Additional complex fractionated atrial electrogram ablation does not improve the outcomes of non-paroxysmal atrial fibrillation: A systematic review and meta-analysis of randomized controlled trials

BackgroundNon-paroxysmal atrial fibrillation (AF) has a complex pathophysiological process. The standard catheter ablation approach is pulmonary vein isolation (PVI). The additional value of complex fractionated electrogram (CFAE) ablation is still unclear. We aimed to investigate the additional value of CFAE ablation for non-paroxysmal AF.MethodsWe performed a systematic review and meta-analysis of randomized controlled studies up to May 2020. Articles comparing pulmonary vein isolation (PVI) plus CFAE ablation and PVI alone for AF were obtained from the electronic scientific databases. The pooled mean difference (MD) and pooled risk ratio (RR) were assessed.ResultsA total of 8 randomized controlled trials (RCTs) including 1034 patients were involved. Following a single catheter ablation procedure, the presence of any atrial tachyarrhythmia (ATA) with or without the use of antiarrhythmic drugs (AADs) between both groups were not significantly different (RR = 1.1; 95% confidence interval [CI] = 0.97–1.24; p = 0.13). Similar results were also obtained for the presence of any ATA without the use of AADs (RR = 1.08; 95% CI = 0.96–1.22; p = 0.2). The additional CFAE ablation took longer procedure times (MD = 46.95 min; 95% CI = 38.27–55.63; p = < 0.01) and fluoroscopy times (MD = 11.69 min; 95% CI = 8.54–14.83; p = < 0.01).ConclusionAdditional CFAE ablation failed to improve the outcomes of non-paroxysmal AF patients. It also requires a longer duration of procedure times and fluoroscopy times.     

Functional characterization of the crista terminalis in patients with atrial flutter: implications for radiofrequency ablation

OBJECTIVES: The aim of the study was to investigate the conduction properties and anisotropy of the crista terminalis (CT) in patients with atrial flutter (AFL) using non-contact mapping. BACKGROUND: The CT is a posterior barrier during typical AFL. However, the CT has transverse conduction capabilities in patients with upper loop re-entry (ULR). METHODS: Twenty-two patients (16 males, 63 +/- 15 years) with typical AFL and ULR were included. Non-contact mapping of the right atrium during AFL and pacing from coronary sinus (CS) and low anterolateral right atrium (LARA) was performed to evaluate transverse conduction across the CT. During ULR, the longitudinal (CV(L)) and transverse (CV(T)) conduction velocity along and across the CT were measured. The width of the CT conduction gap was evaluated to guide radiofrequency ablation (RFA). RESULTS: No transverse CT gap conduction was found during typical AFL. Transverse CT gap conduction was found in three patients during CS pacing and in three patients during LARA pacing. During ULR, CV(L) was greater than CV(T) (1.28 +/- 0.43 vs. 0.73 +/- 0.30 m/s, p < 0.001). The CV(L)/CV(T) ratio was 1.95 +/- 0.77, which was inversely related to the CT gap width (15.7 +/- 6.8 mm) (p < 0.001). The RFA of the CT gap was successful in 18 patients. Four patients had recurrence of arrhythmias during the follow-up of 11 +/- 3 months. CONCLUSIONS: Most of the CT conduction gaps were functional and only appeared during ULR. The width of the CT gap was inversely related to the anisotropic ratio of the CT. The RFA of the CT gap was effective in eliminating ULR.     

Pyriform sinus fistula

Pyriform sinus fistulae/sinuses are rare causes of recurrent cervical abscess, especially on the left side. They can also present as acute thyroiditis. Treatment in the form of simple incision and drainage is invariably unsuccessful, and the entity may be confused with the residual tract of a second branchial arch anomaly. We report a case of pyriform sinus fistula, and believe that this is only the second case report in India. We feel that greater awareness can lead to proper and appropriate diagnosis of this anomaly.     

Correlation between free thyroxin levels and left ventricular ejection fraction in Graves' disease (preliminary study)

AIM: to determine the correlation between free thyroid hormone level and left ventricular ejection fraction in newly diagnosed Graves' patients. METHODS: this is a preliminary study with an initial cross-sectional design using free thyroxine level as a parameter of thyroid hormone state and left ventricular ejection fraction (LVEF) as a parameter of left ventricular systolic function. Free thyroxine level was measured in the laboratory and the LVEF was assessed by Simpson's methods of echocardiography study. RESULTS: ten patients (7 men and 3 women; age 18-52 years old) were studied. Their average of fT4 was 5.75 (SD 0.96) ng/dL and their average of LVEF was 70.57 (SD 4.50)%. There was positive correlation coefficient between free thyroxine level and left ventricular ejection fraction (r=0.711, p=0.021) in newly diagnosed Graves' patients. CONCLUSION: in this study strong positive correlation was found between free thyroxine (fT4) and left ventricular ejection fraction (LVEF) in newly diagnosed Graves' patients.     

Substrate mapping to detect abnormal atrial endocardium with slow conduction in patients with atypical right atrial flutter.

OBJECTIVES: The purpose of this study was to investigate the relationship between the abnormal substrate and peak negative voltage (PNV) in the right atrium (RA) with atypical flutter. BACKGROUND: The impact of a local abnormally low voltage electrogram on the local activation pattern and velocity of atrial flutter (AFL) remains unclear. METHODS: Twelve patients with clinically documented AFL were included to undergo noncontact mapping of the RA. The atrial substrate was characterized by the: 1) activation mapping; 2) high-density voltage mapping; and 3) conduction velocity along the flutter re-entrant circuit. The normalized PNV (i.e., the relative ratio to the maximal PNV) in each virtual electrode recording was used to produce the voltage maps of the entire chamber. The protected isthmus was bordered by low voltage zones. RESULTS: Atypical AFL of the RA was induced by atrial pacing in 12 patients, including 10 upper loop re-entry and 2 RA free wall re-entry flutter. These protected isthmuses were located near the crista terminalis. The mean width of the protected isthmus was 1.7 +/- 0.3 cm and mean voltage at the isthmus was -0.91 +/- 0.39 mV. The conduction velocities within these paths were significantly slower than outside the path (0.30 +/- 0.18 m/s vs. 1.14 +/- 0.41 m/s, respectively; p = 0.004). The ratiometric PNV of 37.6% of the maximal PNV had the best cut-off value to predict slow conduction, with a high sensitivity (92.3%) and specificity (85.7%). CONCLUSIONS: Characterization of the RA substrate in terms of the unipolar PNV is an effective predictor of the slow conduction path within the critical isthmus of the re-entrant circuit.     

Mechanism of repolarization change during initiation of supraventricular tachycardia

INTRODUCTION: Previous literature has documented the association between narrow QRS supraventricular tachycardia (SVT) and pronounced ST-T segment change. The aim of this study was to evaluate repolarization changes during SVT initiation and demonstrate the possible mechanism. METHODS AND RESULTS: Fifty-one consecutive patients (20 men and 31 women; mean age 46.1 +/- 16.4 years) with narrow QRS SVT (32 patients with AV nodal reentrant tachycardia and 19 patients with AV reentrant tachycardia) were included. We retrospectively analyzed the intracardiac recordings and ST-T segment changes on 12-lead surface ECGs during SVT initiation. Twenty-six (51%) patients developed ST segment repolarization changes during SVT initiation. Patients with shorter baseline sinus cycle length, shorter tachycardia cycle length, elevated systolic blood pressure before tachycardia induction, and greater reduction of systolic blood pressure had a higher incidence of repolarization changes. However, multivariate analysis showed that reduction of systolic blood pressure after SVT induction was the only independent predictor of repolarization changes. Furthermore, the maximal degree of ST segment depression during SVT correlated with the reduction of systolic blood pressure (r = 0.75, P < 0.001). CONCLUSION: Repolarization changes during SVT initiation were caused mainly by concurrent hemodynamic change after SVT initiation with abrupt cycle length shortening.