e-Herz: Case study Herz 2013 DOI 10.1007/s00059-013-4002-0 Received: 23 August 2013 Revised: 16 September 2013 Accepted: 26 September 2013 © Urban & Vogel 2013
e-Herz
Sarcoidosis is a multisystem granulomatous disease of unknown etiology characterized by noncaseating granulomas in involved organs. Cardiac involvement in patients with sarcoidosis is being increasingly recognized and is associated with a poor prognosis [1, 2]. It may be detected alone and may precede, follow, or occur concurrently with involvement of the lungs. There is clinical evidence of myocardial involvement in approximately 5% of patients with sarcoidosis, although autopsy studies indicate that subclinical cardiac involvement is present in 20– 70% of cases [3]. Since it is caused by involvement of the basal interventricular septum by scar tissue, granulomas, or involvement of the nodal artery causing ischemia in the conduction system [4], complete atrioventricular block (AVB) is one of the most common finding in patients with clinically evident cardiac sarcoidosis (CS) and occurs at a younger age in patients with sarcoidosis than in those with complete AVB of other cause [1, 4, 5].Therefore, CS should be considered in patients younger than 55 years presenting with unexplained AVB and in patients with idiopathic cardiomyopathy and sustained ventricular tachycardia, or in a patient with known sarcoidosis who develops arrhythmias, conduction disease, or heart failure [1, 2].
Case report A 53-year-old woman with a history of pulmonary sarcoidosis was hospitalized
B. Sensoy · O. Ozeke · U. Canpolat · A. Colak · E. Grbovic · S. Cay · S. Topaloglu · D. Aras · S. Aydogdu Department of Cardiology, Turkiye Yuksek Ihtisas Hospital, Ankara
Phase-4 paroxysmal atrioventricular block in sarcoidosis following three episodes of witnessed syncope. The syncope occurred upon standing and it was preceded by some dizziness and lightheadedness. Her baseline 12-lead electrocardiogram (ECG) was normal, but on telemetry there were numerous episodes of paroxysmal AVB with asystolic periods lasting up to 11.8 s. Analysis of the rhythm strips revealed phase-4 intra-His bundle block characterized by critical P-P intervals that triggered the AVB, and a narrow range of junctional escape to subsequent P-wave intervals that were required to release the AVB. Physical examination findings were normal. The ECG morphology and echocardiogram were normal. Holter recordings revealed numerous episodes of paroxysmal AVB with ventricular escape beats (VEB) with pauses of up to 11.8 s of duration (. Fig. 1). However, the most interesting finding was that most but not all pauses due to paroxysmal AVBs were terminated by a VEB (arrows in . Fig. 2) and AV conduction returned. Owing to the patient’s increased risk for sudden cardiac death (SCD) [5, 6], she received an implantable cardioverter-defibrillator (ICD).
Discussion Complete AVB is the most common abnormality and has been reported in 23 to 30% of CS patients [1, 5], whereas ventricular tachycardia is the second most common manifestation of CS and has been reported in 23% of CS patients.
Therefore, SCD, due to either ventricular arrhythmia or complete AVB, is the most feared complication and can be the first manifestation of CS. Considering the increased risk of SCD, CS is an indication for early treatment with corticosteroids or other immunosuppressive agents and with a pacemaker or preferentially ICD to prevent SCD [5, 6]. In refractory cases, cardiac transplantation should be considered [7]. Paroxysmal AVB, defined as the sudden and unexpected repetitive block of the atrial impulse on its way to the ventricles, is an important etiology of syncope primarily caused by the delayed emergence of an adequate escape rhythm [8]. It is a poorly defined clinical entity and there are some hypothetical electrophysiological mechanisms to explain the occurrence and/or resolution of paroxysmal AVB such as phase-3 block, phase-4 block, and supernormal conduction [8, 9, 10, 11, 12]. The most interesting finding in our case was that paroxysmal AVBs were terminated by a VEB (arrows in . Fig. 2), after which AV conduction returned. Rosenbaum et al. [8] were the first to describe in detail the characteristics of phase-3 and phase-4 paroxysmal AVB [13]. Whereas tachycardia-dependent paroxysmal (phase-3 block) AVB develops in conjunction with an increased rate of the atrial input to the AV conduction system and is related to delayed recovery of a segment of the conduction system, pause-dependent (phase-4 block) Herz 2013
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e-Herz: Case study
Fig. 1 8 Selected Holter recordings demonstrating paroxysmal atrioventricular block with 15 A-A interval without ventricular conduction reaching 11.8 s
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Fig. 2 8 Selected Holter recordings demonstrating the resolution of all paroxysmal atrioventricular blocks by only (arrows) but not all (asterisks) ventricular escape beats
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e-Herz: Case study paroxysmal AVB is related to hypopolarization plus spontaneous diastolic depolarization [8, 14]. The bundle is a critical site in the development of paroxysmal AVB [14]. Sudden change from normal 1:1 AV conduction to complete AVB is precipitated by a pause following a premature atrial, ventricular, or His-extrasystole triggering phase-4 depolarization in a diseased His-Purkinje system. Paroxysmal AVB occurs if a single P wave is delayed and falls on the phase-4 range when the cell is no longer at resting membrane potential and is therefore unable to transmit the action potential. Subsequent impulses continue to find the diseased conduction system during its phase 4 leading to inability to depolarize. During phase-4 AVB, only those VEBs that occur distal to the blocking zone can conduct to the ventricles. This AVB persists until another atrial or VEB captures the His-Purkinje system prior to phase-4 depolarization, thereby restoring normal conduction. In phase-3 and phase-4 blocks, retrograde conduction tends to be preserved at a time when orthograde conduction has already failed [8]. The VEB, however, can only restore conduction if the P wave that follows the VEB does not again fall in the phase-4 range of conduction block (asterisks in . Fig. 2). The VPB with retrograde conduction at the critical short cycle conducts through the AV node and the proximal portion of the His-bundle and affects their refractoriness and repolarizes the site of block to reestablish a normal resting potential (arrows in . Fig. 2); finally, since there is no delay, phase-4 depolarization does not develop resulting in a normal QRS complex.
Corresponding address O. Ozeke Department of Cardiology, Turkiye Yuksek Ihtisas Hospital 06100 Ankara Turkey [email protected]
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Compliance with ethical guidelines Conflict of interest. B. Sensoy, O. Ozeke, U. Canpolat, A. Colak, E. Grbovic, S. Cay, S. Topaloglu, D. Aras, and S. Aydogdu state that there are no conflicts of interest. Consent was obtained from all patients identifiable from images or other information within the manuscript. In the case of underage patients, consent was obtained from a parent or legal guardian.
References 1. Youssef G, Beanlands RS, Birnie DH, Nery PB (2011) Cardiac sarcoidosis: applications of imaging in diagnosis and directing treatment. Heart 97:2078–2087 2. Nery PB, Leung E, Birnie DH (2012) Arrhythmias in cardiac sarcoidosis: diagnosis and treatment. Curr Opin Cardiol 27:181–189 3. Mantini N, Williams B Jr, Stewart J et al (2012) Cardiac sarcoid: a clinician’s review on how to approach the patient with cardiac sarcoid. Clin cardiol 35:410–415 4. Sekhri V, Sanal S, Delorenzo LJ et al (2011) Cardiac sarcoidosis: a comprehensive review. Arch Med Sci 7:546–554 5. Kandolin R, Lehtonen J, Kupari M (2011) Cardiac sarcoidosis and giant cell myocarditis as causes of atrioventricular block in young and middle-aged adults. Circ Arrhythm Electrophysiol 4:303–309 6. Kron J, Sauer W, Schuller J et al (2013) Efficacy and safety of implantable cardiac defibrillators for treatment of ventricular arrhythmias in patients with cardiac sarcoidosis. Europace 15:347– 354 7. Zaidi AR, Zaidi A, Vaitkus PT (2007) Outcome of heart transplantation in patients with sarcoid cardiomyopathy. J Heart Lung Transplant 26:714– 717 8. Rosenbaum MB, Elizari MV, Levi RJ, Nau GJ (1973) Paroxysmal atrioventricular block related to hypopolarization and spontaneous diastolic depolarization. Chest 63:678–688 9. El-Sherif N, Jalife J (2009) Paroxysmal atrioventricular block: are phase 3 and phase 4 block mechanisms or misnomers? Heart rhythm 6:1514–1521 10. Butschek R, Powell BD, Littmann L (2013) Phase 4 paroxysmal AV block in a patient with scleroderma. J Electrocardiol. doi:10.1016/j.jelectrocard.2013.06.003 11. Zahid M, Arora S (2012) Reverse Wenckebach “pseudo-supernormal” conduction or paroxysmal atrioventricular block. J Cardiovasc Dis Res 3:225– 227 12. Langendrof R (1973) The role of spontaneous diastolic depolarization in second degree A-V block: the mechanism of “paroxysmal” A-V block and of a new form of pseudo-supernormal A-V conduction. Chest 63:652
13. Corrado G, Levi RJ, Nau GJ, Rosenbaum MB (1974) Paroxysmal atrioventricular block related to phase 4 bilateral bundle branch block. Am J Cardiol 33:553–556 14. el-Sherif N, Scherlag BJ, Lazzara R et al (1974) The pathophysiology of tachycardia-dependent paroxysmal atrioventricular block after acute myocardial ischemia. Experimental and clinical observations. Circulation 50:515–528
e-Herz
Sarcoidosis is a multisystem granulomatous disease of unknown etiology characterized by noncaseating granulomas in involved organs. Cardiac involvement in patients with sarcoidosis is being increasingly recognized and is associated with a poor prognosis [1, 2]. It may be detected alone and may precede, follow, or occur concurrently with involvement of the lungs. There is clinical evidence of myocardial involvement in approximately 5% of patients with sarcoidosis, although autopsy studies indicate that subclinical cardiac involvement is present in 20– 70% of cases [3]. Since it is caused by involvement of the basal interventricular septum by scar tissue, granulomas, or involvement of the nodal artery causing ischemia in the conduction system [4], complete atrioventricular block (AVB) is one of the most common finding in patients with clinically evident cardiac sarcoidosis (CS) and occurs at a younger age in patients with sarcoidosis than in those with complete AVB of other cause [1, 4, 5].Therefore, CS should be considered in patients younger than 55 years presenting with unexplained AVB and in patients with idiopathic cardiomyopathy and sustained ventricular tachycardia, or in a patient with known sarcoidosis who develops arrhythmias, conduction disease, or heart failure [1, 2].
Case report A 53-year-old woman with a history of pulmonary sarcoidosis was hospitalized
B. Sensoy · O. Ozeke · U. Canpolat · A. Colak · E. Grbovic · S. Cay · S. Topaloglu · D. Aras · S. Aydogdu Department of Cardiology, Turkiye Yuksek Ihtisas Hospital, Ankara
Phase-4 paroxysmal atrioventricular block in sarcoidosis following three episodes of witnessed syncope. The syncope occurred upon standing and it was preceded by some dizziness and lightheadedness. Her baseline 12-lead electrocardiogram (ECG) was normal, but on telemetry there were numerous episodes of paroxysmal AVB with asystolic periods lasting up to 11.8 s. Analysis of the rhythm strips revealed phase-4 intra-His bundle block characterized by critical P-P intervals that triggered the AVB, and a narrow range of junctional escape to subsequent P-wave intervals that were required to release the AVB. Physical examination findings were normal. The ECG morphology and echocardiogram were normal. Holter recordings revealed numerous episodes of paroxysmal AVB with ventricular escape beats (VEB) with pauses of up to 11.8 s of duration (. Fig. 1). However, the most interesting finding was that most but not all pauses due to paroxysmal AVBs were terminated by a VEB (arrows in . Fig. 2) and AV conduction returned. Owing to the patient’s increased risk for sudden cardiac death (SCD) [5, 6], she received an implantable cardioverter-defibrillator (ICD).
Discussion Complete AVB is the most common abnormality and has been reported in 23 to 30% of CS patients [1, 5], whereas ventricular tachycardia is the second most common manifestation of CS and has been reported in 23% of CS patients.
Therefore, SCD, due to either ventricular arrhythmia or complete AVB, is the most feared complication and can be the first manifestation of CS. Considering the increased risk of SCD, CS is an indication for early treatment with corticosteroids or other immunosuppressive agents and with a pacemaker or preferentially ICD to prevent SCD [5, 6]. In refractory cases, cardiac transplantation should be considered [7]. Paroxysmal AVB, defined as the sudden and unexpected repetitive block of the atrial impulse on its way to the ventricles, is an important etiology of syncope primarily caused by the delayed emergence of an adequate escape rhythm [8]. It is a poorly defined clinical entity and there are some hypothetical electrophysiological mechanisms to explain the occurrence and/or resolution of paroxysmal AVB such as phase-3 block, phase-4 block, and supernormal conduction [8, 9, 10, 11, 12]. The most interesting finding in our case was that paroxysmal AVBs were terminated by a VEB (arrows in . Fig. 2), after which AV conduction returned. Rosenbaum et al. [8] were the first to describe in detail the characteristics of phase-3 and phase-4 paroxysmal AVB [13]. Whereas tachycardia-dependent paroxysmal (phase-3 block) AVB develops in conjunction with an increased rate of the atrial input to the AV conduction system and is related to delayed recovery of a segment of the conduction system, pause-dependent (phase-4 block) Herz 2013
| 1
e-Herz: Case study
Fig. 1 8 Selected Holter recordings demonstrating paroxysmal atrioventricular block with 15 A-A interval without ventricular conduction reaching 11.8 s
2 |
Herz 2013
Fig. 2 8 Selected Holter recordings demonstrating the resolution of all paroxysmal atrioventricular blocks by only (arrows) but not all (asterisks) ventricular escape beats
Herz 2013
| 3
e-Herz: Case study paroxysmal AVB is related to hypopolarization plus spontaneous diastolic depolarization [8, 14]. The bundle is a critical site in the development of paroxysmal AVB [14]. Sudden change from normal 1:1 AV conduction to complete AVB is precipitated by a pause following a premature atrial, ventricular, or His-extrasystole triggering phase-4 depolarization in a diseased His-Purkinje system. Paroxysmal AVB occurs if a single P wave is delayed and falls on the phase-4 range when the cell is no longer at resting membrane potential and is therefore unable to transmit the action potential. Subsequent impulses continue to find the diseased conduction system during its phase 4 leading to inability to depolarize. During phase-4 AVB, only those VEBs that occur distal to the blocking zone can conduct to the ventricles. This AVB persists until another atrial or VEB captures the His-Purkinje system prior to phase-4 depolarization, thereby restoring normal conduction. In phase-3 and phase-4 blocks, retrograde conduction tends to be preserved at a time when orthograde conduction has already failed [8]. The VEB, however, can only restore conduction if the P wave that follows the VEB does not again fall in the phase-4 range of conduction block (asterisks in . Fig. 2). The VPB with retrograde conduction at the critical short cycle conducts through the AV node and the proximal portion of the His-bundle and affects their refractoriness and repolarizes the site of block to reestablish a normal resting potential (arrows in . Fig. 2); finally, since there is no delay, phase-4 depolarization does not develop resulting in a normal QRS complex.
Corresponding address O. Ozeke Department of Cardiology, Turkiye Yuksek Ihtisas Hospital 06100 Ankara Turkey [email protected]
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Herz 2013
Compliance with ethical guidelines Conflict of interest. B. Sensoy, O. Ozeke, U. Canpolat, A. Colak, E. Grbovic, S. Cay, S. Topaloglu, D. Aras, and S. Aydogdu state that there are no conflicts of interest. Consent was obtained from all patients identifiable from images or other information within the manuscript. In the case of underage patients, consent was obtained from a parent or legal guardian.
References 1. Youssef G, Beanlands RS, Birnie DH, Nery PB (2011) Cardiac sarcoidosis: applications of imaging in diagnosis and directing treatment. Heart 97:2078–2087 2. Nery PB, Leung E, Birnie DH (2012) Arrhythmias in cardiac sarcoidosis: diagnosis and treatment. Curr Opin Cardiol 27:181–189 3. Mantini N, Williams B Jr, Stewart J et al (2012) Cardiac sarcoid: a clinician’s review on how to approach the patient with cardiac sarcoid. Clin cardiol 35:410–415 4. Sekhri V, Sanal S, Delorenzo LJ et al (2011) Cardiac sarcoidosis: a comprehensive review. Arch Med Sci 7:546–554 5. Kandolin R, Lehtonen J, Kupari M (2011) Cardiac sarcoidosis and giant cell myocarditis as causes of atrioventricular block in young and middle-aged adults. Circ Arrhythm Electrophysiol 4:303–309 6. Kron J, Sauer W, Schuller J et al (2013) Efficacy and safety of implantable cardiac defibrillators for treatment of ventricular arrhythmias in patients with cardiac sarcoidosis. Europace 15:347– 354 7. Zaidi AR, Zaidi A, Vaitkus PT (2007) Outcome of heart transplantation in patients with sarcoid cardiomyopathy. J Heart Lung Transplant 26:714– 717 8. Rosenbaum MB, Elizari MV, Levi RJ, Nau GJ (1973) Paroxysmal atrioventricular block related to hypopolarization and spontaneous diastolic depolarization. Chest 63:678–688 9. El-Sherif N, Jalife J (2009) Paroxysmal atrioventricular block: are phase 3 and phase 4 block mechanisms or misnomers? Heart rhythm 6:1514–1521 10. Butschek R, Powell BD, Littmann L (2013) Phase 4 paroxysmal AV block in a patient with scleroderma. J Electrocardiol. doi:10.1016/j.jelectrocard.2013.06.003 11. Zahid M, Arora S (2012) Reverse Wenckebach “pseudo-supernormal” conduction or paroxysmal atrioventricular block. J Cardiovasc Dis Res 3:225– 227 12. Langendrof R (1973) The role of spontaneous diastolic depolarization in second degree A-V block: the mechanism of “paroxysmal” A-V block and of a new form of pseudo-supernormal A-V conduction. Chest 63:652
13. Corrado G, Levi RJ, Nau GJ, Rosenbaum MB (1974) Paroxysmal atrioventricular block related to phase 4 bilateral bundle branch block. Am J Cardiol 33:553–556 14. el-Sherif N, Scherlag BJ, Lazzara R et al (1974) The pathophysiology of tachycardia-dependent paroxysmal atrioventricular block after acute myocardial ischemia. Experimental and clinical observations. Circulation 50:515–528
