HISTORY, CURRENT ILLNESS AND PHYSICAL EXAMINATION

History
This is a 66-year-old female patient with no family history of early ischaemic heart disease or sudden death. Mother died of stroke at 73 years of age.

Personal history: No documented drug allergies. Lifestyle: active life, walks 45-60 minutes daily with her group of friends. Currently retired. Previously employed in perfumery. Cardiovascular risk factors: ex-smoker for 25 years (IPA 10 packs/year), slightly overweight (body mass index 27 kg/m2). No other risk factors. Cardiovascular history: symptomatic non-valvular paroxysmal paroxysmal atrial fibrillation since 2017 (EHRA 3: could not keep up with her companions while walking). No structural heart disease on echocardiogram (left atrium of borderline size and preserved LVEF). Radiofrequency ablation of pulmonary veins was performed in January 2018, still paroxysmal) achieving bidirectional isolation. He presented acute reconnection during the procedure through the ligament of Marshall, successfully ablated in the anterior carina region. During the blanking period she was treated with flecainide 100 mg/12h and dabigatran 150 mg/12h. The patient underwent cardiac rhythm self-measurements every 48 h with a Kardia device and a 24 h Holter at 3 months without evidence of arrhythmic recurrence being documented in any of these controls. Anticoagulation was discontinued due to CHA2DS2VASc 1 point (female) and the antiarrhythmic was progressively reduced until discontinuation. Other history: untreated mild psoriasis. No history of asthma, nor previous need for bronchodilators.


Current illness
Since the summer of 2020, she presents clinical deterioration, which she refers to as recurrence of palpitations, mainly with exertion, but also during periods of rest, which she describes as similar to those prior to the diagnosis of atrial fibrillation (AF) and limitation of physical activity with a marked feeling of "tiredness". These episodes have increased in frequency and duration, persisting for several hours. No orthopnoea, paroxysmal nocturnal dyspnoea (PND) or oedema of the lower extremities. No associated chest pain at rest or on exertion. She has never presented syncopal or presyncopal symptoms. With the suspicion of recurrence of atrial fibrillation, in a first consultation, an electrocardiogram (ECG) in sinus rhythm was performed and the patient was again urged to use her ECG monitoring device when symptoms recurred. Similarly, a new, regular echocardiogram was requested.

Physical examination in consultation Good general condition, blood pressure (BP) 125/60 mmHg, heart rate (HR) 80 bpm. Basal oxygen saturation 99%. Afebrile. Head and neck: no jugular venous engorgement. Cardiac auscultation: rhythmic sounds at 75 bpm without murmurs. Pulmonary auscultation: normoventilation in all fields. Abdomen: nondescript. Lower extremities: no oedema or signs of deep vein thrombosis.

COMPLEMENTARY TESTS
Initial ECG consultation: sinus rhythm at 90 bpm, PR 170ms, narrow QRS with normal axis, without repolarisation alterations. Normal QTc. ECG tracings obtained with a closed loop recorder (Kardia), symptomatic and non-symptomatic: there were several recordings in sinus rhythm and increasingly frequent events labelled as possible atrial fibrillation with rapid ventricular response. When analysing these recordings in detail, there is a clear RR irregularity and absence of P waves, highly suggestive of atrial fibrillation with rapid ventricular rate. Echocardiogram (performed in sinus rhythm) (video 1): left atrium (LA) slightly dilated (AP diameter at PEL: 41 mm, Vol index: 40 ml/m2). Thin leaflet mitral valve with preserved mobility and opening; mild insufficiency. Diastolic pattern of impaired relaxation, with no increase in filling pressures (E/e ́septal=12). Left ventricle slightly dilated, not hypertrophied (IVS= 11 mm; LVED= 59 mm; PP= 10 mm) with moderately depressed systolic function (biplane LVEF 34%), due to diffuse involvement, without clear segmental alterations. Thin, trivalve aortic valve with good opening and mobility; normal flow (max. v. 1.2 m/s). Valvular annulus and aortic root of normal dimensions. Right ventricle not dilated; preserved contractility (TAPSE= 21 mm). Tricuspid valve with good opening and mobility; minimal regurgitation that does not allow estimation of systolic pulmonary artery pressure (PAPS). Inferior vena cava (IVC) not dilated. No evidence of pulmonary hypertension. No pericardial effusion. Coronary and LA CT scan prior to AF ablation procedure: coronary calcium score 26. Non-invasive coronary angiography: epicardial coronary arteries without angiographically significant lesions. Left atrial study: slight left atrial dilatation (25 cm2). Four pulmonary veins are identified: two left pulmonary veins and two right pulmonary veins. The dimensions of the ostia are: IPSV 19x15 mm; IIPV 18.5x12.2 mm; DPSV 20x15.8 mm and IDPV 17.8x11.6 mm. The oesophagus is 3 mm from the posterior wall of the left venous trunk. There is no persistence of right superior vena cava. Transesophageal echocardiogram during ablation: absence of intracavitary thrombi and left atrial appendage with good flow measured by pulsed Doppler (v: 0.6 m/s). Atrial septum intact with no patent foramen ovale. Left ventricle with mildly moderate depression of contractile function. No pericardial effusion. A first manoeuvre was performed to approach the fossa ovalis with a puncture needle, locating a puncture site somewhat close to the aortic root. Due to this proximity, another approach manoeuvre is performed, placing the needle in a more posterior location (video 3). Finally, transseptal puncture was monitored and passed without complications.

Electrophysiological study and ablation:

Diagnostic mapping assessment of the LA: after effective electrical cardioversion, a detailed mapping of the left atrium is performed. This chamber is accessed via transseptal puncture. Using the navigation system and traversing a large number of points of the atrial wall with the catheter, a reproduction of the volume and geometry of the left atrium is obtained, representing it in three-dimensional form on a computer application that allows virtual mobility of the established geometry in all directions of space. A cartography map of the pulmonary veins is also drawn up using the same technique described above and labelled, establishing the existence of 4 pulmonary veins (2 left and 2 right). In the same way, the mitral valve annulus is conformed and labelled. Reconnection of the left superior pulmonary vein (LSPV) was confirmed, and a pace and map manoeuvre was performed to locate the gap, which was finally located in the posterosuperior region of the LSPV. Voltage mapping of both atria was performed, with no areas of low voltage. A protocol was initiated to assess atrial fibrillation triggers not originating from pulmonary veins by infusion of isoproterenol at increasing doses until reaching 20 mcg/kg. Under this perfusion, frequent extrasystolic activity and small spurts of AT began, mapping early extrasystolic activity as a possible trigger of atrial fibrillation from the posterior roof of the left atrium and superior vena cava, where even an initiation of AF was recorded without catheter contact with the venous wall. Ablation procedure (temperature controlled up to 43 oC and 30W power). An LSI of 5 in posterior zones and 5.5 in anterior zones is limited. Two radiofrequency applications are performed in the posterosuperior region (better pace and map with a venous-atrial conduction time of 50 ms achieving bidirectional isolation in VPSI). Two lines of applications are performed, delimiting a box in the posterior roof, encompassing the focus of the left atrial roof that could not be delimited in its exact location, joining antral ablation lines of previous pulmonary veins that presented conduction block. A total of 21 applications were made between the two lines. Subsequently, electrical isolation was checked by blocking the outflow of this region. Next, in AD, a crown of applications is formed encompassing the superior vena cava, with a total of 27 applications (714 seconds). In applications of the external face of this venous antrum, stimulation is performed at maximum output prior to applications to ensure the absence of phrenic capture and minimise the risk of phrenic paralysis. Effective isolation of the vein is achieved after the last few applications inside the ablation line, in the area of greatest premature extrasystoles. Verification: after 30 minutes of waiting, isolation and blockage verification manoeuvres carried out previously are repeated, verifying the absence of acute reconnection and persistence of conduction blockage of previous isolation lines. By administering i.v. adenosine (12 mg), the absence of dormant conduction in the pulmonary veins and superior vena cava is verified. The catheters are removed, normal contractility of the cardiac silhouette is checked and the procedure is concluded.

CLINICAL EVOLUTION
In the consultation for review of the results, the patient showed increasingly frequent and long-lasting ECG recordings in atrial fibrillation with rapid ventricular response. The echocardiogram showed moderate systolic dysfunction due to diffuse involvement, but no segmental alterations in contractility. At the time of consultation, he was again in sinus rhythm, but with abundant supraventricular extrasystolic activity. Anticoagulant treatment was started with dabigatran 150 mg/12 h (CHA2DS2VASc score of 3 points (age 1, female 1 and heart failure or reduced LVEF 1 point) and antiarrhythmic treatment with amiodarone 200 mg/24 h, ramipril 2.5 mg/24 h and bisoprolol 2.5 mg/24 h. It was first suspected that the left ventricular dysfunction could be caused by tachycardiomyopathy, and for this reason, together with the presence of symptomatic paroxysms of atrial fibrillation, a new ablation procedure was indicated. However, given the patient's age and history of ex-smoking and slight overweight, assessment of the coronary tree was considered. As the patient required a CT scan of the left atrium and pulmonary veins prior to ablation, this test was used for non-invasive coronary angiography, which showed no significant lesions in the coronary arteries. One month after starting anticoagulation and after discontinuation of antiarrhythmic medication, a second atrial fibrillation ablation procedure was performed. During the procedure, VPSI reconnection was verified, and the VPSI was isolated and checked again. Subsequently, triggers not originating from the pulmonary veins were sought by infusion of isoproterenol, locating a focus in the posterior roof of the left atrium, which was treated by performing a posterior roof box up to the venous antrum and another focus in the superior vena cava, which required circumferential isolation of the same. After the procedure, the patient presented no complications and, given her good evolution, she was discharged from hospital after 24 hours, previously restarting anticoagulant medication and her antiarrhythmic treatment. One month after ablation (still in the blanking period), the patient came for a check-up with evident clinical improvement, being in NYHA functional class I, and with no sensation of tachycardia. She provided ECG recordings which were all in sinus rhythm and in the echocardioscopy performed during the consultation, the LVEF had improved significantly and appeared to be preserved/borderline. A further consultation was scheduled 3 months after the ablation procedure.

DIAGNOSIS
Paroxysmal AF in a patient with probable tachycardiomyopathy (absence of coronary artery disease on CT scan prior to ablation).
Left superior pulmonary vein reconnection.
Presence of extrapulmonary foci manifested by isoproterenol infusion in the posterior roof of the left atrium and superior vena cava.
Radiofrequency ablation of reconnection and extrapulmonary foci with acute success (electrical isolation and electrogram ablation).
