Isolated Left Circumflex Coronary Artery Disease

Georg Couturier, Alexander Kasatkin, John Fox, Deepika Misra, and Paul Schweitzer

Beth Israel Medical Center, New York, USA

Correspondence: G Couturier, Beth Israel Medical Center, 11Dazian, 1Avenue at 16th, New York, NY 10003, United States.
E-mail gcouturi@chpnet.org, phone 001-212-844-8823, fax 001-419-831-1273

---

---

1.  Introduction

Coronary artery disease involving only the circumflex coronary artery is rare and the specific clinical features are not well known.^{2, 5} The goal of this retrospective study was to determine the presence of specific electrocardiogram (ECG) changes, ejection fraction (EF) and mitral regurgitation (MR) in patients with isolated left Circumflex coronary artery (CX) disease and to determine the all-cause mortality rate.

2.  Material and Methods

At our institution 12,673 patients underwent coronary angiography between January 1997 and June 2001. Isolated CX stenosis was defined as 70% or greater reduction in luminal diameter of the CX in the absence of stenosis greater than 50% in the left anterior descending or right coronary arteries or greater than 30% in left main artery. The patients were selected as illustrated in figure 1.

Figure 1. Patient selection.

The indication for the angiography in the 148 study patients was acute myocardial infarction (34%), unstable angina pectoris (28%) and stable angina pectoris (38%). The ECG was obtained prior to coronary angiography and interpreted by two independent cardiologists. The angiographic estimation of degree of stenosis was based on the reduction in luminal diameter as judged in multiple projections.

EF and MR were assessed by left ventriculogram in 123 patients (83.1%) or by echocardiogram in 25 patients (16.9%). Using ventriculography the EF was calculated in percentage by standard planimetry technique. The presence and severity of MR was semi-quantitatively assessed by two experienced angiographers. Using Echocardiography the EF and MR were semi-quantitatively assessed by two experienced echocardiographers.

The Follow-up through 1, January 2002 was 100% complete. Information about the death a patient are available on two websites: http://ssdi.genealogy.rootsweb.com and http://www.ancestry.com/search/rectype/vital/ssdi/main.htm.

3.  Results

Only 30 of the 148 patients (20%) with isolated CX stenosis had a normal ECG. Ischemic ST-T wave changes were the most common abnormal findings.

Table 1.    ECG in Isolated CX disease.

Normal	Q-waves	Ischemic ST-T	LBBB	RBBB	LVH
30	44	84	6	6	17
(20.3%)	(29.7%)	(56.8%)	(4.1%)	(4.1%)	(11.5%)

If Q-waves were present, these were found in the inferior leads (84%), in the lateral leads (39%) and as reciprocal changes of posterior Q-waves (30%). Moderate or severe left ventricular dysfunction was significantly more often found in the presence of Q-waves as in absence of thereof (χ² test, p <0.05). The likelihood of MR did not statistically differ with the presence of Q-waves (χ² test, p = 0.057).

Only 84 of the 148 patients (57%) with isolated CX stenosis had preserved systolic left ventricular function. All 30 patients with normal ECG were found to have also normal (>55%) or only mildly reduced EF (45-55%). A normal ECG was associated with a normal EF (χ² test, p < 0.05).

Table 2.    ECG and Ejection Fraction (EF).

	Normal EF	EF 55-45%	EF 44-30%	EF <30%	Total
Normal ECG	23	7	0	0	30
Abnormal ECG	61	33	22	2	118
Total	84	40	22	2	148

Only 25 of the 148 patients (17%) with isolated CX stenosis had mitral regurgitation. Out of the 30 patients with normal ECG 28 patients (93%) had no MR and the remaining 2 patients (7%) had only mild MR. There was however no statistically significant difference in the likelihood of MR depending on the ECG (χ² test, p > 0.05)

Table 3.    ECG and Mitral Regurgitation (MR).

	No MR	Mild MR	Moderate MR	Severe MR	Total
Normal ECG	28	2	0	0	30
Abnormal ECG	95	12	7	4	118
Total	123	14	7	4	148

Four out of 148 patients (2.8%) with isolated CX disease had died during the average follow-up period of 31.55 months +/- 16.7. All 4 patients had reduced EF (χ² test, p < 0.05), an abnormal ECG (χ² test, p > 0.05) and their average age was 78 years - markedly higher than the average of the study population of 61years (χ² test, p < 0.05). The yearly all-cause mortality rate was 1%.

4.  Discussion

The presence of ECG-changes, left ventricular dysfunction, MR and the mortality rate are largely dependent on the clinical presentation, with acute myocardial infarction^3,5,6 and chronic stable angina pectoris being the extremes of the spectrum. Less selective cohort studies have found similar ECG changes and similar low mortality rates.^{1, 4}

Prospective studies are needed to compare the outcome for isolated involvement of each of the three major coronary arteries and to provide guidance in the optimal therapy.

5.  Conclusions

The mortality in isolated CX disease is low and patients with preserved EF carry a better prognosis. A normal ECG predicts normal or near normal left ventricular systolic function. No hemodynamically relevant MR was found in patients with normal ECG.

References

1. Dunn RF, Newman HN, Bernstein L et al: The clinical features of isolated left circumflex coronary artery disease. Circulation 1984; 69 (3): 477-484.

2. Moskowitz RM, Kronzon I, Schloss M, Glassman E: The clinical and angiographic spectrum of isolated, nondominant left circumflex coronary artery disease. Catheterization & Cardiovascular Diagnosis 1976; 2 (3): 281-7.

3. Sheehan FH: Left ventricular dysfunction in acute myocardial infarction due to isolated left circumflex coronary artery stenosis. AJC 1989; 64 (8): 440-447.

4. Shen WF, Tribouilloy C, Lesbre JL: Relationship between electrocardiographic patterns and angiographic features of isolated left circumflex coronary artery disease. Clin.Cardiol. 1991; 14: 720-724.

5. Yip, HK, Wu CJ, Fu M, et al: Clinical features and outcome of patients with direct percutaneous coronary intervention for acute myocardial infarction resulting from isolated left circumflex artery occlusion. Chest 2002; 122 (6): 2068-2074.

6. Zimetbaum PJ, Josephson ME: Use of the electrocardiogram in acute myocardial infarction. NEJM 2003; 348: 933-940.