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AV block. Which type and where?
Journal of Electrocardiology 40 (2007) 358 – 359 www.jecgonline.com
AV block. Which type and where? Kartikeya Bhargava, MD, DNB,a,4 Sameer Shrivastava, MD, DM,a Balbir Singh, MD, DM,a Hein J. Wellens, MDb b
a Escorts Heart Institute and Research Center, New Delhi, India Cardiovascular Research Institute, University of Maastricht, The Netherlands Received 23 October 2006; accepted 22 November 2006
Abstract
An electrocardiogram (ECG) showing sinus tachycardia with sinus rate exceeding the ventricular rate suggesting atrio-ventricular (AV) block in a patient with old anterior wall infarction is presented. The presence of varying PR intervals, irregular RR intervals and P-QRS relationship not consistent with 2nd degree type 1 AV block was seen. The possible site(s) and degree of AV block in the case is discussed. D 2007 Elsevier Inc. All rights reserved.
Keywords:
Multilevel AV block; Wenckebach AV block
A 56-year-old nondiabetic, nonhypertensive, asthmatic man with a history of anterior wall myocardial infarction 2 months earlier was admitted with acute left ventricular
failure. His postinfarct coronary angiography had shown noncritical coronary disease with a dyskinetic anteroapical area and a left ventricular ejection fraction of 30%. He was
Fig. 1. Twelve-lead ECG showing a regular sinus rhythm at 115/min, with more P waves than QRS complexes. The RR intervals are irregular, but a repetitive pattern of the irregularity is present. The QRS shows low voltage and an extensive old anteroapical myocardial infarction. 4 Corresponding author. Tel.: +91 011 26825000; fax: 91 011 26825013. E-mail address: [email protected] 0022-0736/$ – see front matter D 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.jelectrocard.2006.11.007
K. Bhargava et al. / Journal of Electrocardiology 40 (2007) 358 – 359
359
Fig. 2. Ladder diagram showing 2-level AV block during sinus tachycardia with a 5:4 type I conduction pattern at the upper level and a 4:3 type I pattern at the lower level.
on an angiotensin converting enzyme inhibitor, antiplatelet agents, and statin, but not on digitalis or a b-blocker. The electrocardiogram on admission showed a sinus tachycardia with atrio-ventricular block (Fig. 1). An electrophysiologic study (EPS) was not performed at that time because of his unstable clinical condition. He was stabilized with noninvasive ventilation and medication for heart failure. Two days later, his ECG showed a sinus rhythm with a rate of 105 beats/min with a classical 4:3 AV Wenckebach sequence. The EPS (not shown) confirmed a suprahisian second-degree type 1 AV block. The ECG in Fig. 1 shows regular sinus P waves at a rate of 115/min with irregular RR intervals ruling out complete AV block. Careful analysis reveals that there is a regular sequence of 3 QRS complexes for each 5 sinus beats. This 5:3 block can only be explained by a 2-level block in AV conduction—5:4 block at the upper level and 4:3 block at the lower level.1 The possible sites of AV block are atrium, AV node, His bundle, and the bundle branches. The atrium as the site of second-degree AV block during sinus rhythm is very rare and is ruled out by the presence of a constant P wave duration. In addition, the narrow QRS complexes exclude the bundle branches as the site of AV block. Thus, 2-level block in the AV node-His pathway becomes likely. Because the His bundle is an uncommon site of Wenckebach block and lead V1 shows initial positivity excluding a high septal infarction, the possibility that both levels of block were located in the AV node due to transverse or horizontal
dissociation of this structure has to be considered.2 Only an EPS at the time of the conduction disturbance could have given an answer about the exact site of the block. Therefore, we have to conclude that the ECG shows a 2-level AV block with a 5:4 type I block at the upper level and a 4:3 type I block at the lower level, with the 2 levels being somewhere in the AV node and the His bundle (Fig. 2). Multilevel AV block can be seen during atrial flutter or high-rate atrial pacing during EPS, but it is an uncommon finding during sinus rhythm.2,3 In addition, the occurrence of type 1 AV block at both levels is very uncommon. Usually, a combination of type 1 block and 2:1 block is seen at the 2 levels. Correct management of multilevel block during sinus rhythm will depend upon accurate determination of the sites of the block with an indication for pacemaker implantation when both sites or the lower site of block is infra-AV nodal. The presence of AV block with irregular RR intervals with a pattern not fitting into a simple type 1 block should suggest the presence of multilevel block. References 1. Schindler S, Albers W, Luria MH. Letter to the editor. Circulation 1977; 56:689. 2. Castellanos A, Interian Jr A, Cox MM, Myerburg RJ. Alternating Wenckebach periods and allied arrhythmias. Pacing Clin Electrophysiol 1993;16:2285. 3. Kosowsky BD, Latif P, Radoff AM. Multilevel atrioventricular block. Circulation 1976;54:914.
AV block. Which type and where? Kartikeya Bhargava, MD, DNB,a,4 Sameer Shrivastava, MD, DM,a Balbir Singh, MD, DM,a Hein J. Wellens, MDb b
a Escorts Heart Institute and Research Center, New Delhi, India Cardiovascular Research Institute, University of Maastricht, The Netherlands Received 23 October 2006; accepted 22 November 2006
Abstract
An electrocardiogram (ECG) showing sinus tachycardia with sinus rate exceeding the ventricular rate suggesting atrio-ventricular (AV) block in a patient with old anterior wall infarction is presented. The presence of varying PR intervals, irregular RR intervals and P-QRS relationship not consistent with 2nd degree type 1 AV block was seen. The possible site(s) and degree of AV block in the case is discussed. D 2007 Elsevier Inc. All rights reserved.
Keywords:
Multilevel AV block; Wenckebach AV block
A 56-year-old nondiabetic, nonhypertensive, asthmatic man with a history of anterior wall myocardial infarction 2 months earlier was admitted with acute left ventricular
failure. His postinfarct coronary angiography had shown noncritical coronary disease with a dyskinetic anteroapical area and a left ventricular ejection fraction of 30%. He was
Fig. 1. Twelve-lead ECG showing a regular sinus rhythm at 115/min, with more P waves than QRS complexes. The RR intervals are irregular, but a repetitive pattern of the irregularity is present. The QRS shows low voltage and an extensive old anteroapical myocardial infarction. 4 Corresponding author. Tel.: +91 011 26825000; fax: 91 011 26825013. E-mail address: [email protected] 0022-0736/$ – see front matter D 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.jelectrocard.2006.11.007
K. Bhargava et al. / Journal of Electrocardiology 40 (2007) 358 – 359
359
Fig. 2. Ladder diagram showing 2-level AV block during sinus tachycardia with a 5:4 type I conduction pattern at the upper level and a 4:3 type I pattern at the lower level.
on an angiotensin converting enzyme inhibitor, antiplatelet agents, and statin, but not on digitalis or a b-blocker. The electrocardiogram on admission showed a sinus tachycardia with atrio-ventricular block (Fig. 1). An electrophysiologic study (EPS) was not performed at that time because of his unstable clinical condition. He was stabilized with noninvasive ventilation and medication for heart failure. Two days later, his ECG showed a sinus rhythm with a rate of 105 beats/min with a classical 4:3 AV Wenckebach sequence. The EPS (not shown) confirmed a suprahisian second-degree type 1 AV block. The ECG in Fig. 1 shows regular sinus P waves at a rate of 115/min with irregular RR intervals ruling out complete AV block. Careful analysis reveals that there is a regular sequence of 3 QRS complexes for each 5 sinus beats. This 5:3 block can only be explained by a 2-level block in AV conduction—5:4 block at the upper level and 4:3 block at the lower level.1 The possible sites of AV block are atrium, AV node, His bundle, and the bundle branches. The atrium as the site of second-degree AV block during sinus rhythm is very rare and is ruled out by the presence of a constant P wave duration. In addition, the narrow QRS complexes exclude the bundle branches as the site of AV block. Thus, 2-level block in the AV node-His pathway becomes likely. Because the His bundle is an uncommon site of Wenckebach block and lead V1 shows initial positivity excluding a high septal infarction, the possibility that both levels of block were located in the AV node due to transverse or horizontal
dissociation of this structure has to be considered.2 Only an EPS at the time of the conduction disturbance could have given an answer about the exact site of the block. Therefore, we have to conclude that the ECG shows a 2-level AV block with a 5:4 type I block at the upper level and a 4:3 type I block at the lower level, with the 2 levels being somewhere in the AV node and the His bundle (Fig. 2). Multilevel AV block can be seen during atrial flutter or high-rate atrial pacing during EPS, but it is an uncommon finding during sinus rhythm.2,3 In addition, the occurrence of type 1 AV block at both levels is very uncommon. Usually, a combination of type 1 block and 2:1 block is seen at the 2 levels. Correct management of multilevel block during sinus rhythm will depend upon accurate determination of the sites of the block with an indication for pacemaker implantation when both sites or the lower site of block is infra-AV nodal. The presence of AV block with irregular RR intervals with a pattern not fitting into a simple type 1 block should suggest the presence of multilevel block. References 1. Schindler S, Albers W, Luria MH. Letter to the editor. Circulation 1977; 56:689. 2. Castellanos A, Interian Jr A, Cox MM, Myerburg RJ. Alternating Wenckebach periods and allied arrhythmias. Pacing Clin Electrophysiol 1993;16:2285. 3. Kosowsky BD, Latif P, Radoff AM. Multilevel atrioventricular block. Circulation 1976;54:914.