Analysis of J waves during myocardial ischaemia.
ABSTRACT The aim of this study was to investigate the relationship between J-wave dynamics and arrhythmias during myocardial ischaemia in patients with vasospastic angina (VSA).
Sixty-seven consecutive patients diagnosed with VSA by a provocation test for coronary spasm were grouped according to whether they had a J wave in the baseline electrocardiograms or not (VSA-JW group, n = 14; VSA-non-JW group: n = 53). We retrospectively studied the associations between J-wave and ST-segment dynamics and induced ventricular fibrillations (VFs) during coronary spasm. In the VSA-JW group, 7 of the 14 patients showed changes in J-wave morphology and/or gains in J-wave voltage, followed by VF in 4 patients. Compared with patients without VF, the four patients with VF showed similar maximal voltage in the baseline J waves but a higher voltage during induced coronary spasms (0.57 ± 0.49 vs. 0.30 ± 0.11 mV; P = 0.011). In three patients with VF, J waves progressively increased and were accompanied by the characteristic coved-type or lambda-shaped ST-segment elevations. In the VSA-non-JW group, only four patients showed new appearances of J waves during coronary spasms and another patient without a distinct J wave developed VF. Ventricular fibrillations were induced more frequently in the VSA-JW group than in the VSA-non-JW group [4/14 (29%) vs. 1/53 (2%); P = 0.012].
J-wave augmentations were caused by myocardial ischaemia during coronary spasms. The presence and augmentation of J waves, especially prominent J waves with the characteristic ST-elevation patterns, were associated with VF.
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ABSTRACT: BACKGROUND: A substantial number of patients with idiopathic ventricular fibrillation (IVF) present with no specific electrocardiographic (ECG) findings. OBJECTIVE: To evaluate complete right bundle branch block (RBBB) among IVF patients. METHODS: IVF patients showing complete RBBB were included in the present study. Structural and primary electrical diseases were excluded, and provocation tests were performed to exclude the presence of spastic angina or Brugada syndrome (BrS). The prevalence of complete RBBB and the clinical and ECG parameters were compared either with IVF patients without RBBB or with the general population and age and sex comparable control with RBBB. RESULTS: Out of 96 IVF patients, 9 patients were excluded for the presence of BrS. Out of 87 patients studied, 10 (11.5%) patients revealed complete RBBB. None had structural heart diseases, BrS or coronary spasms. Average age was 44±15 years, and 8 of the 10 were male. Among the ECG parameters, only the QRS duration was different from the other IVF patients without complete RBBB. VF recurred in three: two in the form of storms which were well suppressed by isoproterenol. Complete RBBB was found less often in control subjects (1.37%, P<0.0001), and the QRS duration was more prolonged in the IVF patients:139±10 versus 150±14 ms (P=0.0061). CONCLUSION: Complete RBBB exists more often among IVF patients than in controls. A prolonged QRS complex suggests a conduction abnormality. Our findings warrant further investigation of the role of RBBB in the development of arrhythmias among patients with IVF. (243 words).Heart rhythm: the official journal of the Heart Rhythm Society 03/2013; · 4.56 Impact Factor