Introduction. Echocardiography is a highly operator-dependant technique which requires adequate training and skills that are frequently not present, considering the widespread use of cardiovascular ultrasound. This could particularly be true for hand-held echo devices which made echocardiography more accessible but are frequently used by non-cardiologists and non-experts. Outline of Cases. We present a 45-year-old female and a 37-year-old male with heart murmurs due to atrial and ventricular septal defect, respectively. Congenital septal defects were undiagnosed in both patients during several outpatient examinations due to challenging image acquisition. Careful re-evaluation revealed that, depending on the scanning technique, it was possible to detect or overlook the real cause of the murmur using either hand-held or high-end echo device. Conclusion. Our report underlines the need of adequate knowledge and training of medical professionals performing pocket-size hand-held echocardiography, since potential misdiagnoses may not be related to limited imaging capabilities of pocket-sized echo devices only, but also to inability of insufficiently trained users to obtain good quality images and interpret them adequately.