A 12-lead electrocardiogram (ECG) of a dual-chamber pacemaker with different paced QRS morphologies is presented. Such an observation is usually made when there are different degrees of fusion, in association with the intrinsic rhythm in the presence of spontaneous changes of the stimulation mode of the pacemaker.
We present a case of massive pulmonary embolism where the electrocardiogram (ECG) demonstrated transient T-wave inversion and marked QT-prolongation. The pathomechanism and clinical significance of these changes are discussed.
Surface 12-lead ECG remains in the 21st century, one of the diagnostic tools most extensively used in clinical practice (1).