14th International Congress
THE "NEW FRONTIERS"
OF ARRHYTHMIAS 2000

Jan. 29 - Feb. 5, 2000
Marilleva, Trento, Italy

RT-197

Concomitant heart disease. Coronary disease and arrhythmias

Leo A. Bockeria, Elena Z.Golukhova.
Bakoulev Scientific Centre for Cardiovascular Surgery, Moscow, Russia

Atherosclerotic coronary artery disease is the most common cause of sudden cardiac death. Acute coronary syndromes (and underlying ischemia) and ventricular arrhythmias are the direct causes of these fatal disturbances. Of the survivors, about 85% have ventricular tachycardia and 15-20% bradyarrhythmias¹. Thus, keeping in mind the widespread of ischemic heart disease (IHD) among the whole population the real meaning of the problem could hardly be overestimated. The wide spectrum of therapeutic and surgical approaches estimates the necessity of certain algorithms in different clinical situations influencing patient management decision.

The aim of our study was the investigation of clinical and functional features in patients with IHD and high grade ventricular arrhythmias (VA) and estimation of clinical approach in this group.

We evaluated 197 patients (pts) with IHD since 1983 up to 1998; 97 underwent bypass surgery with or without arrhythmia mapping and special antiarrhythmic procedure. Mean age was 54.6±8.72, 186 men and 11 women. One hundred and seventy-nine (98%) pts experienced myocardial infarction (MI). In 96 pts (49%) MI resulted in left ventricular aneurysm (LVA). Most of pts (138-70%) were in III-IY NYHA functional class.

Eighty-eight (45%) of our pts also had ventricular arrhythmias (ventricular premature beats- VPB 3-5 grades according to Lown-Wolf classification, including 20 pts with monomorphic VT). Twenty-four pts also had left ventricular bundle branch block. The investigation of all those pts included routine ECG, Holter monitoring (Rozinn, USA), M- and B-mode echocardiography (echo, HP 5500), stress-echo (with dobutamine), high-resolution ECG (HRECG, PREDICTOR 1, ART, USA), heart rate variability analysis (HRV, ART), body surface multichannel mapping (Cardiag 128.1, Chech Rep), coronary- and ventriculography, electrophysiologic study (Phillips Integris).

Due to VA we divided all investigated pts into 2 groups: the first one with VA and the second one without VA. According to our data the main differences of those groups were: 1. much more malignant course of IHD in first group (87% of pts were in III-IY NYHA functional class versus 46% of pts in the second group). The left ventricular ejection fraction (LVEF) in the first group was much lower (37%±10.6 versus 50%±11.7, p<0.033). The low LVEF (<40%) was found in 63% of the first group of pts versus 33% in the second one. According to the results of high resolution ECG (HRECG) late ventricular potentials (LVP) were found in 63% of pts with high grade VA versus 28% of cases without VA. The evolution of arrhythmias in pts with IHD correlated with filtered QRS duration (especially in cases with QRS more than 120 msec). Mean QRS duration in pts of the first group was 131.6±28.7 msec versus 114.1±22.3 msec in second group (p<0.05). Thus, this parameter was the most strong predictor of VA among other HRECG indexes. We could not found out the correlation between the MI scar localisation and the frequency of LVP.

The autonomic nervous system modulates cardiac activity and in some cases became critical for the occurrence of complex arrhythmias². We investigated some time-domain and frequency domain parameters of HRV in our pts. The standard deviations of cycle lengths (SDNN) was lower (31.5±12.1 and 39.2±13.1, p<0.08) and spectral analysis parameters (total power TP) were statistically lower in pts with complex VA. Low frequency (LF) and very low frequency power consisted 78% of TP versus 54% in pts without VA. The specificity and sensitivity of low HRV in pts with IHD and VA were 92% and 67%. We also found converse relation between LF power and filtered QRS duration in pts with IHD and VA (Fig. 1). We consider this tendency to be the result of the evolution of the ischemic heart disease which led to arrhythmias and QRS prolongation. Among different non-invasive indexes the combination of low HRV and abnormal HRECG obtained the highest specificity and sensitivity (Tab. I).

TABLE I – The specificity and sensitivity of different non-invasive predictors of VA in patients with IHD

Among pts undergone open heart surgery (BS-97) mean LVEF was 40.4%±8.6. Forty-six% of pts had multivessel coronary artery disease (³3 coronary arteries). In 52 cases (53.5%) the BS was added with specific procedure with preliminary ventricular mapping³. In most cases we use cryoablation of arrhythmic foci (30 pts – 57.5%) and subendocardial scar resection (38 cases). Fifty-six pts underwent BS and cryoablation. Thirty-four among 43 pts with LVA experienced LV reconstruction procedure; in the remaining cases LVA resection was carried out. All those cases were added with cryoablation procedure or/and subendocardial resection.

The operative mortality was 12% (12 pts). The long-term results were analysed in 74 among 97 operated cases (76%). The mean follow-up was 38.0±26.23 mths (up to 127 mths). During that period 9 pts died: 2 SCD, progressive heart failure was observed in 4 cases and recurrent arrhythmias in 3 pts. The positive results were found in 57 pts (77%). The recurrence of arrhythmias occured in 2 pts (2.6%). All those pts have had much better life quality after operation because of malignant arrhythmia disappearence. Comparing our own results with the ones known from literature in pts with IHD, VA and ICVD^4,5 we’d like to express the following remarks:

–in pts with preserved LV function and monomorphic VA, in whom coronary artery lesion is discrete BS added with ventricular mapping and specific surgery procedure allow to get satisfactory results. This approach provides dramatic improvement (versus ICVD). It also seems to be cost-effective (but it should be proved);

–in pts with extremely low LVEF, multiple arrhythmogenic foci and incurable coronary artery disease ICVD implantation is preferenced. These two opportunities create “dynamic equilibrium” and should be considered in every patient with IHD and severe arrhythmias.

Fig. 1: Correlation between results of high resolution ECG (filtered QRS duration) and frequency-domain heart rate variability (low frequency power) in patients with IHD with (A) and without high grades ventricular arrhythmias (B). Pearson correlation coefficient is -0.5 in first group and -0.1 in the second one.