Insertion of right ventricular assist device and its removal under local anesthesia.

A patient with acute right ventricular infarction was treated with coronary artery bypass grafting. A few days later developed right ventricular failure and required insertion of a right ventricular assist device through a sternotomy approach (TandemHeart, CardiacAssist, Inc., Pittsburgh, PA, USA). We herein report a technique in which the removal of the right ventricular assist device is performed under local anesthesia without a sternotomy incision.

Tachycardia-induced right ventricular cardiomyopathy: epicardial radiofrequency ablation of an unusual and unexpected ventricular tachycardia.

A 38-year-old man without prior medical history was hospitalized for sustained monomorphic ventricular tachycardia (VT) left bundle branch block pattern with inferior QRS axis resistant to beta blockers. Right ventricular (RV) ejection fraction (EF) was 28%. Left ventricular EF was normal. Right and left endocardial ablation failed. Percutaneous epicardial radiofrequency application at the lateral mitral annulus was successful. The RVEF later normalized. Some VTs originating from the left ventricular epicardium are potential mimickers of benign VTs originating from the ventricular outflow tract (right or left) or arrhythmogenic right ventricular cardiomyopathy VT and they may induce isolated RV dysfunction.

Spatial resolution of pace mapping of idiopathic ventricular tachycardia/ectopy originating in the right ventricular outflow tract.

BACKGROUND: Pace mapping has been used to identify the site of origin of focal ventricular arrhythmias. The spatial resolution of pace mapping has not been adequately quantified using currently available three-dimensional mapping systems. OBJECTIVE: The purpose of this study was to determine the spatial resolution of pace mapping in patients with idiopathic ventricular tachycardia or premature ventricular contractions originating in the right ventricular outflow tract. METHODS: In 16 patients with idiopathic ventricular tachycardia/ectopy from the right ventricular outflow tract, comparisons and classifications of pace maps were performed by two observers (good pace map: match >10/12 leads; inadequate pace map: match < or =10/12 leads) and a customized MATLAB 6.0 program (assessing correlation coefficient and normalized root mean square of the difference (nRMSd) between test and template signals). With an electroanatomic mapping system, the correlation coefficient of each pace map was correlated with the distance between the pacing site and the effective ablation site. The endocardial area within the 10-ms activation isochrone was measured. RESULTS: The ablation procedure was effective in all patients. Sites with good pace maps had a higher correlation coefficient and lower nRMSd than sites with inadequate pace maps (correlation coefficient: 0.96 +/- 0.03 vs 0.76 +/- 0.18, P <.0001; nRMSd: 0.41 +/- 0.16 vs 0.89 +/- 0.39, P <.0001). Using receiver operating characteristic curves, appropriate cutoff values were >0.94 for correlation coefficient (sensitivity 81%, specificity 89%) and < or =0.54 for nRMSd (sensitivity 76%, specificity 80%). Good pace maps were located a mean of 7.3 +/- 5.0 mm from the effective ablation site and had a mean activation time of -24 +/- 7 ms. However, in 3 (18%) of 16 patients, the best pace map was inadequate at the effective ablation site, with an endocardial activation time at these sites of -25 +/- 12 ms. Pace maps with correlation coefficient > or =0.94 were confined to an area of 1.8 +/- 0.6 cm2. The 10-ms isochrone measured 1.2 +/- 0.7 cm2. CONCLUSION: The spatial resolution of a good pace map for targeting ventricular tachycardia/ectopy is 1.8 cm2 in the right ventricular outflow tract and therefore is inferior to the spatial resolution of activation mapping as assessed by isochronal activation. In approximately 20% of patients, pace mapping is unreliable in identifying the site of origin, possibly due a deeper site of origin and preferential conduction via fibers connecting the focus to the endocardial surface.