Functional Assessment of Ventricular Tachycardia Circuits and Their Underlying Substrate Using Automated Conduction Velocity Mapping.

OBJECTIVES: This study sought to describe the utility of automated conduction velocity mapping (ACVM) in ventricular tachycardia (VT) ablation. BACKGROUND: Identification of areas of slowed conduction velocity (CV) is critical to our understanding of VT circuits and their underlying substrate. Recently, an ACVM called Coherent Mapping (Biosense Webster Inc) has been developed for atrial mapping. However, its utility in VT mapping has not been described. METHODS: Patients with paired high-density VT activation and substrate maps were included. ACVM was applied to paired VT activation and substrate maps to assess regional CV and activation patterns. A combination of ACVM, traditional local activation time maps, electrogram analysis, and off-line calculated CV using triangulation were used to characterize zones of slowed conduction during VT and in substrate mapping. RESULTS: Fifteen patients were included in the study. In all cases, ACVM identified slow CV within the putative VT isthmus, which colocalized to the VT isthmus identified with entrainment. The dimensions of the VT isthmus with local activation time mapping were 37.8 ± 13.7 mm long and 8.7 ± 4.2 mm wide. In comparison, ACVM produced an isthmus that was shorter (length: 25.1 ± 10.6 mm; mean difference: 12.8; 95% CI: 7.5-18.0; P < 0.01) and wider (width: 18.8 ± 8.1 mm; mean difference: 10.1; 95% CI: 6.1-14.2; P < 0.01). In VT, the CV using triangulation at the entrance (8.0 ± 3.6 cm/s) and midisthmus (8.1 ± 4.3 cm/s) was not significantly different (P = 0.92) but was significantly faster at the exit (16.2 ± 9.7 cm/s; P < 0.01). In the paired substrate analysis, traditional local activation time isochronal mapping identified 6.3 ± 2.0 deceleration zones. In contrast, ACVM identified a median of 0 deceleration zones (IQR: 0-1; P < 0.01). CONCLUSIONS: ACVM is a novel complementary tool that can be used to accurately resolve complex VT circuits and identify slow conduction zones in VT but has limited accuracy in identifying slowed conduction during substrate-based mapping.

Assessment of ablation catheter contact on valve annulus: Implications on accessory pathway ablation.

BACKGROUND: Catheter-tissue contact force is an important factor influencing lesion size and efficacy and thereby potential for arrhythmia recurrence following accessory pathway (AP) radiofrequency ablation. We aim to evaluate adequacy and perception of catheter contact on the tricuspid and mitral annuli. METHODS: Data were collected from 42 patients undergoing catheter ablation. Operators were blinded to contact force information and reported perceived contact (poor, moderate, or good) while positioning the catheter at four tricuspid annular sites (12, 9, 6 and 4 o'clock positions; abbreviated as TA12, TA9, TA6 and TA4) and three mitral annular sites (3, 5 and 7 o'clock positions; abbreviated as MA3, MA5 and MA7) through long vascular sheaths. RESULTS: The highest and lowest mean contact forces were obtained at MA7 (13.3 ±â€¯1.7 g) and TA12 (3.6 g ±â€¯1.3 g) respectively. Mean contact force on tricuspid annulus (6.1 g ±â€¯0.9 g) was lower than mitral annulus (9.8 ±â€¯0.9 g) locations (p = 0.0036), with greater proportion of sites with <10 g contact force (81.7% vs 60.4%; p = 0.0075). Perceived contact had no impact on measured mean contact force for both mitral and tricuspid annular positions (p = 0.959 and 0.671 respectively). There was correlation of both impedance and atrial electrogram amplitude with contact force, though insufficient to be clinically applicable. CONCLUSION: A high proportion of annular catheter applications have low contact force despite being performed with long vascular sheaths in the hands of experienced operators. In addition, there was no impact of operator perceived contact force on actual measured contact force. This may carry implications for success of AP ablation.

Psychological Distress and Suicidal Ideation in Patients With Atrial Fibrillation: Prevalence and Response to Management Strategy.

Background An association between atrial fibrillation ( AF ), anxiety, and depression is recognized, but the spectrum of psychological distress remains unclear. We aimed to characterize the severity and predictors of distress associated with AF in a tertiary population and its response to AF management. Methods and Results Seventy-eight patients with symptomatic AF underwent evaluation, including of AF symptom severity, health-related quality of life, psychological distress, suicidal ideation, and specific personality traits. Twenty participants underwent AF ablation and 58 were managed medically, with repeat assessments at 4, 8, and 12 months. Severe distress (Hospital Anxiety and Depression Scale score, ≥15/42) was identified in 27 of 78 (35%). Independent predictors were a personality marked by vulnerability to stress (Perceived Stress Scale: R2, 0.54; ß=0.7±0.1; t=7.8; P<0.001) and 1 marked by negativity/social inhibition (Type D Personality Scale: R2, 0.47; ß=0.7±0.1; t=6.7; P<0.001). Suicidal ideation was reported by 16 of 78 (20%) and was predicted by personality traits (Perceived Stress Scale score: R2, 0.35; odds ratio, 1.22±0.06; P<0.001; Type D Personality Scale score: R2, 0.48; odds ratio, 1.43±0.14; P<0.001). Effective AF ablation (median AF burden 1% [0-1%] over 12 months) was associated with significant reductions in distress (Hospital Anxiety and Depression Scale score, 13.9±1.8 to 4.3±1.8; P<0.05) and prevalence of suicidal ideation (30-5%; P=0.02). Conclusions There was a high prevalence of severe psychological distress (35%) and of suicidal ideation (20%) in a tertiary AF population, with personality traits predicting both. Effective AF ablation was associated with significant improvements, suggesting AF itself may be a treatable causative factor of distress.

Ten-year trends in the use of catheter ablation for treatment of atrial fibrillation vs. the use of coronary intervention for the treatment of ischaemic heart disease in Australia.

AIMS: Percutaneous coronary intervention (PCI) and catheter ablation are well-accepted therapeutic interventions for treatment of coronary artery disease and atrial fibrillation (AF), respectively. We sought to examine temporal trends in the provision of these services over the past decade in Australia. METHODS AND RESULTS: A retrospective review of the numbers of PCIs and AF ablations from 2000/01 to 2009/10 was performed on data from three sources: the Australian Institute of Health, Welfare and Aging (AIHW), Medicare Australia database (MA), and local records at a high volume tertiary referral centre (RMH) for AF ablation. Linear regression models were fitted comparing trends in population-adjusted procedural numbers over the 10-year period. There was a 5% per year population-adjusted increment in PCIs over 10 years from both the AIHW and MA sources, respectively (P < 0.001). This was similar to the growth rate of all cardiovascular procedures (AIHW: 5.1 vs. 3.8%/year, P = 0.27). Atrial fibrillation ablations showed a 30.9, 23.2, and 39.8% per year population-adjusted increment over 10 years from the AIHW, MA, and RMH sources respectively (P < 0.001 for all). Growth of AF ablations was significantly higher than PCIs (P < 0.001 for AIHW and MA sources) and all cardiovascular procedures (AIHW: 30.9 vs. 3.8%/year, P < 0.001). CONCLUSION: The provision of catheter-based AF ablation services in Australia has increased exponentially over the past decade. Its annual growth rate exceeded that of PCIs and all cardiovascular procedures. Given the increasing epidemic of AF, these data have critical implications for public health policy assessing the adequacy of infrastructure, training, and funding for AF ablation services.

Usefulness of phased-array intracardiac echocardiography for the assessment of left atrial mechanical "stunning" in atrial flutter and comparison with multiplane transesophageal echocardiography(*).

We compared transesophageal and phased-array intracardiac echocardiography (TEE/ICE) for the 2-dimensional and spectral Doppler assessment of left atrial (LA) mechanical function. TEE is commonly used to assess LA body and LA appendage mechanical function in patients who are undergoing radiofrequency ablation of typical atrial flutter. Fifteen patients underwent TEE and ICE imaging before and after ablation of typical atrial flutter. The following parameters were measured: (1) LA appendage emptying velocity and fractional area change, (2) severity of LA spontaneous echo contrast (graded 0 to 4), (3) maximal inflow velocity of the left and right upper pulmonary veins, and (5) maximal mitral valve E- and A-wave inflow velocities in sinus rhythm. Diagnostic quality imaging was achieved in all patients with TEE and ICE. Comparing TEE and ICE, the following absolute values and linear correlation coefficient (R) were obtained: preablation LA appendage emptying velocity: 0.45 +/- 0.21 versus 0.44 +/- 0.21 m/s (r = 0.95, p = <0.001); postablation LA appendage velocity: 0.33 +/- 0.24 versus 0.34 +/- 0.24 m/s (r = 0.97, p <0.001); LA appendage fractional area change: 35.3 +/- 13.7 versus 35.9 +/- 17.1% (r = 0.81, p <0.001); left upper/right upper pulmonary vein inflow velocity: 0.50 +/- 0.17/0.49 +/- 0.18 versus 0.51 +/- 0.17/0.47 +/- 0.20 m/s (r = 0.93/0.90, p <0.001); mitral valve E/A wave: 0.66 +/- 0.14/0.31 +/- 0.14 versus 0.69 +/- 0.17/0.35 +/- 0.23 (r = 0.84/0.97, p <0.002); LA spontaneous echo contrast (pre- and postablation): 1.1 +/- 1.2/1.3 +/- 1.2 versus 1.2 +/- 1.3/1.4 +/- 1.3 (r = 0.92/0.90, p <0.001). No patients were identified with LA appendage thrombus. Thus, TEE and phased-array ICE provided equivalent imaging data with high statistical correlation. ICE may be an imaging alternative to TEE in the evaluation of a "stunned" left atrium.