Long-term outcomes of cryoballoon pulmonary vein isolation for paroxysmal and persistent atrial fibrillation in Chinese patients.

PURPOSE: We aimed to study the long-term outcomes of cryoballoon (CB) pulmonary vein isolation (PVI) in treating Chinese patients with atrial fibrillation (AF). METHODS: A total of 122 patients (48 women, mean age 57.4 ± 11.3) underwent CB PVI (first generation CB 44.3%, second generation CB 55.7%) for AF (paroxysmal 65.6%, persistent 10.7% and long-standing persistent 23.8%). RESULTS: PVI was achieved in 113 (92.6%) patients with CB alone, and it was achieved in all patients with additional touch-up by 8-mm-tip cryocatheter. The mean procedural and fluoroscopic duration were 171.9 ± 41 and 46.6 ± 14.6 min respectively. The recurrence-free survival for paroxysmal and non-paroxysmal AF was 77% and 59% respectively at 1 year and progressively declined over time to reach a plateau of 52% and 30% for paroxysmal and non-paroxysmal AF respectively at 5 years. In patients undergoing PVI with second-generation CB, the recurrence-free survival was 75% for paroxysmal AF and 45% for non-paroxysmal AF at 5 years. With multivariate Cox regression analysis, the types of CB (use of second-generation CB: HR 0.49; 95% CI 0.28-0.85; p = 0.011) and size of left atrium (LA) (larger LA size: HR 1.52; 95% CI 1-2.14; p = 0.017) independently predicted recurrence. Transient phrenic nerve injury (PNI) occurred in four (3.3%) patients and persistent PNI occurred in four (3.3%) patients. Other complications occurred in 10 (8.2%) patients with no procedure-related death. CONCLUSIONS: Long-term success of CB PVI for AF declined over time and reached a plateau at 5 years. CB types and LA size are independent predictors for long-term recurrence.

A Very Long-term Longitudinal Study on the Evolution and Clinical Outcomes of Persistent Iatrogenic Atrial Septal Defect After Cryoballoon Ablation.

BACKGROUND: Persistent iatrogenic atrial septal defect (iASD) is a common but poorly characterized complication after cryoballoon (CB) pulmonary vein isolation (PVI) procedures. We therefore investigate its prevalence, evolution, risk factors, and clinical outcomes in a prospective longitudinal study. METHODS: A total of 108 patients (41 women, mean age 57 ± 11.3) underwent CB PVI for AF. Serial transesophageal echocardiography (TEE) was performed 9 months and then annually until 6 years after the procedure to study the characteristics of persistent iASD. RESULTS: Persistent iASD occurred in 33 (30.6%) patients 9 months after CB PVI. Spontaneous closure of iASD was found in 6 (22.2%) and 3 (15.8%) patients 2 and 3 years after the procedures, respectively. No spontaneous closure was observed on 4, 5, and 6-year TEE follow-up. The projected long-term persistence rate of iASD after CB PVI was therefore 20% (30.6% × 0.778 × 0.842). Using multivariate logistic regression, a higher number of cryoapplications (≥ 2 minutes) was the only independent predictor of persistent iASD 9 months after CB PVI (odds ratio [OR] 1.207; 95% confidence interval [CI], 1.033-1.411, P = 0.018). Two (1.9%) patients with significantly larger iASD size than the others (long diameter 12.6 ± 0.8 vs 3.7 ± 1.5 mm, P < 0.001; short diameter 10.9 ± 0.2 vs 3 ± 1.1 mm, P < 0.001) required percutaneous closure because of exertional dyspnea and right ventricular enlargement. Over 129.7 patient-years follow-up, during which iASD persisted, there was no occurrence of neurologic events. CONCLUSIONS: Approximately one fifth of patients undergoing CB PVI will have permanently persistent iASD. Patients with defect sizes of greater than 10 mm may need percutaneous closure due to significant left-to-right shunting.

Effectiveness of a nongovernmental organization-led large-scale community atrial fibrillation screening program using the smartphone electrocardiogram: An observational cohort study.

BACKGROUND: Opportunistic screening for atrial fibrillation (AF) in patients older than 65 years is currently recommended. OBJECTIVE: We aim to examine the effectiveness of a nongovernmental organization-led community-based AF screening program carried out by trained layperson volunteers. METHODS: AF screening was performed using a smartphone electrocardiogram in 11,574 participants. RESULTS: Among all participants, smartphone electrocardiograms were interpretable in 10,735 citizens (92.8%; 8564 female citizens [79.8%]; mean age 78.6 ± 8.1 years). Two hundred forty-four participants (2.3%; 95% confidence interval [CI] 2-2.6%; 172 female participants [70.5%]; mean age 79.5 ± 7.9 years) had AF and were advised over phone by a nurse to seek medical attention. Newly diagnosed AF was found in 74 participants (0.69%; 95% CI 0.54-0.84%) with a mean CHA2DS2-VASc score of 3.9 ± 1.5. Thirty-six of them (48%; 95% CI 36.6-59.4%) were asymptomatic. The number needed to screen for 1 newly diagnosed AF was 145. Telephone follow-up of participants with AF was conducted 9 months after screening. Of 72 participants with newly diagnosed AF and indicated for oral anticoagulation, 47 (65.3%; 95% CI 54.3-76.3%) sought medical attention, 17 (23.6%; 95% CI 13.8-33.4%) received oral anticoagulants, and 16 (22.2%; 95% CI 12.6-31.8%) had 100% compliance. The number needed to screen for 1 appropriately treated newly diagnosed AF was 671. CONCLUSION: This nongovernmental organization-led community-based AF screening program is effective in identifying citizens with newly diagnosed AF. However, the effectiveness of the program in subsequently leading them to receive appropriate oral anticoagulation therapy is weakened by the lack of a more structured downstream management pathway.

Screening for atrial fibrillation in 13†122 Hong Kong citizens with smartphone electrocardiogram.

OBJECTIVE: The purpose of this study was to assess the feasibility of community screening for atrial fibrillation (AF) using a smartphone-based wireless single-lead ECG (SL-ECG) and to generate epidemiological data on the prevalence and risk factors of AF in Hong Kong. METHODS: In the period between 1 May 2014 to 30 April 2015, 13 122 Hong Kong citizens consented and voluntarily participated in a territory-wide community-based AF screening programme. RESULTS: 56 (0.4%) out of 13 122 SL-ECG were uninterpretable. 101 (0.8%) participants had newly diagnosed AF, with 66 (65.3%) being asymptomatic. The congestive heart failure, hypertension, age>75(doubled), diabetes, stroke(doubled), vascular disease, age 65-74, sex(female) score (CHA2DS2VASc score) of participants with newly diagnosed AF was 3.1±1.3. The prevalence rates for AF detected by SL-ECG was 1.8% and for AF detected by SL-ECG or self-reported by participants was 8.5%. Using multivariable logistic regression analysis, independent predictors of AF include age, sex, height, weight, body mass index, history of heart failure, valvular heart disease, stroke, hyperlipidaemia, coronary artery disease, peripheral artery disease and cardiothoracic surgery. CONCLUSION: Community screening for AF with SL-ECG was feasible and it identified a significant proportion of citizens with newly diagnosed AF. The prevalence of AF in a Chinese population in Hong Kong was comparable with that of contemporary Western counterparts. Apart from age and sex, different anthropometric parameters and cardiovascular comorbid conditions were identified as independent predictors of AF.

Successful percutaneous retrieval of a dislodged left atrial appendage occlusion device with double transseptal sheaths and biopsy bioptome.

A 64-year-old woman underwent left atrial appendage occlusion with an Amplatzer Cardiac Plug device. Displacement of the device was detected on day 1 with transesophageal echocardiographic checking. The device became dislodged and flitted in the left atrium after unsuccessful retrieval with a snare and 12 Fr steerable transseptal sheath. A double transseptal sheath technique was then attempted. The flitting device was stabilized by one 12 Fr steerable transseptal sheath and successfully retrieved with a biopsy bioptome through another similar transseptal sheath. The patient suffered from no long-term sequelae.

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.

Treatment of atrioventricular nodal re-entrant tachycardia by cryoablation with an 8-mm-tip catheter versus radiofrequency ablation.

PURPOSE: Catheter cryoablation (CRYO) may eliminate inadvertent atrioventricular block (AVB) in the treatment of atrioventricular nodal reentrant tachycardia (AVNRT). However, higher recurrence was observed with CRYO delivered by 4 mm or 6 mm-tip catheter. This study was performed to investigate whether a comparably low treatment failure and recurrence rate as in radiofrequency (RF) ablation is achievable by CRYO with an 8-mm-tip catheter. METHODS: This is a retrospective case-control study including 40 patients with AVNRT treated with CRYO (n = 20) using an 8 mm-tip catheter or RF ablation (n = 20) from March 2009 to March 2011. Treatment failure was defined as the composite of acute procedural failure including inadvertent permanent AVB and documented recurrence. RESULTS: Acute procedural success of 90% (18/20) and 95% (19/20) were achieved in CRYO and RF ablation group, respectively (p = 0.998), with no permanent AVB in either group. With Kaplan-Meier analysis, there was no significant difference between the treatment groups in terms of recurrence rate (5.6% [1/18] vs. 0%; log-rank test p = 0.304) and treatment failure (15% [3/20] vs. 5% [1/20]; log-rank test p = 0.301). Shorter fluoroscopy time (15 ± 8.6 vs. 25.2 ± 12.1 min; p = 0.005) and more energy applications (median 4 [2-15] vs. 2 [1-8]; p = 0.005) were observed in the CRYO group compared with RF ablation group. CONCLUSIONS: Compared to RF ablation, CRYO with an 8-mm-tip catheter for treating AVNRT achieves a comparable acute procedural success, comparably low recurrence rate and composite endpoint of treatment failure. Shorter fluoroscopy time and more energy applications were observed in the CRYO group.

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.

A Chinese patient with severe takotsubo cardiomyopathy.

A 66-year-old woman presented with acute pulmonary edema followed by cardiogenic shock. Emergency left ventriculography demonstrated typical apical ballooning of takotsubo cardiomyopathy. Coronary angiogram and intravascular ultrasonography did not reveal significant coronary artery disease. Within days, the left ventricular systolic function returned to normal.