الفهرس 
Heart FailureOnly 14 pages are availabe for public view
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Abstract
C
ardiac resynchronization therapy CRT is an established treatment of heart failure with reduced LVEF and wide QRS complex. It is well established that CRT improves LVEF in patients with heart failure. However, the systematic assessment of RV dimensions and function has not been uniformly carried out prior to CRT.
This study aimed at studying the effect of CRT on RV dimensions and function assessed by echocardiography. Also to study the value of echocardiographic assessment of RV function prior to CRT in predicting response to CRT.
This study included 30 patients with LVEF of <35% and QRS complex of ≥120 ms, with at least NYHA class 3 who did not respond to optimal medical therapy who underwent CRT implantation at Ain Shams university hospitals. Baseline echocardiography with systematic assessment of RV dimensions and function was done before and 3 months after CRT.
The main age of the patients was 52.8 ±15.4. Our study included 24 males (80 %) and 6 females (20 %). Twelve patients (40%) had history of ischemic heart disease as the cause of HF; while 18 patients (60 %) were diagnosed as DCM.
History taking included NYHA class and revealed that 24 patients (80%) had NYHA class III and 6 patients (20%) had ambulatory class IV. The effect of HF symptoms on daily activities during last 4 months was assessed using Minnesota HF questionnaire. Mean questionnaire score was 70.8 ± 15.1.
Twelve leads ECG was recorded for all patients and analysis revealed that 23 patients had and ECG showing LBBB and 7 patients had non-LBBB morphology with a mean QRS duration 148.1 ± 10.1 msec.
Baseline echocardiography was done for all patients with assessment of cardiac chambers and valves and we found:
• All patients had dilated LV with impaired systolic function with mean EF of 25.9± 5.9 % as assessed by Simpson method.
• Mean LVEDD was 71.5 ± 9.1 mm, LVESD 62.6 ± 9 mm, LVEDV was 223.9 ± 73.1 ml and mean LVESV was 166.1 ± 60.7 ml.
• Mean basal transverse RV diameter was 43.8 ± 9.5 mm, mid-level diameter was 28.9± 6.4 mm and mean longitudinal diameter was 82.7± 13.6 mm.
• Mean FAC was 37.4± 9.1 %, TAPSE 19.8 ± 5.6 mm, S’ 11.3 ±3 cm/s and mean MPI was 0.46 ± 0.09.
• Twenty patients (93.7 %) had RV diastolic dysfunction grade I, while only 2 patients (6.7 %) had normal RV diastolic function.
• Regarding RVSP mean was 29.3 ± 10.5 mmHg and mean PAT 109 ± 23.1 msec.
• Eighteen patients (60 %) had mild TR, 8 patients (26.7 %) had moderate TR and 4 patients (13.3 %) had severe TR.
Follow up after 3 months was done and patient clinical improvement was assessed by:
• Assessment of patient clinical condition, Minnesota HF questionnaire, NYHA class and history of decompensation or hospital admission.
• Most of the patients had improved clinical condition as evidenced by improvement of HF questionnaire which had a mean of 43 .8 ±22.9. Regarding HYHA class, 5 patients (16.7%) had NYHA class I, 16 patients (53.3 %) had NYHA class II, 8 patients 26.7 % with NYHA class III and only 1 patient had NYHA class IV.
Echocardiographic assessment of right and left ventricular function and volumes was done. Analysis of echocardiographic data revealed:
• Improvement of overall systolic function with mean EF of 33.8 ± 10.7.
• Mean basal transverse RV diameter was 39.7 ± 11.8 mm, mid-level diameter was 26.8 ± 9.9 mm and mean longitudinal diameter was 75.6 ± 15.4 mm.
• Mean FAC was 41 ± 12.8 %, TAPSE 21.5 ± 6.9 mm, S’ 12.8 ± 4.2 cm/s and mean MPI was 0.44 ± 0.12.
• Regarding RVSP mean was 28.8 ± 9.7 mmHg and mean PAT 113.9 ± 22.1 msec.
• Eighteen patients (60 %) had mild TR, 7 patients (23.3 %) had moderate TR and 5 patients (16.7 %) had severe TR.
When we compared clinical data pre and post CRT, we found a significant improvement in NYHA class and Minnesota HF questionnaire. Regarding echocardiography parameters, there was no significant difference in LA diameter, volume, LVEDV and LV diastolic function. However there was a highly significant difference in LVEDD, LVESD, LESV and EF.
Regarding RV systolic function in our study, FAC improved significantly after CRT from 37.4±5.6 % to 41±12.8 (p=0.010), also TAPSE increased from 19.8±3.1 mm to 21.5±6.9 mm (p=0.002). RV systolic function assessed by tissue Doppler imaging S’ also showed a highly significant improvement from 11.3± 3 cm/s to 12.8±4.2 cm/s (p< 0.0001). The change in MPI before and after CRT was statistically non significant 0.46±0.10 to 0.44±0.12 (p=0.148).
Patients who had a reduction of LVESV more than 15 % were defined as volumetric responders of CRT, whereas those with a lesser degree of reduction were called non-responders. According to this figure 20 patients (66.7 %) were considered as responders and 10 patients (3.3 %) were found to be non-responders.
Comparison between both groups revealed no significant difference regarding age, gender, NYHA class or etiology of heart failure. Statistically significant difference was found between both groups regarding QRS morphology and duration. Patients with LBBB and wider QRS duration responded to CRT therapy better than those with non LBBB and narrower QRS duration.
Regarding RV parameters; baseline basal and mid transverse diameters were smaller in responders group and FAC, TAPSE, S’ and MPI were better than non-responders group. The difference between the two groups in baseline longitudinal RV diameter, RVSP, degree of TR and PAT was statistically non significant.
ROC curve analysis to find a relation between pre-CRT RV parameters and response to CRT was performed. Baseline FAC of >32 % has 100% sensitivity and 80 % specificity in predicting CRT response (P value= 0.0034). Baseline TAPSE of >18 mm has 90% sensitivity and 80 % specificity to CRT response (P value< 0.0001).
Also we found that baseline S’ of >8 cm/s % has 100% sensitivity and 70 % specificity in predicting CRT response (P value<0.0001). Baseline MPI<0.52 has 100% sensitivity and 70 % specificity to CRT response (P value<0.0001).
Multivariate stepwise logistic regression analysis with each of pre-CRT RV function parameters showed that pre-CRT S’ was the only significant independent predictor of response to CRT (p=0.01, odds = 3.21, 95% CI=1.32 to 7.82).
Regarding RV parameters post CRT; all RV diameters and systolic function measures have improved significantly in the responders group. Also the degree of TR has improved significantly in the responders group.
There was a significant correlation between change in RV diameters and systolic function and change in NYHA class, HF questionnaire, changes in LVESV and EF. The correlation between change in RVSP, PAT and TR and the clinical and data and EF wan not statistically significant.
We concluded that CRT leads to significant improvement of RV systolic function and reverse remodelling of RV. Systematic assessment of RV dimensions and systolic function prior to CRT implantation is very important and may help in predicting response to CRT.