Cannon A wave validation as a diagnostic tool in paroxysmal supraventricular tachycardias.

OBJECTIVE: The presence of cannon A waves, the so called "frog sign", has traditionally been considered diagnostic of atrioventricular nodal re-entrant tachycardia (AVNRT). Nevertheless, it has never been systematically evaluated. The aim of this study is to assess the independent diagnostic utility of cannon A waves in the differential diagnosis of supraventricular tachycardias (SVTs). METHODS: We prospectively included 100 patients who underwent an electrophysiology (EP) study for SVT. The right jugular venous pulse was recorded during the study. In 61 patients, invasive central venous pressure (CVP) was registered as well. CVP increase is thought to be related with the timing between atria and ventricle depolarization; two groups were prespecified, the short VA interval tachycardias (including typical AVNRT and atrioventricular reciprocating tachycardia (AVRT) mediated by a septal accessory pathway) and the long VA interval tachycardias (including atypical AVNRT and AVRT mediated by a left free wall accessory pathway). RESULTS: The relationship between cannon A waves and AVNRT did not reach the statistical significance (OR: 3.01; p = .058); On the other hand, it was clearly associated with the final diagnosis of a short VA interval tachycardia (OR: 10.21; p < .001). CVP increase showed an inversely proportional relationship with the VA interval during tachycardia (b = -.020; p < .001). CVP increase was larger in cases of AVNRT (4.0 mmHg vs. 1.2 mmHg; p < .001) and short VA interval tachycardias (3.9 mmHg vs. 1.2 mmHg; p < .001). CONCLUSION: The presence of cannon A waves is associated with the final diagnosis of short VA interval tachycardias.

Anatomy of the left atrial appendage for the interventional cardiologist.

Exact knowledge of the anatomy of the left atrial appendage (LAA) is crucial for LAA isolation by catheter ablation and for interventional LAA occlusion in patients with atrial fibrillation. This review outlines the current anatomical understanding of LAA morphology from ostium to distal lobes, myocardial fiber orientation and wall structure, and adjacent structures such as the left upper pulmonary vein with the Coumadin ridge, the circumflex artery with its side branches, the aortic root, pulmonary artery, and the pericardial space. Insight into these details will facilitate these interventions and reduce the risk of complications.

Anatomical knowledge for the ablation of left and right atrial flutter.

The different forms of atrial flutter (AFL) and atrial macroreentrant tachycardias are strongly related to the atrial anatomy in structurally normal atria, and even more so in patients with dilated chambers or with previous interventions. Atrial anatomy, macro- and microscopic tissue disposition including myocardial fibers, conduction system and connective tissue is complex. This review summarizes knowledge of atrial anatomy for the interventional electrophysiologist to better understand the pathophysiology of and ablation options for these complex arrhythmias, as well as to perform catheter ablation procedures safely and effectively.

Device complications with addition of defibrillation to cardiac resynchronisation therapy for primary prevention.

OBJECTIVE: In patients indicated for cardiac resynchronisation therapy (CRT), the choice between a CRT-pacemaker (CRT-P) versus defibrillator (CRT-D) remains controversial and indications in this setting have not been well delineated. Apart from inappropriate therapies, which are inherent to the presence of a defibrillator, whether adding defibrillator to CRT in the primary prevention setting impacts risk of other acute and late device-related complications has not been well studied and may bear relevance for device selection. METHODS: Observational multicentre European cohort study of 3008 consecutive patients with ischaemic or non-ischaemic dilated cardiomyopathy and no history of sustained ventricular arrhythmias, undergoing CRT implantation with (CRT-D, n=1785) or without (CRT-P, n=1223) defibrillator. Using propensity score and competing risk analyses, we assessed the risk of significant device-related complications requiring surgical reintervention. Inappropriate shocks were not considered except those due to lead malfunction requiring lead revision. RESULTS: Acute complications occurred in 148 patients (4.9%), without significant difference between groups, even after considering potential confounders (OR=1.20, 95% CI 0.72 to 2.00, p=0.47). During a mean follow-up of 41.4±29 months, late complications occurred in 475 patients, giving an annual incidence rate of 26 (95% CI 9 to 43) and 15 (95% CI 6 to 24) per 1000 patient-years in CRT-D and CRT-P patients, respectively. CRT-D was independently associated with increased occurrence of late complications (HR=1.68, 95% CI 1.27 to 2.23, p=0.001). In particular, when compared with CRT-P, CRT-D was associated with an increased risk of device-related infection (HR 2.10, 95% CI 1.18 to 3.45, p=0.004). Acute complications did not predict overall late complications, but predicted device-related infection (HR 2.85, 95% CI 1.71 to 4.56, p<0.001). CONCLUSIONS: Compared with CRT-P, CRT-D is associated with a similar risk of periprocedural complications but increased risk of long-term complications, mainly infection. This needs to be considered in the decision of implanting CRT with or without a defibrillator.