Marked First Degree Atrioventricular Block: an extremely prolonged PR interval associated with Atrioventricular Dissociation in a young Nigerian man with Pseudo-Pacemaker Syndrome: a case report

Abstract

BackgroundThe diagnosis of Marked First Degree Atrioventricular Block is made with electrocardiogram when PR interval ≥0.30 s. A PR interval of up to 0.48 s had been reported in literature. Data is sparse on an extremely prolonged PR interval associated with Atrioventricular Dissociation and Pseudo-Pacemaker Syndrome. Electrocardiogram with this type of uncommon features poses diagnostic and management challenges in clinical practice.Case presentationWe report a case of a 22 year old Nigerian male from Igbo ethnic group who presented himself for medical screening with a history of exercise intolerance, occasional palpitation and fainting spells. He has no history of cough, orthopnoea, paroxysmal nocturnal dyspnoea nor body swelling. A physical examination revealed that the patient has a pulse rate of 64 beats per minute, blood pressure of 110/70 mmHg and soft heart sounds. Standard 12-lead electrocardiogram showed an uncommon Marked First Degree Atrioventricular Block with an extremely prolonged PR interval of 0.56 s. Long rhythm strips of the electrocardiogram showed extremely prolonged PR interval associated with Atrioventricular Dissociation and variable degrees of Atrioventricular Block (Mobitz type I and II).ConclusionsAn extremely prolonged PR interval may occur in First Degree Atrioventricular Block and it may be associated with Atrioventricular Dissociation and Pseudo-Pacemaker Syndrome which may pose diagnostic and management challenges. This suggests that not all cases of First Degree Atrioventricular Block are benign and so should be sub-classified based on degree of PR interval prolongation and associated electrical abnormalities.

Progressive First-Degree Atrioventricular Block as a Warning Sign for Perioperative Bradyarrhythmia

“…[8][9][10] An episode of syncope in our patient four years before the breast surgery was, however, likely unrelated to this syndrome because reported patients presented with much longer PR intervals (PR interval >0.3 seconds) than our patient. 8,9 Hence, we did not conduct any further examination, such as a treadmill stress test or a temporary pacing study, 7 to exclude symptomatic first-degree AVB.…”

“…Although the first-degree AVB is almost always asymptomatic, an extremely prolonged PR interval, by itself, may cause dyspnea upon exertion, palpitation, or fainting spells (a pacemaker-like syndrome.) [7][8][9][10] Here, the atrioventricular desynchrony occurred due to the profound delay of the electrical conduction, resulting in retrograde ventricular-atrial conduction and "negative atrial kick." [8][9][10] An episode of syncope in our patient four years before the breast surgery was, however, likely unrelated to this syndrome because reported patients presented with much longer PR intervals (PR interval >0.3 seconds) than our patient.…”

“…[7][8][9][10] Here, the atrioventricular desynchrony occurred due to the profound delay of the electrical conduction, resulting in retrograde ventricular-atrial conduction and "negative atrial kick." [8][9][10] An episode of syncope in our patient four years before the breast surgery was, however, likely unrelated to this syndrome because reported patients presented with much longer PR intervals (PR interval >0.3 seconds) than our patient. 8,9 Hence, we did not conduct any further examination, such as a treadmill stress test or a temporary pacing study, 7 to exclude symptomatic first-degree AVB.…”

Pseudo‐pacemaker syndrome with prolonged PR interval: A narrative review

“…Ogunlade et al., 6 Follansbee et al., 14 and Skakun et al 15 . described Nigerian, 6 African‐American, 14 and Ukrainian 15 cases, respectively.…”

“…The retrieved 17 cases of PPMS—including our case report—are outlined in Table 1 2,6,10,12–21 . Most (88.2%) were adults with an average age of 47 years ranging from 13 to 86 years old.…”