Delayed ventricular pacing failure and correlations between pacing thresholds, left ventricular ejection fraction, and QTc values in a male with Takotsubo cardiomyopathy.

BACKGROUND: Transient pacing failure caused by transient increased pacing threshold has been reported in patients with transient left ventricular apical dysfunction (Takotsubo cardiomyopathy [TC]). Normal pacing thresholds usually recover after normalization of systolic dysfunction. HYPOTHESIS: Pacing failure correlates with clinics of TC. METHODS: We report the case of a 76-year-old man with a dual chamber pacemaker, admitted for acute chest pain and dyspnea and final diagnosis of TC. One month after index admission, the patient came back complaining again of chest pain. Unexpectedly, admission electrocardiogram showed ventricular pacing failure and an increased pacing threshold. In the following weeks, pacing threshold gradually recovered with left ventricular ejection fraction and QTc values. RESULTS: Ventricular pacing threshold correlated directly to QTc values and inversely to left ventricular ejection fraction over time (P < 0.05). CONCLUSIONS: This is one of the first cases of delayed transient ventricular pacing failure in a male patient with transient left ventricular apical ballooning, in the presence of spared right ventricular function. Given the possibility of acute transient anomalies in myocardial impedance and pacing failure even in the subacute phase of TC several weeks after clinical onset of transient systolic dysfunction, pacing threshold should be carefully monitored in subjects with TC, both during the acute phase of the disease and in first months of follow-up after discharge. Ventricular pacing threshold correlated directly to QTc values and inversely to left ventricular ejection fraction over time.

Catecholaminergic polymorphic ventricular tachycardia associated with sinus node dysfunction and junctional rhythm: Case report and literature review.

We report the case of a 38-year-old woman with history of syncope and polymorphic ventricular tachycardia; tachycardia was inducible at exercise stress test, not at electrophysiologic study. Phases of QT prolongation were found at ambulatory electrocardiogram monitoring. The woman came to our attention for periodic control of implantable loop recorder. Rest electrocardiogram at admission unexpectedly showed sinus bradycardia, junctional rhythm, and ventricular premature beats. Furthermore, loop recorder control revealed a short run of bidirectional tachycardia, not associated with syncope. Final diagnosis was catecholaminergic polymorphic ventricular tachycardia, and the patient was implanted with an ICD. We therefore report an unusual case of bidirectional ventricular tachycardia associated with sinus node dysfunction and junctional escape rhythm. We hypothesize that a diffuse dysfunction of cardiac conduction system, presumably based on diffuse disorder of calcium handling, may be responsible for both sinus node failure and ventricular tachycardia.

"Ischemic" ST elevation in a woman with left ventricular hypertrophy.

We report the case of a woman who presented with ST elevation and episodes of chest pain, mimicking an acute myocardial infarction. At coronary angiography no sign of coronary stenosis was found and ECG anomalies were related to asymmetric left ventricular hypertrophy and aortic stenosis.