Fig. 1

Fig. 2
![Diagram presenting normal ECG and ECG with characteristic features of preexcitation syndrome [Ventricular pre-excitation: WPW and LGL syndromes. [stan z 12.03.2014] http://www.frca.co.uk/article.aspx?articleid=100691#faq]
Ryc. 2 Prawidłowy zapis EKG oraz zapis EKG z cechami charakterystycznymi dla zespołu preekscytacji.](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64721c96215d2f6c89dbc603/j_devperiodmed.20182202.113122_fig_002.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=ASIA6AP2G7AKOOUFAOCM%2F20251220%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251220T010143Z&X-Amz-Expires=3600&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEO%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEaDGV1LWNlbnRyYWwtMSJGMEQCIGZKLc3vZHFmdmjhuZDDhokrOfzU0OyJlKJ3uXGYdk2jAiBmi8sq2TWp3a6uiqZ9a9aKXIVbAgZS%2BJ25wFHEEuozwirEBQi4%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F8BEAIaDDk2MzEzNDI4OTk0MCIMF%2BvP1UrCLVpOtx5oKpgFdVbjE6GKcbIYgxFSRDSDUt5gmWaBIJQrspThg7LeYDkOyTs%2BaH55aaWUWaW3IgU1EwiO2jan4lCVmKxWRc1EljaibVwDl%2Fp2xcXwwM%2BiEXxuvQdbu%2FdHWNVExg4gQOQ3y4oPKQHkG4roEyWRI9K%2FR4r1b4YJFZ6DtZGm7vpesEkBtEu3iSDKu3STWz5HWaCpB99XCpovf0kN1hsEyhXRoGp8UPwzw3GlyWiQ%2FoBiSEJJ2ELPcCKWZh0B71gbbVcH8RHzumjyV2HDXfLN4SNrzzmg8pZbd1IqGhopkizbuGxlZQ6QDk9ASqT0stxD106DO%2FEgdnwwWj%2F9OBF3R92U1bTK2gI2PeV1KYnMTQ%2B%2Fd8Dr1EAzqey5a9YRwMlSiK5Y5tuKzz%2F6dE5ay0n8lA13VQTqsa7JQ3GsXLPsNSW60oHC6lrfOsAcvYnJyh%2FKtyPtF2U1BnUlpC03yWmNkbEbSj9d9K3RqaWPaiB9G7H%2BX%2BS%2FwVni7PNMCu04Rldq1oR0hfA4bZJdlJMiwAPPrNMVB5%2BKynfzsOAfug8KVBJz0de8sSiEYb61yUGP%2FhTWZpYH0voNb3YCs4hfWoiI%2BYG9KPtTs7YJOYnLGgU%2FcMjAXVs%2FJGQSuPio6rd4YOR5cTBIiksUpVWEAG%2BoVt07enUP6VggWoZ8clR59UTwTQqVdmdNnfCJ0NxkNCfXxWbG4zyWU%2B%2FW4561WghKUB5VI1x02pAhde2gp0Lk4L7wFp7j04%2B2Bys0X4c%2F%2FsqBBYTCiWIfFKZBCbIWGKfCUQszYeeUANCEgz7B1sMPXeG7KWgVAnIfL6lnHZL%2BbDpbER6%2BF7W02Fdbw5gFv8%2BhvgHeDX4V0I7z1GPW8Nq%2BtgkWm8z24ol2kMuSQ6A5UTCJppfKBjqyAaL%2Fs09ueasdI0Y9P0RB%2BvzQLxZvjDsM0QRSi7zvvQ7Y%2BtDKRMwTTlbUWFtiCDtyYX5cHdG0eI82H43crK2rdgilCo%2BfsQAI5245ciSnh8B70WEdynjXWfoN8MCsoCAUUF9Ga4DyMjJQPQQpXQj4TJwGQ4Bg8iaHQm4Gk10kxPk%2FrGDpryVt65NnlIIXE%2FyLyXIqXK8HrovkP1V%2BiBsPiq%2Btb78zQaJHkc83zexAzXKFFv4%3D&X-Amz-Signature=6c2be68a52b284640aa4cade43739073dc445284db1d0a68c6e4f448257ad4b7&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 3

Fig. 4

Fig. 5
![ECG of a 9-year-old patient with orthodromic atrioventricular recurrent tachycardia. Heart Rate = 240 bpm [own material].
Ryc. 5. EKG 9-letniego pacjenta z ortodromowym nawrotnym częstoskurczem przedsionkowo-komorowym. Rytm serca o częstości 240/min [materiał własny].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64721c96215d2f6c89dbc603/j_devperiodmed.20182202.113122_fig_005.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=ASIA6AP2G7AKOOUFAOCM%2F20251220%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251220T010143Z&X-Amz-Expires=3600&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEO%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEaDGV1LWNlbnRyYWwtMSJGMEQCIGZKLc3vZHFmdmjhuZDDhokrOfzU0OyJlKJ3uXGYdk2jAiBmi8sq2TWp3a6uiqZ9a9aKXIVbAgZS%2BJ25wFHEEuozwirEBQi4%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F8BEAIaDDk2MzEzNDI4OTk0MCIMF%2BvP1UrCLVpOtx5oKpgFdVbjE6GKcbIYgxFSRDSDUt5gmWaBIJQrspThg7LeYDkOyTs%2BaH55aaWUWaW3IgU1EwiO2jan4lCVmKxWRc1EljaibVwDl%2Fp2xcXwwM%2BiEXxuvQdbu%2FdHWNVExg4gQOQ3y4oPKQHkG4roEyWRI9K%2FR4r1b4YJFZ6DtZGm7vpesEkBtEu3iSDKu3STWz5HWaCpB99XCpovf0kN1hsEyhXRoGp8UPwzw3GlyWiQ%2FoBiSEJJ2ELPcCKWZh0B71gbbVcH8RHzumjyV2HDXfLN4SNrzzmg8pZbd1IqGhopkizbuGxlZQ6QDk9ASqT0stxD106DO%2FEgdnwwWj%2F9OBF3R92U1bTK2gI2PeV1KYnMTQ%2B%2Fd8Dr1EAzqey5a9YRwMlSiK5Y5tuKzz%2F6dE5ay0n8lA13VQTqsa7JQ3GsXLPsNSW60oHC6lrfOsAcvYnJyh%2FKtyPtF2U1BnUlpC03yWmNkbEbSj9d9K3RqaWPaiB9G7H%2BX%2BS%2FwVni7PNMCu04Rldq1oR0hfA4bZJdlJMiwAPPrNMVB5%2BKynfzsOAfug8KVBJz0de8sSiEYb61yUGP%2FhTWZpYH0voNb3YCs4hfWoiI%2BYG9KPtTs7YJOYnLGgU%2FcMjAXVs%2FJGQSuPio6rd4YOR5cTBIiksUpVWEAG%2BoVt07enUP6VggWoZ8clR59UTwTQqVdmdNnfCJ0NxkNCfXxWbG4zyWU%2B%2FW4561WghKUB5VI1x02pAhde2gp0Lk4L7wFp7j04%2B2Bys0X4c%2F%2FsqBBYTCiWIfFKZBCbIWGKfCUQszYeeUANCEgz7B1sMPXeG7KWgVAnIfL6lnHZL%2BbDpbER6%2BF7W02Fdbw5gFv8%2BhvgHeDX4V0I7z1GPW8Nq%2BtgkWm8z24ol2kMuSQ6A5UTCJppfKBjqyAaL%2Fs09ueasdI0Y9P0RB%2BvzQLxZvjDsM0QRSi7zvvQ7Y%2BtDKRMwTTlbUWFtiCDtyYX5cHdG0eI82H43crK2rdgilCo%2BfsQAI5245ciSnh8B70WEdynjXWfoN8MCsoCAUUF9Ga4DyMjJQPQQpXQj4TJwGQ4Bg8iaHQm4Gk10kxPk%2FrGDpryVt65NnlIIXE%2FyLyXIqXK8HrovkP1V%2BiBsPiq%2Btb78zQaJHkc83zexAzXKFFv4%3D&X-Amz-Signature=73a913ba7eeb301d03300c8a1b94a048498c9a0e0632582af43c6b423010fd47&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 6
![Termination of atrioventricular reentrant tachycardia in response to administration of adenosine. Heart rate = 300 bpm [own material].
Ryc. 6. Przerwanie nawrotnego częstoskurczu przedsionkowo-komorowego w odpowiedzi na podaż adenozyny. Rytm serca o częstości 300/min [materiał własny].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64721c96215d2f6c89dbc603/j_devperiodmed.20182202.113122_fig_006.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=ASIA6AP2G7AKOOUFAOCM%2F20251220%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251220T010143Z&X-Amz-Expires=3600&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEO%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEaDGV1LWNlbnRyYWwtMSJGMEQCIGZKLc3vZHFmdmjhuZDDhokrOfzU0OyJlKJ3uXGYdk2jAiBmi8sq2TWp3a6uiqZ9a9aKXIVbAgZS%2BJ25wFHEEuozwirEBQi4%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F8BEAIaDDk2MzEzNDI4OTk0MCIMF%2BvP1UrCLVpOtx5oKpgFdVbjE6GKcbIYgxFSRDSDUt5gmWaBIJQrspThg7LeYDkOyTs%2BaH55aaWUWaW3IgU1EwiO2jan4lCVmKxWRc1EljaibVwDl%2Fp2xcXwwM%2BiEXxuvQdbu%2FdHWNVExg4gQOQ3y4oPKQHkG4roEyWRI9K%2FR4r1b4YJFZ6DtZGm7vpesEkBtEu3iSDKu3STWz5HWaCpB99XCpovf0kN1hsEyhXRoGp8UPwzw3GlyWiQ%2FoBiSEJJ2ELPcCKWZh0B71gbbVcH8RHzumjyV2HDXfLN4SNrzzmg8pZbd1IqGhopkizbuGxlZQ6QDk9ASqT0stxD106DO%2FEgdnwwWj%2F9OBF3R92U1bTK2gI2PeV1KYnMTQ%2B%2Fd8Dr1EAzqey5a9YRwMlSiK5Y5tuKzz%2F6dE5ay0n8lA13VQTqsa7JQ3GsXLPsNSW60oHC6lrfOsAcvYnJyh%2FKtyPtF2U1BnUlpC03yWmNkbEbSj9d9K3RqaWPaiB9G7H%2BX%2BS%2FwVni7PNMCu04Rldq1oR0hfA4bZJdlJMiwAPPrNMVB5%2BKynfzsOAfug8KVBJz0de8sSiEYb61yUGP%2FhTWZpYH0voNb3YCs4hfWoiI%2BYG9KPtTs7YJOYnLGgU%2FcMjAXVs%2FJGQSuPio6rd4YOR5cTBIiksUpVWEAG%2BoVt07enUP6VggWoZ8clR59UTwTQqVdmdNnfCJ0NxkNCfXxWbG4zyWU%2B%2FW4561WghKUB5VI1x02pAhde2gp0Lk4L7wFp7j04%2B2Bys0X4c%2F%2FsqBBYTCiWIfFKZBCbIWGKfCUQszYeeUANCEgz7B1sMPXeG7KWgVAnIfL6lnHZL%2BbDpbER6%2BF7W02Fdbw5gFv8%2BhvgHeDX4V0I7z1GPW8Nq%2BtgkWm8z24ol2kMuSQ6A5UTCJppfKBjqyAaL%2Fs09ueasdI0Y9P0RB%2BvzQLxZvjDsM0QRSi7zvvQ7Y%2BtDKRMwTTlbUWFtiCDtyYX5cHdG0eI82H43crK2rdgilCo%2BfsQAI5245ciSnh8B70WEdynjXWfoN8MCsoCAUUF9Ga4DyMjJQPQQpXQj4TJwGQ4Bg8iaHQm4Gk10kxPk%2FrGDpryVt65NnlIIXE%2FyLyXIqXK8HrovkP1V%2BiBsPiq%2Btb78zQaJHkc83zexAzXKFFv4%3D&X-Amz-Signature=4ba505989d7e8bfee81c619042b5829cfdf949f24bca14fe5542e4cdaaa2f573&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 7

Fig. 8
![ECG of a 9-year-old patient with Wolff-Parkinson-White Syndrome. Sinus rhythm, heart rate = 85 bpm, normal cardiac axis, P-R interval =80 ms, QRS complex= 140 ms, J-T interval =300 ms, delta wave on an ascending arm of a QRS complex. Electrophysiological study prior to ablation confirmed presence of bilateral right-sided and anteroseptal accessory pathway [own material].
Ryc. 8. EKG 9-letniego pacjenta z zespołem Wolffa-Parkinsona-White’a. Rytm zatokowy, o częstości 85/min, pośrednia oś serca, odstęp P-R = 80 ms, QRS = 140 ms, odstęp J-T = 300 ms, fala delta na ramieniu wstępującym zespołu QRS. Badanie elektrofizjologiczne przed ablacją potwierdziło obecność drogi dodatkowej prawostronnej oraz przednio-przegrodowej [materiał własny].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64721c96215d2f6c89dbc603/j_devperiodmed.20182202.113122_fig_008.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=ASIA6AP2G7AKOOUFAOCM%2F20251220%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251220T010143Z&X-Amz-Expires=3600&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEO%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEaDGV1LWNlbnRyYWwtMSJGMEQCIGZKLc3vZHFmdmjhuZDDhokrOfzU0OyJlKJ3uXGYdk2jAiBmi8sq2TWp3a6uiqZ9a9aKXIVbAgZS%2BJ25wFHEEuozwirEBQi4%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F8BEAIaDDk2MzEzNDI4OTk0MCIMF%2BvP1UrCLVpOtx5oKpgFdVbjE6GKcbIYgxFSRDSDUt5gmWaBIJQrspThg7LeYDkOyTs%2BaH55aaWUWaW3IgU1EwiO2jan4lCVmKxWRc1EljaibVwDl%2Fp2xcXwwM%2BiEXxuvQdbu%2FdHWNVExg4gQOQ3y4oPKQHkG4roEyWRI9K%2FR4r1b4YJFZ6DtZGm7vpesEkBtEu3iSDKu3STWz5HWaCpB99XCpovf0kN1hsEyhXRoGp8UPwzw3GlyWiQ%2FoBiSEJJ2ELPcCKWZh0B71gbbVcH8RHzumjyV2HDXfLN4SNrzzmg8pZbd1IqGhopkizbuGxlZQ6QDk9ASqT0stxD106DO%2FEgdnwwWj%2F9OBF3R92U1bTK2gI2PeV1KYnMTQ%2B%2Fd8Dr1EAzqey5a9YRwMlSiK5Y5tuKzz%2F6dE5ay0n8lA13VQTqsa7JQ3GsXLPsNSW60oHC6lrfOsAcvYnJyh%2FKtyPtF2U1BnUlpC03yWmNkbEbSj9d9K3RqaWPaiB9G7H%2BX%2BS%2FwVni7PNMCu04Rldq1oR0hfA4bZJdlJMiwAPPrNMVB5%2BKynfzsOAfug8KVBJz0de8sSiEYb61yUGP%2FhTWZpYH0voNb3YCs4hfWoiI%2BYG9KPtTs7YJOYnLGgU%2FcMjAXVs%2FJGQSuPio6rd4YOR5cTBIiksUpVWEAG%2BoVt07enUP6VggWoZ8clR59UTwTQqVdmdNnfCJ0NxkNCfXxWbG4zyWU%2B%2FW4561WghKUB5VI1x02pAhde2gp0Lk4L7wFp7j04%2B2Bys0X4c%2F%2FsqBBYTCiWIfFKZBCbIWGKfCUQszYeeUANCEgz7B1sMPXeG7KWgVAnIfL6lnHZL%2BbDpbER6%2BF7W02Fdbw5gFv8%2BhvgHeDX4V0I7z1GPW8Nq%2BtgkWm8z24ol2kMuSQ6A5UTCJppfKBjqyAaL%2Fs09ueasdI0Y9P0RB%2BvzQLxZvjDsM0QRSi7zvvQ7Y%2BtDKRMwTTlbUWFtiCDtyYX5cHdG0eI82H43crK2rdgilCo%2BfsQAI5245ciSnh8B70WEdynjXWfoN8MCsoCAUUF9Ga4DyMjJQPQQpXQj4TJwGQ4Bg8iaHQm4Gk10kxPk%2FrGDpryVt65NnlIIXE%2FyLyXIqXK8HrovkP1V%2BiBsPiq%2Btb78zQaJHkc83zexAzXKFFv4%3D&X-Amz-Signature=a285e1e34542be89ffe6be4b9526eebc3613248add7a7ad2661e61cc97b2caa1&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Arrhythmias registered in the 24-hour Holter ECG_Tabela II_ Zaburzenia rytmu zarejestrowane w 24-godzinnym zapisie EKG metodą Holtera_
| Division of patients according to age | ||
|---|---|---|
| Abnormalities registered in the 24-hour Holter ECG | Patients over the age of 5 (36 children) | Patients under the age of 1 (9 children) |
| Premature Ventricular Contractions | 33.3% | 11.1% |
| Premature Atrial Contractions | 33.3% | − |
| Sinus tachycardia | 13.3% | − |
| Sinoatrial II° block | 6.7% | − |
| Atrioventricular II° block type 2:1 | 2.2% | − |
| Atrioventricular reentrant tachycardia | 2.2% | − |
Abnormalities registered in the 12-lead ECG_ Tabela I_ Zmiany rejestrowane w 12-odprowadzeniowym spoczynkowym zapisie EKG_
| Division of patients according to age | ||
|---|---|---|
| Abnormalities registered in the 12-lead ECG Nieprawidłowości rejestrowane | Patients over the age of 5 (36 children) | Patients under the age of 1 (9 children) |
| Leti axis deviation | 38.9% | 11.1% |
| Right axis deviation | − | 66.6% − a correct feature in this age group. |
| Atrioventricular reentrant tachycardia | 36.1% | 88.9% |
| Apparent preexcitation | 80.5% | 55.6% |
| Intermittent preexcitation | 16.7% | 44.4% |
| Latent preexcitation | 2.8% | − |