Cardiovascular Journal of Africa: Vol 32 No 6 (NOVEMBER/DECEMBER 2021)

CARDIOVASCULAR JOURNAL OF AFRICA • Volume 32, No 6, November/December 2021 292 AFRICA Cardiovascular Topics Assessment of P- to delta-wave interval and its relationship with accessory pathway properties in patients with pre-excitation Osman Can Yontar, Ahmet Yanik, Gokhan Aksan Abstract Background: The first clinical manifestation of the Wolff– Parkinson–White syndrome in previously asymptomatic individuals may be sudden cardiac death. The options for non-invasive risk stratification are limited in the current era beyond ambulatory rhythm monitoring and an exercise stress test. In our study, we sought to investigate whether there was a relationship between the shortest measured P- to delta-wave time interval (PDI) on the conduction properties of surface electrocardiogram and accessory pathways expressed as ante- grade effective refractory period (APERP). Methods: Demographic data, symptom status, electrocardio- grams (ECG) and intra-cardiac recordings of invasive electro- physiology testing of 103 patients who underwent accessory pathway ablation procedures were collected. Exclusion crite- ria were: (1) intermittently occurring pre-excitation, which was detected in previous ECGs, (2) delta-wave resolution on treadmill test, (3) presence of multiple accessory pathways, and (4) accessory pathway locations other than the septum. The PDI was measured as the time interval from the begin- ning of the P wave to the earliest upstroke or downstroke of the delta wave on V1 and V2 derivations of the surface ECG, and the shortest measurement was recorded. Results: Patients were grouped into two groups: group I, if APERP was < 240 ms and group II if APERP was ≥ 240 ms. PDI was significantly shorter in group II. By correlation anal- ysis, a positive and moderate correlation between PDI and APERP ( r = 0.598, p < 0.001) and PDI and age ( r = 0.800, p < 0.001) was found, and a negative and moderate correlation between PDI and inducible AF ( r = –492, p < 0.001). The best cut-off value for PDI to predict APERP ≥ 240 was 90.5 ms with a sensitivity of 80% and a specificity of 83%. Conclusion: Our results demonstrate that there was a strong correlation between the P- to delta-wave interval and univer- sally accepted risk factors, such as low age, low APERP and atrial fibrillation inducibility. Further studies with larger patient groups and follow-up data are needed to appraise its predictive value. Keywords: delta wave, pre-excitation, electrocardiogram Submitted 26/5/20, accepted 1/12/20 Published online 19/5/21 Cardiovasc J Afr 2021; 32 : 292–296 www.cvja.co.za DOI: 10.5830/CVJA-2020-057 The Wolff–Parkinson–White (WPW) pattern, which is demon- strated by a typical pre-excitation on surface electrocardiogram (ECG), is estimated to show a prevalence of 0.1%. 1 The first clin- ical manifestation of the WPW syndrome in previously asymp- tomatic individuals may be sudden cardiac death. 2,3 According to the latest guidelines, the WPW syndrome is considered to carry a risk of increased life-threatening arrhythmic events when the following factors are observed: 4 young age, effective refractory period of the accessory pathway (APERP) < 240 ms, inducibility of atrioventricular re-entrant tachycardia on electrophysiological study (EPS) and multiple accessory pathways. Although risk stratification in asymptomatic patients with invasive electrophysiological procedures has been extensively discussed, there is a lack of data in the literature utilising non-invasive surface ECG on this subject. The intermittent appearance of delta waves on surface ECG seems to be a marker of lower risk in this patient group; however its predictive value is debatable. 5 We hypothesised that the time interval from the beginning of the P wave to the beginning of the earliest delta wave (PDI) on ECG may provide a clue about the conduction property of the accessory pathway. Therefore, we sought to investigate whether there was a relationship between the shortest measured PDI on precordial V1 and V2 derivations and conduction properties, expressed as APERP. Methods Patient records of the Electrophysiology Department, Samsun Training and Research Hospital, were retrospectively analysed. Demographic data, symptom status, ECGs and intra-cardiac recordings of invasive electrophysiological testing of 103 patients who underwent accessory pathway ablation procedures were collected. Patients were deemed symptomatic if they had a documented tachycardia episode or they complained about episodes of palpitation, dizziness or syncope. Exclusion criteria Department of Cardiology, Samsun Training and Research Hospital, Health Sciences University, Samsun, Turkey Osman Can Yontar, MD Ahmet Yanik, MD Gokhan Aksan, MD, aksan55@yahoo.com