J Interv Card Electrophysiol (2014) 40:81–86 DOI 10.1007/s10840-014-9878-y
Development of mitral and tricuspid regurgitation in right ventricular apex versus right ventricular outflow tract pacing Sevil Hemayat & Akbar Shafiee & Saeed Oraii & Farideh Roshanali & Farshid Alaedini & Amirhossein Sami Aldoboni
Received: 8 September 2013 / Accepted: 28 January 2014 / Published online: 14 March 2014 # Springer Science+Business Media New York 2014
Abstract Purpose This study aimed at comparing the development of tricuspid and mitral regurgitation between the right ventricular outflow tract (RVOT) and right ventricular apex (RVA) pacing. Methods We prospectively enrolled 164 patients for permanent pacemaker implantation due to sick sinus syndrome or atrioventricular block and randomly divided them into two equal groups to receive either RVOT or RVA pacing. Patients with heart failure or valvular disease were excluded. The postprocedural echocardiographic evaluations were performed 1 year after the pre-procedural echocardiography, and the results were compared with respect to the development of mitral and tricuspid regurgitation and probable changes in the ejection fraction (EF). Results Age, gender, pacing mode, and baseline cardiac rhythm did not significantly differ between the RVOT and RVA pacing groups. The incidence of mitral regurgitation was significantly S. Hemayat Faculty of Medicine, Islamic Azad University, Tehran, Iran A. Shafiee Tehran Heart Center, Tehran University of Medical Sciences, Tehran, Iran S. Oraii (*) Tehran Arrhythmia Clinic, 30 Tavanir Street, Vali-Asr Ave, P. O. Box 15175-536 Tehran, Iran e-mail: [email protected] F. Roshanali Department of Echocardiography, Day General Hospital, Tehran, Iran F. Alaedini Islamic Republic of Iran Academy of Medical Sciences, Tehran, Iran A. S. Aldoboni Department of Cardiology, Faculty of Medicine, Islamic Azad University, Tehran, Iran
higher in the RVA group (p=0.03), but the incidence of tricuspid regurgitation was similar in both groups. There was a trend toward less tricuspid regurgitation in the RVOT group; however, it was not statistically significant. The mean EF was not significantly different between the study groups. Conclusion It seems that the incidence of mitral regurgitation in RVA pacing is significantly higher than that in RVOT pacing. The formation of tricuspid regurgitation needs to be discussed in the future. Clinical trial registration number IRCT201103146061N1 Keywords Pacemaker . Right ventricular outflow tract . Right ventricular apex . Mitral regurgitation . Tricuspid regurgitation Abbreviations AV Atrioventricular ECG Electrocardiography EF Ejection fraction LV Left ventricle MR Mitral regurgitation PPM Permanent pacemaker RV Right ventricle RVA Right ventricular apex RVOT Right ventricular outflow tract TR Tricuspid regurgitation TTE Transthoracic echocardiography
1 Introduction Cardiac pacing is currently the standard treatment for sick sinus syndrome and other conductive disorders [1, 2]. Due to the increasing number of people who received pacemakers in recent years, it is important to identify different aspects of pacing and reduce its potential complications [3]. Selecting a proper site for pacing has always been a challenge for cardiologists [4]. The
82
right ventricular apex (RVA) has been a site of choice for years; there are now, however, question marks over the safety and benefits of this location, and that is why other positions such as the right ventricular outflow tract (RVOT) have been proposed as an alternative [5, 6]. The RVOT is regarded as a feasible and safe position for ventricular electrode fixation and is even believed to confer a better hemodynamic state [7–9]. Studies that compared the efficacy and safety of these two methods are limited and controversial, although it has been observed that RVA pacing—unlike RVOT pacing—can trigger the asynchronous activation of the left ventricle and result in impaired hemodynamic function related to myocardial perfusion defects, especially in long-term pacing [10–12]. Be that as it may, little is known about the effects of right ventricle (RV) lead positioning in the development of valvular problems, specifically mitral or tricuspid regurgitation [13, 14]. Considering the influence of pacing on cardiac remodeling, it seems that the location of pacing electrodes may have a considerable impact on this process [15]. This in turn may exert certain effects on the valves that bear the ventricular blood pressure during systole in the long term. The fact that the existing literature abounds with inconsistent evidence on this phenomenon warrants further investigation. The present study, therefore, sought to investigate the prevalence and severity of mitral and tricuspid valves insufficiency based on the placement site of the RV lead.
2 Methods 2.1 Patients This single-blind randomized clinical trial enrolled 164 patients with sick sinus syndrome or atrioventricular (AV) block scheduled for permanent pacemaker (PPM) implantation. Consecutive patients with no documented history of heart failure, valvular disease, or mitral/tricuspid regurgitation (MR and TR, respectively) were included and divided randomly into two groups to receive either RVA or RVOT pacing. The study population comprised of 68 (41.4 %) men and 94 (58.6 %) women. Mean age in the RVA and RVOT groups were 63.93± 16.1 and 58.46±23.9 years, respectively. Having received clear description of the procedure, each participant gave informed written consent prior to implantation; however, they were unaware of the lead location. The study protocol was reviewed and approved by the research board and ethical committee at the Islamic Azad University, Faculty of Medicine. 2.2 Procedure The patients were equally randomized to RVA and RVOT pacing groups. Positioning of the leads was performed by an experienced operator under fluoroscopy and continuous surface
J Interv Card Electrophysiol (2014) 40:81–86
electrocardiography (ECG). During the implantation process, the atrial active lead was located in the right atrial appendage. Active electrodes were utilized for ventricular pacing. The electrode was typically fixed in the right ventricular apex for RVA pacing. Passing the tricuspid valve, the RVOT lead was advanced into the right ventricle and its tip was positioned and fixed right below the pulmonary valve and against the interventricular septum. The position of attachment in the RVOT was confirmed in the 40° left anterior oblique projection (Fig. 1). After reassuring about the stability of the electrodes, the leads were connected to the generator. Pacing mode was selected according to the underlying rhythm abnormality; the selected modes were DDD, DDDR, VVI, and VVIR. The values of the lower and upper limits were programmed individually and remained unchanged during the study. Following the procedure, posteroanterior and lateral chest X-rays were performed to make sure of the proper site of implantation. ECG was also double-checked after implanting the device. 2.3 Echocardiographic measurements Two-dimensional transthoracic echocardiography (TTE) was conducted in a standard setting using a Vivid 7 (GE Medical Systems, Milwaukee, WI, USA) echocardiography machine at baseline and after 12 months. After a careful selection of the highest possible quality image via our digital storing system, echocardiographic measurement was performed with the best frame in all the patients. The effect of varied RV preload caused by irregular beats was minimized by averaging the values of the echocardiographic parameters over five cardiac cycles in the patients with atrial fibrillation. The ratio of the maximal TR area on the color flow mapping to the right atrium (RA) area (%TR) was measured in the apical four-chamber view, and TR severity was assessed by a color Doppler flow mapping of the spatial distribution of the regurgitant jet within the RA. The TR jet area on the color flow mapping and the RA area in the same frame were measured by planimetry, and the ratio of the maximal regurgitant area to the RA area (%TR) was thereafter obtained. In accordance with previous studies, residual TR was graded as mild if it occupied 34 % on follow-up echocardiography. The recording of TV systolic velocity with continuous-wave Doppler was followed by the calculation of RV systolic pressure using the simplified Bernoulli equation. Left ventricular ejection fraction was obtained from the apical four-chamber and two-chamber views by using the Simpson method. The estimation of the MR grade on TTE was based on the vena contracta of the regurgitant jet. Vena contracta, measured by Doppler color flow imaging, is the narrowest portion of the regurgitant jet (vena contracta width 7 mm, severe).
J Interv Card Electrophysiol (2014) 40:81–86
83
Fig. 1 An X-ray example of typical positioning of RVOT lead in anteroposterior (a) and left anterior oblique (b) projections. Arrow tip of the right ventricular lead; arrowhead tip of the right atrial lead
2.4 Statistics The statistical analyses of the data were conducted using SPSS (Statistical Package for the Social Sciences, Version 13.0). Two sets of statistical analyses were used: (1) descriptive statistics, including prevalence, percentage, mean, and standard deviation for each of the measurable variables and (2) inferential statistics, using the t test and Pearson’s chi-square test. A p value 0.05 for all variables). The global systolic left ventricle (LV) function and EF were normal in all the patients (mean EF=58.48±5.20). Studied patients had no evidence of valvular abnormality before the procedure. The general characteristics of the study groups are depicted in Table 1. Major indications for a PPM implantation were sick sinus syndrome and atrioventricular block (23 [29.3 %] and 58 [71.6] cases in both groups, respectively). There were no significant differences between the groups regarding age, gender, cardiac rhythm, pacing mode, and atrial or ventricular pacing. Post-procedure echocardiography was carried out 12 months after PPM implantation for all the patients, and all of the variables were rechecked. Whereas MR was shown to be more significant in the RVA group (p=0.03), there was
Variable
RVA group (n=82)
RVOT group (n=82)
p value*
Gender (Men) (n, %) Age (mean±SD) Indication for PPM (n, %)
37 (37.8) 63.93±16.1
31 (37.8) 58.46±23.9
0.24 0.19 –
Sick sinus syndrome Atrioventricular block Baseline cardiac rhythm (n, %) Sinus bradycardia Heart block Tachycardia/bradycardia Atrial fibrillation/bradycardia Pacing mode (n, %) DDDR DDD VVI VVIR Atrial pacing (%, mean±SD) Ventricular pacing (%, mean±SD)
24 (29.3) 58 (70.7)
24(29.3) 58 (70.7)
23(30.7) 39(52) 4(5.3) 9 (10.7)
22 (28.6) 47 (61) 5 (6.5) 3 (3.9)
34 (41.5) 40 (48.8) 3 (3.7) 5 (6.2) 27.95±14.16 55.61±32.36
35 (42.7) 43 (52.4) 2 (2.4) 2 (2.4) 24.83±12.60 62.49±22.42
0.69
0.31
0.13 0.11
84
J Interv Card Electrophysiol (2014) 40:81–86
no statistical difference between the two groups regarding TR. However, there was a trend toward less TR in the RVOT group. No difference was noted in the post-procedural EF between the groups (p>0.05) (Table 2). Atrial and ventricular pacing were not significantly different between the groups (Apacing: 27.95±14.16 vs. 24.83±12.60 (p=0.13); V-pacing: 55.61±32.36 vs. 62.49±22.42 (p=0.11) in the RVOT and RVA groups, respectively). Complications during the followup period included five lead dislodgements (three in the RVOT group and two in the RVA group) and one case of pocket infection in the RVA group, without any significance. These patients were successfully treated regarding their condition, and there were no more cardiac complications during the observation period.
4 Discussion In this study, we compared the results of the RVOT and RVA pacing and their influence on cardiac function and valvular competency in a 1-year follow-up period. Our findings indicated that RVOT pacing was associated with a significantly less development of MR. However, the development of TR was not significant in this study. Previous studies have reported different complications following chronic RVA pacing as a result of changes in the sequence and synchronic activation of the heart. It has been observed that MR, cardiac dyssynchrony, interventricular delay, and even LV dysfunction are significantly correlated with RVA pacing [14, 16, 17]. Also, one study has reported a significant increase in the prevalence and severity of TR and MR following RVA pacing in midterm follow-up [18]. Table 2 Development of MR and TR in the 12-month follow-up echocardiography Variable
Degree of MR (n, %) None/trivial Mild Moderate Severe Degree of TR (n, %) None/trivial Mild Moderate Severe LVEF (%, mean±SD)
RVA group (n=82)
RVOT group (n=82)
p value*
0.03 65 (79.3) 14 (17.1) 3 (3.7) 0
76 (92.7) 5 (6.1) 1 (1.2) 0
72 (87.8) 6 (7.3) 4 (4.9) 0 58.1±6.1
75 (91.5) 6 (7.3) 1 (1.2) 0 59.3±3.8
0.23
0.41
LVEF left ventricular ejection fraction, MR mitral regurgitation, SD standard deviation, TR tricuspid regurgitation *p
Development of mitral and tricuspid regurgitation in right ventricular apex versus right ventricular outflow tract pacing Sevil Hemayat & Akbar Shafiee & Saeed Oraii & Farideh Roshanali & Farshid Alaedini & Amirhossein Sami Aldoboni
Received: 8 September 2013 / Accepted: 28 January 2014 / Published online: 14 March 2014 # Springer Science+Business Media New York 2014
Abstract Purpose This study aimed at comparing the development of tricuspid and mitral regurgitation between the right ventricular outflow tract (RVOT) and right ventricular apex (RVA) pacing. Methods We prospectively enrolled 164 patients for permanent pacemaker implantation due to sick sinus syndrome or atrioventricular block and randomly divided them into two equal groups to receive either RVOT or RVA pacing. Patients with heart failure or valvular disease were excluded. The postprocedural echocardiographic evaluations were performed 1 year after the pre-procedural echocardiography, and the results were compared with respect to the development of mitral and tricuspid regurgitation and probable changes in the ejection fraction (EF). Results Age, gender, pacing mode, and baseline cardiac rhythm did not significantly differ between the RVOT and RVA pacing groups. The incidence of mitral regurgitation was significantly S. Hemayat Faculty of Medicine, Islamic Azad University, Tehran, Iran A. Shafiee Tehran Heart Center, Tehran University of Medical Sciences, Tehran, Iran S. Oraii (*) Tehran Arrhythmia Clinic, 30 Tavanir Street, Vali-Asr Ave, P. O. Box 15175-536 Tehran, Iran e-mail: [email protected] F. Roshanali Department of Echocardiography, Day General Hospital, Tehran, Iran F. Alaedini Islamic Republic of Iran Academy of Medical Sciences, Tehran, Iran A. S. Aldoboni Department of Cardiology, Faculty of Medicine, Islamic Azad University, Tehran, Iran
higher in the RVA group (p=0.03), but the incidence of tricuspid regurgitation was similar in both groups. There was a trend toward less tricuspid regurgitation in the RVOT group; however, it was not statistically significant. The mean EF was not significantly different between the study groups. Conclusion It seems that the incidence of mitral regurgitation in RVA pacing is significantly higher than that in RVOT pacing. The formation of tricuspid regurgitation needs to be discussed in the future. Clinical trial registration number IRCT201103146061N1 Keywords Pacemaker . Right ventricular outflow tract . Right ventricular apex . Mitral regurgitation . Tricuspid regurgitation Abbreviations AV Atrioventricular ECG Electrocardiography EF Ejection fraction LV Left ventricle MR Mitral regurgitation PPM Permanent pacemaker RV Right ventricle RVA Right ventricular apex RVOT Right ventricular outflow tract TR Tricuspid regurgitation TTE Transthoracic echocardiography
1 Introduction Cardiac pacing is currently the standard treatment for sick sinus syndrome and other conductive disorders [1, 2]. Due to the increasing number of people who received pacemakers in recent years, it is important to identify different aspects of pacing and reduce its potential complications [3]. Selecting a proper site for pacing has always been a challenge for cardiologists [4]. The
82
right ventricular apex (RVA) has been a site of choice for years; there are now, however, question marks over the safety and benefits of this location, and that is why other positions such as the right ventricular outflow tract (RVOT) have been proposed as an alternative [5, 6]. The RVOT is regarded as a feasible and safe position for ventricular electrode fixation and is even believed to confer a better hemodynamic state [7–9]. Studies that compared the efficacy and safety of these two methods are limited and controversial, although it has been observed that RVA pacing—unlike RVOT pacing—can trigger the asynchronous activation of the left ventricle and result in impaired hemodynamic function related to myocardial perfusion defects, especially in long-term pacing [10–12]. Be that as it may, little is known about the effects of right ventricle (RV) lead positioning in the development of valvular problems, specifically mitral or tricuspid regurgitation [13, 14]. Considering the influence of pacing on cardiac remodeling, it seems that the location of pacing electrodes may have a considerable impact on this process [15]. This in turn may exert certain effects on the valves that bear the ventricular blood pressure during systole in the long term. The fact that the existing literature abounds with inconsistent evidence on this phenomenon warrants further investigation. The present study, therefore, sought to investigate the prevalence and severity of mitral and tricuspid valves insufficiency based on the placement site of the RV lead.
2 Methods 2.1 Patients This single-blind randomized clinical trial enrolled 164 patients with sick sinus syndrome or atrioventricular (AV) block scheduled for permanent pacemaker (PPM) implantation. Consecutive patients with no documented history of heart failure, valvular disease, or mitral/tricuspid regurgitation (MR and TR, respectively) were included and divided randomly into two groups to receive either RVA or RVOT pacing. The study population comprised of 68 (41.4 %) men and 94 (58.6 %) women. Mean age in the RVA and RVOT groups were 63.93± 16.1 and 58.46±23.9 years, respectively. Having received clear description of the procedure, each participant gave informed written consent prior to implantation; however, they were unaware of the lead location. The study protocol was reviewed and approved by the research board and ethical committee at the Islamic Azad University, Faculty of Medicine. 2.2 Procedure The patients were equally randomized to RVA and RVOT pacing groups. Positioning of the leads was performed by an experienced operator under fluoroscopy and continuous surface
J Interv Card Electrophysiol (2014) 40:81–86
electrocardiography (ECG). During the implantation process, the atrial active lead was located in the right atrial appendage. Active electrodes were utilized for ventricular pacing. The electrode was typically fixed in the right ventricular apex for RVA pacing. Passing the tricuspid valve, the RVOT lead was advanced into the right ventricle and its tip was positioned and fixed right below the pulmonary valve and against the interventricular septum. The position of attachment in the RVOT was confirmed in the 40° left anterior oblique projection (Fig. 1). After reassuring about the stability of the electrodes, the leads were connected to the generator. Pacing mode was selected according to the underlying rhythm abnormality; the selected modes were DDD, DDDR, VVI, and VVIR. The values of the lower and upper limits were programmed individually and remained unchanged during the study. Following the procedure, posteroanterior and lateral chest X-rays were performed to make sure of the proper site of implantation. ECG was also double-checked after implanting the device. 2.3 Echocardiographic measurements Two-dimensional transthoracic echocardiography (TTE) was conducted in a standard setting using a Vivid 7 (GE Medical Systems, Milwaukee, WI, USA) echocardiography machine at baseline and after 12 months. After a careful selection of the highest possible quality image via our digital storing system, echocardiographic measurement was performed with the best frame in all the patients. The effect of varied RV preload caused by irregular beats was minimized by averaging the values of the echocardiographic parameters over five cardiac cycles in the patients with atrial fibrillation. The ratio of the maximal TR area on the color flow mapping to the right atrium (RA) area (%TR) was measured in the apical four-chamber view, and TR severity was assessed by a color Doppler flow mapping of the spatial distribution of the regurgitant jet within the RA. The TR jet area on the color flow mapping and the RA area in the same frame were measured by planimetry, and the ratio of the maximal regurgitant area to the RA area (%TR) was thereafter obtained. In accordance with previous studies, residual TR was graded as mild if it occupied 34 % on follow-up echocardiography. The recording of TV systolic velocity with continuous-wave Doppler was followed by the calculation of RV systolic pressure using the simplified Bernoulli equation. Left ventricular ejection fraction was obtained from the apical four-chamber and two-chamber views by using the Simpson method. The estimation of the MR grade on TTE was based on the vena contracta of the regurgitant jet. Vena contracta, measured by Doppler color flow imaging, is the narrowest portion of the regurgitant jet (vena contracta width 7 mm, severe).
J Interv Card Electrophysiol (2014) 40:81–86
83
Fig. 1 An X-ray example of typical positioning of RVOT lead in anteroposterior (a) and left anterior oblique (b) projections. Arrow tip of the right ventricular lead; arrowhead tip of the right atrial lead
2.4 Statistics The statistical analyses of the data were conducted using SPSS (Statistical Package for the Social Sciences, Version 13.0). Two sets of statistical analyses were used: (1) descriptive statistics, including prevalence, percentage, mean, and standard deviation for each of the measurable variables and (2) inferential statistics, using the t test and Pearson’s chi-square test. A p value 0.05 for all variables). The global systolic left ventricle (LV) function and EF were normal in all the patients (mean EF=58.48±5.20). Studied patients had no evidence of valvular abnormality before the procedure. The general characteristics of the study groups are depicted in Table 1. Major indications for a PPM implantation were sick sinus syndrome and atrioventricular block (23 [29.3 %] and 58 [71.6] cases in both groups, respectively). There were no significant differences between the groups regarding age, gender, cardiac rhythm, pacing mode, and atrial or ventricular pacing. Post-procedure echocardiography was carried out 12 months after PPM implantation for all the patients, and all of the variables were rechecked. Whereas MR was shown to be more significant in the RVA group (p=0.03), there was
Variable
RVA group (n=82)
RVOT group (n=82)
p value*
Gender (Men) (n, %) Age (mean±SD) Indication for PPM (n, %)
37 (37.8) 63.93±16.1
31 (37.8) 58.46±23.9
0.24 0.19 –
Sick sinus syndrome Atrioventricular block Baseline cardiac rhythm (n, %) Sinus bradycardia Heart block Tachycardia/bradycardia Atrial fibrillation/bradycardia Pacing mode (n, %) DDDR DDD VVI VVIR Atrial pacing (%, mean±SD) Ventricular pacing (%, mean±SD)
24 (29.3) 58 (70.7)
24(29.3) 58 (70.7)
23(30.7) 39(52) 4(5.3) 9 (10.7)
22 (28.6) 47 (61) 5 (6.5) 3 (3.9)
34 (41.5) 40 (48.8) 3 (3.7) 5 (6.2) 27.95±14.16 55.61±32.36
35 (42.7) 43 (52.4) 2 (2.4) 2 (2.4) 24.83±12.60 62.49±22.42
0.69
0.31
0.13 0.11
84
J Interv Card Electrophysiol (2014) 40:81–86
no statistical difference between the two groups regarding TR. However, there was a trend toward less TR in the RVOT group. No difference was noted in the post-procedural EF between the groups (p>0.05) (Table 2). Atrial and ventricular pacing were not significantly different between the groups (Apacing: 27.95±14.16 vs. 24.83±12.60 (p=0.13); V-pacing: 55.61±32.36 vs. 62.49±22.42 (p=0.11) in the RVOT and RVA groups, respectively). Complications during the followup period included five lead dislodgements (three in the RVOT group and two in the RVA group) and one case of pocket infection in the RVA group, without any significance. These patients were successfully treated regarding their condition, and there were no more cardiac complications during the observation period.
4 Discussion In this study, we compared the results of the RVOT and RVA pacing and their influence on cardiac function and valvular competency in a 1-year follow-up period. Our findings indicated that RVOT pacing was associated with a significantly less development of MR. However, the development of TR was not significant in this study. Previous studies have reported different complications following chronic RVA pacing as a result of changes in the sequence and synchronic activation of the heart. It has been observed that MR, cardiac dyssynchrony, interventricular delay, and even LV dysfunction are significantly correlated with RVA pacing [14, 16, 17]. Also, one study has reported a significant increase in the prevalence and severity of TR and MR following RVA pacing in midterm follow-up [18]. Table 2 Development of MR and TR in the 12-month follow-up echocardiography Variable
Degree of MR (n, %) None/trivial Mild Moderate Severe Degree of TR (n, %) None/trivial Mild Moderate Severe LVEF (%, mean±SD)
RVA group (n=82)
RVOT group (n=82)
p value*
0.03 65 (79.3) 14 (17.1) 3 (3.7) 0
76 (92.7) 5 (6.1) 1 (1.2) 0
72 (87.8) 6 (7.3) 4 (4.9) 0 58.1±6.1
75 (91.5) 6 (7.3) 1 (1.2) 0 59.3±3.8
0.23
0.41
LVEF left ventricular ejection fraction, MR mitral regurgitation, SD standard deviation, TR tricuspid regurgitation *p
