique (RAO) and left anterior oblique (LAO) views are shown. The duodecapolar catheter seen in the LAO view has electrodes spanning from the coronary sinus (CS) to the right atrium (RA). The ablation catheter (ABL) is in the left superior pulmonary vein. HIS, hexapolar His-bundle recording catheter; and LAA, left atrial appendage circular mapping catheter.Answer OptionsA. Crista terminalisB. Triangle of KochC. Noncoronary aortic sinus of ValsalvaD. Left atrial posterior wallE. Left atrial appendageAnswer to April 2nd QuestionB. Left ventricular inferior (posteromedial) papillary muscleExplanationThe premature ventricular complex in the Figure has a right bundle branch block-like morphology (monophasic R wave in V1) with a left superior axis (small r waves in the inferior leads) and a precordial transition in lead V3 through V4, which suggest an origin from the left ventricular midinferior wall. In patients with idiopathic premature ventricular complexes, the most common sites of origin are the perivalvar regions or intracavitary structures. The ECG pattern in the Figure is typical of an origin from the left ventricular inferior (posteromedial) papillary muscle (Option B).1,2 The leftward/superior axis suggests an inferior (medial) site of origin. These features exclude an origin from the superior (anterolateral) papillary muscle (which would have inferior axis), left anterior fascicle (which would have inferior axis with RSR′ pattern in lead V1), mitral annulus (which would have positive precordial QRS concordance), and epicardium (which would have Q waves in the ECG leads corresponding to site of origin as opposed to the rS configuration in inferior leads in this case).3Download figureDownload PowerPointFigure. Electrocardiogram showing premature ventricular complexes in 54-year-old woman with mitral valve prolapse.Mitral valve prolapse is associated with premature ventricular complexes originating from left ventricular papillary muscles, as well as premature ventricular complexes from the left fascicles.4 Malignant bileaflet mitral valve prolapse syndrome is the occurrence of life-threatening ventricular tachyarrhythmias in a patient with mitral valve prolapse.5,6Footnoteshttp://circep.ahajournals.org