Wellens’ syndrome

ECG 1A: Sinus rhythm, normal PR interval; presence of a narrow Q-wave in leads III and aVF; isoelectric ST-segment; biphasic T-wave (positive/negative) in V2, V3, V4; this  is a pattern of Wellens’ syndrome type 1;

ECG 1B: Sinus rhythm, normal PR interval; isoelectric ST-segment; negative and symmetrical T-wave in V1, V2, V3, V4; this is a pattern of Wellens’ syndrome type 2;

Comments: These two patients had an electrocardiogram compatible with Wellens’ syndrome. In both cases, coronary angiography showed a proximal LAD lesion (sub-occlusion for the first patient, severe stenosis for the second).

Wellens’ syndrome, described initially in the 1980s, corresponds to a form of unstable angina associating the occurrence of chest pain, with no significant elevation in cardiac enzymes, and an electrocardiographic pattern characteristic of negative or bifid T-waves in the anterior leads, in conjunction with a proximal LAD disease (most often critical stenosis). It should be noted that electrical abnormalities can be observed in the absence of pain. This clinical and electrical presentation is associated with a major risk of progression to myocardial infarction in the following days in the absence of treatment.

The electrocardiogram of Wellens’ syndrome presents certain characteristics:

• The changes in the T-wave can be observed at rest, when chest pain has disappeared; the electrical abnormalities may be permanent or intermittent and therefore justify performing repeated electrocardiograms;
• There are usually no signs of prior infarction (Q-waves in the anterior territory or poor R wave progression);
• The ST-segment is generally isoelectric with no significant elevation or depression (< 1 mm);
• The changes in T-wave can take 2 forms: 1) type 1: observed in approximately 25% of Wellens’ syndrome cases; biphasic T-waves (initial positivity followed by negativity) most often in V2, V3 but occasionally in V1 and up to V5-V6; 2) type 2: this is the most common form; it is observed in about 75% of cases; negative, deep, rather narrow and symmetrical T-waves, usually in V2, V3 but often in V1 and V4 and sometimes up to V5-V6;
• In the absence of treatment, the pattern can evolve from type 1 to type 2 and thereafter to evocative signs of acute coronary syndrome with ST-segment elevation;

Wellens’ syndrome corresponds to a proximal LAD disease. It is likely that the sequence begins with a complete or nearly complete occlusion of the LAD with transient ST elevation not recorded on the electrocardiogram followed most often by a spontaneous reperfusion explaining the chest pain resolution and the ST elevation disappearance. The T-wave then becomes biphasic or negative in the territory of the LAD with a pattern very similar to that observed in patients initially presenting an anterior infarction with elevation and having undergone reperfusion by angioplasty. The problem in these patients is that the lesion remains unstable with a major risk of re-occlusion on the short term reflected by the resumption of pain and by characteristic modifications of the electrocardiogram: initially negative or biphasic T-waves becoming positive and tall. The early diagnosis of Wellens’ syndrome is therefore crucial to avoid a progression to an anterior infarction (increased risk of sudden death and cardiac decompensation). Performing a stress test or stress ultrasound should be avoided in this context. The coronary lesion observed in almost all patients is the proximal LAD.

Take-home message: It is important to recognize a Wellens’ syndrome on the electrocardiogram (negative or biphasic T-waves in V2, V3 in absence of pain, without ST-segment elevation) in order to propose aggressive management and avoid the occurrence of anterior infarction by complete occlusion of the proximal LAD.