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Aims: Catheter ablation (CA) of atrial fibrillation (AF) might be a definitive curative therapy for selected groups of patients (pts). However, current ablation protocols are not standardized and predictors of CA success and sinus rhythm maintenance are not clearly defined. To evaluate whether left atrium (LA) volume quantification provided by multi-detector computed tomography (MDCT) might predict the success of pulmonary vein (PV) isolation procedure., Methods and Results: We evaluated 99 pts, 66 male, mean age 54.4 +/- 10.1 years, referred for CA because of drug resistant AF. All pts were submitted to 64-slice MDCT scan for electroanatomic mapping integration, pulmonary veins anatomy delineation, LA thrombi exclusion, and LA volume estimation. Complete isolation of all the PVs was always performed with eventual cavo-tricuspid isthmus ablation. For a mean follow-up period (Fup) of 16.7 +/- 6.6 months, clinical success was assessed after a 3-month blanking period. Anti-arrhythmic drug therapy was discontinued or modified at the clinician's criteria. At the end of the Fup, 29 pts suspended anti-arrhythmic drug therapy and 26% were of oral anticoagulation. Univariate analysis showed that the probability of AF relapse after CA was higher in pts with non-paroxysmal forms of AF. The probability of relapse was significantly higher in pts with LA volumes greater than 100 mL when assessed by MDCT. We found that the LA volume of 145 mL was a good cut-off value for AF recurrence prediction. Patients with LA volumes greater than 145 mL had significantly higher recurrence rates of arrhythmia, even when adjusted for the effect of age, gender, body mass index, hypertension, and type of AF., Conclusion: Left atrium volume estimated by MDCT may be useful to identify pts in whom successful AF ablation can be achieved with simpler ablation procedures, restricted to PV isolation.

The case of a 19-year-old female with a neonatal diagnosis of Tetralogy of Fallot and complete atrioventricular (AV) septal defect is described. She had had a corrective surgery at the age of 6. She did well afterwards despite recent complain of fatigability with mild arterial hypoxaemia. Transoesophageal echocardiography depicted a 12 mm atrial septal defect (ASD) with a bidirectional shunt, with features of a defect of the Ostium Primum type. The reason for the bidirectional shunt was unclear, and cardiac catheterization was performed. The presence of an ASD of the Ostium Primum type was confirmed with normal pulmonary arterial pressures and resistances. The distance to the AV valves seemed compatible with the implantation of a small device and percutaneous closure of the ASD was attempted. However, it was noted that the device deployment would cause deviation of the tricuspid regurgitation jet to the left atrium. Direct coronary sinus catheterization demonstrated its direct roof opening to the left atrium. The device impaired the drainage of the coronary sinus, actually increasing the right-to-left shunt (Figure 4). The implantation was aborted and surgical correction was proposed. Coronary sinus septal defect is a rare form of ASD. Its diagnosis is often difficult because of non-specific features. In this case, oxygen desaturation at presentation seemed to be explained by the regurgitating jet of the right component of AV valve through the Ostium primum defect into the left atrium. Percutaneous closure of the defect was attempted. However, it became clear that the device-increased the right-to-left shunt is also allowing the diagnosis of an unroofed coronary sinus. Under these circumstances, surgery seemed to be the best option.

A 60-year-old male with previous hypertension, left ventricle hypertrophy, and coronary artery disease was referred for stress echocardiography because of exertional chest pain. The electrocardiogram revealed deep T-wave inversion in the anterolateral leads. Contrast echocardiography was notable for an apical filling defect consistent with the apical form of hypertrophic cardiomyopathy. Cardiac magnetic resonance demonstrated the 'ace of spades' left ventricle cavity, confirming the diagnosis. Single photon emission computed tomography showed increased apical left ventricle tracer uptake. Velocity vector imaging study depicted lower than normal absolute maximal longitudinal tissue velocities. The apical longitudinal strain was negative without base to apex gradient. There were normal longitudinal strain values in the basal and mid myocardial segments (Figure 1). Apical hypertrophic cardiomyopathy is a rare condition occasionally missed by conventional echocardiographic studies. Intravenous contrast enhancement might improve diagnosis accuracy. Newer Doppler-based techniques allowing tissue characterization may complement contrast echocardiography in its diagnosis.