PMC7239032_01
(A) ECG findings in patient 1: (a) QTc prolongation (530 ms); (b-d) recurrent episodes of self-terminating Torsades de Pointes. (B) ECG findings in patient 2: sinus bradycardia with marked QTc prolongation (610 ms). Red vertical lines in lead V4 show the QT interval.
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PMC7239032_02_fphar-11-00684-g002.jpg
f2
The ECG on admission demonstrated sinus bradycardia and marked QTc prolongation (~620 ms) (Figure 2B).
PMC7239032_02
(A) ECG findings in patient 1: (a) QTc prolongation (530 ms); (b-d) recurrent episodes of self-terminating Torsades de Pointes. (B) ECG findings in patient 2: sinus bradycardia with marked QTc prolongation (610 ms). Red vertical lines in lead V4 show the QT interval.
fphar-11-00684-g002.jpg
PMC7239032_02_fphar-11-00684-g002.jpg
f2
The ECG on admission demonstrated sinus bradycardia and marked QTc prolongation (~620 ms) (Figure 2B).
PMC7239032_03
ECG findings in patient 3: (A) QTc prolongation (530 ms) during paced rhythm (QRS 200 ms). Episodes of Torsades de Pointes, as recorded by ECG monitoring (B) and by interrogating the PM (C). Red vertical lines in lead III show the QT interval.
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f3
On admission, ECG showed PM-induced rhythm (75 bpm) and QTc, although sub-optimally measured on a ventricular paced beat, was prolonged (~530 ms) (Figure 3A), while echocardiography revealed left ventricular dilation, with diffuse contraction abnormalities resulting in a severe reduction of the global ejection fraction (~25-30%). However, few days later, the patient suddenly presented repeated episodes of TdP (Figures 3B, C) rapidly degenerating to VF and cardiac arrest, requiring multiple DC-shocks.
PMC7239032_04
ECG findings in patient 4: (A) QTc prolongation (640 ms); (B, C) recurrent episodes of nonsustained Torsades de Pointes. Red vertical lines in lead II show the QT interval.
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PMC7239032_04_fphar-11-00684-g004.jpg
f4
The ECG on admission showed first-degree atrioventricular block (PR ~500 ms), complete left bundle branch block (QRS ~140 ms), and marked QTc prolongation (~640 ms) (Figure 4A). However, during nighttime, recurrent episodes of nonsustained TdP occurred (Figures 4B, C), and intravenous magnesium sulfate was started.