Tachycardia-induced cardiomyopathy in patients with idiopathic ventricular arrhythmias: the incidence, clinical and electrophysiologic characteristics, and the predictors.

INTRODUCTION: Idiopathic ventricular arrhythmias in the form of monomorphic premature ventricular contractions (PVC) and/or ventricular tachycardia (VT) can cause tachycardia-induced cardiomyopathy (TICMP). The aim of this study was to determine the incidence, clinical and electrophysiologic characteristics, and the predictors of TICMP in patients with idiopathic ventricular arrhythmias. METHODS: Study population consisted of 249 consecutive patients (148 F/101 M, 45 ± 20 y/o) with frequent PVCs and/or VT. All patients underwent transthoracic echocardiography and 24-hour Holter monitoring. TICMP was defined as left ventricular ejection fraction (LVEF) of ≤50% in the absence of any detectable underlying heart disease and improvement of LVEF ≥15% following effective treatment of index ventricular arrhythmia. RESULTS: Seventeen (6.8%) patients had TICMP. Patients with TICMP compared to patients with preserved LVEF were more likely to be male (65% vs 39%, P = 0.043) and asymptomatic (29% vs 9%, P = 0.018), and were more likely to have higher PVC burden (29.4 ± 9.2 vs 8.1 ± 7.4, P < 0.001), persistence of PVCs throughout the day (65% vs 22%, P = 0.001), and repetitive monomorphic VT (24% vs 0.9%, P < 0.001). PVC burden of 16% by ROC curve analysis best separated the patients with TICMP compared to patients with preserved LVEF (sensitivity 100%, specificity 87%, area under curve 0.96). CONCLUSIONS: TICMP was relatively common (∼1 in every 15 patients) in our study population. The predictors of TICMP were male gender, absence of symptoms, PVC burden of ≥16%, persistence of PVCs throughout the day, and the presence of repetitive monomorphic VT.

Stress cardiomyopathy (Tako-Tsubo) following radiofrequency ablation in the right ventricular outflow tract.

A 44-year-old female undergoing radiofrequency ablation in the right ventricular outflow tract for symptomatic, frequent premature ventricular contractions developed stress cardiomyopathy (Tako-Tsubo). Stress cardiomyopathy was probably due to hyperadrenergic state induced by the procedure itself, dobutamine infusion, sympathetic nerve stimulation at the ablation site, and parasympathetic withdrawal with atropine administration.

Beta1 and beta2-adrenergic receptor polymorphisms and idiopathic ventricular arrhythmias.

INTRODUCTION: Idiopathic ventricular arrhythmias commonly refer to ventricular tachycardia (VT) and/or frequent/monomorphic premature ventricular contractions (PVC) in patients with structurally normal heart. Activation of sympathetic tone has been shown to play an important role in the provocation and maintenance of these arrhythmias. We investigated whether common single nucleotide polymorphisms in the beta(1) and beta(2)-adrenergic receptors are associated with idiopathic ventricular arrhythmias. METHODS: A total of 143 unrelated patients presenting with idiopathic ventricular arrhythmias were prospectively included in a case-control association study. Patient population was matched by age and gender to the unrelated, healthy control subjects (N = 307). All study subjects were of Turkish (Anatolian Caucasian) descent. Allele and genotype frequencies of the Gly389Arg and Ser49Gly polymorphisms of the beta(1)-adrenergic receptor and Arg16Gly, Gln27Glu, and Thr164Ile polymorphisms of the beta(2)-adrenergic receptor were compared between patient population and control subjects. The genotype frequencies were in Hardy-Weinberg equilibrium. RESULTS: Patients with idiopathic ventricular arrhythmias had higher frequency of Arg389Arg genotype (22.4% vs 1.6%, P < 0.001), Arg389Gly49 (5.24% vs 0.73%, P = 0.005), and Arg389Ser49 (36.7% vs 13.6%, P < 0.001) haplotypes of the beta(1)-adrenergic receptor, and higher frequency of Gly16Gly (31.5% vs 13.4%, P < 0.001), Glu27Glu genotypes (18.2% vs 10.1%, P = 0.006) and Gly16Gln27Thr164 (15.3% vs 7.4%, P = 0.002), Gly16Glu27Thr164 (13.1% vs 7%, P = 0.004), and Gly16Glu27Ile164 (13.2% vs 6%, P = 0.002) haplotypes of the beta(2)-adrenergic receptor compared to control subjects. CONCLUSION: Our data suggest that common single nucleotide polymorphisms in the beta(1) and beta(2)-adrenergic receptors are significantly associated with idiopathic ventricular arrhythmias in Turkish population.

Pseudonormalization: clinical, electrocardiographic, echocardiographic, and angiographic characteristics.

OBJECTIVE: Spontaneous pseudonormalization (PN) is a unique 12-lead electrocardiography (ECG) finding which has been reported to be associated with severe, transmural myocardial ischemia. To date, a paucity of data exists about the incidence and clinical characteristics of patients with PN. Therefore the aim of this study was to investigate the incidence and the electrocardiographic, echocardiographic, and angiographic characteristics of patients with PN. METHODS: Clinical, laboratory, electrocardiographic, echocardiographic, and angiographic characteristics of 12 consecutive patients with PN on 12-lead ECG (Group 1) were compared with patients (Group 2, n=28) presenting with acute coronary syndrome (ACS) associated with ST-T wave changes without PN. RESULTS: All patients presented with chest pain. The incidence of PN among patients presenting with ACS was 1%. Pseudonormalization was present in precordial leads in 11 and in inferior leads in 1 patient. Nine out of 12 (75%) patients in Group 1, 16 out of 28 (57%) patients in Group 2 had elevation of cardiac enzymes compatible with acute myocardial infarction. Severely narrowed or totally occluded ischemia and/or infarction-related coronary arteries were present in all patients in Group 1, in 20 (71%) patients in Group 2. Three patients in Group I and one patient in Group 2 had coronary artery thrombus formation. Group 1 patients had worse coronary collateral grading in comparison to Group 2 patients. CONCLUSION: Pseudonormalization is a rare entity and it is typically associated with severely narrowed or totally occluded coronary arteries along with thrombus formation, and poor coronary collateral development.

Angiographic analysis of the anatomic relation of coronary arteries to mitral and tricuspid annulus and implications for radiofrequency ablation.

Coronary artery (CA) narrowings and/or occlusions after radiofrequency ablation (RFA) have been reported. The aim of this study was to describe the in vivo topographic anatomy of CAs and their anatomic relation to the mitral and tricuspid annulus using selective coronary angiography. Fifty consecutive patients undergoing RFA for narrow QRS complex tachycardia were included in the study. Multipolar electrode catheters were inserted into the right atrial appendage, His bundle region, distal coronary sinus (CS), and right ventricle. A mapping catheter was placed across the subeustachian isthmus (SEI). Selective coronary angiography was performed. The maximum and minimum distances between the distal CAs and the mapping catheter located along the mitral and tricuspid annulus were measured during systole and diastole and in right and left anterior oblique projections. The large (> or =1.5 mm) distal right CA was < or =5 mm from the mapping catheter in the SEI in 4 patients (8%). The large posterolateral branch of the right CA was < or =2 mm from the CS Os-middle cardiac vein in 10 patients (20%). The large left circumflex CA was < or =2 mm from the floor or ceiling of the CS in 7 patients (14%) and < or =2 mm from the CS catheter at the lateral and anterolateral mitral annulus in 12 patients (24%). RFA was canceled in 2 patients because of the close proximity (< or =2 mm) of the distal CA to the ablation site. In conclusion, large CAs are frequently located in close proximity to the common ablation sites. Coronary angiography should be considered in children and adults who may develop any signs or symptoms suggestive of acute CA occlusion until larger controlled series are available.

Demonstration of ventricular myocardial extensions into the pulmonary artery and aorta beyond the ventriculo-arterial junction.

BACKGROUND: A subgroup of outflow tract (OT) ventricular tachycardias (VT) originate from the aortic sinuses or the main stem of the pulmonary artery. The anatomic substrate for these tachycardias is unknown. The aim of this study was to investigate the presence of ventricular myocardial extensions (VME) into the pulmonary artery (PA) and aorta (Ao) beyond the ventriculo-arterial junction (VAJ) and determine the anatomical and histological characteristics of these muscle extensions. METHODS: Ninety-five consecutive human hearts obtained at autopsy were studied. Longitudinal strips of tissue containing each cusp, aortic, and pulmonary artery walls and left and right ventricular outflow tracts were excised and histologically analyzed. Anatomical measurements, including length and thickness of VMEs, obtained at autopsy, were made. RESULTS: VMEs beyond the VAJ were found in 21 of 95 (22%) patients studied. VMEs were found in 16 of 95 PAs (17%) and 7 of 95 Aos (7%) were examined. VMEs were located within the adventitia in 23 (88%) and on the epicardial surface in three (12%). The majority of VMEs were in continuity with the underlying ventricular OT muscle tissue. Myocellular hypertrophy and fibrosis were present in 19 (73%) and fatty tissue between the layers of VME in 18 (69%). Clinical data were available in 14 of 21 patients with positive VME. None of the patients (clinical data available group) had history of cardiac disease or signs or symptoms (palpitations or syncope) of cardiac disease. CONCLUSIONS: VMEs into the PA and Ao beyond the VAJ are relatively common. It seems that their mere presence does not predispose to OT VTs. There are probably intrinsic arrhythmogenic properties in tissues specific to these regions in those patients who develop OT VTs.

Isotretinoin (13-cis-retinoic acid) associated atrial tachycardia.

We describe a 16-year-old boy who presented with palpitations for 1 week while being on isotretinoin treatment for nodulocystic facial acne for 3 months. Twenty four-hour Holter monitoring showed frequent premature atrial beats and episodes of nonsustained atrial tachycardia. He never had any episodes of palpitations previously. His complaints almost disappeared within a week after stopping the treatment. He remained asymptomatic since the discontinuation of the drug. The temporal relationship between isotretinoin treatment and patient's symptoms in the presence of documented arrhythmia suggests a drug-related cause. As a result, clinicians should be aware of the possible arrhythmogenic effect of isotretinoin.