José M. Montero-Cabezas

Flutter auricular 1:1 tras la administración de vernakalant para cardioversión de fibrilación auricular

Vernakalant is a novel antiarrhythmic drug that has proved its efficacy at restoring sinus rhythm in recent-onset atrial fibrillation (AF). Its mechanism of action is based on selective partial blocking of potassium currents in the atrial myocardium, prolonging the atrial refractory period without significantly affecting ventricular refractoriness. This makes it potentially beneficial as a low-effect ventricular proarrhythmogenic, even in patients with structural heart disease. Class IC drugs–used to restore sinus rhythm and prevent AF recurrence–favor the appearance of flutter, often with 1:1 ventricular conduction. Vernakalant also appears to favor the development of flutter, although 1:1 atrioventricular conduction has not been reported to date. We present the case of a 77-year-old man with coronary disease without infarction, with hypertensive cardiopathy, normal ventricular function, and 1 previous episode of persistent AF requiring electrical cardioversion. Treatment was with acenocoumarol, enalapril, and simvastatin. The patient was referred for electrophysiologic study for typical paroxystic atrial flutter with 240 ms cycle length in the electrocardiogram. Initially in sinus rhythm, during placement of the circular multipolar catheter used to record electrocardiograms and for stimulation he developed sustained AF after a 10-min observation period. We decided to use intravenous vernakalant for cardioversion. After a first 3 mg/kg infusion, the AF organized into flutter with 320 ms cycle length, descending atrial activation sequence in the anterior right atrium, and exact return cycle in the cavotricuspid isthmus, compatible with typical flutter (Fig. 1). Atrioventricular conduction was initially variable, later stabilizing to 1:1 with right bundle branch block (Fig. 2). Given good tolerance despite rapid ventricular frequency, we decided to interrupt the drug infusion and perform radiofrequency ablation of the cavotricuspid isthmus. The Class IC antiarrhythmic drugs flecainide and propafenone slow atrial conduction by blocking voltage-dependent rapid sodium channels, favoring the stability of macro re-entry circuits in anatomic regions with predisposed structures (IC flutter). In the right atrium, they condition the slowing of atrial conduction and limit transversal conduction through the crista terminalis, facilitating the appearance of flutter circuits around the tricuspid annulus. Due to atrial conduction slowing, IC flutter is usually slow and can be led 1:1 to the ventricles. This greatly accelerates ventricular frequency that is often accompanied by aberrant conduction, which can condition poor hemodynamic tolerance of the arrhythmia. Although experience in the clinical use of vernakalant is very limited, data on its efficacy and safety in 4 controlled clinical trials has been published. Vernakalant has demonstrated efficacy superior to a placebo plus amiodarone in cardioversion of recent-onset AF (52% vs 4%-5% at 90-min observation) with 8% post-dose incidence of atrial flutter–which is far superior to amiodarone (0.9%), above all in patients receiving antiarrhythmic drugs.

Delayed positive response to a flecainide test in a patient with suspected Brugada syndrome: a worrisome finding.

Servei de Cardiologia, Hospital Universitari de la Vall d’Hebron, Vall d’Hebron Institute of Research (VHIR), Barcelona, Spain Servei de Cardiologia, Hospital Universitari de la Vall d’Hebron, Barcelona, Spain Unitat de Cardiopaties Congènites de l’Adolescent i de l’Adult (UCCAA), Hospital Universitari de la Vall d’Hebron, Barcelona, Spain Unitat de Cardiopaties Congènites de l’Adolescent i de l’Adult (UCCAA), Hospital Universitari de la Santa Creu i Sant Pau, Barcelona, Spain

Accuracy and reproducibility of fast fractional flow reserve computation from invasive coronary angiography

Fractional flow reserve (FFR) guided percutaneous coronary intervention (PCI) is associated with favourable outcome compared with revascularization based on angiographic stenosis severity alone. The feasibility of the new image-based quantitative flow ratio (QFR) assessed from 3D quantitative coronary angiography (QCA) and thrombolysis in myocardial infarction (TIMI) frame count using three different flow models has been reported recently. The aim of the current study was to assess the accuracy, and in particular, the reproducibility of these three QFR techniques when compared with invasive FFR. QFR was derived (1) from adenosine induced hyperaemic coronary angiography images (adenosine-flow QFR [aQFR]), (2) from non-hyperemic images (contrast-flow QFR [cQFR]) and (3) using a fixed empiric hyperaemic flow [fixed-flow QFR (fQFR)]. The three QFR values were calculated in 17 patients who prospectively underwent invasive FFR measurement in 20 vessels. Two independent observers performed the QFR analyses. Mean difference, standard deviation and 95% limits of agreement (LOA) between invasive FFR and aQFR, cQFR and fQFR for observer 1 were: 0.01 ± 0.04 (95% LOA: −0.07; 0.10), 0.01 ± 0.05 (95% LOA: −0.08; 0.10), 0.01 ± 0.04 (95% LOA: −0.06; 0.08) and for observer 2: 0.00 ± 0.03 (95% LOA: −0.06; 0.07), −0.01 ± 0.03 (95% LOA: −0.07; 0.05), 0.00 ± 0.03 (95% LOA: −0.06; 0.05). Values between the 2 observers were (to assess reproducibility) for aQFR: 0.01 ± 0.04 (95% LOA: −0.07; 0.09), for cQFR: 0.02 ± 0.04 (95% LOA: −0.06; 0.09) and for fQFR: 0.01 ± 0.05 (95% LOA: −0.07; 0.10). In a small number of patients we showed good accuracy of three QFR techniques (aQFR, cQFR and fQFR) to predict invasive FFR. Furthermore, good inter-observer agreement of the QFR values was observed between two independent observers.

Proximal Left Anterior Descending Artery Acute Occlusion With an Unusual Electrocardiographic Pattern: Not Everything Is ST Elevation

Early detection of electrocardiogram (ECG) abnormalities indicative of acute coronary artery occlusion is crucially important to identify candidates for emergency revascularization. In most cases, ST elevation is the finding that enables diagnosis to be established. However, in some situations, ST elevation corresponding to the territory affected by coronary artery occlusion may not be present, resulting in a delay in reperfusion treatment and larger infarcted areas. We present 2 cases of acute occlusion of the left anterior descending artery with an uncommon but characteristic ECG pattern. The first patient was 61-year-old man with no relevant history of cardiac events, who was attended at home by the emergency services for acute chest pain. In the first ECG performed, approximately 30 minutes after onset of pain, marked ST-segment depression of up to 3 mm was observed after the J point, with steep Q and T waves in the precordial leads V2-V5, 0.5 mm ST elevation in leads aVL and aVR, and ST-segment depression of 1 mm in the inferior leads (Figure 1A). The patient was referred to the catheterization laboratory, where total occlusion of the left anterior descending artery (Figure 1B) was observed with no collateral filling. The lesion was treated by angioplasty and placement of a drug-eluting stent. During the same procedure, 2 lesions with 70% occlusion of the circumflex artery and the right coronary artery were treated by angioplasty and stent placement (Figure 1C). The ECG recorded after the procedure (Figure 1D) showed electrical abnormalities characteristic of the outcome of an anterior infarction, with QS complexes in V1-V2, rS in lead V3, persistent ST elevation, and a negative T wave. The second patient was a 65-year-old man with no relevant history, who was attended for sudden chest pain. The first ECG once again showed ST-segment depression of up to 3 mm after the J point, with minimal Q wave, loss of R wave progression, and prominent T waves in the precordial leads (particularly in leads V2-V3) (Figure 2A). In this case, there was ST elevation in lead aVR of up to 1.5 mm, Q wave in lead aVL, and ST-segment depression in the inferior leads, which reached 2 mm in lead II. Emergency

One-stop-shop cardiac CT: 3D fusion of CT coronary anatomy and myocardial perfusion for guiding revascularization in complex multivessel disease.

A 59-year old male, with a history of inferoposterior myocardial infarction and multiple coronary stenting, presented to the out-patient clinic with exercise-related chest discomfort. The electrocardiogram showed sinus rhythm with Q-waves in the inferior leads (Figure 1). Coronary computed tomography angiography (CTA) showed stents in the right coronary artery (RCA), left anterior descending artery (LAD), and intermediate branch (IM), however, obstructive coronary artery disease (CAD) could not be reliably assessed (Figure 2). Sequentially, adenosine stress CT myocardial perfusion (CTP) was performed and indicated anterolateral ischemia and the old inferoposterior scar (Figure 3). Using 3Dimensional (3D) fusion of the coronary anatomy and stress perfusion images, the new myocardial ischemia could be allocated to the territory of the first diagonal branch (D1) (Figure 4). Invasive coronary angiography demonstrated patency of the previous stents and a significant lesion of the proximal D1, which was successfully stented (Figure 5).

The Descending Septal Artery: Description of This Infrequent Coronary Anatomical Variant in Three Different Clinical Scenarios

Pilar Molina, Nancy Govea, and David Crémer Servicio de Cardiologı́a, Hospital Son Llátzer, Palma de Mallorca, Islas Baleares, Spain Instituto de Investigación Sanitaria Palma (IdISPa), Palma de Mallorca, Islas Baleares, Spain Servicio de Cardiologı́a, Hospital La Fe, Valencia, Spain Servicio de Histopatologı́a, Instituto Medicina Legal, Valencia, Spain Sección de Genética, Hospital Son Espases, Palma de Mallorca, Islas Baleares, Spain