Rate dependent left bundle branch block: The pattern of myocardial perfusion SPECT

Ali Gholamrezanezhad, Sahar Mirpour, Farhad Sarabandi, Behnam Jazayeri

Research output: Contribution to journalArticlepeer-review

Abstract

We report myocardial perfusion SPECT pattern in four subsequent patients with rate dependent left bundle branch block (LBBB). Three females and one male (aged 48, 51, 63 and 67 years) were studied. None of the patients had history of typical chest pain and all suffered from atypical chest pain or dyspnea on exertion. All patients were tested for baseline and serial heart rate, blood pressure, and electrocardiogram recordings. The exercise treadmill tests (ETT) were carried out under the strict supervision of a cardiologist, a nuclear medicine physician and close availability of an expert cardio-pulmonary resuscitation team and cardiac care unit within just few seconds. Maximal stress test (at least 85% of calculated heart rate, following development of LBBB) was achieved in all four patients according to standard Bruce protocol. No adverse cardiac events were noted and all ETT stress protocols terminated completely and safely. Myocardial perfusion SPECT imaging showed no evidence of reversible perfusion defects. The only patient with past history of exercise induced LBBB showed nonreversible perfusion defects in the septal and anteroseptal regions and mild LV cavity dilatation. The limited number of patients enrolled in our study does not allow us to draw a definite conclusion. Despite the presence of false-positive defects in myocardial perfusion SPECT in patients with sustained LBBB, such a finding is not a consistent finding in patients with rate dependent or exercised-induced LBBB, unlike that which we expected to see. Maybe it is possible to continue ETT for those patients undergoing myocardial perfusion scintigraphy and developing rate dependent LBBB.

Original languageEnglish (US)
Pages (from-to)143-148
Number of pages6
JournalNuclear Medicine Review
Volume15
Issue number2
StatePublished - 2012
Externally publishedYes

Keywords

  • Left bundle branch block
  • Myocardial perfusion scintigraphy
  • Rate-dependent

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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