Takotsubo’s syndrome

ECG 2A: Entry ECG shows the presence of atrial fibrillation; moderate ST-segment elevation in V3; minimal Q-waves from V3 to V6 and in leads I, aVL; negative shallow T-waves from V1 to V5;

ECG 2B: Coronary angiography revealed healthy coronary arteries, the angiography pattern in highly suggestive of Takotsubo’s syndrome; ECG performed on D2; persistence of AF; disappearance of Q-waves from V3 to V6; negative, wide and deep T-waves in leads I, II, aVL, aVF and from V2 to V6;

Comments: This observation highlights the different clinical, biological, electrocardiographic and angiographic characteristics of a Takotsubo’s syndrome. A Takotsubo’s syndrome is accompanied by dynamic electrocardiographic changes modifying the morphology of QRS-complexes, the ST-segment and the T-wave. These changes are poorly specific since they are also observed in acute coronary syndrome (ACS). The differentiation between these two diagnoses is therefore difficult albeit essential to decide the usefulness of an emergency reperfusion. A Takotsubo’s syndrome remains an exclusion diagnosis that is retained only after coronary angiography has been performed to formally eliminate ACS. During the acute phase, no single parameter can differentiate between ACS and Takotsubo with coronary angiography often deemed indispensable.

The electrocardiographic changes can be broken down into 4 phases in conjunction with the onset of symptoms, and even though the perception of symptoms is subjective, the exact time of onset of pain is often difficult to determine in this setting.

• phase 1: in the 6 hours after the occurrence of symptoms, the electrocardiogram reveals a ST-segment elevation. This elevation is preferentially found in the precordial leads, is maximal in V2-V3, can extend to V5-V6 and is also observed in the inferior leads in just under 50% of patients. This extensive distribution is correlated with the site of abnormalities of the segmental kinetics which is centered on the apex but can extend to the lateral and inferior medial segments without any direct relation to an isolated coronary territory. Different elements have been proposed to differentiate prior ACS and Takotsubo’s syndrome even if neither has a positive or negative predictive value if considered individually. The amplitude of the elevation is generally lower for a Takotsubo. While the number of leads with an elevation in a Takotsubo can be high suggesting circumferential disease, the elevation is not generally observed in the V1 lead facing the anterior and right ventricular paraseptal region. During this first phase, Q-waves are observed in just under half of the patients. They ultimately disappear in the majority of cases with an increase in the amplitude of the R waves suggesting the presence of a cardiac stunning or a subsequently-regressing edema. The T-waves are somewhat less tall and the QTc interval more prolonged in Takotsubo than in ACS.During this first phase, it is therefore difficult to differentiate between ACS and Takotsubo, even if there is often a clinico-electrocardiographic discrepancy in the Takotsubo with extensive circumferential-like electrocardiographic changes in paucisymptomatic patients with a moderate elevation in troponin. The performing of a coronary angiography allows validating the absence of coronary obstruction or plaque rupture.
• phase 2: an inversion of the T-waves may occur concomitantly with the elevation or its disappearance (D1 to D3). These changes in T-wave are generally diffuse, present in a high number of leads (from V2 to V6, in leads I, II, aVL). An increase in the prolonged QT interval over time can also be observed. A few cases of torsades de pointes have been described in the literature.
• phase 3: between day 2-3 and 6, the T-waves may normalize;
• phase 4: a new inversion of the waves can be highlighted and persist for 2 to 12 weeks. The impairment is widespread, with large amplitude negative T-waves and a frequent prolongation of the QT interval. The presence of these negative T-waves could be related to the presence of large viable myocardial plaques but with sympathetic denervation. The complete normalization of the tracing is the rule within several days to a few weeks in parallel with the complete recovery of cardiac function.

Take-home message: The electrocardiographic pattern of Takotsubo’s syndrome evolves in 4 phases in conjunction with the onset of the symptoms; phase 1: in the first 6 hours, there is appearance of a diffuse elevation although not usually affecting the V1 lead; phase 2: from D1 to D3, a reversal of the T-waves may occur concomitantly with the elevation or its disappearance; phase 3: between D2-3 and D6, the T-waves may normalize; phase 4: a new wave inversion can be highlighted and persist for 2 to 12 weeks. The complete normalization of the tracing in several days to a few weeks is observed in a vast majority of patients.