الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Coronary artery disease is the most common cause of hospitalization and premature mortality in the industrial countries. The clinical presentations of CAD include stable angina, unstable angina, acute myocardial infarction (AMI), heart failure, silent myocardial ischemia or sudden cardiac death.
Many methods have been proposed to predict the risk of sudden cardiac death form arrhythmogenic causes such as ventricular tachycardia or ventricular fibrillation in patients with ischemic or non-ischemic heart disease. One of them is HRV analysis which is considered one of the most promising non-invasive diagnostic methods increasingly used nowadays.
The aim of this study was to evaluate the impact of elective PCI on HRV and its prognostic value in patients with CAD.
The study included 100 patients undergoing elective PCI when clinically indicated either by patient’s symptoms or if there was an evidence of ischemia either by a stress test or a viability study.
We excluded patients with contraindication to contrast or dual antiplatelet therapy, patients with atrial fibrillation or multiple premature beats or pacemaker programmed in a non-tracking mood, patients receiving anti-arrhythmic drugs except class II, IV and patients who underwent previous PCI or CABG.
All subjects were evaluated by history taking and clinical examination. Standard 12-lead ECG and 2D echocardiography were done before PCI. Coronary angiography and PCI data were recorded with SYNTAX and residual SYTANX score were calculated before and after PCI.
HRV measurement was done before PCI, 24 hours and 6 months after PCI with follow-up of the patients during the hospital stay, 1 month and 6 months after PCI for the occurrence of MACCE.
The 100 consecutive patients were 85 males (85%) and 15 females (15%). Their age ranged from 27 to 80 years with mean age of 56.89 ± 10.75 years with 76 patients were <65 years (76.0%) and 24 patients were ≥65 years (24%).
47 patients (47%) were hypertensives, 41 patients (41%) were diabetics, 11 patients (11%) had a family history of premature CAD, 21 patients (21%) were non-smokers, 54 patients (54%) were current smokers and 25 patients (25%) were former smokers, 8 patients (8%) were dyslipidemic, 2 patients (2%) had PVD while 1 patient (1%) had ESRD on MHD and 1 patient (1%) had CVS.
Among the 100 studied cases, 6 patients (6%) had typical ischemic symptoms, 8 patients (8%) had a positive stress test, while 86 patients (86%) had a history of ACS, 18 of them (20.9%) had a history of unstable angina while 68 (79.1%) hada post-MI angina, 45 of them (66.2%) had a history of STEMI while 23 patients (33.8%) had a history of NSTEMI. Of the 45 patients that had a history of STEMI, 27 of them (60%) had a history of anterior STEMI while 18 patients (40%) had a history of inferior STEMI. Of all the patients who had post-MI angina, 11 patients (24.4%) did a viability study, 10 of them (90.9%) did dobutamine stress echocardiography (DSE) while only one patient (9.1%) did a Thallium radioisotope scanning. 83 patients (83%) were on beta-blockers. The mean heart rate was 77.95 ± 11.79 beats/minute. The mean EF of the studied cases was 54.03 ± 11.08%. 42 patients (42%) had multi-vessel CAD while 58 patients (58%) had a single vessel CAD. the mean SX was 13.11 ± 8.52. 5 patients (5%) had left main disease, 77 patients (77%) had LAD disease, 8 patients (8%) had diagonal disease, 19 patients (19%) had LCX disease, 9 patients (9%) had OM disease, 5 patients (5%) had Ramus Intermedius disease, 31 patients (31%) had RCA disease and 2 patients (2%) had PDA disease.
Among the studied cases, the target vessel for revascularization was a single vessel in 69 patients (69%) while in 31 patients (31%) was multi-vessel. 90 patients (90%) had complete revascularization, while 10 patients (10%) had incomplete revascularization with a mean RSS of 2.0 ± 5.77. 73 patients (73%) underwent PCI of the LAD, 23 patients (23%) underwent PCI of the RCA, 16 patients (16%) underwent PCI of the LCX, 6 patients (6%) underwent PCI of the OM, 4 patients (4%) underwent PCI of LM, 4 patients underwent PCI of ramus intermedius and 2 patients (2%) underwent PCI of the PDA.
Before PCI, multivariate regression analysis of patient characteristics that affect HRV parameters showed that type of CAD and Syntax score are the strongest independent factors that affect HRV parameters before PCI. There was a strong negative correlation with all HRV parameters except LF/HF ratio which showed strong positive correlation and SX score.
After PCI, there was a statistically significant difference between HRV parameters at different time intervals before PCI, 24 hours and 6 months after PCI. There was a statistically significant difference between HRV parameters 24 hours and 6 months after PCI in patients who had complete revascularization (RSS <8) with those who had incomplete revascularization (RSS ≥8).
During the follow-up intervals, 4 patients had MACCE, 3 of them had sudden cardiac death and 1 patient had reinfarction at the territory of the target vessel of revascularization while 1 patient had non-cardiac death (terminal hepatocellular carcinoma) and 3 patients were lost to follow-up.
All 4 patients (100%) had multi-vessel CAD with a mean Syntax score of 31.50 11.71. All patients (100%) had incomplete revascularization with a mean RSS of 22.75 7.96. In all MACCE patients, there was no statistically significant difference between the HRV parameters before and 24 hours after PCI.
The study concluded that HRV parameters in patients with CAD are strongly correlated to the complexity of CAD quantified by SYNTAX score. Also, compared to HRV parameters before PCI, HRV parametes improved significantly 24 hours and 6 months after PCI with better results in patients underwent complete revascularization compared to patients underwent incomplete revascularization.