Experience of left atrial appendage closure performed under conscious sedation.

BACKGROUND: Percutaneous left atrial appendage closure is typically performed with transesophageal echocardiography guidance under general anesthesia. This study was performed to investigate the safety, feasibility, procedural characteristics, and outcomes of performing this procedure under conscious sedation without an anesthetist's support. METHODS: Eleven patients (6 men; mean age 64.6 ± 10.4 years) with atrial fibrillation (median CHA2DS2VASc score 3) underwent transesophageal echocardiography-guided left atrial appendage occlusion under conscious sedation. RESULTS: All patients had successful procedures. Procedural duration and fluoroscopic times were 93.8 ± 25.3 and 16.2 ± 6.5 min, respectively. The doses of midazolam and fentanyl required were 5.4 ± 1.8 mg and 54.5 ± 27 µg, respectively. No complications arose from conscious sedation. Watchman (mean size 29 ± 5 mm) and Amplatzer Cardiac Plug (mean size 24 ± 4 mm) devices were implanted in 5 and 6 patients, respectively. One patient had device displacement due to over-compression on day one, and underwent successful percutaneous retrieval without any long-term sequelae. Warfarin was stopped in all patients after day 45, with transesophageal echocardiography showing optimal device position without a significant jet flow. In a mean follow-up of 12.1 ± 10.1 months, no thromboembolic complications were observed. CONCLUSIONS: Percutaneous left atrial appendage occlusion can be performed safely and effectively under conscious sedation. This approach will significantly reduce the complexity and costs of this increasingly performed procedure.

Left ventricular volumes and systolic function after long-term right ventricular pacing may be predicted by paced QRS duration, but not pacing site.

BACKGROUND: Long-term right ventricular apical (RVA) pacing causes adverse left ventricular (LV) remodelling and clinical outcomes. METHODS: Forty-one patients (19 men, mean age 70.9±14.2, 23 right ventricular septal and 18 RVA pacing) underwent pacemaker implantation for atrioventricular block. LV volumes and left ventricular ejection fraction (LVEF) were assessed by echocardiography 39.3±17.2 months after implantation. Predictors of left ventricular systolic volume (LVESV), left ventricular diastolic volume (LVEDV) and LVEF were analysed. RESULTS: No difference was found between RVA pacing and right ventricular septal pacing groups in LVESV (40.6±22.6 vs 33±14.4ml; p=0.199), LVEDV (88.2±31.2 vs 73.7±23.9ml; p=0.102) and LVEF (56.1±8.6 vs 56±6.6%; p=0.996). With multivariate stepwise regression, only pQRSd and renal impairment independently predicted LVESV (ß=0.522, 95% CI: 0.242-0.802; p=0.001 and ß=40.3, 95% CI: 17.6-62.9; p=0.001 respectively), LVEDV (ß=0.786, 95% CI: 0.338-1.235; p=0.001 and ß=42.8, 95% CI: 6.6-79; p=0.022 respectively) and LVEF (ß=-0.161, 95% CI: -0.283 to -0.04; p=0.011 and ß=-14.8, 95% CI: -24.6 to -5.0; p=0.004 respectively). CONCLUSIONS: pQRSd and renal impairment, but not pacing site or baseline LVEF, may be predictors for LV volumes and systolic function after long-term RV pacing. pQRSd may be target for pacing site optimisation.

Inner lumen mapping catheter-facilitated big cryoballoon treatment for atrial fibrillation shortens procedural duration and fluoroscopic exposure with comparable mid-term efficacy.

PURPOSE: This study aims to investigate whether the use of a novel inner lumen circular mapping catheter (IMC) can shorten the procedural duration and fluoroscopic exposure of the single transseptal big cryoballoon (CB) pulmonary vein isolation (PVI) procedures in patients with atrial fibrillation (AF). METHODS: This is a prospective non-randomized case-control study. Forty-two patients (28 men, mean age 55.7 ± 12.1) with drug-refractory paroxysmal or persistent AF and underwent CB PVI procedures were divided into Group A (conventional single transseptal big CB approach, n = 21) and Group B (IMC-facilitated approach, n = 21). They were compared in the co-primary endpoints: (1) procedural duration and (2) fluoroscopic exposure and secondary endpoints: (1) 6-month AF-free survival and (2) number of cryo-applications. RESULTS: Both the procedural duration (162 ± 26 vs. 215 ± 25 min; p < 0.001) and fluoroscopic exposure (44.1 ± 10.4 vs. 56.8 ± 11.7 min; p = 0.001) were significantly shorter in Group B than Group A patients. With multivariate stepwise regression, only the use of IMC was an independent predictor for procedural duration (ß = -59; 95 % CI, -84.1 to -33.8; p < 0.001) and fluoroscopic exposure (ß = -16.9; 95 % CI, -28.4 to -5.4; p = 0.006). The number of cryo-applications was significantly fewer in Group B than Group A patients (median 8 vs. 11; p = 0.001). There was no significant difference in the 6-month AF-free survival between the two approaches (57 % vs. 71 %; p = 0.351). CONCLUSIONS: Compared to conventional single transseptal big CB PVI procedures, the use of IMC may reduce procedural duration, fluoroscopic exposure and the number of cryo-applications with comparable mid-term efficacy.

Utility of a novel pacing guidewire in pre-implantation testing at different left ventricular sites in cardiac resynchronization therapy procedures.

PURPOSE: This study aimed to evaluate the utility of a novel pacing guidewire in pre-implantation testing of different left ventricular (LV) sites during cardiac resynchronization therapy (CRT) procedures. METHODS: Ten consecutive patients (8 male, mean age 65.8 ± 4.9) undergoing CRT procedures were studied. Pacing threshold and R-wave sensing measured by the guidewire and LV lead at different LV sites were compared. RESULTS: Thirty sites (6 apical, 13 middle, and 11 basal; 15 lateral and 15 anterior) were tested. There was significant correlation between pacing threshold (r = 0.878, p < 0.0001), and R-wave sensing (r = 0.896, p < 0.0001) obtained by guidewire and those obtained by LV lead. Separating into lateral and anterior sites, significant correlation was also found in pacing threshold (lateral r = 0.658, p = 0.008; anterior r = 0.886, p < 0.0001) and R-wave sensing (lateral r = 0.887, p < 0.0001; anterior 0.865, p < 0.0001). For basal and middle sites, significant correlation was found in pacing threshold (basal r = 0.890, p < 0.0001; middle r = 0.878, p < 0.0001), and R-wave sensing (basal r = 0.930, p < 0.0001; middle r = 0.823, p < 0.001). No and borderline correlation was found in pacing threshold (r = 0.548, p = 0.26) and R-wave sensing (r = 0.835, p = 0.039), respectively, for apical sites. Concordance rate for the presence of phrenic nerve stimulation at high pacing output was 87%. CONCLUSION: The accuracy of the novel pacing guidewire in pre-implantation testing in CRT procedures is site-dependent. There was good correlation with LV lead in the measurement of pacing threshold and R-wave sensing at basal and middle sites, but not apical sites. Presence of phrenic nerve stimulation can be predicted by guidewire testing with high accuracy.

Persistent iatrogenic atrial septal defect after pulmonary vein isolation by cryoballoon: an under-recognized complication.

AIMS: Iatrogenic atrial septal defect (IASD) has been reported as a complication of transseptal puncture. This study aims to investigate the incidence, echocardiographic characteristics, and clinical outcome of persistent IASD after pulmonary vein isolation (PVI) by cryoballoon catheter delivered by a large transseptal sheath. METHODS AND RESULTS: Thirteen patients (9 males, mean age 54.9 ± 13.0) with paroxysmal (10) or persistent (3) atrial fibrillation underwent PVI with cryoballoon catheter. Single transseptal puncture was performed with a BRK-1 shaped Brockenbrough needle and an 8 F sheath which was exchanged for a steerable transseptal sheath (15 F outer diameter and 12 F inner diameter) with the support of a stiff guidewire. Pulmonary vein isolation was performed with a 28 mm cryoballoon catheter. The incidence of persistent IASD was evaluated by transoesophageal echocardiography performed at 6 and 9 months after the procedure. At 6 months, five (38%) patients had persistent IASD with left-to-right shunt. The mean size of the IASD was 5.5 ± 2.4 mm. At 9 months, one patient had closure of the IASD and four (31%) patients had persistent IASD with mean size of 4.6 ± 1.4 mm. No patient died or suffered clinically from paradoxical embolism. CONCLUSIONS: Persistent IASD is a common complication after PVI by cryoballoon catheter. Only left-to-right, but not right-to-left, interatrial shunting occurred as a result of the IASD. There was no clinical occurrence of paradoxical embolism. Patients should be screened for this complication after cryoballoon procedures and regular reassessment with echocardiographic or other techniques should be performed for monitoring.

Cryoablation versus radiofrequency ablation for atrioventricular nodal reentrant tachycardia: patient pain perception and operator stress.

BACKGROUND: Cryoablation (CRYO) is an alternative to radiofrequency (RF) ablation in the treatment of atrioventricular nodal reentrant tachycardia (AVNRT). This study aims to evaluate the differences in patient pain perception and operator stress between CRYO and RF ablation in the treatment of AVNRT. METHODS: Patients with supraventricular tachycardia underwent electrophysiology study. Twenty patients (eight males, age 46.5 ± 12.5 years) diagnosed with AVNRT were randomized to receive CRYO (11) with a 6-mm-tip catheter or RF (nine) with a 4-mm-tip catheter. Patients' pain perception and operator stress were assessed with a visual analogue scale (VAS) from 0 to 10 at the end of procedure. RESULTS: There was no significant difference in acute procedural success (CRYO 100% vs RF 89%, P = 0.257). There was no complication of permanent atrioventricular block in either group. The number of energy applications was significantly higher in the CRYO group (2.8 ± 1.2 vs 1.6 ± 0.9, P = 0.02). The fluoroscopic time was significantly reduced in the CRYO group (6.0 ± 4.9 vs 10.9 ± 5.4 minutes, P = 0.049) with no difference in procedure time (CRYO 49.3 ± 12.5 vs RF 54.5 ± 17.0 minutes, P = 0.462). Patients in the CRYO group experienced significantly less pain than patients in the RF group (VAS 2.3 ± 2.8 vs 5.4 ± 3.4, P = 0.024). The operator also experienced significantly less stress during CRYO than RF (VAS 1.9 ± 0.8 vs 6.2 ± 1.6, P < 0.001). There was no recurrence in both groups at 6-month follow-up. CONCLUSIONS: CRYO, as compared with RF, produces less pain in patients and less stress in operator in the treatment of AVNRT.

Echocardiographic mapping of left ventricular resynchronization during cardiac resynchronization therapy procedures.

BACKGROUND: Cardiac resynchronization therapy (CRT) is an effective electrical therapy for patients with moderate to severe heart failure and cardiac dyssynchrony. This study aimed to investigate the degree of acute left ventricular (LV) resynchronization with biventricular pacing (BVP) at different LV sites and to examine the feasibility of performing transthoracic echocardiography (TTE) to quantify acute LV resynchronization during CRT procedure. METHODS: Fourteen patients with NYHA Class III-IV heart failure, LV ejection fraction < or = 35%, QRS duration > or = 120 ms and septal-lateral delay (SLD) > or = 60 ms on tissue Doppler imaging (TDI), underwent CRT implant. TDI was obtained from three apical views during BVP at each accessible LV site and SLD during BVP was derived. Synchronicity gain index (Sg) by SLD was defined as (1 + (SLD at baseline--SLD at BVP)/SLD at baseline). RESULTS: Seventy-two sites were studied. Positive resynchronization (R+, Sg > 1) was found in 42 (58%) sites. R+ was more likely in posterior or lateral than anterior LV sites (66% vs. 36%, P < 0.001). Concordance of empirical LV lead implantation sites and sites with R+ was 50% (7/14). CONCLUSIONS: The degree of acute LV resynchronization by BVP depends on LV lead location and empirical implantation of LV lead results in only 50% concordance with R+. Performing TTE during CRT implantation is feasible to identify LV sites with positive resynchronization.

Treatment of atrioventricular nodal re-entrant tachycardia by cryoablation with a 6 mm-tip catheter vs. radiofrequency ablation.

AIMS: To compare recurrence rate and other procedural characteristics in patients undergoing atrioventricular nodal re-entrant tachycardia (AVNRT) treatment with catheter cryoablation (CRYO) delivered by 6 mm-tip catheter or radiofrequency (RF) ablation. METHODS AND RESULTS: This is a retrospective case-control study including 80 patients with AVNRT treated with CRYO from March 2002 to June 2008. They were compared with another 80 consecutive patients who underwent RF ablation for AVNRT within the same period. Procedural success of 97.5 and 95% were achieved in CRYO and RF group, respectively. There was no permanent atrioventricular block (AVB) in the CRYO group, whereas two (2.5%) patients developed permanent first-degree or second-degree AVB in RF group (P = 0.155). Higher recurrence was found in the CRYO group (9 vs. 1.3%; P = 0.032) with no difference in the composite endpoint of procedural failure and recurrence between the groups (P = 0.263). There was significantly shorter fluoroscopy time (18.6 +/- 10.8 vs. 25.9 +/- 17.0 min; P = 0.002) and more energy applications required (3.1 +/- 1.7 vs. 1.9 +/- 1.1; P < 0.001) in the CRYO than the RF group. CONCLUSION: Compared with RF ablation, CRYO with 6 mm-tip catheter for treating AVNRT results in higher recurrence and potentially lower incidence of permanent AVB. Fluoroscopy time has been shown to be reduced by CRYO.

Impacted left ventricular lead technique in cardiac resynchronization therapy.

Left ventricular (LV) lead dislodgement is a significant problem in cardiac resynchronization therapy and re-operation is required to rectify the situation. In this case report, we describe a new technique to stabilize an LV lead which is prone to dislodgement by impacting an inactive LV lead in the same cardiac vein.

Ketoconazole induced torsades de pointes without concomitant use of QT interval-prolonging drug.

Ketoconazole is not known to be proarrhythmic without concomitant use of QT interval-prolonging drugs. We report a woman with coronary artery disease who developed a markedly prolonged QT interval and torsades de pointes (TdP) after taking ketoconazole for treatment of fungal infection. Her QT interval returned to normal upon withdrawal of ketoconazole. Genetic study did not find any mutation in her genes that encode cardiac IKr channel proteins. We postulate that by virtue of its direct blocking action on IKr, ketoconazole alone may prolong QT interval and induce TdP. This calls for attention when ketoconazole is administered to patients with risk factors for acquired long QT syndrome.