Young subjects with apparently idiopathic complex ventricular arrhythmias: Non-invasive cardiological evaluation and follow-up

The prognosis of patients (pts) with ventricular arrhythmias (VA) not associated with structural heart disease is not well defined. Aim of this study was to evaluate the presence of myocardial disease and the prognosis in a group of pts with complex VA and apparently normal heart. We studied 19 pts, 13 M and 6 F, aged < 50 years (mean 33, range 15-45), with > 100 ventricular premature beats (VPBs)/hour at Holter recording and no signs of heart disease at clinical examination. Baseline examination consisted of resting ECG, chest X-ray, exercise ECG testing, transthoracic echocardiography (TTE) and radionuclide angiocardiography (RNA). After a mean follow-up period of 53 ± 9.5 months all pts but four that refused to attend the clinical examination, were revaluated. In addition to the baseline work-up, 8 pts performed transesophageal echocardiography (TEE) and 11 magnetic resonance imaging (MRI). Resting ECG was normal in all pts but one with inverted T waves in V1-V3 leads. Exercise ECG testing did not show ischemia or worsening of VA in any pts. The mean number of VPBs at 24 hour Holter monitoring was 11.6 ± 8.946; 9 pts (47%) had repetitive forms (couplets and non sustained ventricular tachycardia). The VPBs morphology was LBBB in 16 pts (84%) and polymorphous in 3 (16%). TTE showed mild abnormalities, such as mitral valve prolapse and left ventricular false tendonsi in 4 pts, exaggerated right ventricular trabecular appearance in 6, while it was normal in 9. The RNA right ventricular ejection fraction (RVEF) was lower than normal in the majority of pts (mean 38.9 ± 9), while RNA left ventricular ejection fraction (LVEF) was < 50% only in 5 pts (mean 53.7 ± 8.6). During the follow-up period no cardiac events or symptoms worsening occurred in any pts. Resting ECG and TEE was unchanged in all pts, while the mean number of VPBs at 24 hour Holter recording was reduced (6.622 ± 11.407); 3 pts had < 10 VPBs/hour. TEE showed exaggerated right ventricular trabecular appearance without abnormalities of segmental contraction in 4 pts and was normal in the other 4 pts. The MRI excluded the present of right ventricular cardiomyopathy in all 11 pts that performed it. In conclusion, our data suggest that these pts with apparently idiopathic complex VA and no signs of significant heart disease detectable by non invasive tests are clinically stable over time and have no cardiac events during a more than 4 years follow-up period. Minor abnormalities, particularly mild right ventricular dysfunction, are frequently detected and therefore TEE should be routinely performed to evaluate with more accuracy the right ventricle. MRI is an extremely valuable diagnostic tool and is recommended whenever the other non-invasive tests give conflicting results and are not sufficient to rule out a myocardial disease.