We tested application of a grading system describing complex fractionated electrograms (CFE) in atrial fibrillation (AF) and used it to validate automated CFE detection (AUTO).
Ten seconds bipolar electrograms were classified by visual inspection (VI) during ablation of persistent AF and the result compared with offline manual measurement (MM) by a second blinded operator: Grade 1 uninterrupted fractionated activity (defined as segments ≥70 ms) for ≥70% of recording and uninterrupted ≥1 s; Grade 2 interrupted fractionated activity ≥70% of recording; Grade 3 intermittent fractionated activity 30–70%; Grade 4 discrete (<70 ms) complex electrogram (≥5 direction changes); Grade 5 discrete simple electrograms (≤4 direction changes); Grade 6 scar. Grade by VI and MM for 100 electrograms agreed in 89%. Five hundred electrograms were graded on Carto and NavX by VI to validate AUTO in (i) detection of CFE (grades 1–4 considered CFE), and (ii) assessing degree of fractionation by correlating grade and score by AUTO (data shown as sensitivity, specificity, r): NavX ‘CFE mean’ 92%, 91%, 0.56; Carto ‘interval confidence level’ using factory settings 89%, 62%, –0.72, and other published settings 80%, 74%, –0.65; Carto ‘shortest confidence interval’ 74%, 70%, 0.43; Carto ‘average confidence interval’ 86%, 66%, 0.53.
Grading CFE by VI is accurate and correlates with AUTO.
It is unclear how the amplitude of bipolar electrogram relates to the local conduction velocity (CV) in patients with atrial fibrillation (AF). For 50 AF patients (paroxysmal/persistent AF: 40/10 patients), contact bipolar voltage maps of the left atrium (LA) were constructed during sinus rhythm using EnSite version 6.0J in a point-by-point recording fashion. Patients were divided into Groups A (n = 16), B (n = 19), and C (n = 15) according to the level of the lowest electrogram amplitudes: <0.5, 0.5–0.75, and 0.75–1.0 mV, respectively. Low-voltage zone (LVZ) was defined separately for these groups as a bipolar electrogram amplitude of <0.5, 0.5–0.75, and 0.75–1.0 mV, respectively. The local CV through the LVZ and non-LVZ was calculated along the direction of local activation within each zone for all groups.
Low-voltage zone was consistently found at the septal, anterior, and posterior LA in all groups. In Group A, CV through the LVZ was significantly slower compared with the non-LVZ (0.8 ± 0.5 vs. 1.4 ± 0.6 m/s, P = 0.004), but those through the LVZ and non-LVZ were similar in Group B (1.2 ± 0.5 vs. 1.3 ± 0.5 m/s, P = 0.07) and Group C (1.5 ± 0.5 vs. 1.4 ± 0.6 m/s, P = 0.79). The percentage of points showing fractionated or double potentials in the LVZ was significantly more in Group A (76/293 points, 26%) than in Group B (11/185 points, 6%), and Group C (7/135 points, 5%) (P < 0.0001 and P < 0.0001, respectively).
There was a significant slowing of local conduction in the LVZ defined as <0.5 mV and was frequently associated with fractionated or double potentials in patients with AF.
Cryothermal energy balloon ablation (CBA), using cryogenic ablative energy, has proven very effective in producing pulmonary vein (PV) isolation in patients with paroxysmal atrial fibrillation (AF). Adenosine testing after PV isolation has demonstrated to be able to unmask incomplete lesion after radiofrequency (RF) ablation. The aim of our study was to assess the rate of transient atriovenous reconnection induced by adenosine after successful PV isolation with the CBA in a group of patients with paroxysmal AF.
We prospectively enrolled 39 patients (31 male; age 59 ± 11 years) elected to circumferential PV isolation with CBA for highly symptomatic paroxysmal AF. A total of 149 PVs were evidenced. Adenosine testing after CBA induced a left atrium–PV reconnection only in 7 (4.6%) of PV.
Our study showed a low rate of transient PV reconnection after adenosine infusion following successful PV isolation with CBA. However, larger studies will be needed in order to confirm our findings and the prognostic value of adenosine testing after successful PV isolation obtained with CBA.
This study examined the difference in autonomic modification (AM) and its effect on paroxysmal atrial fibrillation (PAF) recurrence between segmental pulmonary vein isolation (S-PVI) and circumferential PVI (C-PVI).
Successful S-PVI or C-PVI with a basket catheter was achieved in 120 consecutive PAF patients. Serial 24 Holter-recordings were obtained before, immediately, and 1, 3, 6, 12 months after the PVI to analyse the heart rate variability (HRV). Nineteen patients were excluded from analysis because of additional ablation for recurrent PAF after successful PVI. Among the residual 101 patients, 33 had PAF recurrences (S-PVI = 44.0%, C-PVI = 21.6%) at 1 year of follow-up. The root mean square of successive differences and high-frequency power reflecting parasympathetic nervous activity were significantly lower in patients with and without PAF recurrences after C-PVI and patients without PAF recurrences after S-PVI than patients with PAF recurrences after S-PVI (P < 0.005–0.0001). However, there were no significant differences in any HRV parameters in the immediate aftermath of PVI among the patients without PAF recurrences after S-PVI and those with and without PAF recurrences after C-PVI.
Although additional radiofrequency ablation for AM may be recommended after S-PVI to reduce PAF recurrences, it should be carefully determined after C-PVI.
Bepridil is highly effective in terminating persistent atrial fibrillation (AF). Despite continued treatment, a high rate of AF recurrence after pharmacological cardioversion (PC) with bepridil has been reported. Bepridil therapy is also associated with significant adverse effects.
This retrospective case–control study included 82 patients with persistent AF (PEF). Group 1 (22 patients) comprised cases undergoing AF ablation following attempted PC with bepridil. Group 2 (60 patients) comprised control that underwent AF ablation without bepridil pre-treatment. In Group 1, 15 patients (68%) restored sinus rhythm (SR) with bepridil (SR group) and 7 continued to have AF (AF group). SR group underwent extensive pulmonary vein isolation (EPVI) alone. AF group and Group 2 underwent linear ablation after EPVI, if AF was inducible. At the end of 18 ± 5 months off antiarrhythmic drugs, the AF-free rate was 87% in SR group, 29% in AF group, and 72% in Group 2 (72 vs. 29%, P = 0.02).
Following AF ablation in patients who successfully restored SR with bepridil pre-treatment, AF-free rate was significantly higher than in those who failed to do so. Conversion to SR with bepridil might help select the optimal patients with PEF for catheter ablation.
Transvenous pulmonary vein isolation (PVI) is the cornerstone of non-pharmacological rhythm control therapy in symptomatic atrial fibrillation (AF). Success and complications rates are, however, still not optimal. New techniques and energy sources are therefore being developed.
Fifteen patients with lone AF refractory for antiarrhythmic drugs (AADs) underwent PVI by minimal invasive epicardial off-pump monolateral right-sided video-assisted thoracic surgery (VATS) using the UltraCinch with high-intensity focused ultrasound (HIFU). Primary endpoint was successful ablation defined as absence of AF or atrial flutter/tachycardia after 6 months assessed by complaints, 12 lead electrocardiogram, and 96 h Holter monitoring. Secondary endpoints were ablation success at the end of follow-up irrespective of AADs use or re-ablation and complications related to the procedure. Mean age was 47 ± 10 years and 14 (93%) were male. Eleven (73%) had paroxysmal, and 4 (27%) patients had persistent AF. Median AF history was 5 (1–12) years. At 6 months, six (40%) patients had sinus rhythm after one epicardial PVI (four on AADs). After 1.3 ± 0.6 years, four (27%) patients had sinus rhythm after one epicardial PVI (two on AADs) and in six (40%) patients endocardial radiofrequency re-ablation was performed, which was successful in three patients (20%). Two patients (13%) were planned for re-ablation. Three others (20%) refused re-ablation. Two major complications occurred (one late tamponade and one bleeding during surgery, necessitating sternotomy).
Epicardial PVI using monolateral right-sided VATS with the UltraCinch delivering HIFU is feasible, but is associated with substantial complications. Furthermore, the success rate was low. More research is therefore warranted to assess optimal ablation techniques and energy sources to perform PVI.
clinicaltrials.gov Identifier: NCT00448656.
Although electrical cardioversion (CV) is effective in restoring sinus rhythm in patients with atrial fibrillation (AF), AF frequently recurs in spite of antiarrhythmic medications. We investigated the predictors of failed CV and AF recurrence after successful CV.
In 81 patients (M:F = 63:18, 59.1 ± 10.5 years old) with AF who underwent CV, clinical, image, and CV findings (energy requirement, immediate recurrence of AF < 15 min), and pre-CV serological markers were evaluated. Results: (i) During 13.1 ± 10.6 months of follow-up, 8.6% (7/81) showed failed CV, 59.26% (48/81) showed AF recurrence, and 32.1% (26/81) remained in sinus rhythm (no recurrence). (ii) Failed CV showed higher plasma levels of transforming growth factor (TGF)-β (P = 0.0260) than those with successful CV. (iii) Patients with AF recurrence were older (60.4 ± 9.0 years old vs. 55.3 ± 12.5years old, P = 0.0220), had a higher incidence of spontaneous echo contrast (SEC; 68.1 vs. 40.0%, P = 0.0106), a lower prescription rate of angiotensin-converting enzyme inhibitor (ACE-I)/angiotensin receptor blocker (ARB; 27.0 vs. 50.0%, P = 0.0248) or spironolactone (0.0 vs. 19.2%, P = 0.0007), and lower plasma levels of stromal cell-derived factor (SDF)-1 (P = 0.0105).
Post-CV recurrence commonly occurs in patients with age >60 years, SEC, under-utilization of ACE-I/ARB or spironolactone, and low plasma levels of SDF-1. High plasma level of TGF-β predicts failed CV.
Estimates of the left ventricular ejection fraction (LVEF) in patients with life-threatening ventricular arrhythmias related to coronary artery disease (CAD) have rarely been reported despite it has become the basis for determining patient's eligibility for prophylactic defibrillator. We aimed to determine the extent and distribution of reduced LVEF in patients with sustained ventricular tachycardia or ventricular fibrillation.
252 patients admitted for ventricular arrhythmia related to CAD were included: 149 had acute myocardial infarction (MI) (Group I, 59%), 54 had significant chronic obstructive CAD suggestive of an ischaemic arrhythmic trigger (Group II, 21%) and 49 patients had an old MI without residual ischaemia (Group III, 19%). 34% of the patients with scar-related arrhythmias had an LVEF ≥40%. Based on pre-event LVEF evaluation, it can be estimated that less than one quarter of the whole study population had a known chronic MI with severely reduced LVEF. In Group III, the proportion of inferior MI was significantly higher than anterior MI (81 vs. 19%; absolute difference, –62; 95% confidence interval, –45 to –79; P ≤ 0.0001), though median LVEF was higher in inferior MI (0.37 ± 10 vs. 0.29 ± 10; P = 0.0499).
Patients included in defibrillator trials represent only a minority of the patients at risk of sudden cardiac death. By applying the current risk stratification strategy based on LVEF, more than one third of the patients with old MI would not have qualified for a prophylactic defibrillator. Our study also suggests that inferior scars may be more prone to ventricular arrhythmia compared to anterior scars.
This retrospective analysis sought to develop and validate a model using the measured diagnostic variables in cardiac resynchronization therapy (CRT) devices to predict mortality.
Data used in this analysis came from two CRT studies: Cardiac Resynchronization Therapy Registry Evaluating Patient Response with RENEWAL Family Devices (CRT RENEWAL) (n = 436) and Heart Failure-Heart Rate Variability (HF-HRV) (n = 838). Patients from CRT RENEWAL were used to create a model for risk of death using logistic regression and to create a scoring system that could be used to predict mortality. Results of both the logistic regression and the clinical risk score were validated in a cohort of patients from the HF-HRV study. Diagnostics significantly improved over time post-CRT implant (all P < 0.001) and were correlated with a trend of decreased risk of death. The regression model classified CRT RENEWAL patients into low (2.8%), moderate (6.9%), and high (13.8%) risk of death based on tertiles of their model predicted risk. The clinical risk score classified CRT RENEWAL patients into low (2.8%), moderate (10.1%), and high (13.4%) risk of death based on tertiles of their score. When both the regression model and the clinical risk score were applied to the HF-HRV study, each was able to classify patients into appropriate levels of risk.
Device diagnostics may be used to create models that predict the risk of death.
To analyse left ventricular (LV) synchrony and function with respect to the epicardial pacing site in the young.
Left ventricular function and synchrony (M-mode, speckle tracking) were evaluated during mid-term follow-up in 32 children with complete non-surgical (n = 15) or surgical (n = 17) atrioventricular block (structural heart disease in 21/32) paced from LV apex (n = 19), right ventricular (RV) apex (n = 7), and RV free wall (n = 6), respectively. Data are in the following order: LV apical, RV apical, and RV free wall pacing. Septal to posterior wall motion delay (SPWMD) = median 0, 69, and 136 ms (P < 0.001), septal to lateral mechanical delay = 54 ± 29, 73 ± 24, and 129 ± 70 ms (P = 0.001), apical to basal mechanical delay = 96 ± 37, 106 ± 50, and 79 ± 18 ms (P NS), and LV ejection fraction (LVEF) = 57 ± 9, 49 ± 12, and 33 ± 10% (P < 0.001), respectively. Left ventricular ejection fraction correlated negatively with SPWMD (R2 = 0.454, P < 0.001) and septal to lateral mechanical delay (R2 = 0.320, P < 0.001) but not with apical to basal mechanical delay. Right ventricular free wall pacing (P = 0.014) and SPWMD (P = 0.044) were negative multivariable predictors of LVEF.
Compared with other sites, LV apical pacing preserves septal to lateral LV synchrony and systolic function and may be the preferred epicardial pacing site in the young.
The immediate effects of electric remodelling on the left ventricular (LV) function by dual-chamber pacemakers remain unknown. The purpose of our study was to assess the interaction between heart rates and right ventricular pacing (VP) on LV contractility and diastolic function.
Twenty-five patients with dual-chamber pacemakers and sick sinus syndrome were evaluated. Echocardiographic examinations included standard and tissue-Doppler echocardiography at bilateral mitral annulus margins under either the intrinsic atrio-ventricular sequential conduction (ventricular sensing; VS) mode or right ventricular apical pacing (VP) mode. Under either mode, we accelerated the pacing rate at an increment of 15 b.p.m. step-by-step from 60 to 90/min. The tissue-Doppler echocardiography of mitral annulus showed that under the VS status, accelerating atrial pacing rate from 60 to 90 b.p.m. enhanced A'-wave velocity (P less double equals 0.002), whereas no significant change of LV ejection fraction (LVEF) and E'-wave velocity were noted. Under the VP status, acceleration of pacing rates exerted no effect on the LVEF, E'-, and A'-wave (P = NS). While shifting the pacemaker mode from VS to VP, the E'-wave velocity (P less double equals 0.002) and E'/A' ratio decreased significantly (P less double equals 0.001). The A'-wave velocity also increased significantly during shifting to VP mode at 60 b.p.m. (P less double equals 0.004).
At fixed pacing rates, shifting from VS to VP mode impaired LV diastolic function immediately with preserved LV contractility. The acceleration of heart rate impaired LV diastolic function under VS mode.
Non-invasive cardiac output monitoring (NICOM) based on bio-reactance offers a portable method to assess ventricular function. Optimization of cardiac resynchronization therapy (CRT) by echocardiography is labour-intensive. We compared the ability of NICOM and echocardiography to facilitate optimum CRT device programming.
Forty-seven patients in sinus rhythm were evaluated within 14 days of CRT implantation. The atrio- (AV) and interventricular (VV) delay intervals were incrementally adjusted and at each setting, NICOM and echocardiographic data were recorded. Left ventricular (LV) volumes and function were assessed by echocardiography at baseline and 3 months. Response to CRT was defined as a reduction in LV end-systolic volume (LVESV) by >15%. In all patients, cardiac output (CO) increased significantly at optimized settings compared with baseline (5.66 ± 1.4 vs. 4.35 ± 1.1 L/min, P < 0.001). A 20% increase in acute CO following CRT predicted LVESV reduction of >15% with a sensitivity of 81% and specificity of 92% (AUC 0.86). The optimum AV delay determined by NICOM was confirmed by echocardiography in 40 of 47 patients (85%, r = 0.89, P < 0.01) and for VV delay in 39 of 47 patients (83%, r = 0.89, P < 0.01).
Non-invasive cardiac output monitoring is a simple, reliable, and portable alternative to echocardiography to program CRT devices.
Some authors recommend avoiding fusion with left ventricular (LV) intrinsic depolarization during cardiac resynchronization therapy (CRT). If fusion is still present during optimized biventricular (Biv) pacing and its long-term effects on the response to CRT are currently unknown. The aim of the study was to analyse the endocardial LV activation pattern induced by echocardiographically optimized Biv pacing and its influence on LV reverse remodelling.
Contact electro-anatomical mapping was performed in 15 heart failure (HF) patients with left bundle branch block and echocardiographically optimized CRT (seven ischaemic aetiology, 64 ± 8 years, three women, New York Heart Association class 3 ± 0.4, LV ejection fraction 25 ± 5%). Left ventricular activation maps were performed in sinus rhythm (SR), during DDD right ventricular apical (RVA) and optimized Biv pacing. Fusion with intrinsic rhythm during pacing was considered when LV septal activation was produced at least partially by intrinsic depolarization, when compared with LV activation map during SR. Patients were considered responders to CRT if they had ≥10% reduction in LV end-systolic volume (LVESV) after 6 months of CRT. During SR, the LV breakthrough was mid-septal (n = 12), basal septum (n = 2), and apical (n = 1). During RVA pacing, LV breakthrough shifted apical in all patients. Right ventricular apical/Biv pacing proved fusion with intrinsic depolarization in 8 of 15 patients. The PR interval was shorter in patients with fusion RVA/Biv pacing (164 ± 24 vs. 234 ± 55 ms, P = 0.006). There was a trend for shorter LV activation time (LVat) in patients with fusion during RVA pacing (87 ± 33 vs. 113 ± 21 ms, P = 0.08) as well as during optimized Biv pacing (83 ± 18 vs. 104 ± 24 ms, P = 0.07), although LVat was similar in SR (100 ± 22 vs. 106 ± 20, P = NS). In patients with fusion, 6 months responder rate was significantly higher (100 vs. 28.5%, P < 0.007) as was the degree of LVESV reduction (39 ± 17 vs. 1.0 ± 14%, P < 0.001).
Biventricular pacing with fusion may substantially increase the structural responder rate probably by shortening LVat.
The purpose of the current study is to evaluate the patients’ entrance skin dose (ESD) during cardiac resynchronization therapy (CRT).
Entrance skin doses were assessed during 16 CRT procedures. Seven of the 16 patients were upgrade of conventional pacemaker to CRT. The patients wore jackets which had 100 radiosensitive indicators placed on the back during the procedures. After the procedure, the patients’ ESDs were calculated from the colour difference of the indicators. Eleven of the 16 patients were implanted devices with a defibrillator, and three patients those without a defibrillator. In the other two, the procedures failed. The average total fluoroscopic time (TFT), total numbers of cine frames, and the maximum ESDs were 56.7 ± 28.0 min, 674 ± 342 frames, and 1.0 ± 0.6 Gy, respectively. Of the 16 patients, six received ESDs exceeding 1 Gy, TFT, total number of cine frames, and the maximum ESD tended to decrease as the operator experience increased.
The patients’ ESDs during CRT procedures can exceed the thresholds for radiation skin injuries due to prolonged fluoroscopic times. Therefore, interventionalists should estimate the doses.
Congenital left ventricular aneurysm (LVA) and diverticulum (LVD) are rare cardiac anomalies and can be associated with ECG abnormalities and rhythm disturbances. We sought to investigate the prevalence and the spectrum of ECG abnormalities in such patients.
We assessed 125 patients with isolated LVA or LVD for the prevalence of ECG abnormalities and compared the findings to an age- and gender-matched control group. The 12-lead ECG patterns were evaluated according to commonly used criteria and were classified into three subgroups (distinct, mildly, and minor). Fifty-four of the 125 patients (43.2%) had normal and 71 (56.8%) abnormal ECGs. Mean age was 66 years. Forty-nine (39.2%) were male. Distinct abnormal ECG patterns were more prevalent in patients with LVD (38.2 vs. 15.8%, P = 0.04), and apical location of the anomaly (36.6 vs. 16.6%, P = 0.02). Older age (>66 years) was associated with a trend for a higher prevalence of abnormal ECG pattern (33 vs. 18%, P = 0.06), whereas gender had no influence (32 vs. 16%, P = 0.14). This study also shows that the sensitivity, specificity, positive predictive value and negative predictive value of a 12-lead ECG for the diagnosis of LVA or LVD are low.
This large single-centre study suggests that the prevalence of abnormal ECG patterns in patients with isolated LVA or LVD is as high as 56.8%. However, ECG is not specific and sensitive to be used as a screening tool in such patients.
During head-up tilt (HUT) testing, a period of haemodynamic instability, marked by oscillations in blood pressure, often precedes vasovagal syncope. We hypothesized that the presence of oscillations in blood pressure during HUT testing predicts a positive diagnosis for vasovagal syncope.
The haemodynamic profiles of 42 consecutive patients non-responsive to passive HUT and glyceryl trinitrate (GTN) provocation (‘non-responders’) and, contemporaneously, 41 consecutive patients responsive to passive HUT and GTN provocation (‘responders’) were assigned oscillation-positive or oscillation-negative depending on the presence or absence of a characteristic oscillation in systolic blood pressure which varied by ≥30 mmHg (peak-to-trough). All the non-responders proceeded to an isoprenaline (Iso) challenge test. Of the 42 non-responders, 27 patients were Iso tilt-positive; all of these patients were assigned oscillation-positive. The other 15 non-responders were Iso tilt-negative; of these 9 were assigned oscillation-positive and 6 were assigned oscillation-negative. Of the 41 responder patients, 33 were assigned oscillation-positive, whereas 8 were assigned oscillation-negative. Overall, the presence of oscillations as a diagnostic predictor for vasovagal syncope had a sensitivity of 88% (positive predictive value of 87%) and a specificity of 40% (negative predictive value of 43%).
In patients non-responsive to passive HUT and GTN provocation, the presence of an oscillating systolic blood pressure varying ≥30 mmHg may still indicate a diagnosis of vasovagal syncope, possibly obviating the need for Iso testing.