Mitral Flutter Research Articles

Invasive management of atrial tachycardias using a novel lattice-tip catheter combining high-density mapping and dual ablation properties: initial real-world experience.

Invasive management of atrial tachycardias(ATs) requires proper diagnosis of the mechanism followed by elimination of the responsible substrate. A novel lattice-tip catheter with both high-density mapping and dual ablation properties(radiofrequency-RF/pulsed field ablation-PFA) has been recently introduced for catheter ablation of atrial fibrillation. We present the first study to assess its performance in the management of ATs (diagnostic and therapeutic). Patients with documented ATs were selected. Activation mapping was used for the establishment of the AT mechanism. Confirmation with entrainment was performed, whenever appropriate. Accuracy of the activation mapping in diagnosis, acute ablation efficacy, and procedural characteristics were the study endpoints. Twenty patients were included (12 cavotricuspid isthmus-dependent atrial flutters, 5 mitral flutters, 2 roof flutters, and 2 focal ATs). Proper diagnosis was established by activation mapping in all cases. The mean mapping time was 7.85 ± 3.06 min with 296.82 ± 150.9 mean mapping points/minute. The mean ablation time was 54.25 ± 42.97 s. Conversion to sinus rhythm during ablation was achieved in all cases with the exception of a roof flutter that converted to mitral flutter and a case of a parahisian AT in which ablation was not attempted. Patients that received ablation did not experience any arrhythmia recurrence in a mean follow up of 4.14 ± 0.91months. No major or minor complications occurred. The lattice-tip catheter and its dedicated electroanatomical mapping system provided sufficiently detailed activation mapping for the diagnosis of the AT mechanism. The delivered lesions were highly effective acutely, with no adverse events. However, limitations exist and should be acknowledged.

Abstract 10897: Severe Atrial Dysfunction and Sick Sinus Syndrome in a Patient With Scn5a Mutation

Introduction: SCN5A mutations are associated with numerous cardiovascular conditions, including dilated cardiomyopathy, atrial fibrillation, and sick sinus syndrome. Specific variants in patients with severe atrial dysfunction may be associated with increased risk of stroke even in young patients. Case: This case describes a previously healthy 38-year-old male of French descent who presented with intermittent palpitations and presyncope associated with atrial flutter followed by prolonged conversion pauses up to 7.5 seconds, then followed by junctional bradycardia. Echocardiogram showed a mildly dilated left atrium. Electrophysiology study demonstrated extensive scarring in the left atrium with normal sinus node function and right atrial voltage. No atrial fibrillation was noted. He was also found to have typical atrial flutter and mitral flutter. He underwent cavotricuspid isthmus ablation and mitral annular flutter ablation. Due to his vagal-mediated pauses and junctional rhythm, he also underwent cardioneuroablation aimed at partial denervation. Following this, he had further episodes of junctional rhythm on the days after exercise. He underwent further total cardioneuroablation and was found to have progressive scarring at the sinus node area and sinus node dysfunction, so a permanent pacemaker was placed. He underwent genetic testing which demonstrated SCN5A heterozygous missense pathogenic variant c.2823G>A. Conclusion: The SCN5a gene encodes the alpha subunit of the cardiac sodium channel, which is responsible for initiation and propagation of action potentials. SCN5A variants are associated with a number of cardiovascular conditions. There are reports of stroke in young French patients with severe atrial dysfunction and SCN5A mutations, including variant c.2823G>A, demonstrating that severe atrial dysfunction is a risk factor for stroke regardless of CHADS2VASc score, and specific SCN5A mutations may be associated with increased risk of stroke. Given these reports and absence of relevant guidelines, apixaban was continued indefinitely for prevention of stroke. At follow-up two months later, the patient resumed physical activity and reported symptomatic improvement, without any episodes of syncope or near syncope.

A case of pseudo-endocardial gap during mitral flutter: Pitfalls of the auto-annotation algorithm on the ultra-high-resolution mapping system

We herein report a 53-year-old man with atrial tachycardia (AT) recurrence after atrial fibrillation (AF) ablation. In the initial procedure, pulmonary vein isolation (PVI) for AF and a mitral isthmus (MI) line for the intraprocedural mitral flutter were successfully performed. In the second procedure for recurrent AT, an endocardial activation map with an ultra-high-resolution mapping system (RhythmiaTM; Boston Scientific, Marlborough, MA, USA) showed clockwise mitral flutter (cycle length [CL]: 240ms) via epicardial fiber with a breakout site 11 mm posterior from the previous MI line that simultaneously demonstrated a residual endocardial gap near the left inferior PV (Movie).

The ridge line of left pulmonary vein isolation from left atrial appendage can subsequently increase the completion rate of the mitral isthmus block line.

Mitral isthmus (MI) ablation for mitral flutter is technically difficult, and incomplete block line is not uncommon. The objective of this study is to investigate the effect of the ridge line of left pulmonary vein isolation (LPVI) from left atrial appendage (LAA) on completion rate of mitral isthmus (MI) block line and recurrence rate of atrial tachycardia (AT) or atrial flutter (AFL) after the first MI ablation. We identified 611 patients who underwent first MI ablation for mitral flutter during the study period. Finally, 559 patients were enrolled and divided into two groups according to the method of ridge line ablation of LPVI (LAA group, n = 467, conventional group, n = 92). Outcome measures were the completion of MI block line by first MI ablation, the recurrence of AT/AFL, and repeat MI ablation after the first MI ablation. The first MI block line completion rate was significantly higher in the LAA group than the conventional group (95% vs. 85%, p < 0.001). The recurrence rate of AT/AFL after 3months from first MI ablation was significantly lower in the LAA group. The requirement of additional MI ablation tended to be lower in the LAA group. Our novel approach of ablating LPV-LAA ridge from the LAA side during PVI can increase the success rate of MI block line completion, and reduce the recurrence rate of AT/AFL and the need for additional MI block line ablation. Graphical abstract Ablation of the left pulmonary vein-left atrial appendage ridge from the left atrial appendage side during PVI increased the success rate of mitral isthmus block line completion.

B-PO05-204 LATE ONSET ATYPICAL ATRIAL FLUTTER IN A TRANSPLANTED HEART

Cardiac denervation, allograft rejection and vasculopathy increase the risk of cardiac arrhythmias and pose management challenges in a heart transplant patient. To discuss the management of atrial arrhythmia in a transplanted heart. N/A A 71-year-old Caucasian woman with a history of orthotopic heart transplant in 2001, paroxysmal atrial fibrillation, and transplant vasculopathy status post left circumflex artery stent presented with palpitations. External monitoring revealed supraventricular tachycardia. Twelve lead ECG confirmed an atrial flutter with variable block. Echocardiography showed normal ventricular function. Cardiac biopsy showed focal moderate cellular allograft rejection. Left heart catheterization did not show significant coronary obstruction. The finding of graft rejection prompted commencement of steroids. Following steroid therapy, repeat biopsy was negative for rejection; however, atrial arrhythmia persisted requiring multiple cardioversions. Antiarrhythmic drug therapy caused intolerable side effects. An electrophysiology study revealed atypical mitral flutter in the donor atria. Catheter ablation of the anterior mitral line terminated the flutter. Allograft rejection causes inflammation and fibrosis leading to slowing of conduction in the atria forming the substrate for intra-atrial arrhythmia. Bi-atrial anastomosis might have increased the risk of transmitral flutter in the donor heart. Catheter ablation should be considered for late onset atrial arrhythmia in transplant patients.

Long-term efficacy and safety of adjunctive ethanol infusion into the vein of Marshall during catheter ablation for nonparoxysmal atrial fibrillation.

We aimed to clarify the effect of vein of Marshall (VOM) ethanol infusion for treating VOM triggers and/or mitral flutter after first-attempt endocardial ablation in patients with nonparoxysmal atrial fibrillation (AF). Of the 254 consecutive patients (age, 56 ± 10 years; 221 male) undergoing catheter ablation for drug-refractory nonparoxysmal AF, 32 (12.6%) received VOM ethanol infusion. The patients were stratified into group 1 (pulmonary vein isolation [PVI], substrate modification, VOM ethanol infusion), group 2 (PVI, substrate modification), and group 3 (PVI alone). Propensity-matched analysis (N = 128) of long-term outcomes (3.9 ± 0.5 years) revealed a higher AF recurrence risk in group 2 (hazard ratio [HR], 4.17; 95% confidence interval [95% CI], 1.63-10.69; P = .003) and group 3 (HR, 1.82; 95% CI, 1.09-3.04; P = .021) than in group 1, as well as a higher atrial arrhythmia recurrence risk in group 2 than in group 1 (HR, 2.42; 95% CI, 1.16-5.03; P = .018). A higher procedural termination rate was observed in group 1 than groups 2 and 3 (41.7% vs 17.2% vs 18.8%; P = .042). On multivariate analysis, VOM ethanol injection was an independent predictor of freedom from recurrence of AF (HR, 0.20; 95% CI, 0.08-0.52; P = .001) and atrial arrhythmia (HR, 0.35; 95% CI, 0.17-0.74; P = .005), whereas a left atrial diameter >45 mm and hypertension were independent risk factors for recurrence. Periprocedural complications rates were comparable among the groups. Adjunctive VOM ethanol infusion is effective and safe for treating nonparoxysmal AF in patients with VOM triggers and/or refractory mitral flutter, providing good long-term freedom from AF and atrial arrhythmia.

Feasibility of percutaneous epicardial mapping and ablation for refractory atrial fibrillation: Insights into substrate and lesion transmurality

Recurrences of atrial fibrillation (AF) after ablation have been attributed to conduction gaps and nontransmural ablation lesions. The purpose of this study was to assess the feasibility of adjunctive percutaneous mapping of the epicardial regions of the left atrium to characterize the transmural extent of substrate and ablation lesions. Between 2014 and 2018, combined epicardial and endocardial mapping of AF was performed in 18 patients via an inferior subxiphoid percutaneous approach (16 with previously failed ablation procedures and 2 patients with long-standing persistent AF) at 2 centers. Epicardial substrate mapping was compared with endocardial mapping to assess transmural uniformity. Of 18 patients, 4 (22%) demonstrated nontransmural atrial low-voltage regions with relative epicardial sparing in the left atrial posterior wall. Transmural isolation of the posterior wall was achieved after an endocardial "box" lesion set in 6/9 (67%), guided by epicardial voltage data, while epicardial and endocardial dissociation during AF was observed in 1 patient. In 3 patients, epicardial capture along the endocardial pulmonary vein lesion set despite endocardial capture loss and bidirectional block was observed. Two cases of mitral flutter were terminated from the epicardium. A balloon was positioned in the pericardial space in 6 patients for esophageal protection during ablation. A percutaneous epicardial approach for mapping and ablation of the left atrium is feasible in the electrophysiology laboratory during endocardial catheter ablation for AF and may be useful as an adjunctive approach in refractory cases. High-density epicardial mapping can provide direct evidence of nonuniform lesion and substrate transmurality of the human left atrium before and after ablation.

An effective case of anterior mitral line ablation after incomplete posterior line in mitral isthmus on peri- mitral flutter after ablation for persistent atrial fibrillation.

An effective case of anterior mitral line ablation after incomplete posterior line in mitral isthmus on peri- mitral flutter after ablation for persistent atrial fibrillation.

Statistical comparison of M mode and two dimensional echocardiographic diagnosis of flail mitral leaflets

Forty-five patients who had surgical therapy for pure mitral insufficiency were evaluated prospectively with both M mode and two dimensional echocardiography; 26 patients (Group I) had a flail mitral valve leaflet, and 19 patients (Group II) had intact chordae tendineae. The M mode echocardiographic criteria of a flail valve (systolic left atrial echoes, systolic mitral valve flutter, diastolic mitral flutter and chaotic paradoxic diastolic posterior leaflet motion) were compared statistically with the two dimensional echocardiographic criterion (loss of systolic leaflet coaptation). The presence of one M mode echocardiographic finding had a sensitivity of 60 percent, a specificity of 53 percent, a predictive accuracy of 63 percent and a predictive value of 50 percent. The sensitivity (96 percent), specificity (84 percent), predictive accuracy (89 percent) and predictive value (94 percent) of the two dimensional echocardiogram were statistically superior to those of the M mode study (p < 0.05 or better for each criterion). Thus, two dimensional echocardiography is distinctly superior to M mode echocardiography in the diagnosis of flail mitral valve leaflets.

M mode and cross-sectional echocardiographic features of flail posterior mitral leaflets

Seventeen patients with accepted M mode echocardiographic criteria for flail mitral leaflet were studied. M mode echocardiograms revealed characteristic disordered mitral valve motion: (1) 16 (94 percent) had chaotic diastolic mitral motion; (2) 14 (82 percent) had systolic mitral flutter; (3) 14 (82 percent) had systolic left atrial echoes; and (4) 12 (71 percent) had systolic mitral valve prolapse. In 8 patients (47 percent) all four findings were present, with three findings present in 16 (35 percent) and two findings present in 13 (18 percent); none had fewer than two findings. Cross-sectional echocardiographic studies in 10 patients revealed a systolic whipping motion of the posterior mitral leaflet into the left atrium in all, abnormal systolic mitral coaptation in all and an abnormal mass of systolic left atrial echoes in 4. None of the first three M mode criteria were observed in 230 patients with uncomplicated “mid systolic click-late systolic murmur” syndrome; cross-sectional echocardiography in 30 of 230 patients revealed normal systolic mitral coaptation and no systolic whipping of the tip of the posterior mitral leaflet into the left atrium.

Single and Multiple Beam Echocardiography in Aortic Valve Endocarditis

Three patients with aortic valve endocarditis were studied. The single beam M-mode echocardiographic findings comprised the appearance in diastole of a cluster of shaggy echoes at the aortic valve in all three patients. Mitral flutter was seen in two patients and premature closure of the mitral valve in one patient. At multiple beam two-dimensional echocardiography, the echo cluster could in all three patients be seen to move perpendicular to the sound beams, ascending into the aorta in systole and descending in diastole. At valve replacement, vegetations were found that explained the abnormal echo cluster. The multiple beam echocardiography facilitated the interpretation of the single beam findings and increased the confidence therein. By applying the non-invasive modality of echocardiography in these patients with their high risk of embolism, cardiac catheterization may possibly be avoided.

Systolic mitral flutter, an echocardiographic clue to the diagnosis of ruptured chordae tendineae

A new finding of fine systolic fluttering of the mitral leaflet is described in two patients with ruptured chordae tendinease and severe mitral regurgitation. The flutter is caused by the action of high-velocity blood flow upon the leaflet margin that has lost its support. The jet stream of blood evokes a high-frequency vibratory motion of the tensed leaflet as opposed to the previously described, lower frequency, less specific, diastolic flutter. This finding was not seen in the echocardiograms of 75 patients with other forms of mitral regurgitation. Systolic flutter appears to be specific for ruptured chordae tendineae.

Flutter of left ventricular structures in patients with aortic regurgitation, with special reference to patients with associated mitral stenosis

Echocardiography was performed in 45 patients with aortic regurgitation. Forty showed a high frequency diastolic flutter of the mitral valve, which was holodiastolic in all but the patients with associated mitral stenosis. Of four patients with coexisting mitral stenosis, mitral flutter was absent in two; in the other two, in atrial fibrillation, mitral flutter occurred, but only during a fixed interval after mitral valve opening, irrespective of cycle length. A fine flutter of similar frequency was observed on the left ventricular aspect of the ventricular septum in 12 patients. In six of these it was of slight degree and restricted to early diastole and the high septum; in four others (three of whom had associated mitral stenosis), the septal flutter was more marked, holodiastolic, and present over all parts of the septum scanned; in two, it was holodiastolic over the high septum but early diastolic at lower septal levels. Aortography performed in 19 patients showed that septal flutter was present in seven of 12 patients in whom the regurgitant aortic jet was directed forward to the ventricular septum, whereas in the other seven patients with no septal flutter, the jet was directed away from the septum. Septal flutter is useful as an echocardiographic sign of aortic regurgitation, especially in the presence of mitral stenosis when mitral flutter may be absent or exceeded by septal flutter in both amplitude and duration, and when the mitral valve has been replaced by a prosthetic valve. Vibration of the septum appears to be attributable to the regurgitant aortic jet impinging on it and may contribute to the production and radiation of the characteristic diastolic murmur of aortic regurgitation.