Accelerated Idioventricular Rhythm Publications (233)
Accelerated Idioventricular Rhythm Publications
Three cases of AIVR were identified among 27,912 fetuses. Performances of the following Doppler ultrasonographic approaches in identifying intrauterine criteria of AIVR were as follows: - Superior vena cava/Aorta: atrioventricular dissociation (ventricular rates within 20% of atrial rates) recorded in all 3 fetuses, episodes of isorhythmic AV dissociations observed in 1 fetus; - M-mode: atrioventricular dissociation identified in 2 of the 3 fetuses, while left ventricular shortening fraction was normal in all fetuses; - Aortic Isthmus: a fusion beat was observed in 1 fetus; - Aortic Isthmus and Ductus arteriosus: 1 fetus showed signs of right bundle branch block and the 2 others of left bundle branch block; - Ductus venosus: retrograde a-waves in presence of simultaneous atrial and ventricular contractions (3 out of 3 fetuses) leading to an increase in central venous pressure in all and hydrops fetalis in 2 cases without evidence of ventricular dysfunction.
1) Criteria required for postnatal diagnosis of AIVR can be documented in utero using specific ultrasonographic approaches. 2) During fetal life, AIVR is not a benign entity. 3) Hydrops fetalis is frequently associated with AIVR because of increase in central venous pressure related to simultaneous atrioventricular contractions. 4) The ultrasonographic Iinvestigation protocol of fetuses with unexplained hydrops fetalis should aim at ruling out AIVR and include Doppler flow recordings in the following specific vascular targets: superior vena cava/aorta, ductus venosus, aortic isthmus, ductus arteriosus and umbilical vein.
(1) Most data for the use of STK are from the 1990s, which had showed that at best it is effective in only 50% of patients in restoring adequate flow.(2) It is probable that with the current dual-antiplatelet loading dose regimen and other newer medications, this figure could be higher. Also, rescue angioplasty for failed thrombolysis is the standard of care now, unlike before. Hence, we need reliable non-invasive markers to judge successful reperfusion in the present era. While ST segment resolution is the standard marker for reperfusion used in thrombolytic trials, in several instances it is not definitive. An additional marker would thus be very useful, especially in such cases.
This was a prospective observational study carried out at a public teaching hospital. 200 consecutive patients with a diagnosis of acute MI who were given STK within 12h of index pain were included. The STK dose was 1.5 million units, infused over 30min; the ECG was again recorded after 90min of completion of the infusion. Continuous ECG monitoring for the first 24h of ICCU stay was performed and AIVRs during this period were documented. Early AIVR was defined as that occurring within 2h of completing the STK infusion. Echocardiography was performed 24h after presentation. The time course of AIVR was studied vis-a-vis the outcome of thrombolysis.
AIVR was seen in 41% of the patients. Though AIVR was found to have low sensitivity (45%) and specificity (64%) as a predictor of successful thrombolysis, early AIVR was a reliable sign of successful thrombolysis (p<0.05). The sensitivity (45%) of early AIVR was low; however, the specificity (94%) and positive predictive value (94%) were very good.
AIVR is a common arrhythmia in the setting of STEMI receiving thrombolytic therapy. Early AIVR is more common with successful thrombolysis, with an excellent positive predictive value. Thus, early AIVR can be used as an additive criterion to ST segment resolution as a non-invasive marker of successful thrombolysis with STK.
Supraventricular arrhythmias such as supraventricular premature complexes were observed in 60.8% of healthy volunteers, supraventricular tachycardia in 2.2%, and atrial fibrillation in 0.1%. Ventricular arrhythmias included premature ventricular complexes (PVCs) in 43.4%, >200 PVCs per 24 hours in 3.3%, multifocal PVCs in 5.3%, nonsustained ventricular tachycardia in 0.7%, and accelerated idioventricular rhythm in 0.3%. Bradyarrhythmias included sinus pause >3 seconds in 0.3%, and second-degree AV block in 2.4%. Complete heart block and torsades de pointes were not seen in any subject. Based on the observed incidence, we estimated the maximum number of healthy subjects in whom these arrhythmias may be seen as a matter of chance in studies with smaller sample sizes if the study drug has no arrhythmogenic effect. Our results and these estimates could help interpret whether cardiac arrhythmias observed in early-phase studies are due to chance or possibly are a drug effect.
An 18-year-old female with no significant past medical history presented with life-threatening ventricular arrhythmia following about 10 days of use of Hydroxycut Gummies, a legal dietary supplement previously unreported to cause this complication. The patient received external cardioversion due to progressive decline in mental status and persistent hypotension and was initiated on intravenous procainamide at an outside hospital. Left ventricular ejection fraction was 45% to 50%, and cardiac MRI showed no definite finding of infarct, myocarditis, or fibrosis. Beta-blocker therapy was initiated, and there was a progressive reduction in ventricular arrhythmia burden with an improvement of symptoms over the next few days. Two and a half months after the initial hospitalization, follow-up Holter monitor revealed occasional accelerated idioventricular rhythm events and a significant reduction in, but still occasional, long monomorphic ventricular tachycardia events. None of the ingredients listed in this product have been associated with cardiac dysrhythmias in the literature. One phytochemical potentially in the product is alpha-quinidine, which could be the cause of the adverse event. However, there was no other identifiable etiology for the ventricular tachycardia, which resolved after the discontinuation of supplement and the addition of beta-blocker therapy.
Hydroxycut Gummies should be considered a probable cause of this patient's arrhythmia given the lack of another etiology and a Naranjo Scale score of 6.
We immediately performed coronary angiography and found a long dissection starting from the mid-left main coronary artery and progressing into the mid-left anterior descending (LAD) and circumflex arteries. She was then transferred to the operating room for surgery. A saphenous vein was grafted to the distal LAD. Since the patient was hypotensive under noradrenaline and dopamine infusions, she was transferred to the cardiovascular surgery intensive care unit on an extracorporeal membrane oxygenator and intra-aortic balloon pump. During follow-up, her blood pressure remained low, at approximately 60/40 mmHg, despite aggressive inotropic and mechanical support. On the second postoperative day, asystole and cardiovascular arrest quickly developed, and despite aggressive cardiopulmonary resuscitation, she died.
It resolved as the medications used to treat his asthma exacerbation were weaned. There was no ventricular ectopy seen on a 24-hour Holter monitor performed 3 months after his hospitalization, suggesting that the AIVR was related to the medications the patient was receiving at the time. This case suggests that albuterol may be a risk factor for the development of AIVR and highlights the importance of recognizing this rhythm to avoid unnecessary and potentially harmful therapies.