CONGRESS ABSTRACT

The prolongation of the QTc interval on the electrocardiogram is known to be associated with an increased risk of developing life-threatening ventricular arrhythmias such as torsades de pointes (TdP). QTc values exceeding 500 ms can double or even triple the risk of TdP. Many drugs, including amiodarone and some SSRI antidepressants like paroxetine, can prolong the QTc interval. A 57-year-old patient experienced cardiac arrest during an overnight Holter recording prescribed to exclude brady-tachy syndrome in the presence of persistent atrial fibrillation. ECG ambulatory monitoring revealed significant bradycardia with the onset of idioventricular rhythm, followed by TdP triggered by premature ventricular contractions, subsequently degenerating into ventricular fibrillation. The patient was resuscitated by family members and later by emergency medical personnel using 3 DC shocks, leading to the restoration of spontaneous circulation. The patient was transferred to the cardiology intensive care unit where a coronary angiography showed normal results. Blood tests indicated low potassium levels (3.3 mEq/L), with a moderately reduced left ventricular ejection fraction at 45%. The patient was discharged after ICD implantation and during the diagnostic follow-up the genetic testings for long QT syndrome were negative, but showed a mutation of the LMNA lamin A/C gene. During the two months previous to hospital admission, the patient had complained of fatigue in the presence of atrial fibrillation with a low ventricular response. Nonetheless, she had been prescribed oral amiodarone to optimize the chances of successful electrical cardioversion, in combination with paroxetine that the patient was already taking at home. The combination of these two drugs and the patient ‘s idiopathic bradycardia contributed to a marked prolongation of the QT interval, leading to TdP degenerated into ventricular fibrillation. This case, notable for the prolonged recording of ventricular fibrillation and subsequent resuscitation chest compressions during a Holter monitoring, suggests caution in the use of antiarrhythmic drugs unless strongly indicated in the presence of potentially ominous drug interactions. It is encouraging to note how the widespread adoption of cardiopulmonary resuscitation culture has enabled individuals who might not have otherwise received medical attention to be effectively resuscitated.