Trio of Rheumatic Mitral Stenosis, Right Posterior Septal Accessory Pathway and Atrial Flutter: A Case Report

A 57-year-old male presented with recurrent palpitations. He was diagnosed with rheumatic mitral stenosis, right posterior septal accessory pathway and atrial flutter. An electrophysiological study after percutaneous balloon mitral valvotomy showed that the palpitations were due to atrial flutter with right bundle branch aberrancy. The right posterior septal pathway was a bystander because it had higher refractory period than atrioventricular node.

LEFT FREE WALL-SIDED MAHAIM TYPE FIBER AND AV NODAL REENTRY TACHYCARDIA -- UNUSUAL BUT NOT IMPOSSIBLE COMBINATION

A 52-year-old patient with previous catheter ablation of AV nodal reentrant tachycardia (AVNRT) had a redo procedure for reported recurrence. During the study AVNRT was not inducible, but a previously unrecognized left-sided Mahaim type accessory pathway was diagnosed and ablated successfully.

276 Wolff–Parkinson–White syndrome was associated with reduced myocardial work

Aims Paediatric patients with a diagnosis of Wolff–Parkinson–White (WPW) Syndrome may develop a reduction of local myocardial deformation because of accessory pathway-related electrical dyssynchrony, which may lead to an impairment of left ventricular systolic function. The presence of ventricular dysfunction may be an indication for these patients to undergo radiofrequency catheter ablation (RFCA), even if asymptomatic. However, myocardial abnormalities are sometimes subtle and cannot be detected by standard echocardiographic evaluation. The purpose of this study was to assess the diagnostic value of non-invasive myocardial work in predicting subtle myocardial abnormalities in paediatric patients with WPW Syndrome. Methods and results Forty-four paediatric patients (age 8.2 ± 4.3 years) were included in this study: 12 cases with manifest WPW Syndrome and 32 age-, sex-, and arterial pressure-matched controls (CTR). Left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) were evaluated. Global myocardial work index (MWI) was measured as the area of the LV pressure-strain loops. From MWI, global constructive work (MCW), wasted work (MWW), and work efficiency (MWE) were estimated. Despite normal LV systolic function by standard echocardiographic parameters, paediatric patients with WPW Syndrome had lower MWI (1233.5 ± 281.6 mmHg% in WPW vs. 1624.0 ± 305.8 mmHg% in CTR, P = 0.0004), MCW (1833.4 ± 257.9 mmHg% in WPW vs. 2069.0 ± 319.9 mmHg% in CTR, P = 0.03), MWW (187.6 ± 117.7 mmHg% in WPW vs. 90.9 ± 58.9 mmHg% in CTR, P = 0.0008), and GWE (90.5 ± 4.8% in WPW vs. 95.2 ± 2.2% in CTR, P = 0.00006). There were no significant differences in GLS and LVEF between patients with WPW Syndrome and controls. Conclusions WPW Syndrome was found to be associated with a significant reduction of myocardial work indices in the paediatric population. The assessment of MWI may represent a sensitive measure to identify a subtle myocardial dysfunction in an early stage, even when LVEF and GLS are normal. It might be considered a further diagnostic parameter for referring little patients to RFCA.

786 A case of end-stage mitochondrial cardiomyopathy undergoing heart and kidney transplantation

Male, 46 year old. Family history: brother affected by deafness and repeated episodes of stroke at a young age. Pathological history: history of competitive sporting activity in which he underwent periodic outpatient checks and reported sporadic myalgic episodes. The patient was suffering from bilateral keratoconus. For the purpose of discovering Wolf–Parkinson–White syndrome with the presence of a right antero-septal accessory pathway, he underwent an electrophysiological study (2003) negative for inducible arrhythmias. During a routine checkup, a renal biopsy was performed to search for elevated blood creatinine, which concluded with acute interstitial nephritis (2005), treated ineffectively with steroids and resulted in dialysis-dependent stage V renal failure (2020). Following light tiredness, he underwent an echocardiographic examination (2009) which revealed the presence of dilated heart disease with reduced left ventricular systolic function. He underwent a cardiac MRI which showed diffuse spots of subepicardial late enhancement as a possible post-myocarditis outcome. At subsequent clinical-echocardiographic checks, progressive biventricular dysfunction, and signs of congestive heart failure were highlighted, for which medical therapy was progressively increased and insertion of an implantable cardioverter defibrillator in primary prevention for sudden cardiac death. At the subsequent clinical re-evaluations, there was evidence of progressive bilateral hearing loss. In consideration of the clinical picture and family history, considering the syndromic nature of the polypathologies to be likely, genetic investigation was required for mitochondrial diseases. Mutations 3242 and 3271mt-RNA and 13513 mtND5, frequent in the MELAS Syndrome, were searched in peripheral venous samples and resulted as negative. In 2020 he underwent an orthotopic heart transplant sec. Shamway followed by a kidney transplant from a compatible donor. In order to perform further diagnostic investigations, the explanted heart was sent to the Pathological Anatomy laboratory of the Umberto I Hospital: macroscopic analysis showed foci of fat replacement at the level of the anterior and posterior wall of the right ventricle (Figure); under microscopy, marked myocardial hypertrophy was observed, associated with cytoplasmic vacuolization of the cardiomyocytes, fibro-adipose substitution of the right ventricle, and replacement fibrosis in minute foci in the left ventricular level. A widespread and marked reduction in the enzymatic activity of cytochrome oxidase in cardiomyocytes and mitochondrial proliferation was demonstrated using histo-enzymatic staining, by staining for succinate dehydrogenase, concluding with mitochondrial disease. Mitochondrial diseases represent a challenge not only from the prognostic–therapeutic point of view but, remarkably, also from a diagnostic one: the patient received a correct diagnosis of the pathology that afflicted him, with almost two decades of delay. The integrated and multidisciplinary approach is desirable in order to obtain an early diagnosis.

136 Blood vortices analysis in children with Wolff–Parkinson–White syndrome

Aims Wolff–Parkinson–White syndrome (WPW) is a clinical condition characterized by pre-excitation on electrocardiogram (ECG) and symptoms of arrhythmias. It has been described that premature ventricular activation induces septal wall motion abnormalities and ventricular dyssynchrony, causing detrimental effects on cardiac performance. The new speckle-tracking-based technique, blood speckle imaging (BSI), has been previously used to evaluate blood flow characteristics in normal and dysfunctional hearts in patients with normal atrio-ventricular (AV) conduction. We aimed to study the features of left ventricle blood vortices in patients with WPW and short AV conduction by using BSI. Methods and results Nineteen paediatric patients (age 7 ± 2.9 years) were included in the study: 13 patients with manifest WPW (WPW group) and 6 age and sex -matched controls with normal AV conduction (CTR group). A complete echocardiographic evaluation with 2D, color Doppler, and BSI was performed in all the included patients. BSI was recorded in apical 3-chamber view with a 6S-D probe. Vortices characteristics were analysed during the filling phase of the left ventricle. We focused on the anterior vortex generated by the mitral valve, which persisted longer during the cardiac cycle and is assumed to contribute to optimizing cardiac function. For each child in the WPW group, Arruda criteria were used to esteem accessory pathway localization from a 12-lead surface ECG. All patients in the WPW group manifested the accessory pathway in the septal region. All patients in the CTR group presented one major anterior vortex along the septal wall during the filling phase (Figure A), while in the WPW group, 10 patients out of 13 (P = 0.009) lacked this main anterior vortex, showing instead fragmented vortices (Figure B). Interestingly, the main differences in blood vortices pattern were showed in the last part of filling phase, when blood flow could be affected by premature activation of the septal wall. There were no differences in terms of left ventricle function (WPWg 59.8 ± 4.02% vs. CTRg 59.0 ± 2.5%, P = 0.6) and global longitudinal strain (WPWg −18.6 ± 1.0% vs. CTRg −19.6 ± 3.1%, P = 0.5) between the two groups. 136 Figure A and B Conclusions In our preliminary study, patients with WPW showed a fragmented pattern of diastolic blood vortices that adapted to septal dyssynchrony. We speculate this fragmentation may contribute to impair the performance of the left ventricle.

567 Wolff–Parkinson–White syndrome and sport activity: a peculiar case in a young athlete

Aims Wolff–Parkinson–White (WPW) is a cardiac conduction system disorder characterized by abnormal accessory conduction pathways between the atria and the ventricles. Palpitations, presyncope, or syncope that result from supraventricular tachycardia represent classic symptoms; however, especially in young athletes, the syndrome can occur with sudden cardiac death. As result, the presence of an accessory pathway (AP) and tachycardia induced by physical activity contraindicates agonist physical activity and represents an indication to perform an electrophysiology (EP) study to stratify the arrhythmic risk, also allowing an eventual transcatheter ablation (TCA) of the AP. Methods and results An agonist football player, known since the age of 6 years for Wolff–Parkinson–White syndrome from an intermittent right midseptal parahissian AP, underwent a transesophageal EP study and subsequently ineffective TCA with radiofrequency when he was 13 years old. For evidence of intermittent ventricular preexcitation (VPE), at the age of 15 he underwent a further endocavitary EP study with documentation of poor conductive abilities of the AP. Subsequently, at the age of 17, he had a resumption of palpitation and lipotimie during effort; during another sport medical examination with an exercise stress test (EST), a persistent VPE with the start of an orthodromic atrioventricular reentrant tachycardia during the recovery phase was documented. A new EP study with isoprenaline infusion confermed the precence of the parahissian AP and the inducibility of an orthodromic atrioventricular reentrant tachycardia (Picture 1-2B); therefore, after mapping the arrhythmia, a cryoablation of AP was performed (Picture 1c-1d). Nevertheless, 12 h after the procedure, there was still evidence of intermittent VPE. The patient was then discharged and, after a month, he repeated the EST with documentation of persistent VPE which suddenly disappeared at the peak of the exercise and reappeared during the recovery phase. At the 1-year follow-up, no arrhythmic recurrence but persistence of VPE was reported and a successive EST confirmed abrupt interruption of VPE at the peak of the exercise. Due to the low arrhythmic risk, sport activity was not more restricted. Conclusions This represents an original clinical case, as it raises the question of what practical criteria should be defined as an effective TCA of AP in a competitive athlete with unfavorable anatomy. The current guidelines (Sport Cardiology and Exercise 2020) provide useful indications in linear and common cases, but may be a source of doubts in particular cases. Therefore, only the experience and the careful evaluation of the individual patient can provide the key to a correct management of the cases like this.