hrvatski

Congenital complete atrioventricular block in an adult

Introduction: Complete congenital atrioventricular block (CCB) is the most common type of atrioventricular conduction impairment with the incidence of 1 in 15 000 births. It may occur as a result of a structural heart disease or it can be isolated. Estimated mortality rate among adults with isolated CCB is 5%. The exact mechanisms of isolated CCB occurrence is still unknown. The assumption is that the immune response has a major role in its emergence due to transplacental passage of maternal autoantibodies to the nuclear antigens, predominantly SSA/Ro and SSB/La. Consequent inflammation leads to injury and fibrosis of the conduction heart system. Other possible causes include viral infections and long QT syndrome. As patients are predominantly asymptomatic, routine 12-lead ECG is often the first tool in making a diagnosis of CCB. Other diagnostic procedures are 24-hour electrocardiographic recordings (Holter ECG), exercise stress test, and echocardiography. Case report: 22-year old female patient was admitted to hospital due to dizziness. Few months earlier, extensive neurological and otorhinolaryngological examination was done, which showed no signs of any central nervous system or vestibular pathology. 24-hour Holter ECG verified atrioventricular dissociation, with average heart rate 47 (interval 32-88) beats per minute (bpm). Exercise stress test was normal, with adequate chronotropic response, maximum to 158 bpm. In the beginning of the test 2:1 atrioventricular block (AVB) was observed, while in the peak load AVB type I was noticed. Tilt-up table test excluded an orthostatic and vasovagal component. Echocardiography showed minimal prolapse of the mitral anterior cusp with mild mitral and tricuspid regurgitation. Repeated Holter ECG showed sinus rhythm, with average heart rate of 54 bpm (interval 32-114 bpm), and intermittent second degree AVB, Mobitz I and total AVB. Additional testing was performed using overlapping Bruce protocol during which significant decrease in heart rate was registered and followed by presyncopal episodes. Therefore permanent pacemaker was implanted which stimulated the His bundle in order to avoid dyssynchrony. Conclusion: In patient with CCB, without structural heart disease, using overlapping Bruce protocol we have unmasked presyncopal symptoms, and therefore made an indication for permanent pacemaker implantation.

Complete congenital atrioventricular block, overlapping Bruce protocol

nije evidentirano

engleski

Congenital complete atrioventricular block in an adult

Introduction: Complete congenital atrioventricular block (CCB) is the most common type of atrioventricular conduction impairment with the incidence of 1 in 15 000 births. It may occur as a result of a structural heart disease or it can be isolated. Estimated mortality rate among adults with isolated CCB is 5%. The exact mechanisms of isolated CCB occurrence is still unknown. The assumption is that the immune response has a major role in its emergence due to transplacental passage of maternal autoantibodies to the nuclear antigens, predominantly SSA/Ro and SSB/La. Consequent inflammation leads to injury and fibrosis of the conduction heart system. Other possible causes include viral infections and long QT syndrome. As patients are predominantly asymptomatic, routine 12-lead ECG is often the first tool in making a diagnosis of CCB. Other diagnostic procedures are 24-hour electrocardiographic recordings (Holter ECG), exercise stress test, and echocardiography. Case report: 22-year old female patient was admitted to hospital due to dizziness. Few months earlier, extensive neurological and otorhinolaryngological examination was done, which showed no signs of any central nervous system or vestibular pathology. 24-hour Holter ECG verified atrioventricular dissociation, with average heart rate 47 (interval 32-88) beats per minute (bpm). Exercise stress test was normal, with adequate chronotropic response, maximum to 158 bpm. In the beginning of the test 2:1 atrioventricular block (AVB) was observed, while in the peak load AVB type I was noticed. Tilt-up table test excluded an orthostatic and vasovagal component. Echocardiography showed minimal prolapse of the mitral anterior cusp with mild mitral and tricuspid regurgitation. Repeated Holter ECG showed sinus rhythm, with average heart rate of 54 bpm (interval 32-114 bpm), and intermittent second degree AVB, Mobitz I and total AVB. Additional testing was performed using overlapping Bruce protocol during which significant decrease in heart rate was registered and followed by presyncopal episodes. Therefore permanent pacemaker was implanted which stimulated the His bundle in order to avoid dyssynchrony. Conclusion: In patient with CCB, without structural heart disease, using overlapping Bruce protocol we have unmasked presyncopal symptoms, and therefore made an indication for permanent pacemaker implantation.

Complete congenital atrioventricular block, overlapping Bruce protocol

nije evidentirano