Potential additive effects of ticagrelor, ivabradine, and carvedilol on sinus node.

A 51-year-old male patient presented to the emergency room with an anterior ST-elevation myocardial infarction. After a loading dose of both ticagrelor and aspirin, the patient underwent primary-PCI on the left anterior descending coronary artery with stent implantation. After successful revascularization, medical therapy included beta-blockers, statins, and angiotensin II receptor antagonists. Two days later, ivabradine was also administered in order to reduce heart rate at target, but the patient developed a severe symptomatic bradycardia and sinus arrest, even requiring administration of both atropine and adrenaline. Ivabradine and ticagrelor have been then suspended and this latter changed with prasugrel. Any other similar event was not reported during the following days. This clinical case raised concerns about the safety of the combination of beta-blockers and ivabradine in patients treated with ticagrelor, particularly during the acute phase of an acute coronary syndrome. These two latter drugs, in particular, might interact with the same receptor. In fact, ivabradine directly modulates the If-channel which is also modulated by the cyclic adenosine monophosphate levels. These latter have been shown to increase after ticagrelor assumption via inhibition of adenosine uptake by erythrocytes. Further studies are warrant to better clarify the safety of this association.

Long-term follow-up of right atrial ablation in patients with atrial fibrillation:.

INTRODUCTION: The aim of this study was to evaluate the efficacy and the impact on quality of life of a new ablative approach to the right atrium in patients with atrial fibrillation (AF). METHODS AND RESULTS: Seventy-four symptomatic patients with paroxysmal (n = 49) or permanent (n = 25) refractory AF underwent radiofrequency ablation. A nonfluoroscopic electroanatomic mapping system was used to perform the following lesions: (1) an isthmus line between the tricuspid annulus and the inferior vena cava; (2) a posterior intercaval line from the superior vena cava and the inferior vena cava; (3) a septal line from the superior vena cava to the fossa ovalis, proceeding to the coronary sinus ostium where a circumferential line around the ostium was performed, and then on to the inferior vena cava; and (4) a transversal lesion connecting the posterior intercaval and the septal lesions. In addition, electrical disconnection of the superior vena cava was performed. There were no complications. Postablation remapping showed the absence of discrete electrical activity inside and just around the ablation lines. Electrical disconnection of the superior vena cava was obtained in all patients. After 21 +/- 6 months, 49 patients (66%) had stable sinus rhythm with continuation of the previous antiarrhythmic drug therapy, 13 patients (18%) were considered improved, and 12 (16%) received no benefit (unsuccessful procedure). After ablation, quality of life was significantly improved, reaching the levels of the general Italian population. Ejection fraction and the extent of the low-voltage area were found by multivariate analysis to be independent predictors of AF recurrence. CONCLUSION: The results of the present study suggest that this ablative approach in combination with antiarrhythmic drugs is safe and effective in treating AF, leading to a marked increase in quality of life in patients with refractory AF.

Intracardiac echocardiography: from electroanatomic correlation to clinical application in interventional electrophysiology.

Intracardiac echocardiography (ICE), using an ultrasound transducer at the tip of a percutaneously placed catheter, has recently been introduced for the visualization of the intracardiac anatomy and in order to reduce the fluoroscopy time. This review focuses predominantly on the current use of ICE in interventional electrophysiology. ICE has been shown to facilitate the targeting of specific anatomic landmarks, such as the crista terminalis, the Eustachian ridge, the tricuspid annulus, the coronary sinus ostium, and the pulmonary veins that cannot be adequately visualized at fluoroscopy. Direct imaging of these sites can be advantageous in that it facilitates the accurate guidance of the ablative procedure and shortens the fluoroscopy time. ICE has been demonstrated to be useful in the positioning and stabilization of the imaging ablation catheter, the evaluation of the lesion size and continuity and in the immediate identification of complications. Furthermore, in the last few years there has been a revival in the use of transseptal catheterization due to a larger development of radiofrequency catheter ablation in the left atrium. ICE, providing excellent views of the fossa ovalis and of the transseptal apparatus, can be safely used to prevent life-threatening complications following inadvertent puncture of anatomic structures such as the lateral wall of the left atrium or the aortic root. Moreover, ICE appears to be very useful in combining true anatomical features with electrical activation in an attempt to construct realistic electrical-anatomical maps. Finally, the three-dimensional tomographic reconstruction of intracardiac images and the phased array ICE catheter with Doppler capabilities seem to be promising tools both for the guidance of ablation procedures as well as in leading experimental studies.

Transseptal activation during left atrial pacing in humans: electroanatomic mapping using a noncontact catheter and the intracardiac echocardiography.

BACKGROUND: A better understanding of transseptal activation may be important for the treatment of atrial fibrillation, but little is known about preferential routes of conduction from the left atrium (LA) to the right atrium (RA) in humans. METHODS AND RESULTS: Twelve patients were studied. A noncontact mapping system was used to map the RA during pacing from several sites of LA at different cycle lengths. The location of the Bachmann's bundle (BB), the fossa ovalis (FO) and the coronary sinus (CS) ostium were determined using intracardiac echocardiography. The BB was the earliest area of right atrial activation during pacing from the atrial appendage, roof and postero-superior wall in 94% of cases. The FO was the area of earliest activation during pacing from the septum and the right superior pulmonary veins (PV) in 95% of cases. The CS ostium (alone or associated with the FO) was the region of transseptal breakthrough in all patients during pacing from the right inferior PV, postero-inferior wall and distal CS. Various patterns of activation with 2 or 3 distinct areas of transseptal breakthrough were observed during pacing from the lateral wall and the left superior PV. The pacing cycle length did not influence the modality of transseptal activation. CONCLUSIONS: Different patterns of transseptal activation were found during pacing from LA. The preferential routes of conduction from the LA to the RA were related to the sites of stimulation and were not influenced by the pacing cycle length.