Europace Advance Access originally published online on March 30, 2007
Europace 2007 9(5):325-327; doi:10.1093/europace/eum032
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PACEMAKER THERAPY
Pacing-related acute pulmonary edema and mechanical asynchrony illustrated by three-dimensional echocardiography
1 Department of Cardiology, Chang Gung Memorial Hospital, 199, Tunhwa N. Road, Taipei, Taiwan, Republic of China; 2 The Department of Cardiology, RIPAS Hospital, Bander Seri Begawan, Brunei Darussalam
Manuscript submitted 20 November 2006. Accepted after revision 9 February 2007.
* Corresponding author. Tel: +886-3-3281200/extn 8162; fax: +886 3 3271192. E-mail address: chitai{at}adm.cgmh.org.tw
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Abstract |
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Sick sinus syndrome with symptomatic bradycardia is an indication for a permanent pacemaker. Either a single (AAIR) or dual-chamber (DDDR) pacemaker can be implanted in these patients with normal atrioventricular nodal function. This report presents a 92-year-old male with right ventricular apical pacing related recurrent acute pulmonary edema and mechanical asynchrony demonstrated by three-dimensional echocardiogram. Although three-dimensional echocardiography has been available for many years, it has seldom been applied to evaluate pacing-related intraventricular asynchrony. The systolic asynchrony index for this patient was 6.7% during AAIR pacing mode and 22% during DDDR pacing mode.
Key Words: Asynchrony, Three-dimensional echocardiogram, Pacemaker
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Introduction |
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Sick sinus syndrome with symptomatic bradycardia is an indication for permanent pacemaker implantation. To date, conflict remains regarding the appropriateness of single (AAIR) or dual-chamber (DDDR) pacing in these patients with normal atrioventricular (AV) nodal function.1
–3 According to Danish study,4 AAI pacing resulted in less mortality, atrial fibrillation, and severe heart failure compared with VVI pacing. Theoretically, right ventricular apical pacing can cause mechanical asynchrony of the left ventricle due to abnormal depolarization sequence. However, demonstrating this asynchrony using conventional two-dimensional echocardiography is difficult. With three-dimensional echocardiography, we clearly demonstrated this mechanical asynchrony from a patient with a DDDR permanent pacemaker. |
Case report |
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A 92-year-old male underwent dual-chamber pacemaker implantation due to sinus node dysfunction with symptomatic bradycardia. This patient was in sinus rhythm at baseline with normal QRS duration on electrocardiogram (ECG). His baseline left ventricular ejection fraction was
35% and he was in NYHA functional class II prior to pacemaker implantation. Furthermore, he has coronary artery disease proved by angiography. One month after pacing with DDDR mode, his symptoms of heart failure worsened. The patient was sent to our emergency room for four times in the following 3 months all because of acute pulmonary edema. His ECG revealed functioning DDDR pacemaker rhythm with wide QRS complexes (180 ms). Because ventricular pacing-related asynchrony and pulmonary edema was suspected, the pacemaker was programmed to AAIR mode. His symptoms improved several days later and he never suffers from pulmonary edema since that time. Using the Sonos 7500 Live 3D system, transthoracic three-dimensional echocardiography was performed to this patient in DDDR and AAIR pacing modes, each separated by 1 h. Full volume data sets for his left ventricle were obtained for both pacing modes and processed using the TomTec 4D left ventricle analysis software to analyse the degree of mechanical asynchrony. The full volume data sets provided time-volume analysis for global and segmental volumes of the left ventricle. A systolic asynchrony index was derived from the dispersion of time to minimum regional volume for all 16 segments. This index has been validated as a novel method to assess global left ventricular mechanical asynchrony. A high index is correlated with degree of mechanical asynchrony. This patient's index was 6.7% in AAIR pacing mode (Figure 1) and 22% in DDDR pacing mode (Figure 2). The left ventricular ejection fraction by modified Simpson's method was 32% in AAIR pacing mode and 30% in DDDR pacing mode. Moreover, septal contraction was earlier comparing to other segments in the DDDR pacing mode because of pacing from the right ventricular apex. The mechanical asynchrony caused by right ventricular pacing was clearly demonstrated from a patient with impaired left ventricular function.
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Discussion |
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Three-dimensional echocardiography has been available for many years, but has seldom been applied to evaluate pacing-related intraventricular asynchrony. On the basis of the data from this patient, three-dimensional echocardiography can be utilized to access this asynchrony clearly. The effect of pacing-related asynchrony can be subclinical in patients with normal baseline left ventricular function. However, this asynchrony may have clinical impact on some patients with impaired baseline left ventricular function. According to a previous study, ventricular pacing in patients with sick sinus syndrome causes more heart failure and atrial fibrillation than atrial pacing.5
In this case, the left ventricular ejection fraction by conventional echocardiography was similar under both pacing modes. Perhaps the similar ejection fraction was because of the short interval between AAIR and DDDR modes. The difference may increase if we collect the data days apart, but the patient may suffer from pulmonary edema again. We decided not to do this way. Furthermore, intraventricular asynchrony can also worsen mitral regurgitation. The clinical downhill can be obvious without significant change of ejection fraction by two-dimensional echocardiography. Consequently, dual-chamber pacing in patients with sick sinus syndrome and normal AV nodal function is assumed here to be unnecessary and even harmful. Atrial pacing alone may be sufficient and better in this group of patients. Trials with a large population are necessary to prove this hypothesis. |
References |
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[1] Lamas GA, Orav EJ, Stambler BS, Ellenbogen KA, Sgarbossa EB, Huang SK, et al. Pacemaker Selection in the Elderly Investigators: quality of life and clinical outcome in elderly patients treated with ventricular pacing as compared with dual-chamber pacing. N Engl J Med 1998; 338: 1097–104.
[2] Connolly SJ, Kerr CR, Gent M, Roberts RS, Yusuf S, Gillis AM, et al. Canadian Trial of Physiologic Pacing Investigators: effects of physiologic pacing versus ventricular pacing on the risk of stroke and death due to cardiovascular causes. N Engl J Med 2000; 342: 1385–91.
[3] Lamas GA, Lee KL, Sweeney MO, Silverman R, Leon A, Yee R, et al. Ventricular pacing or dual-chamber pacing for sinus node dysfunction. N Engl J Med 2002; 346: 1854–62.
[4] Anderson HR, Nielsen JC, Thomsen PE, Thuesen L, Mortensen PT, Vesterlund T, et al. Long-term follow-up of patients from a randomized trial of atrial versus ventricular pacing for sick sinus syndrome. Lancet 1997; 350: 1210–6.[CrossRef][Web of Science][Medline]
[5] Sweeney MO, Hellkamp AS, Ellenbogen KA, Greenspon AJ, Freedman RA, Lee KL, et al. Adverse effect of ventricular pacing on heart failure and atrial fibrillation among patients with normal baseline QRS duration in a clinical trial of pacemaker therapy for sinus node dysfunction. Circulation 2003; 107: 2932–7.
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