Cardiovasc Interv and Ther DOI 10.1007/s12928-013-0226-4
CASE REPORT
A case of delayed complete atrioventricular block and cardiac arrest after percutaneous coronary intervention of left anterior descending coronary artery Yasuhiro Hamatani • Takashi Unoki • Hisashi Ogawa • Nobutoyo Masunaga • Mitsuru Abe • Masaharu Akao
Received: 24 July 2013 / Accepted: 28 October 2013 Ó Japanese Association of Cardiovascular Intervention and Therapeutics 2013
Abstract Delayed complete atrioventricular (AV) block due to jailed septal branch during percutaneous coronary intervention (PCI) of left anterior descending artery is a rare complication. Here, we present a case of an elderly male who developed episodes of complete AV block and cardiac arrest 2 days after transient occlusion of the septal branch during PCI, and received permanent pacemaker implantation. This case had shown first-degree AV block plus right bundle branch block before PCI, and the presence of these preexisting conduction abnormalities may have been the underlying mechanism by which the transient occlusion of jailed septal branch cause complete AV block. Keywords Complete atrioventricular block Septal branch Side branch occlusion Percutaneous coronary intervention
Introduction Percutaneous coronary intervention (PCI) has become increasingly common over recent decades. Side branch occlusion is a possible complication of PCI [1]. However, delayed complete AV block due to side branch occlusion of the septal branch of left anterior descending artery (LAD) following LAD stenting is uncommon, with few reported cases in the literature. We describe the case of an elderly
Y. Hamatani (&) T. Unoki H. Ogawa N. Masunaga M. Abe M. Akao Department of Cardiology, National Hospital Organization Kyoto Medical Center, 1-1 Fukakusa, Mukaihata-Cho, Fushimi-Ku, Kyoto 612-8555, Japan e-mail: [email protected]
male who developed syncope due to complete AV block 2 days after PCI of LAD during which the septal branch of LAD was occluded.
Case report A 76-year-old male was receiving treatment for hypertension, dyslipidemia, and diabetes mellitus at our hospital. He was taking aspirin, thienopyridine, angiotensin receptor blocker, calcium channel antagonist, statin, metformin, and insulin. He had a history of smoking (20 cigarettes daily for 20 years). He did not have chest symptom either during exercise or at rest. An electrocardiogram (ECG) at rest revealed first-degree AV block and complete right bundle branch block (CRBBB) with ST depression at V4-6 (Fig. 1). Transthoracic echocardiography showed a preserved ejection fraction of left ventricle without local asynergy. He was unable to undergo exercise stress test because of lower back pain. He probably had asymptomatic coronary artery disease. Therefore, he was screened for coronary artery disease on a CT scan. Coronary CT angiography revealed severe stenosis in proximal LAD. Coronary angiography (CAG) was performed and demonstrated severe stenosis from the left main trunk (LMT) to proximal and mid LAD (Fig. 2a). He underwent elective PCI for the stenotic lesions. Following drug eluting stent deployment at mid-LAD, side branch occlusion of the septal branch of LAD occurred (Fig. 2b). The patient developed chest discomfort and an ECG showed ST elevation at V1. The occluded septal branch of LAD was successfully re-crossed with a guidewire and plain old balloon angioplasty (POBA) was performed, resulting in improvement of the flow of the septal branch from TIMI grade 0 to 3 (Fig. 2c). The chest discomfort disappeared and the ST elevation at V1 was
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baseline (before PCI) Fig. 1 An electrocardiogram before PCI of LAD. First-degree AV block, complete right bundle branch block, and ST depression in many leads were shown with negative T waves. ST elevation was noticed in lead aVR
A
B
C
D
Fig. 2 Angiogram during PCI procedure. a Pre-procedural CAG. Severe stenoses were shown at distal LMT and proximal to mid LAD. b White arrow indicates the occluded septal branch of LAD after stenting of LAD. c Guidewire was crossed and POBA was performed with a 1.3 9 10 mm balloon. d Final angiography. The septal branch of LAD was restored to the flow of thrombolysis in myocardial infarction (TIMI) grade 3
resolved. Finally, the patient underwent successful stenting of LMT to LAD with the placement of two drug eluting stents (Fig. 2d).
123
A follow-up ECG the day after PCI showed no specific changes, when compared with the ECG of pre-PCI of LAD, and there was no elevation of cardiac enzymes the day after PCI. The patient showed a good course after PCI, and was discharged home 2 days after PCI. However, at 2 and 3 days after PCI, he experienced syncopal episodes at home. He was taken back to the emergency room in our hospital 3 days after PCI, where he was diagnosed with complete AV block with a heart rate of 48 beats per minute (Fig. 3a). His blood pressure was 133/54 mmHg and consciousness was clear. Physical examination of the chest and abdomen revealed no abnormalities. Laboratory testing demonstrated a positive serum troponin T level, but no elevation of creatine kinase or electrolyte abnormalities. Transthoracic echocardiography showed normal findings. At the emergency room, he developed an episode of unresponsiveness. On an ECG monitor, he lost his escape rhythm and showed cardiac arrest. He received cardiopulmonary resuscitation (CPR) for 1 min, resulting in the return of spontaneous circulation. An ECG after the recovery showed normal sinus rhythm with first-degree AV block, CRBBB, and left anterior fascicular block (LAFB) (Fig. 3b). After the placement of a temporary transvenous pacemaker in the femoral vein, he underwent emergent CAG, which showed patency of both the stented LMT to LAD and the jailed septal branch of LAD. The right coronary artery (RCA) remained unchanged (Fig. 4a, b). Intravascular ultrasound was performed, showing no stent thrombosis or coronary dissection. During reinsertion of the temporary pacemaker from the jugular vein, he again developed complete AV block and a cardiac arrest (Fig. 5). He received CPR, and intravenous atropine and epinephrine, after which the spontaneous circulation was restored, along with a normal rhythm. He was subsequently admitted to the intensive care unit for observation. He was in sinus rhythm with first-degree AV block and CRBBB with a rate of 70–80 beats per minute. The day after admission, transient complete AV block occurred for 10 s. He underwent permanent pacemaker implantation (PMI) 3 days after the emergent admission. He then showed a good course and experienced no complications after PMI. He was discharged days after the emergent admission.
Discussion Our case developed complete AV block 2 days after PCI of LAD. Emergent CAG after the occurrence of complete AV block revealed no stent thrombosis and showed patency of stented LAD. During PCI of LAD, the septal branch of LAD was jailed and transiently occluded. We suspected
Complete AV block after PCI of LAD Fig. 3 An electrocardiogram. a At an emergency room 3 days after PCI of LAD. Complete AV block with a heart rate of 48 beats per minute. b After return to a normal rhythm from complete AV block. Firstdegree AV block, complete right bundle branch block plus left anterior fascicular block
A
complete AV block at ER (3 days after PCI)
A
B
Fig. 4 Angiogram at emergent CAG. a Right coronary artery. b Left coronary artery. Stented LMT to LAD was patent. Septal branch of LAD was also patent and its flow was thrombolysis in myocardial infarction (TIMI) grade 2–3 (white arrow)
aVR aVL aVF V1 V2 V3 V4 V5 V6
the episode of complete AV block and cardiac arrest at cath lab
Fig. 5 An electrocardiogram when a temporary pacemaker was reinserted from the carotid vein at cath lab. Complete AV block occurred without escape rhythm
that the complete AV block was related to the transient occlusion of the septal branch of LAD during PCI. Complete AV block occurs due to many underlying causes, including ischemic heart disease. It is reported to
B
after the recovery from complete AV block and cardiac arrest at ER
occur in 3.3 % of patients with anterior-acute myocardial infarction (AMI) [2]. The AV node is supplied by the RCA in 90 % of individuals and by the left circumflex artery (LCX) in the remaining 10 %. The bundle of His is also supplied by the RCA with a small contribution from the septal branches of LAD. On the other hand, the right bundle branch receives most of its blood supply from the septal branches of LAD. The left anterior fascicle is also supplied by the septal branches of LAD. The left posterior fascicle is supplied by the RCA and the septal branches of LAD [3]. As indicated above, the conduction system partly receives blood supply from LAD, but delayed complete AV block following occlusion of the septal branch after PCI of LAD is a rare complication. We reviewed the literature and found only five published case reports of complete AV block following jailed septal branch of LAD [4–8] (Table 1). All five patients developed complete AV block not during the PCI procedure, but 1 or 2 days after it. Our case also developed delayed complete AV block 2 days after PCI, although an ECG immediately after the procedure and the following day showed no significant change. When he returned to a normal rhythm from complete AV block, an ECG revealed first-degree AV block, CRBBB plus LAFB, and thus the presentation of trifascicular block. Unlike the other five published case reports, our case received POBA for the septal branch of LAD, resulting in successful revascularization about half an hour after the occlusion of that vessel. Transient occlusion of the septal branch of LAD may cause delayed complete AV block, as reported by Nee et al. [6] and Kireyerev et al. [7], where the flow of the septal branch was restored at the end of PCI of LAD. In the other three cases, the septal branch of LAD was occluded at the end of PCI, but was spontaneously recanalized to TIMI grade 2–3 upon the occurrence of complete AV block.
123
Y. Hamatani et al. Table 1 Review of five published case reports plus our report of delayed complete AV block due to jailed septal branch of LAD References
Age/sex
Pre-PCI of LAD conduction abnormalities
Septal branch flow at the end of PCI of LAD
Post-PCI of LAD conduction abnormalities
Complete AV block onset after PCI of LAD
Septal branch flow after the occurrence of complete AV block
Furgerson et al. [4]
74 female
Complete left bundle branch block
Thrombolysis in myocardial infarction (TIMI) 0
Complete left bundle branch block
2 days
TIMI 2
Pillai et al. [5]
67 female
None
TIMI 0
None
2 days
TIMI 1–2
Nee et al. [6]
76 female
Left anterior fascicular block
TIMI 2
Left anterior fascicular block
Next day
TIMI 2
Kireyev et al. [7]
59 male
First-degree AV block
TIMI 3 (90 %)
Complete right bundle branch block ? first-degree AV block
2 days
TIMI 0 ? TIMI 3 (POBA)
Sadiq et al. [8]
75 female
None
TIMI 0
Complete right bundle branch block ? left anterior fascicular block
2 days
TIMI 3
Our case
76 male
Complete right bundle branch block ? firstdegree AV block
TIMI 0 ? TIMI 3 (POBA)
Complete right bundle branch block ? left anterior fascicular block ? firstdegree AV block
2 days
TIMI 2–3
PCI percutaneous coronary intervention, LAD left anterior descending artery, AV atrioventricular, POBA plain old balloon angioplasty
Notably, the majority of cases showed various severities of conduction abnormalities at baseline: first-degree AV block and/or bundle branch block. The case reported by Furgerson et al. [4] was complicated with complete left bundle branch block (CLBBB), that by Nee et al. [6] with LAFB, and that by Kireyev et al. [7] with first-degree AV block. Recently, intracoronary injection of alcohol to the septal branch of LAD, called alcohol septal ablation, was applied for the treatment of hypertrophic obstructive cardiomyopathy [9]. After the procedure of alcohol septal ablation, delayed complete AV block was reported to occur in 1–25 % of cases [10, 11]. Predictors of delayed complete AV block after alcohol septal ablation were the presence of CLBBB (odds ratio: 39.0; 95 % confidence interval (CI) 3.6–413; P \ 0.01) and first-degree AV block (odds ratio: 14.0; 95 % CI 3.0–69.0; P \ 0.01) [12]. In fact, the pre-PCI ECG in our case showed first-degree AV block and CRBBB. It is a matter of debate whether the transient occlusion of septal branch during PCI was a direct cause of delayed complete AV block in our case. However, we believe that it is highly probable because of the following reasons. First, our case presented complete AV block 2 days after PCI, and the time course strongly suggests the association. Second, our case showed first-degree AV block and bundle branch block at baseline. Third, sluggish flow into the septal branch was noted at the occurrence of complete AV block. Lastly, despite the lack of elevation of creatine kinase after PCI, troponin T was elevated 3 days after PCI of LAD. The involvement of coronary artery spasm seemed
123
to be unlikely since he had not complained resting angina and had been prescribed calcium channel antagonist (nifedipine, 20 mg, once daily). However, we could not deny its involvement completely because coronary artery spasm is sometimes asymptomatic in diabetic patients and this dose of nifedipine might be insufficient. Of the patients with anterior AMI, complete AV block developed in 3.3 %, whereas the rate was 6.3 % in patients with inferior AMI [2]. Complete AV block with inferior AMI occurs as a result of accelerated vagal tone or conduction disturbances in the AV node, and in most cases, it is transient and resolves within a few days. On the other hand, complete AV block with anterior AMI occurs as a result of involvement of the conduction system beneath the AV node, persists in most cases [3, 13], and often requires PMI [14]. We decided to perform PMI because our case experienced a cardiac arrest twice. However, routine pacemaker checkup 1 month after PMI revealed no recurrence of complete AV block. Of the five published case reports, three patients underwent PMI. Two of them received PMI due to persistent complete AV block, and the remaining one did so due to the persistence of RBBB and the absence of significant ventricular escape rhythm during complete AV block. Two patients did not undergo PMI because they reverted to a normal rhythm within a few hours and were observed for several days without recurrence of complete AV block. The indication of PMI after complete AV block due to jailed septal branch of LAD should be considered depending on the situation of each case.
Complete AV block after PCI of LAD
Conclusion We present an interesting and rare case of delayed complete AV block perhaps due to transient occlusion of the septal branch of LAD following PCI of LAD. The complication of complete AV block in this setting can occur considering the anatomy of the conduction system, in which bundle branches are mainly supplied by septal branches of LAD in addition to RCA. One may consider protecting the septal branch during the PCI of LAD in the group of patients with preexisting conduction abnormalities including first-degree AV block or bundle branch block. For such patients, careful and longer in-hospital observation following the procedure may have to be considered. Conflict of interest
None.
References 1. Oda H, Tsuchida K, Okamura K, Ozaki K, Takahashi K, Miida T. Two-wire protection of side branches to prevent side branch occlusion during stent implantation for bifurcational lesions. Cardiovasc Interv Ther. 2010;25:112–6. 2. Spencer FA, Jabbour S, Lessard D, Yarzebski J, Ravid S, Zaleskas V, et al. Two-decade-long trends (1975–1997) in the incidence, hospitalization, and long-term death rates associated with complete heart block complicating acute myocardial infarction: a community-wide perspective. Am Heart J. 2003;145:500–7. 3. Zimetbaum PJ, Josephson ME. Use of the electrocardiogram in acute myocardial infarction. N Engl J Med. 2003;348:933–40. 4. Furgerson JL, Sample SA, Gilman JK, Carlson TA. Complete heart block and polymorphic ventricular tachycardia complicating myocardial infarction after occlusion of the first septal perforator with coronary stenting. Cathet Cardiovasc Diagn. 1998;44:434–7.
5. Pillai RV, Daniel R, Joseph DJ. Complete heart block following occlusion of the first septal perforator after coronary stenting. Indian Heart J. 2005;57:728–30. 6. Nee LM, Guttormsen B, Gimelli G. Delayed complete heart block secondary to jailed first septal perforator. J Invasive Cardiol. 2007;19:E338–9. 7. Kireyev D, Page B, Young HG. Septal infarction and complete heart block following percutaneous coronary intervention of the left anterior descending coronary artery. J Invasive Cardiol. 2009;21:E48–50. 8. Sadiq MA, Azman W, Abidin IZ. Irreversible delayed complete heart block secondary to jailed first septal perforator following PCI of the left anterior descending coronary artery. J Invasive Cardiol. 2012;24:E13–5. 9. Chikkabasavaiah NA, Puttegowda B, Panneerselvam A, Ananthakrishna R, Kapanigowda AP, Basavappa R. Remote infarction following percutaneous transluminal septal myocardial ablation: a report of two cases. Cardiovasc Interv Ther. 2011;26:142–6. 10. Alam M, Dokanish H, Lakkis N. Alcohol septal ablation for hypertrophic obstructive cardiomyopathy: a systematic review of published studies. J Interv Cardiol. 2006;19:319–27. 11. Fifer MA, Sigwart U. Controversies in cardiovascular medicine. Hypertrophic obstructive cardiomyopathy: alcohol septal ablation. Eur Heart J. 2011;32:1059–64. 12. Chang SM, Nagueh SF, Spencer WH 3rd, Lakkis NM. Complete heart block: determinants and clinical impact in patients with hypertrophic obstructive cardiomyopathy undergoing nonsurgical septal reduction therapy. J Am Coll Cardiol. 2003;42:296–300. 13. Hindman MC, Wagner GS, JaRo M, Atkins JM, Scheinman MM, DeSanctis RW, et al. The clinical significance of bundle branch block complicating acute myocardial infarction. Clinical characteristics, hospital mortality, and one-year follow-up. Circulation. 1978;58:689–99. 14. Epstein AE, DiMarco JP, Ellenbogen KA, Estes NA 3rd, Freedman RA, Gettes LS, et al. ACC/AHA/HRS 2008 guidelines for device-based therapy of cardiac rhythm abnormalities: a report of the American College of Cardiology/American Heart Association task force on practice guidelines: developed in collaboration with the American Association for Thoracic Surgery and Society of Throacic Surgeons. Circulation. 2008;117: e350–408.
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CASE REPORT
A case of delayed complete atrioventricular block and cardiac arrest after percutaneous coronary intervention of left anterior descending coronary artery Yasuhiro Hamatani • Takashi Unoki • Hisashi Ogawa • Nobutoyo Masunaga • Mitsuru Abe • Masaharu Akao
Received: 24 July 2013 / Accepted: 28 October 2013 Ó Japanese Association of Cardiovascular Intervention and Therapeutics 2013
Abstract Delayed complete atrioventricular (AV) block due to jailed septal branch during percutaneous coronary intervention (PCI) of left anterior descending artery is a rare complication. Here, we present a case of an elderly male who developed episodes of complete AV block and cardiac arrest 2 days after transient occlusion of the septal branch during PCI, and received permanent pacemaker implantation. This case had shown first-degree AV block plus right bundle branch block before PCI, and the presence of these preexisting conduction abnormalities may have been the underlying mechanism by which the transient occlusion of jailed septal branch cause complete AV block. Keywords Complete atrioventricular block Septal branch Side branch occlusion Percutaneous coronary intervention
Introduction Percutaneous coronary intervention (PCI) has become increasingly common over recent decades. Side branch occlusion is a possible complication of PCI [1]. However, delayed complete AV block due to side branch occlusion of the septal branch of left anterior descending artery (LAD) following LAD stenting is uncommon, with few reported cases in the literature. We describe the case of an elderly
Y. Hamatani (&) T. Unoki H. Ogawa N. Masunaga M. Abe M. Akao Department of Cardiology, National Hospital Organization Kyoto Medical Center, 1-1 Fukakusa, Mukaihata-Cho, Fushimi-Ku, Kyoto 612-8555, Japan e-mail: [email protected]
male who developed syncope due to complete AV block 2 days after PCI of LAD during which the septal branch of LAD was occluded.
Case report A 76-year-old male was receiving treatment for hypertension, dyslipidemia, and diabetes mellitus at our hospital. He was taking aspirin, thienopyridine, angiotensin receptor blocker, calcium channel antagonist, statin, metformin, and insulin. He had a history of smoking (20 cigarettes daily for 20 years). He did not have chest symptom either during exercise or at rest. An electrocardiogram (ECG) at rest revealed first-degree AV block and complete right bundle branch block (CRBBB) with ST depression at V4-6 (Fig. 1). Transthoracic echocardiography showed a preserved ejection fraction of left ventricle without local asynergy. He was unable to undergo exercise stress test because of lower back pain. He probably had asymptomatic coronary artery disease. Therefore, he was screened for coronary artery disease on a CT scan. Coronary CT angiography revealed severe stenosis in proximal LAD. Coronary angiography (CAG) was performed and demonstrated severe stenosis from the left main trunk (LMT) to proximal and mid LAD (Fig. 2a). He underwent elective PCI for the stenotic lesions. Following drug eluting stent deployment at mid-LAD, side branch occlusion of the septal branch of LAD occurred (Fig. 2b). The patient developed chest discomfort and an ECG showed ST elevation at V1. The occluded septal branch of LAD was successfully re-crossed with a guidewire and plain old balloon angioplasty (POBA) was performed, resulting in improvement of the flow of the septal branch from TIMI grade 0 to 3 (Fig. 2c). The chest discomfort disappeared and the ST elevation at V1 was
123
Y. Hamatani et al.
baseline (before PCI) Fig. 1 An electrocardiogram before PCI of LAD. First-degree AV block, complete right bundle branch block, and ST depression in many leads were shown with negative T waves. ST elevation was noticed in lead aVR
A
B
C
D
Fig. 2 Angiogram during PCI procedure. a Pre-procedural CAG. Severe stenoses were shown at distal LMT and proximal to mid LAD. b White arrow indicates the occluded septal branch of LAD after stenting of LAD. c Guidewire was crossed and POBA was performed with a 1.3 9 10 mm balloon. d Final angiography. The septal branch of LAD was restored to the flow of thrombolysis in myocardial infarction (TIMI) grade 3
resolved. Finally, the patient underwent successful stenting of LMT to LAD with the placement of two drug eluting stents (Fig. 2d).
123
A follow-up ECG the day after PCI showed no specific changes, when compared with the ECG of pre-PCI of LAD, and there was no elevation of cardiac enzymes the day after PCI. The patient showed a good course after PCI, and was discharged home 2 days after PCI. However, at 2 and 3 days after PCI, he experienced syncopal episodes at home. He was taken back to the emergency room in our hospital 3 days after PCI, where he was diagnosed with complete AV block with a heart rate of 48 beats per minute (Fig. 3a). His blood pressure was 133/54 mmHg and consciousness was clear. Physical examination of the chest and abdomen revealed no abnormalities. Laboratory testing demonstrated a positive serum troponin T level, but no elevation of creatine kinase or electrolyte abnormalities. Transthoracic echocardiography showed normal findings. At the emergency room, he developed an episode of unresponsiveness. On an ECG monitor, he lost his escape rhythm and showed cardiac arrest. He received cardiopulmonary resuscitation (CPR) for 1 min, resulting in the return of spontaneous circulation. An ECG after the recovery showed normal sinus rhythm with first-degree AV block, CRBBB, and left anterior fascicular block (LAFB) (Fig. 3b). After the placement of a temporary transvenous pacemaker in the femoral vein, he underwent emergent CAG, which showed patency of both the stented LMT to LAD and the jailed septal branch of LAD. The right coronary artery (RCA) remained unchanged (Fig. 4a, b). Intravascular ultrasound was performed, showing no stent thrombosis or coronary dissection. During reinsertion of the temporary pacemaker from the jugular vein, he again developed complete AV block and a cardiac arrest (Fig. 5). He received CPR, and intravenous atropine and epinephrine, after which the spontaneous circulation was restored, along with a normal rhythm. He was subsequently admitted to the intensive care unit for observation. He was in sinus rhythm with first-degree AV block and CRBBB with a rate of 70–80 beats per minute. The day after admission, transient complete AV block occurred for 10 s. He underwent permanent pacemaker implantation (PMI) 3 days after the emergent admission. He then showed a good course and experienced no complications after PMI. He was discharged days after the emergent admission.
Discussion Our case developed complete AV block 2 days after PCI of LAD. Emergent CAG after the occurrence of complete AV block revealed no stent thrombosis and showed patency of stented LAD. During PCI of LAD, the septal branch of LAD was jailed and transiently occluded. We suspected
Complete AV block after PCI of LAD Fig. 3 An electrocardiogram. a At an emergency room 3 days after PCI of LAD. Complete AV block with a heart rate of 48 beats per minute. b After return to a normal rhythm from complete AV block. Firstdegree AV block, complete right bundle branch block plus left anterior fascicular block
A
complete AV block at ER (3 days after PCI)
A
B
Fig. 4 Angiogram at emergent CAG. a Right coronary artery. b Left coronary artery. Stented LMT to LAD was patent. Septal branch of LAD was also patent and its flow was thrombolysis in myocardial infarction (TIMI) grade 2–3 (white arrow)
aVR aVL aVF V1 V2 V3 V4 V5 V6
the episode of complete AV block and cardiac arrest at cath lab
Fig. 5 An electrocardiogram when a temporary pacemaker was reinserted from the carotid vein at cath lab. Complete AV block occurred without escape rhythm
that the complete AV block was related to the transient occlusion of the septal branch of LAD during PCI. Complete AV block occurs due to many underlying causes, including ischemic heart disease. It is reported to
B
after the recovery from complete AV block and cardiac arrest at ER
occur in 3.3 % of patients with anterior-acute myocardial infarction (AMI) [2]. The AV node is supplied by the RCA in 90 % of individuals and by the left circumflex artery (LCX) in the remaining 10 %. The bundle of His is also supplied by the RCA with a small contribution from the septal branches of LAD. On the other hand, the right bundle branch receives most of its blood supply from the septal branches of LAD. The left anterior fascicle is also supplied by the septal branches of LAD. The left posterior fascicle is supplied by the RCA and the septal branches of LAD [3]. As indicated above, the conduction system partly receives blood supply from LAD, but delayed complete AV block following occlusion of the septal branch after PCI of LAD is a rare complication. We reviewed the literature and found only five published case reports of complete AV block following jailed septal branch of LAD [4–8] (Table 1). All five patients developed complete AV block not during the PCI procedure, but 1 or 2 days after it. Our case also developed delayed complete AV block 2 days after PCI, although an ECG immediately after the procedure and the following day showed no significant change. When he returned to a normal rhythm from complete AV block, an ECG revealed first-degree AV block, CRBBB plus LAFB, and thus the presentation of trifascicular block. Unlike the other five published case reports, our case received POBA for the septal branch of LAD, resulting in successful revascularization about half an hour after the occlusion of that vessel. Transient occlusion of the septal branch of LAD may cause delayed complete AV block, as reported by Nee et al. [6] and Kireyerev et al. [7], where the flow of the septal branch was restored at the end of PCI of LAD. In the other three cases, the septal branch of LAD was occluded at the end of PCI, but was spontaneously recanalized to TIMI grade 2–3 upon the occurrence of complete AV block.
123
Y. Hamatani et al. Table 1 Review of five published case reports plus our report of delayed complete AV block due to jailed septal branch of LAD References
Age/sex
Pre-PCI of LAD conduction abnormalities
Septal branch flow at the end of PCI of LAD
Post-PCI of LAD conduction abnormalities
Complete AV block onset after PCI of LAD
Septal branch flow after the occurrence of complete AV block
Furgerson et al. [4]
74 female
Complete left bundle branch block
Thrombolysis in myocardial infarction (TIMI) 0
Complete left bundle branch block
2 days
TIMI 2
Pillai et al. [5]
67 female
None
TIMI 0
None
2 days
TIMI 1–2
Nee et al. [6]
76 female
Left anterior fascicular block
TIMI 2
Left anterior fascicular block
Next day
TIMI 2
Kireyev et al. [7]
59 male
First-degree AV block
TIMI 3 (90 %)
Complete right bundle branch block ? first-degree AV block
2 days
TIMI 0 ? TIMI 3 (POBA)
Sadiq et al. [8]
75 female
None
TIMI 0
Complete right bundle branch block ? left anterior fascicular block
2 days
TIMI 3
Our case
76 male
Complete right bundle branch block ? firstdegree AV block
TIMI 0 ? TIMI 3 (POBA)
Complete right bundle branch block ? left anterior fascicular block ? firstdegree AV block
2 days
TIMI 2–3
PCI percutaneous coronary intervention, LAD left anterior descending artery, AV atrioventricular, POBA plain old balloon angioplasty
Notably, the majority of cases showed various severities of conduction abnormalities at baseline: first-degree AV block and/or bundle branch block. The case reported by Furgerson et al. [4] was complicated with complete left bundle branch block (CLBBB), that by Nee et al. [6] with LAFB, and that by Kireyev et al. [7] with first-degree AV block. Recently, intracoronary injection of alcohol to the septal branch of LAD, called alcohol septal ablation, was applied for the treatment of hypertrophic obstructive cardiomyopathy [9]. After the procedure of alcohol septal ablation, delayed complete AV block was reported to occur in 1–25 % of cases [10, 11]. Predictors of delayed complete AV block after alcohol septal ablation were the presence of CLBBB (odds ratio: 39.0; 95 % confidence interval (CI) 3.6–413; P \ 0.01) and first-degree AV block (odds ratio: 14.0; 95 % CI 3.0–69.0; P \ 0.01) [12]. In fact, the pre-PCI ECG in our case showed first-degree AV block and CRBBB. It is a matter of debate whether the transient occlusion of septal branch during PCI was a direct cause of delayed complete AV block in our case. However, we believe that it is highly probable because of the following reasons. First, our case presented complete AV block 2 days after PCI, and the time course strongly suggests the association. Second, our case showed first-degree AV block and bundle branch block at baseline. Third, sluggish flow into the septal branch was noted at the occurrence of complete AV block. Lastly, despite the lack of elevation of creatine kinase after PCI, troponin T was elevated 3 days after PCI of LAD. The involvement of coronary artery spasm seemed
123
to be unlikely since he had not complained resting angina and had been prescribed calcium channel antagonist (nifedipine, 20 mg, once daily). However, we could not deny its involvement completely because coronary artery spasm is sometimes asymptomatic in diabetic patients and this dose of nifedipine might be insufficient. Of the patients with anterior AMI, complete AV block developed in 3.3 %, whereas the rate was 6.3 % in patients with inferior AMI [2]. Complete AV block with inferior AMI occurs as a result of accelerated vagal tone or conduction disturbances in the AV node, and in most cases, it is transient and resolves within a few days. On the other hand, complete AV block with anterior AMI occurs as a result of involvement of the conduction system beneath the AV node, persists in most cases [3, 13], and often requires PMI [14]. We decided to perform PMI because our case experienced a cardiac arrest twice. However, routine pacemaker checkup 1 month after PMI revealed no recurrence of complete AV block. Of the five published case reports, three patients underwent PMI. Two of them received PMI due to persistent complete AV block, and the remaining one did so due to the persistence of RBBB and the absence of significant ventricular escape rhythm during complete AV block. Two patients did not undergo PMI because they reverted to a normal rhythm within a few hours and were observed for several days without recurrence of complete AV block. The indication of PMI after complete AV block due to jailed septal branch of LAD should be considered depending on the situation of each case.
Complete AV block after PCI of LAD
Conclusion We present an interesting and rare case of delayed complete AV block perhaps due to transient occlusion of the septal branch of LAD following PCI of LAD. The complication of complete AV block in this setting can occur considering the anatomy of the conduction system, in which bundle branches are mainly supplied by septal branches of LAD in addition to RCA. One may consider protecting the septal branch during the PCI of LAD in the group of patients with preexisting conduction abnormalities including first-degree AV block or bundle branch block. For such patients, careful and longer in-hospital observation following the procedure may have to be considered. Conflict of interest
None.
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